ii - SAARC Agriculture Centreof legumes in crop calendar, Legume based forage production, Silvipasture and silviculture based agriculture, Agro-forestry, Strategies for arresting land

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SAARC Agriculture Centre BARC Complex, Farmgate Dhaka-1215, Bangladesh Phone: 880-2-8115353; Fax: 880-2-9124596 E-mail: [email protected] Web: www.saarcagri.net © 2011 SAARC Agriculture Centre Published 2011 All rights reserved No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, recording or otherwise without prior permission of the publisher. ISBN: 978-984-33-3905-8 Cover Design Mafruha Begum Page Layout Raihana Kabir Price BD Taka 300/- US$ 5.00 for SAARC countries US$ 10.00 for other countries Printed at Momin Offset Press 9 Nilkhet Babupura, Dhaka-1205 Phone: 9675332, 8616471

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Strategies for Arresting Land Degradation in

South Asian Countries

Editors

Dr. Dipak Sarkar Director, NBSS & LUP (ICAR)

Dr. Abul Kalam Azad Director, SAC

Dr. S.K. Singh Principal Scientist, NBSS & LUP (ICAR)

Nasrin Akter Senior Program Officer (Crops), SAC

SAARC Agriculture Centre

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C o n t e n t

PagePreface vii

Part-I Keynote paper 1-31 Introduction, Extent and severity of degradation, Driving

energy for land degradation, Impact of inappropriate land use and management, Techniques for restricting/preventing land degradation, Estimating extent and severity of land degradation, Diversification of agriculture, Conservation agriculture, Gene mining for drought avoidance, Inclusion of legumes in crop calendar, Legume based forage production, Silvipasture and silviculture based agriculture, Agro-forestry, Strategies for arresting land degradation

Part-II Country paper from Bangladesh 33-56 1. Introduction 2. Land degradation: Situation in South Asia

3. Factors affecting Land Degradation 4. Impacts of Land Degradation 5. Major types of land degradation in Bangladesh 6. Levels of Land Degradation 7. Climate Change induced Land Degradation 8. Minimizing Land Degradation 9. Land Resources Conservation Strategy 10. Combating Land Degradation and Appropriate Cropping 11. Conclusion

Part-III Country paper from Bhutan 57-73 1. Introduction 2. Land degradation - a global issue 3. Land

degradation in Bhutan - a natural and man-made process 4. Status of land degradation 5. Types of land degradation 6. Factors contributing to land degradation 7. Current Strategies to address land degradation 8. Conclusion

Part-IV Country paper from India 75-132 1. Introduction 2. Unculturable Wastelands 3. Causes

4. Impacts of Land Degradation 5. Soil Physical Constraints 6. Strategies for Arresting Land Degradation

Part-V Country paper from Nepal 133-149 1. Introduction 2. Land Degradation 3. Causes of Land

Degradation in Nepal 4. Types of Land Degradation and Its Extent 5. Status of Land Degradation in Nepal 6. Impact of Land Degradation in Nepal 7. Government Policy, Strategies and Programs 8. Conclusion and Recommendations

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Part-VI Country paper from Sri Lanka 151-170

1. Abstract 2. Introduction 3. Severity of Land Degradation in Sri Lanka 4. The Policy Issues 5. Arresting Land Degradation: Some Recommendations

Part-VII Special papers from India 171

• Acid Soil Management in India-Challenges and Opportunities

172

• Issues and Strategies for Managing Degraded Lands in Rainfed Ecosystem in India

191

• Land Degradation due to Selenium: Causes, Implications and Management

208

Part-VIII Appendices 233

Appendix-A : Concept note prepared by SAARC Agriculture Centre

234

Appendix-B : Recommendations of the regional consultation

243

Appendix-C : Programme 247

Appendix-D : List of participants of the regional consultation

253

Appendix-E : Consultation Photo Album 257

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Preface

Land degradation is a concept in which the value of bio-physical environment is adversely affected. Deforestation, nutrients depletion, overgrazing, irrigation and over drafting, urban sprawl and commercial development, land pollution are the causes of degradation. Land vulnerable to degradation was estimated to 81, 63, 53, 39.21 and 2.99% in India, Bangladesh, Sri Lanka, Pakistan, Nepal and Bhutan, respectively. About eighty three million hectare is affected by water erosion in the South Asian region or 25% of the total area under crops and pasture. The most affected areas are the populated mountain regions of Himalaya, Deccan region of India (Western Ghats) and Sri Lanka. A part from this a total of 59 million hectare is affected by wind erosion, lying entirely in the arid zone. Wind erosion affects 42% area in Pakistan, whilst the dry region of India has the same total area affected as Pakistan (11 million hectare). Salinity/ sodicity and waterlogging are the other major concern of land degradation in the irrigated command areas and in the coastal regions. In India, Bangladesh and Pakistan together have 14.23 million hectare salt affected area. This also includes dry and sub-humid coastal strip. The sizeable area affected with lower pH and aluminum toxicity which is other form of degradation, are also reported from India, Bangladesh and Sri Lanka. Loss of nutrient and /or organic matter depletion is another form of degradation. It is estimated that about 65% of agriculture land in Bangladesh and 61% in Sri Lanka affected by this type of degradation. In Bangladesh, the average organic matter is said to have declined in 50% area by 2 to 1% over the past twenty years. For the Indian State of Haryana, soil test reports over 15 years show a decrease in soil carbon. Negative soil nutrient balances have been reported for all three major nutrients in Bangladesh and Nepal; for phosphorus and potassium in Sri Lanka and a large deficit for potassium in Pakistan. Nutrient depletion has been reported for each of the 15 agro-climatic regions of India. Imbalance fertilization is one of the dominant causes of nutrient depletion in the region. Fertilization use in the region is dominated by nitrogen; N: P and N: K ratios are higher than the other parts of the world. For example, the N: P: K ratio for India is 1.00:0.33:0.17 compared with 1.00; 0.52:0.40 for the world. This trend obtained in early years of green revolution. In such system nitrogen is simply used as shovel to mine the soil for other nutrients. Long-term experiments in India show depletion of soil P and K are higher for plots with N fertilizer, and depletion of K still higher with N+P fertilizers. Increasing incidence of sulphur and zinc deficiency has been reported in the region. In Bangladesh, 3.9 million hectare is reported deficient in sulphur and 1.75 million hectare in zinc, including areas of continuous swamp rice cultivation. This happened because increase in fertilizer nutrient has not been equaled by the rates of yield increase for wheat, rice and sugarcane. Considering the importance and urgency related to land degradation the present publication on “Strategies for arresting land degradation in the South Asian Countries” would help to (a) formulate policy issue (b) draw strategies (c) undertake joint project

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and also national programmes to address the issue of major concerns collectively (d) find out the measures to minimize the impact of land degradation on the millions of affected people in the SAARC regions. The publication helps in developing strategies for arresting land degradation, reversing the adverse effects of land degradation on land productivity without risk of further degradation. The beneficiaries will be policy makers in the Governments of SAARC countries, agriculture and social scientists, environmentalists, NGO, donor agencies and ultimately the farmers. I acknowledge the sincere efforts of my colleagues and the distinguished contributing authors from different member SAARC countries for completing this daunting task. My compliments to the members of editorial committee for editing the book and bring it in the present status. SAC always appreciates receiving feedback, comments and suggestions from the users of our products and services to help us enable to do better. Dr. Abul Kalam Azad Director SAARC Agriculture Centre (SAC)

2 Strategies for Arresting Land Degradation in South Asian Countries

Strategies for Arresting Land Degradation in South Asian Countries

Abstract Land degradation, synonymous to desertification in arid, semi arid and sub-humid

region, covers the processes adversely affecting productive capacity of land under different land use systems. Present paper reports the extent, type and severity of land degradation in south Asian countries. Impact of land degradation contributing factors including population and poverty, climate change and natural hazards, agriculture globalization, overgrazing and livestock, summer fallowing and inappropriate land use management are discussed. Emerging human induced degradation types such as acidification, nutrient and organic carbon depletion, salinity and sodicity, surface truncation and sub-soils densification are highlighted. Influence of technologies including alternate land use, integrated nutrients and water managements for smothering/arresting land degradation are discussed. Reasons for failure of various technologies in arresting land degradation are elaborated. A conceptual model is suggested to develop strategies for combating land degradation. Essence of the model is the selection of right cultivar and appropriate technologies at the right place. Model is based on GIS database and three expert systems. Database has four modules. First module is polygon based; second module contains point information; third and fourth modules are designed for raster and non-spatial database, respectively. Expert system I delineates management unit at an appropriate scale based on soils, climate and irrigation potentials. The scale may be watershed, district, state or regions. Expert system II identifies land uses and management practices by utilizing the database on socio-economic conditions, land use requirement, available technologies, market trends and demands. Expert system III optimizes the different land use systems for each management unit by using scenario analysis and projections. After validating and refining land use and management, same may be up-scaled, using appropriate algorithms for the use at district, state or regional level planning. The entire process is elaborated in the text by giving suitable examples.

Introduction Land degradation is a concept and signifies the temporary or permanent decline in the

productive capacity of the land under rain-fed, arable, irrigated, rangeland and forest system of land use or in farming systems (e.g. smallholder subsistence). It is synonymous to desertification in arid, semi arid and humid regions and covers the processes which affect the productivity capacity of cropland, rangeland and forests, such as lowering of water table and deforestation. Four set of indicators viz. pressure (driving energy for degradation such as climate, population, socioeconomic, water resources and long-term management practices), state (characterize the state of land resources in terms of wind and water erosion, vegetation degradation, salinization, sodification and water logging), impact (measured by change in land use, land use pattern, socioeconomic, food security, health, infrastructure, air and water quality and land pollution) and implementation (used for studying the influence of management for combating desertification such as

Strategies for Arresting Land Degradation in South Asian Countries 3

socioeconomic standard of the people and improvement in the soil and environmental quality) indicators explain the type and severity of degradation in totality (TPN 2001).

Soil is very important state indicator. It integrates a variety of important processes involving vegetation growth, overland flow of water, infiltration, land use and management. Therefore, soil erosion and soil fertility decline including reduction in soil organic carbon, deterioration of physical properties, change in soil nutrient stock and build up of toxic substances are considered as the state indicator. Water logging, salinity and sodicity, acidity, soil pollution, loss of vegetation, sedimentation or burial of soils and exposure of stoniness/rockiness are the other state indicators of degradation.

South Asian countries with 4.13 million km2 area, covering mountainous belt of Himalaya, alluvial land of Indus and Ganges and uplands of Deccans in India suffer from various kind of degradation. Recent estimates indicated that 42 % of its land is affected with various kind of degradation. Fifty percent area of the dry lands faces the threat of desertification. As many as 63 million hectares of rainfed cropland and 16 million hectares of irrigated land have been lost due to desertification, especially in Pakistan and India. Loss accrued on account of desertification is equivalent to seven percent of the regions combined agricultural gross domestic product.

Agriculture scenario in south Asian countries is characterized by small holdings, too many people on too little land, production largely for subsistence, high rate of tenancy and pre-modern technologies. Rice is the staple food crops generally grown under wet conditions. Forest cover ranges from 64 % in Bhutan to 3 % in Bangladesh and Pakistan. Agriculture still contributes 20 % in GDP and supports 60 % of labour force. Dependency of 90 % labour force on agriculture is reported in Nepal and Bhutan. Productivity of most of the crops is either declined or stagnant in rice, rice-wheat, highland mixed and rainfed mixed systems of farming prevailing in south Asian countries. Further enhancement in productivity is very remote with the present set of management inducing mass degradation of natural resources. Expected change in climate is not encouraging for the agrarians. If the present situation continues, there may be the shortage food for ever growing population in the region.

Therefore, managing degradation and increasing productivity per unit area are the challenges for researchers, administrators, planners, extension workers and farmers. It calls for very systematic studies involving causes of land degradation, its impact in terms of extent and severity on natural resources, status of technologies for arresting/preventing land degradation. Present paper highlights these issues in reference to south Asian countries.

Extent and severity of degradation It is estimated that nearly two billion (Table 1) hectare of soil resource in the world

have been degraded, approximately 22 % of the cropland, pasture, forest and woodlands. Globally soil erosion, chemical deterioration and physical degradation are the important parts amongst various land degradation types. Water erosion is the most important type of soil degradation (55 %) followed by wind erosion (28 %), nutrient depletion (7%), salinization (4%) and compaction (3%). In all countries water erosion is the most


dominant type of land degradation, except for West Asia and Africa, where water and wind erosion have equal importance. In South America nutrient depletion was more important than wind erosion. West Asian countries are severely affected with salinity and compaction. In Europe about 19 million hectare land is affected by soil pollution (Oldeman 1994).

Table 1: Global estimate of degradation

Type Light Moderate Strong+ extreme Total

Water erosion 3.43 5.27 2.24 10.94

Wind erosion 2.69 2.54 0.26 5.49

Chemical degradation 0.93 1.03 0.43 2.39

Physical degradation 0.44 0.27 0.12 0.83

Total 7.49 9.11 3.05 19.65

Source: Oldman (1994)

Land vulnerable to degradation was estimated to be 81, 63, 53, 39.21 and 2.99 % in India, Bangladesh, Sri Lanka, Pakistan, Nepal and Bhutan, respectively (Table 2).

Table 2: Extent of land degradation vulnerability in SAARC Countries

Low Moderate High Very high Countries

(% of total geographical area)

Afghanistan 0.46 6.04 6.77 67.41

Bangladesh 63.30 0.0 0.0 0.0

Bhutan 2.99 0.0 0.0 0.0

India 42.96 25.03 6.94 5.58

Nepal 14.72 6.36 0.0 0.17

Pakistan 4.04 5.09 2.19 23.31

Sri Lanka 9.79 37.68 5.28 0.0

Source: UNEP (1994)

Accelerated water and wind erosion are the dominant manifestations of land degradation. About eighty three million hectare is affected by water erosion in south Asian region or 25 % of the total area under crops and pasture. This is made up of 33 million hectare with slight erosion, 36 million hectare moderate and 13 million hectare strong erosion. The most affected areas are the populated mountain regions of Himalaya, Deccan region of India (Western Ghats) and Sri Lanka. Hot spots vulnerable to degradation screened from different sources are listed in table 3. Apart from this a total of 59 million hectare is affected by wind erosion, lying entirely in the arid zone. Wind


erosion affects 42 % area in Pakistan, whilst the dry region of India has the same total area affected as Pakistan (11 million hectare). The intensity of erosion is predominantly moderate and about 48 % land in the arid region under crops and pasture is affected.

Table 3: Hotspots of land degradation in south Asian Countries

Degradation types Hotspots

Nutrient depletion Mid-altitude hills of Nepal, Northern India

Salinization Indus river basin, Southern coast line of Sri Lanka

Water erosion Foothills of the Himalayas; Riverbank erosion in the major floodplains (Ganges, Brahmaputa, Jamuna , Tista and Meghna rivers) of Bangladesh.

Wind erosion Western Rajasthan, coastal regions of India and dry region of Pakistan

Agro-chemical pollution Pakistan (Heavy use of Agrochemicals)

Salinity/sodicity and water logging are the other major concern of land degradation in the irrigated command areas and in the coastal regions. India, Bangladesh and Pakistan together have 14.23 million hectare salt affected area. This also includes dry and sub humid coastal strip. Lower pH and aluminum toxicity are also included under land degradation. These are reported as sizeable in area from India, Bangladesh and Sri Lanka.

Loss of nutrient and /or organic matter depletion is another form of degradation. It is estimated that about 65 % of agriculture land in Bangladesh and 61 % in Sri Lanka is affected by this type of degradation. In Bangladesh, the average organic matter is said to have declined in 50% area from 2 to 1% over the past twenty years. For the Indian State of Haryana, soil test reports over 15 years show a decrease in soil organic carbon. Negative soil nutrient balances have been reported for all three major nutrients in Bangladesh and Nepal; for phosphorus and potassium in Sri Lanka and a large deficit for potassium in Pakistan. Nutrient depletion has been reported for each of the 15 agro-climatic regions of India.

Desertification is the land degradation in the dry land of India and Pakistan. The desert in the Western India is the biggest in the south Asian countries. The majority of the area suffers from moisture stress, sand movement, high wind velocity and very limited canopy cover. Since Thar Desert constitute the major part of the dry region of south Asian countrie, therefore most of the examples in the present text are quoted from the arid part of India.

Driving energy for land degradation (A) Population and poverty

The region is home to 1.567 billion people (23.7 % of global population). Of the world’s ten most populous countries, three are in south Asia; India, Pakistan, and Bangladesh. South Asia has a population density of 15 people per hectare compared to


world average of 4 people per hectare. World population is expected to grow by some 3 billion people by 2050, and these three countries are expected to account for 30 % of this growth (UNDP 2003).

The share of the region in global land and water resources is however much lower than the population share e.g. regions geographic coverage is mere 3.95 % of global land mass. Population pressure on land is very high because percentage of arable land to total area is much higher than the global average. In a study on population supporting capacity of soils in Central Arid Zone Research Institute (CAZRI), it was estimated that soils of arid region can support 0.71, 1.15 and 1.5 person / hectare / year under low, medium and high management, respectively. The region had supported 0.50 person /hectare /year in the year 1971, which was escalated to 0.81 in 2001 under farmer’s management. Presently in the year of estimation 2004, region supported 1.21 person / hectare / year, and by the end of 2020 figure is expected to rise by 1.5 person /hectare / year. With farmer’s management exploring beyond the capacity of resources triggers mass degradation of natural resources (CAZRI 2004).

Low per capita Gross National Income (GNI) may also be related with the mass degradation of natural resources. GNI in the eight member states ranged from £345 to 3,277; lowest per capita income is in Afghanistan while the highest is in Maldives. Per capita income in India and Pakistan is around £1000. Low level of income is one of the primary cause for non or partial adoption of green revolution technology as a package. This together with increasing demography, climate change ultimately result into the degradation of the natural resources. Poverty and dependency on agriculture for livelihood in SAARC countries are given in table 4.

Table 4: Poverty and dependency on natural resources for livelihoods

Bangladesh Bhutan India Maldives Nepal Pakistan Sri Lanka

HDI ranks (2001) 139 136 127 86 143 144 99

Human Poverty index rank

72 - 53 20 70 65 34

Population below poverty line (less than $1 a day) %

36 - 34.7 - 37.7 13.4 6.6

Traditional fuel consumption (%)

46 - 20.7 - 89.6 29.5 46.5

Source: UNDP (2003)

(B) Climate change and Natural disasters Climate change is now an accepted reality and in some cases is practiced to cause

heavy damage to the region. South Asia is among the most vulnerable regions in the world to natural disasters related to climate change. Two main dimensions of climate change, that would impact agriculture, are increased temperature and changes in


precipitation pattern. It is predicted that drought incidence, cloud burst and frequency of high intensity of precipitation will increase in the changed scenario of climate. Risk of run-off will increase in high latitudes and decreased in mid-latitudes (Arnell 2004 and Nohara et al. 2006). Rise of sea level will be the most serious consequence of climate change in the region. Over 80% of the land area in the Maldives is very vulnerable to inundation and beach erosion. Presently 50% of inhibited islands and 45% of tourist resorts face varying degrees of beach erosion. Climate change and projected sea level rise will aggravate this problem. It can submerge 10-20% of the coastal land of Bangladesh, including the Sundarbans.

According to the World Banks strategy for the region, south Asia stands out as a region most vulnerable to natural disasters such as drought, flood, earthquake and cyclones. From 1990 to 1998, the region accounted for over 60% of disaster related deaths world-wide (Table 5). The geological faults are still active between the south Asian plate and the main Asian plate. This results in earthquakes, which cause the Himalayas to rise further. The earthquakes of September 1999 in Maharashta and 2000 in Gujarat of India are two of the recent examples of the level of seismic action in this area. Earthquakes in Nepal often results in landslides from unstable slopes, which have been deforested and degraded by human activities.

The immediate effect of drought is the reduction of organic residues recycled in the soils. Indirectly drought stimulates soil erosion and increase inorganic carbon sequestration. These altogether activate/or enhance land degradation. An analysis of recent climatic data in CAZRI indicated that frequency of drought years has increased in the block year of five years from 1975 to 2004 (Fig.1). In the scenario of high torrential rainfall, risk of water erosion and landslides will be magnified. It is evident from massive cutting and transportation of sediments (Fig.2) during the flash flood of Barmer in Rajasthan (Singh et al. 2007a).

Table 5: Natural disaster in India

Type Location /area Affected

Cyclones Entire coast line of Southern India covering 9 states 10 million

Floods

08 major river valleys spreading over 40 million Ha of area of entire India

260

Droughts

Around 68% of total sown area and 16% of total Area of the country spread in 14 states

86

Earthquakes

56% of the total area of the country susceptible to seismic disturbances

400

Landslides Entire sub Himalayan region and Western Ghats 10

Avalanches Many parts of the Himalayas 01

Fires States of Bihar, West Bengal, Orissa and North eastern states 140

Source: CPCB/MATMP (2001): Environmental Atlas of India


Fig. 1: Increasing incidence of drought frequency in

Jodhpur, Rajasthan, India

Fig. 2: Devastation of torrential flood in Barmer district, Rajasthan in 2006, India

(C) Globalization of agriculture Subsistence farming is economically favorable on the marginal land and it

simultaneously produces curative action for preserving soil quality. Intensive agriculture appears to be non-sustainable in the absence of holistic land management. In search of high productivity intensive agriculture was pursued and holistic management was ignored. Low water requiring crops is being replaced by high water demanding crops; new areas are brought under irrigation; use of chemical fertilizers and agro-chemicals have increased manifold. Area under irrigation is expanded from 19% in Pakistan to 39%


in India from 1993 to 2020. Excessive tractorization and massive infrastructure development have taken place. These have disturbed the equilibrium among the different facets of landscape and made them prone to severe erosion. Activation of sand dunes increased overburden of sand and truncation of surface horizons at the benchmark sites are the evidence of increased erosion (Singh et al. 2009a). Use of high RSC water for irrigation increased pH and inorganic carbon concentration in soils (Singh et al., 2009a).

(D) Overgrazing and livestock India’s livestock population, which is roughly about 13 % of the world total, depends

on pastures and rangelands accounting for 0.5% of the world total. This implies an average of 42 animals grazing in one hectare of land against the threshold level of 5 animals per hectare. In the absence of adequate grazing lands, the fodder requirements are met from forests, leading to increased deforestation. Annual rate of change of forest cover is negative in most of the SAARC countries except India and Bangladesh (Table 6).

Table 6: Annual rate of change of forest cover in South Asian Countries

Countries Forest cover (000 ha) 2000 as % of land area Annual rate of change

1999 2000

Bangladesh 1169 1334 10 1.3

Bhutan 1316 3016 64 -

India 63732 64113 22 0.1

Maldives 1 1 03 -

Nepal 4683 3900 27 -1.8

Pakistan 2755 2361 03 -1.5

Srilanka 2288 1940 30 -1.6

South Asia 709336 76665 19 -1.2

Source: FAO (2003)

(E) Summer fallowing It is one of the principle causes of soil fertility decline in arid and semi arid part of

the region. Doran and Zeiss (2000) estimated soil organic carbon depletion to the tune of 320 to 350 kg/year in semi arid tropics on account of summer fallowing. About seven to eight months after the harvest of summer crop, fallowing is the most common practice in arid India because of limited water availability for raising second crop in a year. As a result canopy cover, which protects the soil organic carbon from sun beating and intense temperature, is available only for the brief period. The practice together with tillage for summer crop exposes the arid soils for longer duration to the intense sunshine, high temperature and microbial decomposition.


(F) Inappropriate land use and management In the ideal situation of farming, there should be delicate balance between agriculture

and none agriculture uses. The area under crops should not exceed to 70% even on land quality class (LQC) I (Eswaran 2001). However, on the advent of green revolution marginal land not suitable for agriculture was brought under the plough. Study on the marginal lands of arid part of Rajasthan in India indicated that about 16.5 to 149% excess land was put up for arable cropping in 1975 than the recommended area to be utilized for this purpose. The situation worsens on land quality class VI and VII where in 30 to 35 % excess land was being utilized for cropping (Narain and Singh 2006). In 2004 repeated study of the same area indicated that areas under the crops have further increased manifolds (Fig. 3).

An analysis of land use data on the marginal lands of arid India from 1958 to 2002 indicated that about 37% area was utilized for cropping in 1958-59, which has gone to 52.45% in 2001-02 with a simultaneous decline of fallow lands, generally used for community-grazing for sustaining livestock. Similarly area under double cropping has shifted from 0.87% in 1958-59 to 8.58% in 2001-02 (Narain and Singh 2006). Excessive tillage on marginal land break up soil structure, enhances soil erosion that causes mass degradation of soil quality. Inadequate land use management such as imbalanced fertilization and poor quality of water for irrigation further compounded the degradation.

Fig. 3: From left land use of Jhunjhunu district Rajasthan in 1968 and 2004, India

Impact of inappropriate land use and management Acidification

Increased acidity is one of the offshoots of partial or non adoption of complete package of green revolution technology. This form of degradation is dominantly reported in India, Bangladesh and Sri Lanka. The root cause is erosion and movement of acidic


sediments down the slope in high rainfall areas due to the cultivation of high management requiring crops on the marginal land. Such sediment covers good cultivable plain land and acidifies surface layer over neutral non acidic sub-soils. Such process of acidification has been reported dominantly on the fringes of Chhotanagpur plateau in West Bengal (Fig.4) and Bihar, India (NBSS & LUP 2010).

Fig. 4: Induced acidity in the fringes of Chhotanagpur plateau, West Bengal, India

Apart from this, practicing intensive agriculture on marine affected lower part of Indo-Gangetic plains exposes relict organic carbon and sulphur rich sediments. These are expected to induce acidity and/or environmental degradation on the replacement of prevailing rice based cropping sequence with other low water requiring crops. Such problems are very extensive in Haora (Fig.5) and 24-Parganas of West Bengal India. Selection of acid producing crops and cropping sequences are the other factor, which reduces soil pH. Study at Central Rice Research Institute Hazaribagh, India indicated that black gram and rice based cropping sequence enhanced the acidity, while pigeon pea based cropping sequence maintained soil pH to its initial level (Singh et al. 2009b). However, black gram-rice-finger millet is the preferred cropping sequence in Jharkhand, India and that may be one of the reasons for increasing acidity.


Fig. 5: Outcropping of sulphidic material in Haora district, West Bengal, India

Nutrient stock depletion Inappropriate land use and management induces deficiency of single or multiple

nutrients in Bangladesh, SriLanka, Pakistan and all fifteen agro-climatic zones of India. Cultivating hybrids with inadequate and imbalanced fertilizers is the main cause of nutrient depletion. Recent studies in Birbhum district of West Bengal, India indicated that about 97.4% area is affected either with the deficiency of single or multiple nutrients (NBSS&LUP 2010), of which multiple nutrient deficiency of phosphorus, potassium and zinc together was mapped on 47% area of the district. Interpretation of data on smaller scale revealed that potassium mining was extensive in prevailing rice-rice or rice-vegetable or rice-potato cropping sequence (NBSS&LUP 2010).

The influence of imbalanced fertilization on the depletion of phosphorus and potassium was also reported to the tune of 17.2 and 9.2% in a span of twenty seven years under millet production system of arid India (CAZRI 2004). A depletion of potassium was also noticed even at the research farm of Central Arid Zone Research Institute of India at Jodhpur maintained from last thirty years under pearl millet-legume cropping sequence (Singh et al., 2007b).

Soil organic carbon depletion Soil organic carbon oscillates between a threshold limit of maxima and minima,

which is governed by geographic settings and land use (Buyanovsky et al., 1998). In general cultivation depletes soil organic carbon if its value is at maxima (Buyanovsky et al. 1998) by opening them to erosion and microbial decomposition. Otherwise growing of crops enhances soil organic carbon. Therefore, selection of right land use and management at right place is imperative to maintaining/sequestration of soil organic carbon on its upper limit. The hypothesis was evaluated in light of present land use and


management on temporal scale from 1975 to 2002 in arid region of India. During the period a loss of soil organic carbon by 17.2% was reported and fine loamy organic carbon rich soils suffered heavily in the process (Singh et al. 2007c). Another study in 2002 for 0-100 cm soil depth indicated that soil organic carbon was depleted by 9.7% in a span of 27 years. Depletion was the highest (19.7 and 17.7%) in sandy and gravelly soils respectively, while coarse loamy deep soils suffered from soil organic carbon loss of only 0.9% (Singh et al. 2007b). A comparison was also made between the soils organic carbon status in the farmers field and in the field maintained on the research farm under millet production system. Former experienced higher soil organic carbon loss than latter (Singh et al. 2007b). In the end it was concluded that soil organic carbon tended to move from maxima to minima with the present land use and management. Salinity and sodicity

The problem of salinity and sodicity is associated with many ways in cultivating the marginal land with inadequate management. For example an increase of soil pH was reported by 0.2 units in a span of twenty seven years in arid region of India without appreciable increase in salt content (Singh et al. 2009a). Probably in the situation of low soil buffering capacity, clay micelle have high tendency to adsorb sodium (Poonia et al. 1998). That means adequate measures have not been taken up for increasing buffering capacity of marginal soils for sustaining the productivity.

Another problem is associated with irrigation management. The soils which are not suitable for irrigation were brought under the command area. For example excess irrigation in black soils and gypsiferrous soils is the cause of ground water table rise, high salinity and water logging (Fig. 6).

Fig. 6: Rise salinity in Tungbhadra command area, Karnatka, India

One or other kind of drought further deteriorates the situation. As a result many water logged area is completely dried out and become one of the factors for spreading air borne salinity in the adjoining area (Fig. 7). Cultivation of natural saline depressions, which are


the remnants of Tythis and Arbian sea in Indo-Gangetic plain and in arid part of Rajasthan, India respectively, is also one of the reasons of salt movement in the adjoining area.

Fig. 7: Dried waterlogged area in Western Rajasthan, India

Brackish water irrigation is another way of inducing degradation. This is usually observed at the tail end of the command area where water is available for irrigation in the beginning of growing season. However at the fag end of the cropping season, water scarcity is very common and farmers are forced to irrigate their crop with brackish ground water. Such case was noted in Sri Ganganagar, Abohar & Fazilka district in arid part of India and the entire episodes ends with an increased salinity after few years of such practice. The impact is perceptible in terms of surface sealing and deformation of physical properties (Fig. 8). At the extreme end a good cultivable land was converted to a wasteland (Fig. 9).

Fig. 8: Surface sealing Fig. 9: Deformation of morphological properties on brackish water irrigation


Irrigating soils with brackish water also enhances inorganic carbon sequestration. In a study in western Rajasthan, an increase of inorganic carbon was observed by 64, 44, 14 and 3.1 to 5.5 and 3.2 g/m2 in Malkosani, Pipar, Bhagasani, Chirai and Bap variant soil series of Jodhpur, respectively (CAZRI 2004) in a span of 27 years from 1975 to 2002. The increased inorganic carbon in the soil system may be one of the causes for degradation appearing as secondary salinization and sodification (Singh et al. 1999). Irrigating crops with sodic water in upper part of Indo-Gangetic plain could also be correlated with the re-emergence of sodicity in reclaimed soils.

Truncation of surface horizon It is one of the very important processes of land degradation in the cropland.

Ignorance of soil and water conservation practices on the flat or stable landscape for fairly long time is the main cause of this type of degradation. In the known history of twenty five years of cultivation a soils loss of 15 cm from their place in parts of red and lateritic regions of southern peninsular region of India was reported (Fig.10).

Fig. 10: Surface truncation due to sheet erosion in Karnataka, India

Sand dune reactivation Cultivating dunes and inter dunes; overgrazing and deforestation on marginal lands in

arid region results in sand movement, which affects good cultivable land (Fig.11). Sand movement is also related with the deformation of land. During summer sand moves and trapped on the shoulder slope of hills. Cutting of such loose sand during rains forms ravines and Bad lands (Fig.11). Movement of such sand also affects adversely to adjoining good cultivable land on deposition.


Fig. 11: Reactivation of sand dunes Rajasthan, India

Densification of sub-soils Use of high Residual Sodium Carbonate (RSC) and sodic water for irrigation,

excessive ploughing and silt movement down to the depth together or alone densifies subsoil’s (Fig. 12). This results temporary perch water table and restrict solute and root movement. Such problem is very severe and acute in upper part of Indo-Gangetic plain. It is also likely that densification affects grain filling and solute transport adversely in rice.

Fig. 12: Densification of soils and its adverse impact on grain filling rice in upper and middle part of Indo-Gangetic plain.

Techniques for restricting/preventing land degradation Agro-techniques those are sustainable under the aberrant situation of farming or

improve the farming situation are helpful in restricting/preventing land degradation. Adding new organic matter every year is perhaps the most important way to protect the soils from the onslaught of degradation. Regular additions of organic matter improve soil structure, enhance water and nutrient holding capacity, protect soils from erosion and compaction, and support a healthy community of soil organisms. The other practices that increase organic matter in the soils are also helpful in preventing land degradation. We have screened some of the techniques that include: adequate soil erosion preventive measures, moisture conservation, correcting water quality, integrated nutrient


management, diversification of agriculture, conservation tillage and gene mining for drought avoidance and ameliorating acid soils. Alternate land use planning covering inclusion of legumes in crop calendar, legume based forage production, silvipasture and silviculture based agriculture; agro-forestry may be the other focal point for improving present farming situation and restricting deterioration of land in future. Prior to the execution of agro-technique for restricting soil degradation, its extent and severity is to be mapped on an appropriate scale. The importance of these practices is briefly discussed in light of some of the most relevant available data.

Estimating extent and severity of land degradation Desertification/degradation maps generally fails to delineate the line between ‘state’

and ‘process’, i.e. the area already degraded, versus the area thought to be at the risk of degradation (Oldeman and Van Lynden 2001). In such a complex situation, a conventional method of mapping is far from standardization (Hill 2004). Satellite remote sensing technology combined with geographical information systems (GIS) have emerged as a powerful tools for assessment, monitoring and mapping of desertification/ degradation trends (Hussein 2003). More specifically, GIS and/or remote sensing has been or could be used to identify physiographic units, which may be used as common base for assessments of different kinds of soils, degradation and conservation. Overlay data layers for different map units, making area calculations, linking spatial data with non-spatial, making geo-referenced information easily accessible to non-GIS users, bridging the scale gap are added advantage of GIS (Van Lynden and Mantel 2002). Integration of satellite imagery, GPS, GIS, and advanced computer modeling techniques into natural resource management provide managers with the tools to better adapt themselves with the dynamics of multi-use management. GIS and remote sensing technology provides the power to model quantitatively, describe the resource, and objectively analyze the multiple demands of the resource in almost real time (Landsberge and Grower 1997). During desertification/degradation studies, GIS is used to combine vegetation, rain use efficiency, surface runoff and erosion maps for highlighting the areas of greatest degradation susceptibility in sub-Saharan Africa (Simeonakis and Drake 2004).

Generally high resolution remotely sensed data are recommended for accurate, viable and specific applications (Jianjun et al. 2004). NOAA AVHRR data of 1.1x 1.1 km2 resolutions with frequent repetitive coverage, twice daily to the earth, widely used to detect change in biomass production at global and regional scale particularly in cloud free days (Tucker 1980 & 1987). NOAA AVHRR data was also utilized for desertification mapping in China (Long Zing 2002), and for vegetation degradation mapping on 66 million hectare area of South East Asia (Harahsheh and Tateshi 2001). Vegetation degradation dynamics through 1982 to 1994 was studied in Sudan (Ali and Bayoumi 2004), using NOAA AVHRR data.

Landsat images have been successfully utilized to map the change of sand denudation in west Asia (Dwivedi et al. 1993; Mering et al. 1987; Robinov et al. 1981). These on merging with radar data show its ability to detect desertification process more closely (Rebillard et al. 1984). Landsat images of 1982 and 1992 were effectively utilized for


monitoring desertification processes on crop-rangeland boundary of Argentina (Alfredo 2002). Multi-temporal analysis of Landsat TM images highlighted the negative impact of irrigation on vegetation cover during the period of 1983-1997 (Hussein, 2003). Thematic mapper (TM image data) has also been utilized for mapping desertification rate in Egypt (Abid-El Hamid 1994) and in Gazera Sudan (Fadul and Mohmmed 1999). Thus depending upon the complexity and job requirement remote sensing data are to be procured and used.

Adequate soil erosion preventive measures Protecting soils at the place through conservative measures reduces the risk of soil

erosion and runoff. Erosion erodes 5334 and 6 million tones of soils and nutrients yearly. Stubble mulching with the residue of pearl millet (Mishra 1971), alternate strip of erosion susceptible and erosion resisting crops (Gupta and Aggrawal 1980), stabilization of sand dune with vegetative cover consisting of trees, grasses and shrubs in checker board pattern (Kaul 1985), shelterbelts plantation (Gupta et al. 1983) are the effective measures for controlling erosion and runoff. In an experiment of wind erosion during 1994 to 1999, an increase of soil organic carbon, nitrogen, phosphorus and potassium is reported beneath the shelterbelts (Solanki et al. 1999). The practice may indirectly helps in maintaining soil aggregates and good physical condition of soils that may reduce/prevent runoff and erosion vis-à-vis land degradation.

Integrated water management Increased availability of good water quality for irrigation enhances soil organic

carbon by increasing period of vegetative cover, vegetative input to the soils and microbial population. These altogether lead to increase water stable aggregates that offer protection mechanism for preventing land degradation. Ex-situ moisture conservation including storage of rainwater in tanks, revival of farm village ponds, developing small farm reservoir, creation of subsurface barrier for ground water recharge and khadin management are some of the techniques that can be helpful for increasing the availability of fresh water for irrigation. In situ moisture conservation including inter row water harvesting, field bunding, mulching, deep ploughing and other agronomic practices such as drought tolerant cultivars, optimum plant density and proper sowing time, balance fertilization are the other useful techniques. Pressurized irrigation system such as use of sprinklers and drips for irrigation on the undulated topography may have beneficial effect and can increase water use efficiency by 30 to 70 %, reduce runoff and may be helpful in avoiding the drought influence and erosion inducing land degradation. Farm water management including land leveling, methods of irrigation, check basin and border strip irrigation, furrow/surge flow irrigation may be further helpful in enhancing water use efficiency vis-a-vis land degradation.

Correcting ground water quality The present trends of irrigation in India leads to over-exploitation water, which is

manifested in terms of declining water level, saline water intrusion in coastal area, salty and high water upcoming in inland aquifers, arsenic and fluoride contamination.The irrigation of land with such water deteriorates the soil quality and magnifying the menace


of land degradation. Gypsum application reduces the adverse impact of saline and high RSC water used

for irrigation. Joshi and Dhir (1990; 1991) observed that gypsum application @ 50 and 100% of the total requirement effectively reduces the carbonate and bicarbonate salinity of ground water and enhanced soil quality as witnessed in terms of reduced soil pH by 0.3 to 0.4 units and depressed SAR by 6.4 to 10.7. Availability of nutrients also increased during the course of investigation (Joshi and Dhir 1994). Thus decreasing pH and SAR together with increasing available nutrients are favorable for enhancing stable soil aggregates and improving good soil physical conditions. The practice ultimately helps in covering the ill effects of land degradation.

Integrated nutrient management Integrated nutrient management including chemical fertilizers, manures and

biofertilizers such as Azospirillum, Rhizobium, blue green algae, phosphate solubilizing micro organisms, and VAM fungi (Rao and Venkateswarlu 1987) enhanced vegetative cover and over all biomass production. The ultimate effect of which is the greater vegetative input to the soils and higher soil organic carbon. What is equally important is that such increase in soil organic carbon acts as cementing agent for the stability of soil aggregates (Masri et al. 1996), improves total nitrogen content (Harris 1995), mineralization potentials (Ryan 1997) and vis-à-vis stability of soils. These altogether reduce the impact of torrential rainfall or continuous drought possibly expediting land degradation. This could be verified from a long term experiment conducted in drought affected area of Ranchi India on Typic Rhodustalfs where recommended dose of fertilizers and FYM application @ 2.5 t/ha together significantly enhanced the available nitrogen, phosphorus, and potassium over control and also raised soil organic carbon by 27.6 to 43.2% over its initial level in legume and rice based cropping sequence (Singh et al. 2009b). Applying fertilizers through irrigation water, particularly through the drip system, termed as fertigation, provides the most effective way of supplying nutrients to the plant roots and enhancing nutrient use efficiency. It can be used to apply any water soluble fertilizer or chemical in precise amounts, as and when required to match the plant needs. It provides an option of improving nutrient use efficiency as the fertilizer applied remains confined to the root zone of the crop and may helpful in raising the level of soil organic carbon and reducing green house gas emission (Table 7).

Table 7: Integrated Nutrient Management to reduce emissions in paddy

Treatment Rice yield t/ha

Denitrifi-cation Losses

kg/ha

N2O Emissions

kg/ha

Nitrate Leaching

kg/ha

Soil Organic-C

g/kg Control 3.4 18 6.9 59 3.7

120 kg N/ha 5.6 58 12.4 94 3.7 GM20+ 32 kg N/ha 5.9 50 11.8 78 4.1 CR6+GM20 + 32 kg N/ha 5.9 52 11.8 - 4.9 LSD (0.05) 0.2 6 3.4 12 0.4

CR: Crop residue, GM: Green manure;


Source : CRRI, Cuttak, India

Precision agriculture For avoiding the wasteful use of irrigation water and nutrient, precision agriculture is

one of the options to negate land degradation. Currently, in India precision farming implies site specific nutrient management. In reality, it signifies delivery of all inputs including herbicides, pesticides, as per the actual site requirement. It would require a seamless merging of multi-source data through remote sensing, GIS, GPS and sensors of various kinds and appropriate machinery and use of linear and non-linear programming (optimization techniques), response surface methodology and probit analyses for optimizing the land use and management.

Diversification of agriculture Diversified farm means growing of variety of crops in a rotation together with

animals. These are economically sustainable and resilient. Poor soil physical condition that make them prone to soil erosion and runoff, not only occurs because of growing of annual crops, requiring specific and high management but also keeping land out of agriculture. Diversification of agriculture integrating both crops and livestock in the farming system may be beneficial to each other because latter may supplement manure to the soils for increasing/ maintaining soil health. Pasture and forage crops included in rotation may also contribute significantly in raising soil organic carbon and reducing the risk of soil erosion and land degradation.

Conservation agriculture Tillage operations disturb soil structure and redistribute energy rich organic

substances in the soils. Researchers have shown that the use of mould board plough reduced organic matter by an average of 256 lb/acre/year (Reicosky et al. 1995). Conservation agriculture is an umbrella, covering a wide range of diverse tillage practices that have the potential to reduce soil and water loss relative to conventional tillage (Mannering and Fenster 1983). An well accepted operational definition of conservation agriculture is planting and tillage combination that retain a 30 % or higher cover of crop residue on the soil surface. Conservation agriculture also increases soil organic matter, improves nutrients, water use efficiency and physical properties besides restricting soil erosion.

Management tools commonly used to achieve the above operational definition for conservation tillage are; (i) non inversion tillage (usually implies replacement of a mould board plough with a chisel plough or cultivator) (ii) tillage depth confined to <15 cm (Deeper tillage may be retained in the row for row crops and (iii) number of tillage passed minimized. The major outcome of these management option (relative to some conventional system that implies full soil profile tillage) is to provide some degree of permanent soil cover (i.e. 30% or more residue in the non crop period) to increase the organic matter content and structural stability of the soils over the time and to improve soil structure below the plough layer. Soil stratification, which mainly involves enrichment of the soil surface with organic matter, is the dominant management outcome


of the conservation tillage (Franzluebbers 2002). Stratification can also have impact on nutrient storage and soil aggregation, improved water regulation at the surface and throughout the soil profile (Carter 1994).These altogether helps significantly to improve agriculture for avoiding land degradation.

Gene mining for drought avoidance It is the other important practice to develop drought hardy plants. There are several

species in sub-Saharan Africa and other desert, which have very extensive root system for water mining from large volume of soils, such as Prosopis Juliflora serving in the rainfall zone ranging from 200 mm in Bhuj to 1000 mm around Ramnathpuram of east coast. Short duration crop of moth bean is another classical example of deep root system. Genetic and molecular characterization of such plants can help to introduce new genotype in the plants through genetic engineering. Thus genetically modified plants can manage a biotic stress of droughts, salinity, heat and cold waves and such attempts may be beneficial for averting land degradation.

Inclusion of legumes in crop calendar The ability of legume to fix atmospheric nitrogen is perhaps the most notable aspect

that set them apart from another plant. In addition legume has benefit to improve soil structure, reduce soil pH and increases the availability of native phosphorus. This could be seen from a long-term trial conducted at CAZRI Jodhpur; with Pearl millet- moth bean based cropping sequence in a rotation of four years. The sequence maintains initial soil organic carbon of 0.22 and 0.14% in surface and subsurface horizons. Another sequence with legume-legume-legume-pearl millet increased soil organic carbon. Other rotation consisting of fallow-legume-legume-pearl millet also gave the similar results (Kumar et al. 1997). The result from drought prone area of Ranchi with legume based cropping sequence and recommended dose of fertilizers was in agreement with the earlier findings (Singh et al. 2009b). In contrast, rice based cropping sequence with recommended dose of fertilizers produced higher yield on the cost of declining soil quality. Thus legumes are the potential land use that may be frequently utilized for restricting land degradation at the place.

Legume based forage production Growing of grasses is well known for improving soil organic carbon; binding soil

particles and considered as another potential land utilization types in the changed scenario of land degradation. Inclusion of leguminous grasses with traditional forage in arid region is found more beneficial. This type of rotation is known for addition of high residue in the soils, which increases the organic matter, aggregate stability, biological diversity (Magdoff 1992), water movement, aeration, porosity and reduces bulk density (Schnitzer 1991). A study conducted in the arid region indicated that intercropping of Cenchrus cilliaris and Clitoria ternatia and Cenchrus cilliaris and Lablab purpures added higher soil organic matter both at the surface and in the subsurface during three years of experimentation as compared to the pasture with Cenchrus cilliaris alone


(Tripathi et al., 2002) in sandy soils. Silvipasture and silviculture based agriculture

Plantations (silviculture) alone or in combination with grasses (silvipasture) are another very important practice for improving soil organic carbon and maintaining good soil physical conditions for countering the influence of land degradation. Plantations with Acacia tortolis, Colophospermum mopane, Hardwickia binata and Cenchrus ciliaris are noted for increased organic matter, available nitrogen, phosphorus and micronutrients in degradation hit arid region of India (Aggrawal et al. 1978). Silvipasture and plantations have 185 and 141% respectively higher potentiality of soil organic carbon sequestration than traditional pearl millet-fallow system of arid region. These could sequester 9.6 and 7.4 kg/m2 higher CO2 than pearl millet-fallow system, approximately in the same period (Singh et al. 2007b). Therefore, silvipasture and plantations should be integral part of agriculture particularly for improving the severely eroded areas, community land and wasteland for reducing/mitigating the influence of degradation.

Agro-forestry Growing of crops with shrubs, herbs and grasses are the old age practice for

providing fodder to the animals, timber to the farmers and shades to the soils. The practice simultaneously could enrich the soils by sequestering 121% higher organic carbon than the pearl millet-fallow system. Growing of trees with crops could sequester 6.29 kg/m2 higher atmospheric CO2 than the cultivation of crops alone (Singh et al. 2007c). This could be possible because of higher biomass production (Aggrawal et al. 1978) and higher soil moisture profile (Gupta and Saxena 1978) beneath the agro forestry system. Extensive research revealed that agro forestry including moth, cluster bean and local variety of pearl millet as a crop component with Calligonum polygonoides and Lasiurus sindicus as perennial trees and grass, respectively are more successful in 100 to 250 mm rainfall region of arid areas, while plantation of Prosopis and Ziziphus species in the field and Capparis decidua on the boundary with pearl millet, moth bean, sesame and cluster bean is beneficial in 250 to 350 mm rainfall areas. However, growing of Prosopis cineraria and Tecomella undulata with pearl millet, green gram, moth bean and cluster bean is advantageous in the area of 250 to 450 mm rainfall adjoining to the semi arid region. In the irrigated area of arid region plantation of Prosopis cineraria and Acacia nilotica with wheat, barley, mustard and gram in winter cotton, sorghum, pearl millet and sesame in summers are expected to improve soil organic carbon and physical conditions of soils. These altogether may help to sustain agriculture and prevent land degradation.

Strategies for arresting land degradation The following discussion reveals a wide variability in type and severity of land

degradation within and between the set of conditions. A piece of land may be affected with one or combination of land degradation processes. For example erosion, salinity and nutrient depletion may occur independently or these may act together on a piece of land. It may arise either by inappropriate land use and management or by severity of natural hazards or calamities. Number of technologies has evolved and executed targeting to address one or other kind of degradation. Execution of such technology could not bring


desired results on the farmers field. Therefore for solving very complex problem like degradation, which has cascading

effect on natural resources and man kind, a holistic approach is needed. The essence of holistic approach is the selection right type of cultivars and appropriate technologies at right place depending on the specificity of problem. Execution of the programme should be done at right scale. It may be at watershed, district or region depending on problem and client requirement. Use of GIS, GPS, remote sensing data and decision support system may be very handy for the execution and monitoring of preventing/ correcting land degradation programme. A conceptual model for such activity is given in fig 13.

Fig. 13: Conceptual model for integrating land use, technology and planning environment

Database in GIS is very important component of the model. It consists four model.

Module one is polygon based, module two consists of points, whereas module three and four framed for raster and non spatial data, respectively. Component of each module is given in fig. 14.


Module 1 Module 3

Polygon based module Administration Soil resource map on 1:250, 000

scale Soil resource map on 1:50,000

scale Soil resource map on 1:4 to

10,000 scale Geology of the state/region Physiography

Module 2

Point data based module Grid points collected during

SRM Typifying pedons Grids and typifying pedons of

subsequent surveys Climatic variant Ground water status and quality

from prominent locations Land use and yield data Agro-technology - management

and yield of demonstration plots and research farms

Physiography

Fig.14: Database framework in GIS

Expert system is another novel aspect oexpert system in the model. Expert system I iarea with respect to soil, climate and irrigatithe initial stage the exercise is to be performethe land use options and management by conditions, land use requirement, available Expert system III is designed for scenario anrefining land use and management, same mayfor the use at district or regional level plannin

By utilizing expert system I the potentiawas delineated for watershed planning in Sila

Raster based module Ground and surface water

prospects and irrigation potentials

Climatic history punctuated with rainfall pattern and drought frequency

Land use dynamics Periodic RS data Physiography

Module 4

Non-spatial data based module Human and livestock profile Land use requirement Market demand and trends Non-

spatial data based module Human and livestock profile Land use requirement Market demand and trends

f the model. Three is a provision of three s designed for delineating the homogeneous on potentials at various scale. Preferably in d on larger scale. Expert system II identifies utilizing the database on socio-economic technologies, market trends and demands. alysis and projections. After validating and be up-scaled, using appropriate algorithms

g. l area for agriculture and alternate land use i basin of West Bengal depending upon soil


depth, texture and available water capacity (Fig.15).

Fig.15: Potential area for agriculture and alternate

land use in Silai basin of West Bengal, India

Land quality class (Narain and Singh, 2006) has been delineated depending upon various kinds of stresses for district planning (Jodhpur district Rajasthan) by applying expert system I. Similarly other bases for district level planning such as agro-ecounit and land management unit could be delineated by applying expert system I. In the present endeavor agro-ecounit map of Jodhpur district (Fig. 16) and land management unit in Nadia district (Fig. 17) are given an examples (Singh and Tarafdar 2009; NBSS&LUP 2010). For the regional level planning agro-ecological zone map (Singh and Tarafdar 2009) has been developed for arid region of India (Fig. 18).

Fig. 16: Land quality class and agro-ecounit map Jodhpur district, Rajasthan, India


Fig. 17: Soil management units of Nadia district, Agro-ecological sub-zone map for arid regions

By applying expert system II intercropping system and alternate land uses (Narain and

ptimum Land Use Plan for Arid Region by using expert system II

West Bengal, India Fig. 18:of India

Singh 2006) and for different land quality classes of arid region has been identified (Table 8). Table 8: O

Quality Classes Intercropping Alternate land uses

II Pearl millet ow pea Cenchrus cilliaris, acia albida, C. I (50:45)* + green gram/ c(3:1)

Prosopis cineraria, Acmopane,

IV (45:50) illet+ cluster bean/ moth bean cilliaris, Acacia tortolis, Acacia senegal, Pearl m(3:1)

Cenchrus Tecomella undulata

Va (40:55) illet+ green gram/ cow pea/ osopis cineraria, Acacia albida Pearl mmoth bean (2:1)

Cenchrus cilliaris, Pr

Vb(40:55) ter bean/ moth bean Lasiurus sindicus, Acacia tortolis, Acacia senegal Pearl millet+ clus(1:2)

VI (30:65) illet+ cluster bean/ moth bean Lasiurus sindicus, Acacia senegal, Acacia tortolis Pearl m(1:2)

VII (20:75) illet+ cluster bean/ moth bean Lasiurus sindicus, Acacia senegal, Acacia tortolis Pearl m(1:2)

VIII (5:95) r bean + green gram (2:1) Cenchrus cilliaris, Acacia senegal, Acacia tortolis Cluste

IX (5:95) Pearl millet+ cluster bean/ moth bean (1:3)

Lasiurus sindicus, Acacia tortolis, Zizyphus nummuCalligonum polygnoides

laria,


A regression he s on soil organic arid region (SOC 0-100 cm soil profile) = 4.4+

Particle size class Max. potential Inert SOC Added SOC

model for ascertaining tmatter in

impact of intercrops and alternate land usedensity kg/m2 for

0.0001052 (Rainfall, mm) +0.43914 (period of canopy cover)-0.00505 (Clay %) +0.008722 (Silt %) +0.955712 (AWC)-4.53 (tillage) -----R2=0.98 was utilized as expert system III for scenario analysis (Singh et al. 2007c). By utilizing above model potential organic carbon, SOC attached with finer (inert soil organic carbon) and coarser soil particle (Floatable soil organic carbon) were predicted (Table 9).

Table 9: Model potential organic carbon, SOC attached with finer

CL deep 4.3-4.5 2.4-3.0 1.3-1.8

CL mod. deep 4.3-4.5 1.7-3.0 1.4-2.6

Fine loamy 4.2-4.6 2.1-4.1 0.5-1.6

Loamy-skeletal 4.0-4.1 0.4-0.8 3.4-3.7

Sandy 4.2-4.3 0.9-1.5 2.7-3.2

These calculations were canopy cover tained round under prevailing normal situation of rainfall and temperature (Singh et al. 2007). Based on the mod

Fig.19: Untapped soil organic carbon in g/m2 in Arid India

valid if is main the year

el untapped organic carbon (Fig. 19) potential for the soils of Jodhpur district Rajasthan India was calculated (Singh and Tarafdar 2009). Modeled values of soil organic carbon potential was tested under different land use systems (Fig.20). Soil organic carbon was much closer to the predicted potential soil organic carbon under silvipasture system and was far from prediction under pearl millet system of land use.


Fig.20: Validation of module value in different land use system

Conclusions With the advent of green revolution, no doubt food productivity has increased many

non/partial adoption of package of practices, high population pressure, erra

Abd El-Hamid, M.I.E. (1994) Remote sensing and the desertification phenomenon. Proceedings of sium on Desert Studies in the Kingdom of Saudi Arabia, Riyadh, 2-4 October

times. However, tic behavior of monsoon and miseries imposed by nature induced various kind of

degradation. Menace of degradation is more serious in south Asian countries because of high population pressure. Majority of the farmers belonged to low income group and their capacity to adopt green revolution technology in totality is questioned. As a result full package of technology was not adopted and desired impact of technologies could not be perceived. Therefore strategies of holistic approach consisting of right cultivars, appropriate technologies at the right place may be the options for sustainability and for enhancing growth in agriculture

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34 Strategies for Arresting Land Degradation in Bangladesh

C o n t e n t Page 1. Introduction 35 2. Land degradation: Situation in South Asia 35 3. Factors affecting Land Degradation 37 4. Impacts of Land Degradation 39 5. Major types of land degradation in Bangladesh: 40 5.1. Soil erosion 41 5.2. Water erosion 41 5.3. River Bank Erosion 43 5.4. Wind erosion 44 5.5. Salinization 44 5.6. Acidification 45 5.7. Water logging 45 5.8. Decline in Soil Fertility 46 6. Levels of Land Degradation 47 7. Climate Change induced Land Degradation 48 7.1. Rainfall 48 7.2. Temperature 48 7.3. Flood 49 7.4. Carbon Sequestration and Land Degradation 49 7.5. Drought management 50 8. Minimizing Land Degradation 50 8.1. Plantation 50 8.2. Organic agriculture 51 8.3. Shifting cultivation 51

8.4. Preserving soil fertility/Fertilizer management 51 8.5. Carbon Management Approaches 51 9. Land Resources Conservation Strategy 52 10. Combating Land Degradation and Appropriate Cropping 53 10.1. Research 53 10.2. Extension 53 10.3. Policy Options 54 11. Conclusion 54 12. References 55

Strategies for Arresting Land Degradation in Bangladesh 35

1. Introduction Land is the nature’s most precious gift to mankind. Land with all its attributes as a

versatile resource base played the key role here. It is the most fundamental of natural resources which provided all of food, feed, fiber and shelter, for the human race and its civilization to thrive on this planet. About one-fifth of humanity lives in South Asia. Despite rapid urbanization in recent years and a fall in the share of agriculture in GDP, the overwhelming majority of South Asians are still villagers, dependent on land for their livelihood. Bangladesh lies in the north-eastern part of South Asia. The rate of urbanization is for 31.5%, 25.7% and 20% for Pakistan, India and Bangladesh respectively. The pressure in agricultural land is high in all the three countries. However, it is highest in Bangladesh, with 73.8%, while India has 64.9% and Pakistan has 51.2% of the working force dependent on agriculture (Siddique, 1997).

Land degradation is one of the greatest challenges for mankind. Although the problem is old as the settled agriculture, its extent and impact on human welfare and global environment are now more alarming than ever before. Large scale degradation of soil resources has been reported from many parts of the world (Hillel, 1991). Land degradation leading to change in cropping and agricultural productivity and vice versa is threatening the agricultural sustainability of many countries, especially the developing and least developed countries with scare land resources. Soil degradation is "the decline in soil's productivity through adverse changes in nutrient status and soil organic matter, structural attributes and concentrations of electrolytes and toxic chemical (Blaikie and Brookfield, 1987).

In Bangladesh, land and soils are the most valuable natural resources. Unfortunately, these important natural resources are being used non-judiciously without proper replenishment. Boosting crop production has been confronted by many soil related problems like depletion of organic matter, nutrient deficiency/imbalance, soil salinity, soil acidity, topsoil erosion, degradation of physical properties, low water holding capacity and draughtiness, drainage impedance and water-logging prevailing in many parts of the country which hamper crop production. These problems are partly due to natural cycle of events and mostly because of irrational human interventions. In this paper, an attempt has been made to review the nature and kind of soil degradation in South Asian Countries and its possible remedies to improve the situations.

Under the above circumstances, the issue of land degradation has to be addressed. Land degradation, as an issue, is not something new, but recent developments in the food sector do not bode well for the South Asian countries striving to provide food security and improve the quality of life for their teeming millions. Assessment of the land resources and evaluation of the land degradation knowledge is to be developed by creating awareness and develop ways, means and policy level interventions to halt land degradation for the countries are necessary. The vulnerability of agricultural land to degradation and the capacity of the farmers to respond to the threat of degradation thus need social, economic and policy consideration.

2. Land degradation: Situation in South Asia Asia, the most thickly populated area in the world has been influenced by

desertification. With the rapid economic development in Asian countries, the rapidly


growing population is placing ever-increasing demands on the land, clearing natural vegetation and tilling soil without fallow or inadequate nutrient replenishment. With increasing use of unsustainable resources, land degradation further degraded, which leads to increased poverty and many people have to face deteriorating living conditions. About 35% of the arable land in Asia has been influenced by desertification. Nearly 1.3 billion people or 39% of the total population in Asian region are exposed to desertification and arid conditions. Hence the area under land degradation is increasing. World soil degradation situation (FAO, 2000) is presented in Table 1.

The food demand and internal supply situations in most SAARC countries have not been satisfactory as the scope of horizontal expansion of agriculture has almost exhausted and crop yields began to stagnate or even decline in many cases. The recent food price hikes and limited availability of food in the international market have further complicated the issues related to achieving food security in the SAARC countries and at the same time maintaining the pace of their socio-economic development. The implication is that, countries must produce enough food for their present populations and check population growth rates to ensure that food shortage do not occur in the future, virtually all of the food increase will have to come from land. The population growth rate was high, around 2% per annum in the impoverished, developing nations of Asia. For example in the SARC countries, the total population was 1418.5 million in 2004 which is estimated to be about 1800 million by the year 2020 (SAARC Statistical Data Book, 2006-2007), about 22 percent of the world’s population live in the eight SAARC countries.

Table 1: Soil degradation in the world (Land in "00000' hectare, FAO, 2000)

Type of Degradation

Region Plant nutrient depletion

Salinization Chemical pollution Acidification

Organic matter

depletion

Asia 150 530 30 50 20

South East Asia 130 200 15 50 20

West Asia 45 360 15 - -

Africa 500 150 - 25 -

South America 700 20 - - -

Central America 45 20 - - -

North America 22 - - - - Europe 35 40 2 - 20 Oceania 10 10 - - - World (Total) 1637 1330 62 125 75

There are limited data on the latest information and statistics about the nature and extent of the different land degradation components in the SAARC countries varying in content and precision from country to country. However, what is known to date may be


largely qualitative and not always precise but these do provide food for thought for policy makers and agricultural scientists of the region for future action plans to protect the region from the bad effect of land degradation. For the practical purpose of assessment of land degradation in SAARC countries and determination of the needs for technological and policy interventions, the following list showing the causes of land degradation, natural or human induced, should suffice: • Natural hazards e.g., flood, drought, tidal surge, snow melt, etc. (some or the other in

all SAARC countries - e.g., floods and tidal surges in Bangladesh, drought in Pakistan and India, snow melt and landslides in Nepal and Bhutan)

• Erosion by water and wind (e.g., serious land erosion from river water currents in Bangladesh during recurrent floods, wind erosion in the semi-arid regions of India and Pakistan)

• Salinization and acidification (natural and anthropogenic e.g., tidal flooding, shrimp culture in crop land in Bangladesh, faulty irrigation and drainage in India and Pakistan, arid and semi-arid conditions in India and Pakistan, draining and drying of potentially acid sulphate soils, etc.)

• Formation of hardpan, compaction and water logging (mostly human induced in all SAARC countries)

• Deforestation, shrinkage of vegetation cover on land, overgrazing (natural and / or human induced in India and Pakistan, for example)

• Inappropriate management in cultivation of land on steep slopes (human induced - e.g., in Nepal)

• Nutrient mining and inadequate nutrient replenishment (human induced - all SAARC countries)

• Soil organic matter depletion (mostly human induced - e.g., serious problem in Bangladesh)

• Over-exploitation of ground water in excess of natural recharge capacity (faulty irrigation practice, human induced)

• Use of poor quality irrigation water (e.g. use of groundwater containing high arsenic concentrations for irrigation in Bangladesh and West Bengal of India, risk of toxic levels arsenic accumulation in soils and foodstuff)

• Pollution of soil and surface water bodies (rivers, ponds) by urban industrial waste, excessive use of agrochemicals, oil spills etc. (human induced - e.g., in India, the most industrialized SAARC country)

• Global warming and consequent sea level rise, an impending calamity (mostly human induced, mainly responsible are the industrialized countries of North America and Europe, but the SAARC countries are under the influence of severe consequences).

3. Factors affecting Land Degradation A big difficulty in studying these components of land degradation and their impacts

on agricultural production separately is that, these are caused by both natural factors and


human interventions mostly in overlapping ways. For example, soil degradation may occur due to fertility decline caused by loss of nutrients through erosion (natural cause) and simultaneously, intensive cropping without appropriate fertilization (human factor) and it has some adverse affect which result a huge crop loss. The crop loss could be measured, it would be almost impossible to determine exactly which factor contributed how much in causing yield loss. Some statistics gleaned from various countries (SAARC Statistical Data Book, 2006-2007) are given below as references: • Water erosion and chemical degradation are the most devastating land degradation

pathways in the SAARC region. Erosion risk is the highest (53% of the total area) in Bhutan, followed by 42% in Sri Lanka, 31% in Nepal, 29% in India, 15% in Bangladesh and 13% in Pakistan

• Soil salinity/sodicity is a problem in Pakistan (20% of the total area), India (8%) and Bangladesh (6%).

• Land with shallow soils (poor fertility and physical properties): 24% in Pakistan, 21% in Nepal, 13% in Bhutan, 10% in Sri Lanka, 9% in India and 1% in Bangladesh.

• Soil fertility decline due to organic matter depletion is a growing problem in all countries. In Bangladesh about 60% of the soils have low organic matter content, often less than 1%.

• In India 41% of the land area is under major soil constraints, the figures for Sri Lanka, Bangladesh, Nepal, Bhutan and Pakistan are 37%, 29%, 26%, 22% and 9%, respectively.

• On a SAARC regional basis, only 24% of the total land area in without major soil constraints. Land degradation through human activities is progressing at a fast pace in all South

Asian countries. Human induced land degradation in India is the highest (58% of the total degraded area) followed by Sri Lanka 54%, Bangladesh 27%, Nepal 27% and Pakistan 24%. It is in this aspect of land degradation, i.e., human induced land degradation, where there is the greatest scope and necessity to intervene with national and regional policy measures and technological innovations. This is the time to give emphasis to initiate research work extensively to solve the problems of soils of Bangladesh that occupies 60% area of which 0.88 m ha in salinity, 35 m ha in drought, 26 m ha in water-logging, 0.83 m ha in char land and 1.2 m ha in high temperature zone.

A more recent estimate-projection on the impact of land degradation in Bangladesh is quite frightening (Kholiquzzaman, 2007): • Loss of 180 ha arable land/day, 7.5 ha hr-1 due to building of homes, industries, roads

and other structures. • Loss in food production estimated at 5000 t day-1 or 1.6 million t yr-1. • At this rate of loss of arable land, not even a sq inch would be available for

agriculture after fifty years onward. • In 1974 59% of the net land area of the country was under agriculture; decreased to

53% in 1996. During the period 1983-1996, the rate of decrease in arable land area was 87,000 ha yr-1.


• During 1983-1996, food production suffered a loss of about 2.1 million ton due to continuously decreasing arable land area

• In total since 1996, the loss of arable land over 10 years was 0.65 million ha yr-1.

There are some examples of the present and potential impacts from one SAARC country only (Bangladesh). Land degradation in almost all its known forms is going on in all other SAARC countries. The extent and intensity of the various land degradation processes would differ, however, from country to country. For example, arsenic contamination of the irrigation water-soil-crop systems is known to be quite a serious water quality/soil degradation problem in Bangladesh and West Bengal of India, but this is not much of a problem in Pakistan, other parts of India and other SAARC countries. Again, sea level rise due to global warming could be a very serious threat to Bangladesh and Maldives, but Nepal and Bhutan are not supposed to be directly affected. Since no generalization can be made regarding the causes and effects of land degradation, it is imperative that dependable data for each country be available so that scientist, policy makers and farmers can take appropriate measures to face the problem nationally and regionally.

4. Impacts of Land Degradation Estimating the impact of land degradation is a very difficult task as this would

involve not only the biophysical and agro-ecological issues but also socio-economic and development issues. However, this is very important since policy makers, donor agencies and international development partners would be more interested in quantitative estimates of the impacts of land degradation than just qualitative statements about what could happen. A concerted effort by agricultural and social scientists is very much needed. A study of the effect of land degradation in south Asia concluded that land degradation was costing countries in the region and economic loss of the order no less than US$ 10 billion, equivalent to 7% of their combined agricultural GDP (FAO, 1994). The current figures could be much higher.

Over the last 2-3 decades, enormous pressure has been exerted on the land resources of the country. The rapid population growth and the concurrent increase in demand for agricultural land, food, water and shelter has put pressure on the land and water resources. This is resulting in environmental degradation in the region and the trend is intensifying unceasingly. In Bangladesh, roughly 220 hectares of land goes out of cultivation per day which means, nearly 1 percent of the cultivable land is being lost every year (BBS, 1997). This has serious implication on the sustainability of agricultural development potential, food supply and food security of the country.

Due to decline in natural vegetation and unsustainable agriculture, the capacity of soil and water resources to support life has been steadily reduced. According to the data from UNEP in 1997, of the 1.96 billion ha of soil resources in the world, that have been degraded, Asia ranked the highest rate with approximately 38% percent of total declination. Due to overgrazing and deforestation, natural vegetative cover continues to decline, which created negative impact on the biodiversity. There are a number of


interrelated land degradation components, as follows, all of which may contribute to a decline in agricultural production (FAO, 2000): • Soil degradation : Decline in the productive capacity of the soil • Vegetation degradation: Decline in the quantity and quality of the natural biomass

and loss of vegetative cover (For example, the supper cyclone “Sidr” in Bangladesh caused at least 5% loss of the Sundarbans, the largest mangrove forest of the world, As a result the “green wall” against cyclone has been seriously lost in Bangladesh)

• Water degradation : Serious increase of pollution of ground water due to arsenic, industrial effluents. Decline in the quantity and /or quality of the surface and groundwater resources

• Climate deterioration : Changes in climatic conditions that increase the risk of crop failure. This components caused yield reduction in wheat and mustard

5. Major types of land degradation in Bangladesh: Major types of land degradation that occur in Bangladesh constitute: i) soil erosion, ii) water erosion, iii) river bank erosion, iv) salinization, iv)

sedimentation, v) acid sulphate soil, vi) Acidification, vii) water logging and viii) soil fertility depletion. The types of land degradation and extent are provided in Table 2.

Table 2: Different types/areas of land degradation and their extent in Bangladesh

Areas (in m ha) affected by different degrees of degradation

Types of land degradation

Light Moderate Strong Extreme

Total area (m ha)

1. Water Erosion -Bank erosion

0.1 -

0.3 1.7

1.3 -

- -

1.7 1.7

2. Wind Erosion - - - -

3. Soil Fertility Decline - P deficient (for HYV rice) - P deficient (for Upland crops) - K deficient (for HYV rice) - K deficient (for Upland crops) - S deficient (for HYV rice) - S deficient (for Upland crops) Soil Organic Matter depletion

3.8 5.3 3.1 4.0 2.1 4.4 4.1 1.94

4.2 3.2 2.5 3.4 5.4 3.3 4.6 1.56

- - - - - - -

4.05

- - - - - - - -

8.0 8.5 5.6 7.4 7.5 7.7 8.7 7.55

4. Water logging 0.69 0.008 - - 0.7

5. Salinization 0.29 0.43 0.12 - 0.84


Areas (in m ha) affected by different degrees of degradation


Light Moderate Strong Extreme

Total area (m ha)

6. Pan formation - 2.82 - - 2.82

7. Acidification - 0.06 - - 0.06

8. Lowering of water table* - - - - -

9. Active floodplain - - - - 1.53

10. Deforestation - 0.3 - - 0.3

11. Barind - - - - 0.773

Source: BARC, 1999. * No quantitative estimate available

5.1. Soil erosion Soil erosion has been remarkably encountered in the hilly regions of the country

which occupy about 1.7 million hectares and the areas which are susceptible to different degrees of erosion in the hilly areas of Bangladesh is shown in Table 3 (SRDI, 2005). Sheet erosion is a general phenomenon occurring throughout the country. It poses a serious problem locally in parts of level to gently undulating high terraces of the Madhupur, Barind and Akhaura tracts in terms of considerable amount of topsoil and nutrient loss. There is also visible evidence of fertile topsoil loss in the flood plain, but a quantitative estimate of soil loss has not yet been scientifically made.

5.2. Water erosion Water erosion is a serious problem in Bangladesh. Because of high seasonal rainfall,

low organic matter content, poor soil structure, poor soil management and rapid destruction of vegetative covers in different slopes of the hills, the surface soils are being continuously washed away. Water erosion covers all forms of soil erosion by water including sheet and rill erosion and gullying. Human induced enhancement of landslides, caused by clearing of vegetation, earth removal, road construction, etc., are also included. Water erosion is the most widespread form of degradation affecting 25% of agricultural land. Accelerated soil erosion has been remarkably encountered in the hilly regions of the country which occupy about 1.7 million hectares and the areas which are susceptible to different degrees of erosion in the hilly areas of Bangladesh is shown in Table 3 (SRDI, 2005). The data reflects that about 75% of the hilly areas have very susceptibility to erosion while about 20% have high susceptibility and 5% have moderate susceptibility to erosion.


Table 3: Land susceptible to different degree of soil erosion in the hill areas of Bangladesh (in km2)

Areas

Moderately susceptibility

to erosion

High susceptibility

to erosion

Very high susceptibility

to erosion

Total

Chittagong Hill tracts 350 1,814 10,765 12,929

Chittagong & Cox’s Bazar 414 949 954 2,317

Greater Sylhet district 161 462 964 1,587

Others (Comilla, Brahmanbaria, Netrokona, Jamalpur etc)

- 35 102 137

Total 925 (5%) 3,260 (20%) 12,785 (75%) 16,970

Rill and gully erosions in severe forms occur in the hill areas due to rapid removal of the vegetable cover. Over 17% of the growing stock was depleted between 1964 and 1985 in the inaccessible state forest of the Chittagong Hill Tracts (SRDI, 2005), while there is no data available for the unclassed state forests occupying 10,085 km2. They are open to shifting cultivation, pineapple plantation and many other forms of disturbances. A study shows that sediment loss from well stocked slopes ranged from 2.7 to 7.2 t-1ha-

1year-1, while that from the clean field slope was 102 t-1ha-1year-1 (SRDI, 2005). More severe forms of soil erosion are occurring in different parts of the hills due to non-traditional practices of the pineapple and rubber plantations (Layzell, 1982). It was estimated that the annual soil loss under pineapple was in excess of 200 t-1ha-1year-1. Landslide occurs in Bangladesh in the hills with 70% slope or steeper during heavy depressional rainfalls. These are observed in the forms of landslip, mud flow, flow side, slump and occasional rock fall. The area and extent increase with the increase of rapid destruction of vegetable covers in the hills.

About 10,000 hectares of forest land, including reserve forest, have been brought under jhum cultivation in the current season at eight upazilas in Khagrachari. Jhum is a traditional method of cultivation of indigenous people in the Chittagong Hill Tracts. Continuous tilling of hill slopes is also appears as a major concern of massive soil erosion as forests and shrubs are cleared off damaging biodiversity that may cause environmental disaster. It was observed that soil loss from Jhum on steep slope, moderate slope and gentle slope were 40.0, 35.0 and 32.0 t-1ha-1year-1, respectively (Khan et al., 2008). On the other hand Jhum with vegetative barrier resulted soil loss of 9.0, 10.0 and 17.0 t-1ha-1year-1 in gentle slope, moderate slope and steep slope, respectively (Table 4).


Table 4: Soil loss from Agricultural land use at different slopes due to Jhum cultivation

Slope Land use Soil loss (t-1ha-1year-1) Jhum 39.70 Jhum hedgerow 8.85 Local Jhum paddy 13.54 BRRIdhan 26 12.50

Steep slope

BRRIdhan 27 11.60 Jhum 35.05

Jhum hedgerow 9.85 Local Jhum paddy 13.72 BRRIdhan 26 11.63

Moderate slope

BRRIdhan 27 11.95 Jhum 32.48

Jhum hedgerow 16.90 Local Jhum paddy 11.52 BRRIdhan 26 8.35

Gentle slope

BRRIdhan 27 4.70

Source: (SRDI, 2005)

5.3. River Bank Erosion River bank erosion is rampant in areas along the active river channels of the Ganges,

the Jamuna, the Meghna and the Tista and in the coastal and off-shore areas of Bangladesh. In Bangladesh, bank erosion is caused mainly due to strong river current enhanced by mechanized river traffic and/or channel diversion during the rainy season. Bank erosion causes extensive loss of land, crops and hose holds and urban migration of the landless and uprooted rural populace. This has created an unchangeable chronic socio-economic problem in Bangladesh. About 1.7 million hectares of floodplain areas are prone to river bank erosion.

Table 5: Rate of silt deposition in different types in Sylhet district of Bangladesh

Land Types Silt deposition (kg/ha/year)

High land Medium highland Lowland Very lowland

2256 4120 6696

10417

Source: Chowdhury (SRDI, unpublished)


5. 4. Wind erosion In Bangladesh, some areas are affected by wind erosion mainly in the districts of

Rajshahi and Dinajpur during the drier months of the year. Sand dunes in the young alluvial lands (charlands) of Kustia and sandy beaches along the seashore are some of the visual evidence of wind erosion in Bangladesh. Droughty situation leading to wind erosion and its impact on agricultural production has been documented by Karim et al. (1990), but quantitative data has not yet been estimated.

5.5. Salinization In Bangladesh, salinization is one of the major natural hazards contributing towards

land degradation. Soil salinity is a seasonal problem that goes, among the three seasons, in rabi season salinity affects crop production severely in the saline belt whereas in kharif-1 salinity reaches about to neutral and does not affect crop production which is unusual to rabi season. Maximum salinity occurs in the month of March and April, the peak dry season and minimum salinity occurs in the month of July and August after the onset of monsoon rains (Mondol, 1997). The coastal area of Bangladesh is about 710 km long. Out of 2.85 million hectares of coastal and off-shore area (30 % of net cultivable area) about 0.85 hectare of arable land were affected by varying degrees of soil salinity. Recently, salinity both in terms of severity and extent has increased much due to the intrusion of saline sea water because of the diversion of the Ganges water in the dry season.

Impact of salinization is more apparent than other forms of land degradation. This is partly because, its effects are substantial and visibly apparent, partly because the degradation can be readily quantified. In Bangladesh, mainly rabi season crops (wheat, barley, maize, boro, mustard and vegetables) are affected due to different degrees of salinity. Production loss is estimated here for wheat considering an average yield of 2.0 t ha-1 (Table 6).

Table 6 : Loss of production due to Salinization at different degrees of land degradation (Karim and Iqbal, 2001)

Degree of degradation Area (mha) Relative production loss

Total production loss (million ton) of wheat

Light 0.40 15% 0.12

Moderate 1.60 65% 2.1

Strong 1.10 100% 2.2

Total 4.42

For management of saline soil in different areas of Bangladesh, Bangladesh Agricultural Research Institute (BARI) conducted some experiments on mungbean, tomato, watermelon and chilli to find out the effective measures as well as to have better yield and their findings showed that drip irrigation in raised bed with mulch for tomato


and watermelon and manual pump irrigation at an interval of seven days in raised beds with mulch for chilli was found more effective for the production of the crops (BARI Annual Report, 2007). Introducing high yielding salt tolerant variety (BRRI dhan 47) for boro and BR 23, BRRI dhan 40 and BRRI dhan 41 could be able to produce sustainable grain yield in the coastal regions (BRRI Annual Report, 2007). Special crop and soil management practice should be developed for saline water irrigated agriculture. Introduction of salt tolerant varieties and technologies of different crops like mungbean, barley, soybean, mustard and adaptation to coastal crops agriculture to combat salinity under wet-bed-tillage method and tidally flooded agro-ecosystem through conventional relay cropping systems would be better possible option.

Table 7: Comparative study of the salt affected area between 1973 to 2009 in Coastal areas

Year

1973 2000 2009

Salt affected area increased during last

9 years (000’ha, 2000-09)

Salt affected area increased during last

36 years (000’ha, 1973-09)

833.45 1020.75 1056.19 35.44 (3.5%) 222.74 (26.7%)

5. 6. Acidification Loss due to acidification has been estimated in terms of relative loss in rice

production assuming an average yield of 3.0 t ha for high yielding varieties of rice. The relative production (rice) loss due to acidification is 15, 50 and 100 percent due to light, moderate and strong acidity, respectively (Table 8).

Table 8: Land degradation due to Acidification at different degrees (Karim and Iqbal, 2001)

Degree of degradation Area (mha) Relative production loss

Total production loss (million ton)

Light - 15% -

Moderate 0.06 50% 0.09

Strong - 100% -

Total 0.09

5.7. Water logging In Bangladesh 2.6 m ha land is affected by water logging. Sometimes heavy monsoon

rain may cause water logged soil condition which is one of the serious environmental constraints for crop production. Screening and development of waterlogged tolerant varieties, switching to alternative cropping patterns with respect to altered agro-ecological zones etc. could help to mitigate the problem.


The low-lying area surrounded by higher ground and having no natural outlet for surface drainage; usually flooded deeply during wet season is common in Bangladesh and covers the Beel, Jheel, Haor , Baor that accumulates surface runoff water through internal drainage channels. Many of the beels dry up in the winter but during the rains expand into broad and shallow sheets of water. In Bangladesh, there are thousands of beels of different sizes. Some of the most common beels are Chalan beel, Hakaluki haor, Gopalganj-Khulna beel and Arial beel. About 8000 hectares of water logged land in Khulna-Jessore areas (popularly known as Bil Dakatia) is the result of human induced degradation due to faulty construction of embankment. More than 276 numbers of small-big sizes having moderately shallow and deeper depth types comprises in Hakaluki haor from where rice is harvested each year.

The Jheels are commonly seen in the southwestern Ganges deltaic parts of the country. They remain deeply flooded in the wet season. In dry season, jheel lands are used for agriculture and as pasture for cattle. Total gross area of Bhabadah (Avaynagar, Monirampur and Keshabpur upazillas of Jesore district) and its adjacent area is about 94,900 ha. Out of which 61, 280 ha has been promoted to cultivable area though this area is being inundated for a long time and it is curse for the farmers. In the reclaimed area, Aus (3610 ha), Aman (6815 ha) and Boro (10,160 ha) are now cultivated after improvement by the co-operation of Bangladesh Army during 2007-2008 (The Daily Prothom Alo, 25th April, 2008).

Haors are located in the north eastern part of greater Sylhet and greater Mymensingh regions. During monsoon a haor is a vast stretch of turbulent water. The basin includes about 47 major haors (some important haors are; Hail, Hakaluki, Tangua, Kawadighi, Balai, Gurmar) and some 6,300 beels of varying sizes, out of which about 3,500 are permanent and 2,800 are seasonal water bodies. During the dry season, most of the water drains out and these lands are extensively used for Aman rice cultivation. No cropping pattern is developed centering the areas. Boro rice crop is practiced in the haor areas only in dry season of the year.

All wetlands are subject to sedimentation composed of clay soils rich in organic matter, and crops, which can tolerate water logging and inundation are grown. Before the introduction of mechanized dry-season irrigation, deep water rice or broadcast aman rice (floating rice) were is the major crops in the wetlands during the rainy season. The immediate lands adjacent to the highlands are shallowly flooded and should be used for agriculture. BR-22, BR-23, BR-47, BINA shail, Nijershail and local aman rice are recommended to broadcast in the seedbed in early August (AIS, 2007). BARI has developed some water logged varieties on Sesame (BARI Til 3; BARI Annual Report, 2007).

5. 8. Decline in Soil Fertility A good soil should have an organic matter content of more than 3.5 percent. But in

Bangladesh, most soils have less than 1.7 percent, and some soils have even less than 1 percent organic matter. Considering the NARS data base, organic matter content of Bangladesh soils has been summarized (Karim and Iqbal, 2001). In Bangladesh, depletion of soil fertility is mainly due to exploitation of land without proper


replenishment of plant nutrients in soils in addition to decline the organic matter content. The problem is enhanced by intensive land use without appropriate soil management. The situation is graver in areas where HYVs are being cultivated using low and unbalanced doses of mineral fertilizers with little or no organic recycling. Research results have shown that quite high rates of fertilizer (about 200 kg NPKS nutrients/ha) are necessary for HYV rice cultivation where the soil has been degraded (low fertility level) due to prolonged cropping. For light type of degradation, an average input of 100 kg nutrients (NPKS) ha-1 will be required to obtain moderate yield of cereals (Karim and Iqbal, 2001).

Changes in SOM in different AEZ

6. Levels of Land Degradation The degree to which the land is presently degraded is estimated in relation to changes

in agricultural suitability, in relation to declined productivity and in some cases in relation to its biotic functions. Three levels of degradation namely; light, moderate and strong are recognized. In terms of the effects, the farmer is still using land with moderate degrees of degradation, but the boundary with strong degradation is the point at which land use has to be abandoned. It is uncommon for the farmers that they are not aware of the land degradation situation. According to Karim and Iqbal (2001), total cereal production loss was 1.06 and 4.27 t yr-1 due to water erosion and fertility declination, respectively. The estimated cost was 140.72 and 544.18 million U.S. dollar in case of water erosion for cereal and nutrient loss, respectively (Table 9). Similar estimated cost was 566.84 and 461.04 million U.S. dollar in case of fertility for cereal and nutrient loss, respectively. However, in case of salinization, estimated cost was 586.75 U.S. Dollar. In case of severe forms of degradation, like salinization and water logging, land productivity can be restored by reclamation. In case of soil erosion, some of the effects may appear to be reversible. Arresting further erosion by soil conservation measures and restoring lost nutrients and organic matter are some of the measures.

0.0

0.5

1.0

1.5

2.0

2.5

AEZ 28

AEZ 25AEZ 1

AEZ3

AEZ 29

AEZ 19

AEZ 11AEZ 9

OM

%

1969-70 1989-90 1999-2000 2004-2005


Table 9: Estimates of economic losses from different types of land degradation in Bangladesh


Degraded area (million ha)

Degree of degradation

Loss estimate (million ton year-1)

Financial loss (million $ year-1)

Water erosion (mostly floods and riverbank erosion)

1.70 Light to strong

Cereal production loss: 1.06 Nutrient loss: 1.44

140.72

544.18

Fertility decline

3.20 Light to moderate

Cereal production loss: 4.27 additional input loss: 1.22

566.84

461.04

Salinization 3.10 Light to strong

Total production loss: 4.42

586.75

Acidification - Light to moderate

Total production loss: 0.09

11.95

Source: Land degradation situation in Bangladesh, BARC, 1999

7. Climate Change induced Land Degradation Bangladesh will face another hazard, the sea level rise due to global warming. The

losses could be really colossal; i) inundation of the whole coastal belt, ii) displacement of some 30 million people who will become refugees in their own country, iii) huge loss of agricultural production will result in widespread hunger and poverty and iv) more than 10% of the GDP could be lost. The above are some examples of the present and potential impacts in Bangladesh. The extent and intensity of the various land degradation processes would differ, however, from country to country. The sea level rise due to global warming could be a very serious threat to Bangladesh in future. It is the time that the scientists, policy makers and farmers can take appropriate measures to face the problem nationally and regionally. Therefore, climate parameters should be considered seriously to minimize land degradation.

7.1. Rainfall Rainfall is the most important climatic factors in determining land degradation and

potential desertification. Rainfall plays a vital role in the development and distribution of plant life, but the variability and extremes of rainfall can lead to soil erosion and land degradation. Rainfall intensity is the most important factor governing soil erosion caused by rain (Zachar, 1982). Dry land precipitation is inherently variable in amounts and intensities and so is the subsequent runoff.

7.2. Temperature Seasonal and daily changes in temperature can affect the soil moisture, biological

activity, rates of chemical reactions, and the types of vegetation. High temperatures will


also increase evaporation and further reduce available soil moisture for plant growth. The minimum sea level rise of 5.18 millimeter occurred in the Khulna region, south-western part of the country. Although the rate of sea levee rise is very slow, if continues at this rate the sea level may rise 85 centimeter by year 2050. Water stagnation and salinity will increase in many areas.

7.3. Flood Flood is a natural phenomenon that has occurred for millions of years and

continuously shapes the earth. Bangladesh was affected with floods more than 23 times during 1971-2000 at different intensities (FAO, 2000). More than 1.32 m ha of net cultivated area (NCA) was severely affected and 5.05 m ha of NCA was moderately affected due to floods (flash, rain water, river water and tidal floods) which directly and indirectly affect land degradation. The cyclones and wind affect 2.80 m ha of coastal area and are subjected to damaging effect.

Flood water usually causes damage to current crop as well as future crops. Besides, it also hampers seed-bed, orchards and agro-forestry. Moreover, Agro-based material and other properties are affected by flood especially, standing food crops, fisheries, livestock, and house hold and other community structures and roads, trees etc. A havoc cyclone “SIDR” (November 15 2007) affected the southern parts of Bangladesh which causes inflicted losses. These are given below according to “The Daily Ittefaq” (18 December, 2007)

Loss of lives 3363 Monetary losses 6100 crores (Tk.) Affected people 1 crore Damages of crops 13 lacs m tons Household’s affected 15 lacs (fully damaged 5.64 lacs) Affected roads & highways 8000 km Untraced people 871 Injured 55 thousands Affected educational institute 8000 (4489 Pri sch, 3750 H. sch & coll) Affected sanitary systems 70%

7.4. Carbon Sequestration and Land Degradation Scientists agree that global climate change such as global warming is attributable to

elevated levels of atmospheric carbon dioxide which created an impact on the increasing droughts and desertification in the Asian region. Land degradation is an insidious process that threatens the sustainability of agriculture, not only in the arid and semi-arid regions, but also in the sub-humid and humid regions, as a result of the loss of agro-ecosystem capacity to meet its full potential (Lal, 2004). Resulting from complex, and little understood, interactions among periodic weather stresses, extreme climatic events, and management decisions, land degradation is a serious global concern in a world searching


for sustainable development to meet the needs of a rapidly increasing human population, to reverse the negative impacts of our choices on the environment in which we live, and to fairly distribute the world's resources in a socially justifiable manner. Three of the most important green house gases (GHGs) related to agricultural activities is carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) which are responsible for global warming (Schlesinger, 2000).

7.5. Drought management Drought is a major disaster affecting the people, especially in the rural areas, who

maintained their livelihood from farms and natural resources. Since the people of the rural areas are quite dependent on the sources available to them which are prone to drought leading to low products and eventually lower income so they are extremely vulnerable to drought. Poverty is both a cause and consequences of drought.

Drought is a multi-faceted phenomenon which is an inevitable part of normal climate fluctuation and should be considered as a recurring environmental feature. The droughts are of: meteorological, hydrological, agricultural and socio-economic (Wilhite and Glantz, 1985). Drought of different intensities occur in Bangladesh, which severely affects annually about 2.3 million ha in the Kharif season and 1.2 million ha in the dry (Rabi and pre Kharif) seasons (Khan et al., 2008). Drought is a very common natural phenomenon in Bangladesh. It can cause from 30 to 70% crop loss in a year. Drought occurs due to; i) lack of rainfall, ii) lack of irrigation water, iii) excessive heat wave and iv) no organism coverage on sandy and sloppy soils etc.

The inter action between these types of drought is illustrated meteorological, hydrological, agricultural and socio-economic drought occurs less frequently than meteorological drought alone because impacts in these sectors are related to the availability of surface and subsurface water supplies. It usually takes several weeks before precipitation deficiencies begin to produce soil moisture deficiencies leading to stress on crops, pastures and rangeland. Continued dry conditions for several months at a time bring about a decline in stream flow and reduced reservoir and lake levels and potentially, a lowering of the groundwater table. When drought conditions persist for a period of time, agricultural, hydrological and socio-economic drought occurs, producing associated impacts. The droughts are of four types in context of agriculture. These can be classed as; extreme, moderate and regular drought is treated if there is one crop loss is of 70-90, 40-70 and 15-40 percent, respectively.

8. Minimizing Land Degradation In agriculture, there are many management practices that can be employed to counter

land degradation. These are: 8.1. Plantation

Trees can accumulate C in perennial biomass of above-ground and below-ground growth, as well as in the deposition of soil organic matter (Baral and Guha, 2004). Carbon accumulation in the soil is the major sink for hedgerow inter-cropping systems used to produce biomass for improving soil fertility. Since animal manure contains 40-60% C, its application to land should promote soil organic carbon sequestration (Makumba, 2007).


8.2. Organic agriculture Organic agriculture uses a whole system approach based upon a set of processes

resulting in sustainable ecosystems, safe food, good nutrition, animal welfare and social justice. Organic agriculture minimizes carbon dioxide emissions from agricultural eco-systems (Layzell, 1982). 8.3. Shifting cultivation

It avoids the need for farmers to use to restore soil fertility since it increases yield per unit area through organic intensification integrated with animal production. 8.4. Preserving soil fertility/Fertilizer management

Maintanance of soil fertility through enhancing the natural nutrient cycles can combat pests and weeds through ecological techniques and thus reduces fossil fuel consumption. The emphasis on strengthening the internal nutrient and energy cycles inherent in organic agriculture offers a means to sequester carbon dioxide in the soil and in the vegetation. The study looks at how organic agriculture could contribute to reducing green house gas (GHG) emissions and mitigate the impacts of climate change. Specifically, organic agriculture encourages and enhances biological cycles within the farming system; maintains and increases long-term fertility in soils and minimizes all forms of pollution (IFOAM 1998). It is generally recognized that the most important environmental factor that is causing climate change is the production of green house gases (GHG), particularly carbon dioxide, methane and nitrous oxide. Agriculture is the main contributor of methane and nitrous oxide, and to a lesser extent of carbon dioxide (IGBP, 1998). Organic agriculture is often equated with the use of organic fertilization techniques - systematic application of manure and compost from animal and crop residues, crop-legume rotations, green manuring with legumes, and agro-forestry with multipurpose leguminous trees (Franzlubbers, 2004). Much expertise has been developed in these techniques and the use of these practices has produced outstanding improvements to productivity and environmental health. 8.5. Carbon Management Approaches

Maximizing C input to the terrestrial biosphere from the atmosphere is possible in agricultural systems (Lal et al., 1998) through a variety of management options, including: i) plantation, ii) tillage management, iii) fertilizer management, iv) integrated management, v) minimizing C loss on C sequestration, vi) reducing soil disturbance by less intensive tillage and erosion control, vii) maintaining surface residue cover to increase plant water use and production and viii) surface residue cover promotes greater stabilization of soil aggregates and resistance of soil organic C to decomposition.

If the current momentum for expansion of the organic sector in agricultural production can be maintained, it will also bring environmental benefits and significantly contribute to reducing emissions of green house gases and to preventing further land degradation in the region. The availability of huge amount of biomass may be the only problem in expansion of organic farming.


Management Approaches It is the technique for efficient utilization of the soil through an agricultural system

that protects soil against physical and chemical degradation. This protection is a function of all the factors such as slope, initial acidity, morphological and chemical properties of the soil, and ragouts of the climates.

Principles of Soil Conservation from Water Erosion Many practices have been developed to reduce soil erosion by water erosion. Not all

practices are applicable in all regions. However, the principles are same everywhere. These principles are: i) reduce raindrop impact on the soil, ii) reduce runoff volume and velocity of water and iii) increase the soil’s resistance to erosion.

Principles of Soil Conservation from Wind Erosion Many practices have been developed to reduce soil erosion by wind erosion. These

principles are ; i) reduce wind velocity near the ground level below the threshold velocity that will initiate soil movement, ii) remove the abrasive material from the wind stream and iii) reduce the erodibility of the soil.

The purpose and use of various conservation techniques can be described under the widely accepted headings of agronomic or biological measures, soil management, and mechanical methods. Agronomic/biological measures utilize role of vegetation to minimize erosion. Soil management concerned with preparation of soil to improve structure and promote vegetation which will ultimately reduce erosion. Mechanical or physical methods manipulate topography, reduce slope length by structure and thus reduce erosion.

Conservation versus Reclamation Conservation implies continued good management of preferred land uses.

Reclamation of severely degraded land implies drastic costly action. Usually, including remedial changes in land use, soil amelioration and construction of specialized works need to be done. Soil conservation techniques that ensure prevention of damage to the land should be applied in every situation, but reclamation of seriously degraded land should only be attempted when there are compelling reasons to do so.

Planning a Soil Conservation Strategy The success of conservation schemes depends on:

i) how well the nature of the erosion problem has been identified; ii) the suitability of the conservation measures selected to deal with the problem; and iii) the willingness of the farmers to implement the proposed agricultural or land use

system.

9. Land Resources Conservation Strategy The major reasons of land degradation in Bangladesh are human interference and

water-related activities on the land especially in intensive agricultural areas. Considering


the major reasons of land degradation, the following conservation strategies are outlined below: i. In Bangladesh there are many uses of land and there are many misuses and abuses of

land also. That is why there should be a land use policy which comprise of land zoning as per land suitability, proportionate and equitable distribution and protection of land from misuse and abuse.

ii. An effective policy should be framed for the disposition and utilization of fragile newly accreted land in the estuary.

iii. People’s participation needs to be ensured in land resources conservation creating awareness through mass media and other means.

iv. Prioritization in land management research through NARS institute of Bangladesh for sustainable land resources conservation.

v. Institutional facilities need to be developed for effective land resources, land utilization and soil conservation programmes.

10. Combating Land Degradation and Appropriate Cropping • Adjustments in cropping patterns either through rice or jute based cropping patterns

incorporating legume/green-manuring crops and grain-legume crops to improve soil health and status of soil-organic matter and promoting crop diversification.

• Inclusions of Modern Crop Varieties are to be adopted to promote biodiversity as well as for conservation of local germ plasm.

• Land degradation is to be managed for safe environment and sustainable crop production. More attention is needed for the following aspects:

10.1. Research Survey of the present state of degradation, cropping and land capability and

assessment of the severity and extent of the problem. Monitoring of change (both physical and chemical) in soil characteristics. Conduct long term soil fertility researches. Develop practical methods of improving and maintaining soil organic matter status. Research on the underlying causes of degradation, and the integration of land

resource management with wider aspects of population policy. Restoration of degraded land and appropriate crop planning. Reclamation of saline soils and introduction of salt tolerant crop varieties. Soil conservation and watershed management

10.2. Extension Balanced use of chemical fertilizers and adoption of IPNS (Integrated Plant

Nutrition System) Encouragement of organic recycling to maintain soil organic matter and soil health.


Introduction of GM/Grain legumes in the pattern and use of bio-fertilizers in legumes Creation of mass awareness about soil degradation and appropriate cropping Planted withdrawal of ground water to avoid over exploitation Afforestation and development of agro-forestry including applications for

conservation. Mangrove plantation in the coastal and offshore islands in order to create wind-break

against ravaging cyclones and tidal surges

10.3. Policy Options Comprehensive land use policy and its strict adherence Policy framework in line of international/regional agreements on deforestation and

water sharing Development of sustainable long-term and environmentally sound site-specific

production plan for optimum utilization of land, soil and water resources Ensure effective participation of the people

11. Conclusion Land degradation is a threat to natural resources with consequences on food security,

poverty and environment stability. The increase in temperature will create an impact on land degradation processes, including floods, mass movements, soil erosion, salinization, water logging and carbon sequestration in all parts of the globe. It is essential to improve the monitoring of land degradation as well as climate change. Innovative and adaptive land management responses to inherent climatic variability and natural hazards must be identified for sustainable land management. Land degradation typically occurs because of land management practices or intervention that is not sustainable over a period of time. An increase of CO2 will cause an increase in temperature and increased land degradation due to increase in frequency and intensity of severe weather and extreme climatic events (floods & droughts). Global warming and climate change have detrimental impact on soil fertility and crop productivity. Soil organic matter is decreasing due to rise of soil temperature.

Extent and severity of natural disaster like flood, drought, cyclone and tidal surges will be more in the coming years. Increased drought and salinity, prolonged inundation and excessive soil erosion will reduce the crop area and yield. Appropriate crop management practices should be followed in the affected areas. Selection of appropriate crop species/variety should be chosen for specific area. Increased land degradation will lead to reduced retention of soil moisture and increased soil erosion, and hence desert encroachment. The information on land degradation must be applied in developing sustainable practices to land degradation. Many things are common in South Asian countries. There should be some joint program to combat land degradation. All the countries will be mutually benefited if sharing of knowledge, joint pilot program, information and exchange visit of scientist of South Asian countries are made possible. It is the high time to exchange views and share ideas with the SAARC countries and work together to save the man kind from the devastating effect of land degradation and its consequences.


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issue of cost vs. carbon benefit . Biomass Bioenerg 27:41-55. Blaikie, P. and Brookfield, H. 1987. Land Degradation and Society. Methuen London and New

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58 Strategies for Arresting Land Degradation in Bhutan

C o n t e n t Page 1. Introduction 59 2. Land degradation - a global issue 60 3. Land degradation in Bhutan - a natural and man-made process 60 4. Status of land degradation 61 5. Types of land degradation 62 6. Factors contributing to land degradation 63

6.1. Unsustainable Agriculture 63 6.2. Forest degradation 63 6.3. Forest harvesting 63 6.4. Forest Fires 64 6.5. Livestock Rearing and Grazing 64 6.6. Land use intensification and competition 64 6.7. Mining and quarrying 65 6.8. Infrastructure development 65 6.9. Policy gaps 66

7. Current Strategies to address land degradation 66 7.1. Overall policy support 66 7.2 Institutional setting for land and environmental management 67 7.3 Bhutan – party to the United Nations Convention to 67 Combat Desertification (UNCCD) 7.4 Sustainable Land Management (SLM) Projects 68 7.5 National Action Program (NAP) 68 7.6 Land Management Campaign (LMC) 69 7.7 National Land Management Coordination Committee (NLMCC) 69 7.8 Other programs to strengthen SLM to combat land degradation 69

8. Conclusion 71 9. References 73

Strategies for Arresting Land Degradation in Bhutan 59

1. Introduction The Kingdom of Bhutan lies on the steep, long and complex southern slopes of the

eastern Himalayas (latitudes 26o47’N to 28o26’N and longitudes 88o52’E to 92o03’E, landlocked between China to the north and India to the south. It has a geographical area of 38,394 km2 and stretches roughly 300 km east to west and 170 km north to south. The country is mostly mountainous and the elevation ranges from about 150 m asl in the south to over 7,550 m asl in the north, resulting in extreme variation in climate, vegetation, landscape and soils.

The country can be divided into three distinct climatic zones corresponding to three main geographical regions, namely, the southern foothills, inner Himalayas, and higher Himalayas. The southern belt has a hot humid climate with temperatures remaining fairly constant throughout the year, between 150C and 300C and rainfall ranging between 2,500 and 5,500 mm. The central inner Himalayas have a cool, temperate climate with average rainfall of about 1,000 mm and a mean annual temperature of about 15oC. The higher northern region has an alpine climate with annual rainfall around 400 mm and 2 to 6 months of frost per year. Much of the rainfall is concentrated in the summer with the southwest monsoon accounting for 60 percent of the total rainfall.

About 72.5 percent of the land is under forest cover, 7.8 percent is arable land, 3.9 percent of pasture or meadows, 0.1 percent each under horticulture and settlement and the remaining areas are permanent snow, barren rocks and scrubland. Out of the total cultivable land, 17.7 percent is wetland, 76.4 percent is dryland, 5.8 percent is orchard and the rest constitutes pangshin and kitchen garden (Table 1 & 2). The total population of the country in 2005 was 634,982. The urban population consisted of 31 percent while 69 percent were in the rural areas. The population for 2008 was projected at 683,407 (Statistical Yearbook of Bhutan 2008). The population density of 16 persons/km2 is one of the lowest in the world. The annual rate of population growth is estimated at 2.5 percent.

Agriculture is the mainstay of the Bhutanese economy contributing 22 percent to the GDP (Poverty Analysis Report 2007). While about 69 percent of the Bhutanese are still dependent on land-based income or on complete subsistence farming, Bhutan has limited resources of productive land because of its rugged terrain and steep slopes. On an average, each household has about 3.5 acres of arable land but more than 60 percent of the total households have less than 3 acres.

Table 1: Land use of Bhutan Land use Percentage of area (%)

Forest Cover 1. Parks and wildlife sanctuary 2. Biological corridors

72.5 40.2 9.5

Pasture 3.9 Horticulture 0.1 Agricultural land 7.7 Settlement 0.1 Others 15.7

Source: Facts and figures of RNR Sector 2003 & RNR Compendium 2008


Table 2: Distribution of land under Arable Agriculture

Classification Percent Area (acre)

Wetland (irrigated) 17.7 68,382

Dryland (rainfed) 76.5 2,95,252

Orchard 5.8 22,570

Total 100 3,86,204

Source: Statistical Yearbook of Bhutan, 2008

2. Land degradation - a global issue Land degradation is defined as “the aggregate diminution of the productive potential

of the land, including its major uses (rain-fed, arable, irrigated, rangeland, forest), its farming systems (e.g. smallholder subsistence) and its value as an economic resource”. It is seen as a major environment and sustainable development issue across many countries around the world. Its connection to rural poverty, livelihood and climate change are well observed phenomena. The global recognition of this important issue has led to signing of important protocols and conventions. The United Nation Convention to Combat Desertification (UNCCD) was adopted in June 1994 and as of July 2008, 193 countries had become party to this international treaty. Realizing the benefit and the need to join UNCCD, the 81st National Assembly session in August 2003 ratified Bhutan’s membership to the Convention with the aim to combat land degradation.

3. Land degradation in Bhutan - a natural and man-made process Land degradation in Bhutan is a natural phenomenon as well as man-made. In the

dynamic mountain setting of Bhutan, land degradation is a natural and inevitable process. Mass movements, floods and soil erosion occur & driving for gravity are water on steep mountain slopes with complex geology and geomorphology. As in most parts of the relatively young Himalayan mountains, much of the landscape of Bhutan is only quasi stable, and needs only a small trigger to destabilize it from its equilibrium state and for its surface materials to slip down slope and eventually be washed downstream. Therefore, the natural events, waiting to happen, can easily be triggered off by human activities (Chenccho et al., 2003).

The natural process of land degradation is further compounded and accelerated by anthropogenic factors such as unsustainable agriculture practices, deforestation, forest fires, overgrazing, infrastructure development, urbanization and mining. These practices have resulted in the loss of soil and land productivity through erosion and for some households, the land holding sizes have reduced due to mass movements and severe erosion. Further, the limited land resource is constantly competing for, especially between agriculture and fast growing urban areas. The rural-urban migration resulting in increasing fallow land is also reducing the total area of arable land under production. In the absence of regular management and maintenance, land left fallow is susceptible to


degradation through exposure to various forms of erosion. The land fragmentation mainly due to split inheritance among families result in unsustainable intensification of both land and land based resources.

In Bhutan, land degradation occurs mostly in eastern and southern regions. These areas constitute over 70 percent of the country’s arable land with more dryland cultivation on steep slopes in the east and high monsoon rainfall intensity in the south, combined with relatively higher population density. Across the country, the arable land mostly located on steep slopes is often cultivated without any soil conservation measures and hence surface runoff carrying fertile topsoil is a common farming problem throughout the country. Landslides along roads, gullies along water courses, increased stoniness and shallow soil depths, decline in soil fertility in the farmers’ fields and hydropower plant siltation are some visible signs of land degradation.

4. Status of land degradation Land degradation in Bhutan is not well documented. Information on land degradation

aspects such as the cause, extent, trends, and other related issues such as the economic and social implications of land degradation is scarce and sketchy. However, while no definitive figures are available, there are sufficient physical evidences of various forms of land degradation taking place. FAO/AGL, 2005 provides some rough estimates on the extent and severity of land degradation in Bhutan. It is estimated that about 8.39 percent or 3,365 km2 of the country’s land is degraded with varying degrees of intensities. While 1.69 percent and 4.15 percent are degraded lightly and moderately, respectively, about 2.54 percent is degraded very severely (Table 3). The extent of degraded land compared to other countries in the region might be relatively small but in the Bhutanese context this is significant as it has limited area of arable land. Some of the important and common impacts of the current land use pattern and practices in Bhutan could be summarised as: • Farming on steep slopes resulting in soil erosion and decline in soil/land productivity • Limited arable land is limiting the scope of expansion of agriculture • Deforestation in fragile watershed areas is causing soil erosion and mass movements

resulting in sedimentation downstream • Indiscriminate use of land for urbanization and industrialization leading to the risk of

wasting good arable land • Anthropogenic activities exacerbate the natural degradation processes and accelerate

land degradation.

Table 3: Distribution and Extent of land degradation in Bhutan

Severity Area (km2) Percentage of area Light 680 1.69 Moderate 1,667 4.15 Very Severe 1,018 2.54 Total 3,365 8.39

Source: FAO/AGL, 2005


5. Types of land degradation Four types of land degradation in Bhutan have been listed (Table 4).

Table 4: Types of land degradation processes in Bhutan

In Situ Chemical

In Situ Physical

Water erosion Non-water erosion

Others

Depletion of soil organic matter

Top soil capping

Surface erosion (Splash, Sheet, Rill)

Wind erosion of soil

Tectonic natural hazards (earthquakes)

Depletion of soil nutrients (Nutrient mining)

Sub soil compaction

Piping erosion Wind erosion of ash

Urban & industrial (encroachment, pollution, spoil tipping, riverbed mining)

Soil Acidification

Water logging Gully erosion Cultivation or tillage erosion

Mass movement caused by gravity and slope instability factors

Over fertilization

Ravines Glacial erosion

Flash flooding by GLOF and landslide-dammed lakes outburst floods

Ravines

Bank erosion

Flooding

Water-induced degradation e.g. through soil erosion (splash, sheet and rill erosion), gullies, ravines and flash floods is the most prominent and devastating form of land degradation in the country. This form of degradation has resulted in the decline in soil and land productivity through the removal of fertile top soils or loss of land physically through concentrated erosion in rills, gullies and ravines. Mass movements, triggered by gravity, acts as the second main degradation process in the Bhutan Himalayas, through landslides (fall, slide and flows processes). In many parts of the country, water induced degradation is mainly caused by poor management of water often at the tail end of irrigated rice fields. Wind induced degradation is also extensive especially when the fields are kept bare. Although it is difficult to quantify, this form of degradation is assessed as being quite substantial and contribute to reduction in soil fertility status through the removal of the fertile topsoil (SFU, 2005). Deep (up to 2m) aeolian deposits are seen at many places between 2500 to 3500 m asl. (SSU, 2000) indicating some extent of wind erosion.

In-situ chemical degradation, such as depletion of soil organic matter and nutrient mining, and in-situ physical degradation, such as topsoil capping and subsoil compaction are observed throughout Bhutan. These are some concealed but important forms of land degradation contributing to the reduction of land productivity and crop yields.


Other land degradation processes such as the cultivation or tillage erosion is predominant especially in steep dryland cultivation of maize in Eastern Bhutan and potatoes in West-central regions. River or stream bank erosion and flash flooding are extensive in the low lying areas of southern Bhutan and usually concentrated in productive valleys. Salinization and waterlogging occur in pockets only, no reliable data for which are available. Urban and industrial related degradation processes are more severe is fast growing areas.

6. Factors contributing to land degradation 6.1. Unsustainable Agriculture

On the rugged and steep slopes, the proportion of agricultural land on slopes between 50-100 percent is about 29.4 percent and about 1.6. percent is on slopes greater than 100 percent. Cultivation in most cases is practised without proper soil and water management measures. Improper management of irrigated paddy fields on steep slopes, shortening of fallow period of tseri (slash and burn), burning crop residues, and lack of cover crop establishment when necessary contribute to land degradation in numerous places. Further, intensification of agricultural production as farmers move from traditional subsistence farming to market based farming, introduction of high yielding improved crop varieties and increased use of inputs especially of chemical pesticides and fertilizers have added to the problem. With rising population, the land is increasingly used more intensively to meet the food demand and under such condition, the imbalanced use of inorganic fertilizers and nutrient mining are the main contributing factors to land degradation.

6.2. Forest degradation Loss of vegetation due to pressure on forests, which occupy about 70% of the total

land area, is one of the main factors of land degradation. Over harvesting of the trees beyond permissible limits, unsustainable fuel wood extraction, shifting cultivation, encroachment into forest land, leaf litter extraction, forest fires and overgrazing are the main factors leading to forest degradation.

6.3. Forest harvesting To meet the demands for timber and fuel wood of the rapidly growing Bhutanese

population, the forest is increasingly being harvested in an unsustainable manner. The Department of Forest and the Natural Resources Development Corporation Limited (NRDCL) are supplying 284,800 m3 of wood annually. However, the estimated wood demand is about 769,000 m3 per year, indicating a huge demand against the allowable supply and one of the highest consumption rate per capita in the world. The excess demand is somehow met from adhoc sources operated often without following the sustainable forest management planning or system (mainly from rural timber allowances brought into urban areas). Such unplanned extraction of wood from forests leads to excessive extraction causing forest degradation.


6.4. Forest Fires Occurrence of frequent forest fires has been a major cause of degradation in many

parts of the country especially in the eastern region. Nearly half of the forest area burnt between 1999/00-2006/07 in this region. Between 1992/93 and 2004/05, the Department of Forest recorded 870 incidents of forest fires, affecting more than 128,000 hectares of forest land. Between 1999/2000 and 2006/07, 476 incidents of forest fires were recorded, affecting about 65,000 hectares of forest. Most forest fires are deliberate or man-made to invigorate the growth of pasture or commercially valuable grasses such as lemon grass, or sometimes due to general public carelessness. However, the formulation of more stringent legislation and vigorous public awareness programmes and campaigns have helped in reducing forest fire incidents and area burnt in recent years.

Apart from the destruction of vegetation, high intensity forest fires alter the physical, chemical and biological attributes of the soil and leave the land prone to wind and water erosion and also lower its productivity. Surface erosion often increases dramatically from severely burnt forest areas in the initial year after a fire. Forest fires are concentrated in the dry winter season.

6.5. Livestock Rearing and Grazing Livestock rearing, especially of cattle, is an important activity among the rural

communities, particularly in the temperate and subtropical regions of the country. Almost every household rear a certain number of cattle mainly for dairy products, meat, draught power and production of dung and urine for farmyard manure. In the alpine and subalpine regions, the rural semi-nomadic communities subsist largely on yak-herding. Yaks are reared for dairy products, meat and transportation. Cattle population has increased from 320,509 in 2000 to 338,847 in 2005 and yak population from 34,928 to 45,538 during the same period. Based on 1,737 km2 of pasture land in the country, the density of animal (cattle and yak) per km2 of pasture land is 221. Grazing of this huge number, far beyond the carrying capacity may lead to decline in plant species, land productivity and soil erosion. With limited pasture land and land holding size of rural households, grazing is usually on forest land and where grazing is extensive, forest regeneration is hampered and change in vegetation induced. Severe forest degradation and land degradation is reported from those areas that are commonly used for winter grazing by yak and summer grazing by low land cattle.

6.6. Land use intensification and competition With rapidly increasing population and socio-economic development, the limited

land resource is increasingly being competed for by various sectors, especially between agriculture and urban development. Conversion of agricultural and forest land is occurring each year to accommodate various development activities. These conversions often take place with very little or no consideration of the land capability or suitability. Between 1998 and 2007, about 161 hectares of prime agricultural land have been converted to other forms of land use (Fig.1). Between 2003 and 2006, more than 3,600


hectares of forest land have been cleared for various infrastructure development activities such as roads and power transmission lines. Further, as most of the land area suitable for agriculture has already been utilized, marginal land areas are being brought under cultivation to meet the food demand of the increasing population. At the same time, a lot of land is being left fallow because of rural-urban migration, labour shortages, and lack of irrigation facilities or assured irrigation water sources.

6.7. Mining and quarrying Mining and quarrying in Bhutan are not very extensive and are operated mainly to

meet the domestic demand and for nearby markets in India and Bangladesh (marble, gypsum, talc). Mines are located in few districts only and there are strict guidelines for their operation. All mines are required to prepare a mine feasibility report along with an environmental management plan before its operation is approved. Mining, however, has been known to contribute to land degradation wherever it is being practised. The very nature of the operation requires the disturbance of the soil and vegetation, and hence soil erosion and siltation down slope are inevitable. As Bhutan has significant deposits of a number of mineral resources such as limestone, coal, graphite, gypsum, slate and dolomite, mining would become extensive in the coming years. As of October 2007, there were 60 mines and quarries operating in the country.

6.8. Infrastructure development With rapidly increasing population and modernization, the need for infrastructure

development has grown. Among others, roads and electrification are the two major areas of infrastructure development being spread out rapidly and widely across the country. The road network increased from 3,215 km in 2001 to 4,349 km in 2007. With the establishment of several hydro power plants, the electrification programme targets to electrify most rural areas of the country and hence an extensive network of power transmission grids is being constructed across the country. While the development of such infrastructure is inevitable and necessary, on a rugged terrain with fragile geologic conditions it is environmentally challenging. Infrastructure development could leave adverse impacts on landscapes through loss of vegetation, landslides and landslips due to slope instability or geologic disturbances. Clearing of vegetation along transmission lines and road corridors and road cuttings along steep and unstable slopes lead to a whole range of land degradation processes. Road development and in particular farm road construction, with less scope for mitigation works, are main causes of anthropogenic land degradation. Efforts have been undertaken to develop an environmental friendly road construction (EFRC) methodology, but cost concerns have prohibited a general implementation of these guidelines.


Power transmission line

50.8% Government building

19.7%

Road 29.5%

Fig. 1: Types of forest land conversion by percentage, 2003-2006

6.9. Policy gaps Besides the very obvious aforesaid, natural and anthropogenic factors contributing to

land degradation, there are certain policy gaps in addressing land degradation. According to Bhutan: State of the Environment 2000, the policy gaps encompass the following: • Absence of a well defined land and land use polices, leading to haphazard and

unsustainable use of land; • Absence of adequate land suitability and capability information, leading to improper

use of the limited land resource; • Lack of adequate inter-sectoral linkages to decide policies, strategies and practices

for resource conservation and their sustainable utilization; • Lack of adequate focus on a combined land and water (inter-dependent resources)

management strategy to make effective development plans; and • Lack of proper assessment and understanding of linkages between poverty and

sustainable land management.

7. Current Strategies to address land degradation 7.1. Overall policy support

Although there are policy gaps in addressing land degradation problems directly or specifically, policy support towards the environment protection in general are being strengthened rapidly. Bhutan’s Vision 2020 document emphasizes ecologically sensitive approaches to its natural resources such as forest management. Bhutan’s constitution requires a minimum of 60% of the land under forest cover, always. As Bhutan’s development process is guided by the philosophy of “Gross National Happiness’ (GNH), the non-material aspects of development is considered equally if not more important than the gross national product. The conservation of environment is one the four pillars of GNH, the other three being (i) equitable socio-economic development, (ii) preservation and promotion of culture and (iii) promotion of good governance. Under the overall umbrella of the “Conservation of Environment” pillar, protection of land from degradation would also feature as an important area.

Bhutan’s development programs and activities are implemented through FYPs and the current Tenth FYP document addresses environment as a cross cutting theme.


Sustainable land management has been mainstreamed in the Tenth FYP though in a sectoral manner. As compared to the past FYPs, the current Tenth FYP has more SLM elements.

Preparation and finalization of policies, strategies such as the land policy, land rules and regulations, water act, and wetland protection framework are all underway that would protect the land directly or indirectly from degradation. Within the Land Act 2007 of Bhutan, there are provisions for land allotment and land swapping with government reserved forest (GRF) land. With susceptibility to land degradation as one of the criteria, one can qualify for land swapping with GRF or for resettlement to a better land.

7.2 Institutional setting for land and environmental management The National Environment Commission (NEC) is the overall environmental advisor

to the Royal Government of Bhutan (RGoB). It prepares environmental legislation, oversees compliance monitoring of the Environmental Assessment Act, and associated regulations and guidelines. It coordinates the implementation of the National Environment Strategy and national obligations to international environmental conventions. The National Land Commission (NLC) is an independent authority and the highest decision making body to exercise the jurisdiction and powers and discharge the functions conferred by the Land Act of Bhutan. It lays down the policies, programmes, regulations and guidelines related to land. Land acquisition, allotment, compensation and conversion are also guided by the NLC.

7.3 Bhutan – party to the United Nations Convention to Combat Desertification (UNCCD)

As in many countries around the world, land degradation is also seen as a major environment and sustainable development issue in Bhutan. Its connection to rural poverty, livelihood and climate change is a fairly well understood subject in the country, especially with various studies being conducted on land degradation and its linkages to other areas like poverty and environment. Recognizing this as an important issue, Bhutan joined the UNCCD after ratifying it during the 81st National Assembly session in 2003. As of July 2008, Bhutan is one of the 193 countries party to this international treaty.

The National Soil Services Centre (NSSC) of the Ministry of Agriculture and Forests (MoAF) is the national focal agency for the UNCCD. The NSSC with its four units – Soil Survey Unit, Soil Fertility Unit, Soil Microbiology Unit, and Soil and Plant Analytical Laboratory (SPAL) has the mandate to coordinate land and soil management research activities of the Renewable Natural Resources (RNR) sector and provide analytical services. It functions as a referral agency for soil survey, soil and plant analysis, soil fertility management and other soil related programs and projects. In addition, as the UNCCD focal agency, it is also required to shoulder the responsibilities of combating land degradation. The Centre manages two Sustainable Land Management Projects through a multi-sectoral approach involving stakeholders at various levels (national, district and local). The Centre coordinates and provides core technical advisory services to all land management programs and activities in the country.


7.4 Sustainable Land Management (SLM) Projects The NSSC executes two Global Environment Facility (GEF) funded SLM projects.

The projects are expected to put in place more permanent and workable strategies to address land degradation problems in the country. The objective of these projects is to strengthen institutional and community capacity for anticipating and managing land degradation through enhancement of human resource capacity, policies, incentives, technologies and knowledge for better management of land resources in the country. On the whole, the projects aim to mainstream SLM in government policies and plans for greater political and community support in combating land degradation. 7.4.1 SLM planning tools

In order to implement sustainable land management programs and projects effectively, an effective participatory SLM planning method has been developed and implemented successfully in the field. Unlike other planning processes, SLM planning is a complete participatory planning at a community level and it is found to be very effective. The SLM planning process makes use of tools like satellite images, participatory natural resource maps, sketches, group discussions to help farmers come up with simple, realistic, achievable plans. These SLM action plans contain prioritized SLM interventions based on ranked land-based problems and identified causes of these problems. A simple manual on participatory SLM planning has been prepared and a separate manual for participatory natural resource mapping for SLM planning is being prepared.

7.5 National Action Program (NAP) As a member country to UNCCD, Bhutan has developed a National Action Program

(NAP) for land degradation along with an Integrated Financing Strategy (IFS) to help implement the NAP and secure funding. The overall goal of the NAP is to “prevent and mitigate land degradation and its impacts through systems and practices of sustainable land management that protects and maintains the economic, ecological and aesthetic values of our landscapes.” The overall goal will be pursued through the following set of objectives: (a) conservation, rehabilitation and sustainable use of forest resources to maintain well functioning forest landscapes; (b) development and promotion of sustainable agricultural practices that enhances local livelihoods whilst maintaining the productivity and stability of agricultural land; (c) integration of environmental management measures in development activities that pose significant risks of land degradation; (d) strengthening of systemic and institutional capacity to combat land degradation and its impacts; and (e)information, advocacy and education to create increased policy and public support for sustainable land management. The NAP analyses the current policies and legislations of various organizations in relation to land degradation and sustainable land management. It recommends approaches in addressing land degradation issues in the country. This document will be a living document, updated regularly based on the changing scenarios and will be the guiding document for the country to deal with land degradation issues. The Integrated Financing Strategy identifies the three possible sources of financing, i.e. internal, external and innovative, to help in implementing the NAP.


7.6 Land Management Campaign (LMC) With the calamitous impacts of land degradation becoming more and more visible

over the years, the Ministry of Agriculture and Forests initiated a national level land management campaign (LMC) in 2005 and since then this has become an annual event. The campaigns are conducted with the following objectives: a. To create awareness on the importance of protecting land resources in a community

living in a fragile ecosystem b. To be able to understand what are the anthropogenic factors responsible for land

degradation and soil erosions in particular c. To introduce improved land management technologies that would include,

agronomic, vegetative and structural measures; d. To mainstream land management activities into the regular institutional plans at all

levels (community, regional and national)

Thus, once a year event, seeks the participation of farmers, community leaders, students, teachers, civil servants, non-governmental organizations, private entrepreneurs and donors. Involvement of people from almost all occupations contributes to enhanced awareness and mainstreaming of SLM. The campaign involves live demonstration of various land management technologies on both private and government land. The campaign sites are maintained, monitored and evaluated to see the impacts.

7.7 National Land Management Coordination Committee (NLMCC) A National Land Management Coordination Committee (NLMCC) was established

in 2005 to support, oversee and coordinate land management activities at the national level. The functions of the NLMCC has been awareness creation by mobilizing relevant stakeholders particularly the local people in the implementation of land management campaigns in the country. The NLMCC is represented by all relevant agencies within the Ministry of Agriculture. As land degradation is an issue which cuts across various sectors dealing with land, there is a need to establish a multi-sectoral land management coordinating body in the country.

7.8 Other programs to strengthen SLM to combat land degradation Programs to strengthen SLM directly or indirectly includes the following:

(Mainstreaming of SLM, 2008): • Establishment of the National Organic Program (NOP) within the Ministry of

Agriculture and Forests (MoAF) with the aim to work towards the development and/or exploration of more scientific methods of organic farming and promoting them among the farmers.

• Soil fertility and land management program of MoAF aims to create and strengthen data and information for SLM decision-making and mainstreaming into development policies and plans, develop and I mplement SLM practices in the field and develop the capacity of local communities for SLM.


• Feed and fodder development promotes better pasture management on both government and private land and help frame and implement national pasture land and grazing management policies and strategies.

• Promotion of environment-friendly construction techniques and improvement of national highways, feeder roads and farm roads.

• Capacity enhancement in Geo-scientific investigation and mineral development program under the Ministry of Economic Affairs (MoEA) such as systematic mapping, digital creation of database on geology, geomorphology, hydrogeology and lithology and studies on slope stability, landslide mapping and geo-hazard assessment which could enhance SLM.

• Assessment and monitoring of climate change induced geological hazard program under MoEA that focuses on time-series monitoring of glaciers and glacial lakes, implementation of mitigation measures against glacial lake outburst floods, and seismic risk assessment.

• Development and sustainable management of forests through community participation program of MoAF includes activities such as community and private forest management, watershed management, soil conservation, and creation of forest plantation and nurseries.

• Forest resources development and management program of MoAF includes activities such as creation of Forest management Unit (FMU), inventories of FMUs, development of management plans for sustainable use of timber and other forest resources and restocking of forests in the FMUs.

• Forest protection and utilization program of MoAF protects forests from encroachment and illegal use, and promoting the utilization of forest resources for socio-economic development based on sustainable practices.

• Nature conservation program of MoAF focuses on establishment and management of protected areas and biological corridors.

• Conservation of environment program of NEC which focuses on mainstreaming environmental conservation needs in development plans and programs through environment impact assessment (EIA) and strategic environment assessment (SEA) processes, developing environmental legislations, guidelines and standards, strengthening of environmental information, monitoring and reporting systems (State of Environment, Bhutan, 2001).

• The National Land Commission’s cadastral surveying and mapping is being conducted across country in accordance with the relevant policy and legislative framework provided by the Land Acts (1979 and 2007) of Bhutan. This would provide accurate information on household land holding sizes and land use categories for informed planning and decision making;

• Land cover data and maps being updated for better information on land use types and coverage in the country;


• A Dynamic Information Framework (DrukDIF), is being developed, a simulation model with time series data set (biodiversity, land cover, land use, & hydrology) with climatic data to predict scenarios and develop appropriate interventions; and,

• Curriculum on SLM for the non-formal education system developed with the aim to develop it further and incorporate into the formal education system, later on.

8. Conclusion Land degradation in Bhutan constitutes a serious challenge. The dynamic and often

extreme Himalayan landscape, with its steep and long slopes, inherently is prone to natural degradation processes. Loss of agricultural land and decline in productivity through degradation are serious constraints for the almost 70% of the Bhutanese who are dependent on land for their subsistence and livelihoods. Since only 8% of the country’s total land area is arable, any further loss of land or decrease in productivity would have serious implications.

Land degradation is dominated by water as a degrading agent through surface erosion (splash, sheet and rill), gully formation, bank erosion and (flash) flooding. Mass movement driven by gravity is a secondary, but often very destructive process, often interacting closely with water-induced degradation. Other land degradation processes identified are in-situ chemical and physical degradation, wind and glacial erosion, seismic events, flash flooding by GLOF and landslide-dammed lake outburst floods and cultivation or tillage erosion on the steep Bhutanese slopes. Anthropogenic activities, closely related to the strong growth in developmental activities over the last decades, such as road construction and urban growth, have exacerbated and accelerated the existing natural land degradation processes.

A number of factors that contributes to land degradation in Bhutan are: • Unsustainable agriculture as a result of cultivation on steep slopes without proper

water and soil conservation measures, poor water management of irrigated paddy land, imbalanced use of fertilizers leading to nutrient mining, and persistent slash and burn activities resulting in depletion of organic matter and soil erosion.

• Deforestation, unsustainable management (excessive harvesting of timber and fire wood) encroachment by developmental activities, overgrazing and forest fires are resulting in land degradation.

• Increase of cattle and yak population has led to an increased pressure on grazing land (both pastures and forest areas). Forest and pasture degradation deserve serious attention as livestock rearing is an important source of livelihood for many rural households.

• Rapid socio-economic development has resulted in an increased “scramble” for land with various stakeholders competing for land. As a result prime forests and productive agricultural land have been converted for other usages. This process would indirectly lead to more intense use of the limited arable land. This is accompanied by agriculture that becomes more oriented towards cash crops and higher yields with the risk of developing a trend towards unsustainable use of land.


• Mining activity in the country has increased drastically. This has led to severe environmental impacts on and off site, although the total area under mining is relatively limited.

• Infrastructure development along the fragile slopes of Bhutan has led to acceleration of land degradation processes. The strong policy focus on rural access has resulted in a fast extension of the road networks, both feeder and farm roads. Road cuts induce a range of slope instability problems and are an important cause of land degradation in Bhutan. The process of rural electrification has seen a rapid increase of power and transmission lines with negative impact on forest cover and related land degradation along clear cut corridors.

The above mentioned factors contributing to land degradation should be tackled by a comprehensive and targeted government policy to reduce the impact of these factors and to screen and formulate policies that have less impact on the land. At present policy gaps exist and there is a need to improve policies to address land degradation more comprehensively.

The Royal Government of Bhutan is addressing land degradation through different initiatives, policies and institutions. After disastrous floods and landslides in the monsoon season of 2004 the Ministry of Agriculture and Forests started Land Management Campaigns to create awareness, introduce SLM interventions and mainstream SLM activities at all levels of government. A separate National Land Management Committee was established to support, oversee and coordinate land management campaigns. As party to the UNCCD, Bhutan has recognized the serious implication that land degradation has on sustainable development. The National Soil Services Centre under the department of Agriculture is the national focal agency for UNCCD and has the mandate to coordinate land and soil management research. The Centre is the host to two GEF funded SLM projects focusing on strengthening institutional and community capacity to anticipate and address land degradation. The projects have developed participatory tools to identify and map land-based problems and to prioritize, at grass-root level, SLM interventions to mitigate land degradation (as a member country of UNCCD), a National Action Plan for land degradation, along with an Integrated Financing Strategy. The NAP will function as a guiding document for the country to deal with land degradation.

In a broader context it is recognized that land degradation affects mostly the rural poor, who depend on access to and use of natural resources for their livelihoods. It is a real challenge to maintain the delicate balance between the needs of the rural communities and sustainable use of natural resources without depletion and accompanied land degradation. To encourage more sustainable land use by the rural communities it is necessary to combine long-term environmental benefits of proper SLM interventions with short-term gains in income and food security. At policy level there is a need for a comprehensive land use and land planning policy to achieve a more balanced and rational land use approach to steer proper land use and to protect the vulnerable land. As there is so little land available for agriculture and economic development, a more balanced land use policy is essential.


Land degradation results in increased sediment transport by the mountain streams of Bhutan posing a risk to turbines and reservoirs of the hydropower installations upon which Bhutan is increasingly dependent. Integrated watershed management to improve sustainable land use and safeguard the natural resources is therefore also an economic imperative.

Furthermore, with only 8% of Bhutan’s total land area identified as arable and almost 70% of its population deriving their livelihood from it, it is felt imperative for the Royal Government to put in place a comprehensive strategy, outlining a well integrated framework, requiring the involvement of all key stakeholders in addressing land degradation issues. Such a strategy will not only ensure the sustainable management of land for safeguarding the livelihood of our rural masses but also prevent degradation of the ecosystem and help maintain a minimum of sixty percent of the country’s total land under forests cover for all times to come, as required by the Constitution of Bhutan.

9. References Bhutan Environment Outlook (2008). National Environment Commission, Royal Government of

Bhutan. Chencho et. al. (2003). Types of Land Degradation in Bhutan. Journal of Bhutan Studies. Centre

for Bhutan Studies. Royal Government of Bhutan. Facts and Figures of RNR Sector (2003). Policy and Planning Division. Ministry of Agriculture.

October 29, 2003. Karma D Dorji (2008) Agriculture and Soil Fertility Management in Bhutan: An Overview. A

country paper presented in the meeting of Asia-Pacific Net on Integrated Plant Nutrient Management (APIPNM) & International Workshop on Sustainable Nutrient Management: Technology & Policy. Shijiazhuang, Hebei, China.

National Action Program (NAP) of Bhutan for Land Degradation (2009). GEF/UNDP Medium Sized Project on Sustainable Land Management. National Soil Services Centre (NSSC), Ministry of Agriculture and Forests. Thimphu, Bhutan.

Poverty Analysis Report (2007). National Statistics Bureau. Royal Government of Bhutan. Review of Mainstreaming of Sustainable Land Management in Government Policies and Plans in Bhutan (October 2008). National Soil Services Centre (NSSC), Department of Agriculture, Ministry of Agriculture and Forests, Ryyal Government of Bhutan.

RNR Compendium 2008. Ministry of Agriculture & Forests. Royal Government of Bhutan. SFU (2005). Report on the long term study on soil fertility trend of the major farming systems in

Bhutan. Report of Soil Fertility Unit, National Soil Fertility Management, Ministry of Agriculture and Forests, Thimphu, Bhutan.

SSU (2000). Technical Report on semi-detailed soil survey of Radhi geog, Trashigang. Report SS7(a), Soil Survey Unit, National Soil Services Centre (NSSC), Ministry of Agriculture and Forests, Thimphu, Bhutan.

State of the Environment-Bhutan (2001). National Environment Commission. Royal Government of Bhutan.

Statistical Yearbook of Bhutan, (November 2008). National Statistics Bureau, Royal Government of Bhutan.

Statistical Yearbook of Bhutan (2007). National Statistics Bureau. Royal Government of Bhutan.


76 Land Degradation: Status, Impact and Strategies in India

C o n t e n t Page 1. Introduction 77 2. Unculturable Wastelands 80 3. Causes 81

3.1. Water Erosion 82 3.2. Wind Erosion 86 3.3. Waterlogging, Salinization and Acidification 87 3.4. Soil Physical Constraints: Compaction and Scaling 91 3.5. Floods and Droughts 92 3.6. Vegetation Degradation 94 3.7. Nutrient Mining 95 3.8. Depletion of Soil Organic Matter 96 3.9. Over Exploitation of Ground Water 98 3.10. Use of Poor Quality Ground Water 101 3.11. Degradation due to Urban and Industrial Wastes and 104

Excessive Use of Agro-Chemicals 3.12. Coastal Erosion 106 3.13. Gullies and Ravines 107 3.14. Mass Erosion Problems 109 3.15. Landslides 109 3.16. Minespoils 110 3.17. Torrents 111

4. Impacts of Land Degradation 111 5. Soil Physical Constraints 115 6. Strategies for Arresting Land Degradation 125 7. References 126

Land Degradation: Status, Impact and Strategies in India 77

1. Introduction Land degradation is a global phenomenon caused by a variety of factors or processes

which include soil erosion by water/wind, deterioration in physical, chemical and biological or economic properties of the soil and long-term loss of natural vegetation. It is estimated that about 2 billion ha area in the world that once was biologically productive is now affected by various forms of land degradation (Oldeman, 1991). About 5-7 million ha of arable land of the world is lost annually through land degradation (Lal and Stewart, 1992). Globally, land degradation affects about one-sixth of the world’s population, 70 percent of all dry lands (about 3.6 billion ha) and one-quarter of the total land area of the world. The continental percentage of land degradation is highest in Asia (37%) followed by Africa (25%), South America (14%), Europe (11%), North America (4%) and Central America (3%), the world total being 15 percent.

In India, the estimates of land degradation by different agencies vary widely from about 53 Mha to 188 Mha, mainly due to different approaches adopted in defining degraded lands and/or differentiating criteria used (Table 1).

Table 1: Estimates of soil degradation in India by various agencies

Agency Estimated area (Mha)

Criteria for delineation

National Commission of Agriculture (1976)

148.09 Based on secondary data collection

Ministry of Agriculture (1978) 175.00 Based on NCA estimates

Society for Promotion of Wastelands Development (1984)

129.58 Based on secondary data collection

National Remote Sensing Agency (1985)

53.28 Mapping on 1:1 million scale based (1980-82) on remote-sensing techniques (**)

Ministry of Agriculture (1985) 173.64 Land degradation statistics for the states (a)

Ministry of Agriculture (1994) 107.43 Elimination of duplication of area at (a) above

NBSS&LUP (1994) 187.70 Mapping 1:4.4 million scale at country level and then deducting at state level based on Global Assessment of Soil Degradation (GLASOD) guidelines

NRSA (2000) 63.85 Based on satellite data (1986-1996)

NRSA (2005) 55.27 Based on satellite data (LISS-III sensor data of 2003)

NBSS&LUP (2005) 146.82 Mapping of all the states at 1:250,000 scale. Global Assessment of Soil Degradation (GLASOD) guidelines


As per estimates of NBSS&LUP, Nagpur employing GLASOD technique, an area of 187.8 Mha is affected by various land degradation problems with water erosion contributing a maximum of 45.3% followed by chemical deterioration (4.2%), wind erosion (4.1%) and physical deterioration (3.5%) (Sehgal and Abrol, 1994). These estimates were revised to 146.8 Mha on 1:250,000 scale in 2005. The National Remote Sensing Agency (NRSA) estimated that 80 Mha out of about 142 Mha under cultivation and 11 Mha of pasture lands are substantially degraded while 40 Mha out of 75 Mha of forest land has a canopy of less than 40%. Thus a total of 131 Mha (40% of country’s total land mass) has productivity well below its actual potential. According to Wasteland Atlas of India (2005) prepared by Ministry of Rural Development using IRS-LISS III data, 55.27 Mha or 17.45% area of the country is degraded (Table 2) (DES, 2007).

Table 2: Degraded lands in India

Type Area (M ha) Gullied lands 1.90

Land with or without scrub 18.80

Waterlogged 0.97

Saline/alkali 1.20

Shifting Cultivation 1.88

Degraded forest and agricultural land under forest 12.66 Degraded pastures/plantation 2.15

Sands 3.40

Mining and industrial wastelands 0.20

Barren/stony/snow covered 12.11

Total 55.27

Realising the need to harmonize the area statistics on land degradation in the country, the National Academy of Agricultural Sciences (NAAS) took a major initiative in 2006 to evolve a consensus among concerned organizations, viz; NBSS&LUP, Nagpur, CS&WCR&TI, Dehradun, CAZRI, Jodhpur, CSSRI, Karnal, FSI, Dehradun and NRSA, Hyderabad by adopting a common methodology and procedure for synthesizing the datasets on land degradation/wastelands. Fig. 1 presents the harmonized area distribution of degraded/wastelands of India on arable and non-arable lands and the statistics is presented in Table 3 (Maji, 2007).


Table 3: Harmonized Area Statistics of Degraded Lands/ Wastelands of India (Mha)

Sl. No.

Type of Degradation Arable land

(in Mha)

Open forest (<40%

Canopy) (in Mha)

Data source

1 Water erosion (>10 t/ha/yr) 73.27 9.30 Soil loss map, CSWCRTI 2. Wind erosion (Aeolian) 12.40 - Wind erosion map, CAZRI Sub total 85.67 9.30

3. Chemical degradation a) Exclusively salt affected

soils 5.44 -

b) Salt-affected and water eroded soils

1.20 0.10

National salt-affected soil map, CSSRI, NBSS&LUP, NRSA and others

c) Exclusively acidic soils (pH< 5.5)#

5.09 - Acid soil map of NBSS&LUP

Fig. 1: Wastelands/land degradation map of India


d) Acidic (pH < 5.5) and water eroded soils #

5.72 7.13

Sub total 17.45 7.23

4. Physical degradation

a) Mining and industrial waste

0.19

b) Water logging (Permanent surface inundation) $

0.88

Wasteland map of NRSA

Sub total 1.07

Total 104.19 16.53

Grand total (Arable land and Open forest) 120.72

Note: Forest Survey of India map (1999) was used to exclude degraded land under dense fores

2. Unculturable Wastelands • Barren rocky/stony waste: 6.46 Mha, They are the source for runoff water and

building material. • Snow covered/ Ice caps: 5.58 Mha, They are the best source of water and cannot be

treated as wastelands. Note: # For acid soils areas under paddy growing and plantation crops were also included in total acids soils $ Sub-surface waterloging was not considered.

As evident from the table, erosion by water constitutes a major form of land degradation (68.4%) followed by chemical degradation (24.68 Mha), wind erosion (12.40 Mha) and physical degradation (1.07 Mha). The area under physical degradation accounts for only waterlogging due to permanent surface inundation and does not include sub-surface waterlogging. Similarly, barren/stony wastes which are the sources of runoff water and building materials and snow covered/ice caps which are the best sources of water availability were not considered as wastelands/degraded lands. For acid soils on arable lands, areas under paddy growing and plantation crops were also included.

The perusal of area statistics on land degradation provided by NBSS&LUP, Nagpur on three different time scales, viz; 1994, 2005 and 2007 indicates that during 1994 and 2005, the affected area reduced by 41 Mha from 187.8 to 146.8 Mha at a rate of 3.7 Mha/year. It has further reduced by 26 Mha to 120.72 Mha as per harmonized data base during 2005 and 2007. It is ascribed to large-scale watershed development programmes undertaken in the country since 1991. The salt affected area which initially increased from 7.0 Mha in 1976 to 11.0 Mha in 1997 due to expansion of canal irrigation system subsequently declined to 6.0 Mha in 2005 due to many soil reclamation schemes in the last decade (Fig. 2).


Fig. 2: Area (M ha) under salt affliction, 1976-2005

The area under waterlogging, shifting cultivation and degraded forest has declined at an average annual rate of 1.79, 4.74 and 3.78%, respectively during 1994 and 2007. The reduction in degraded forest area is attributed to launch of special schemes like Joint Forest Management (JFM) and National Afforestation Programme under Ministry of Environment and Forests and IWDP (Hills) under Ministry of Rural Development of Govt. of India. Though the area degraded due to mining has declined at a rate of 6.9% during 1994 and 2007, no change has been reported in area affected by ravines and gullies during this period. It is envisaged to treat the remaining 53% degraded area by the end of XIIIth Plan.

3. Causes Degradation of land is a consequence of either natural hazards or direct causes or

underlying causes. Natural hazards are the environmental conditions which lead to high susceptibility to erosion such as high intensity storms on steep slopes and soils having less resistance to water erosion, high speed winds, soil fertility decline due to strong leaching in humid climates, acidity or loss of nutrients, waterlogging etc. The direct causes are human induced which result from unsustainable land use and inappropriate land management practices such as deforestation and over-exploitation of vegetation, overgrazing, cultivation on steep slopes and marginal/fragile lands without adoption of soil conservation measures, shifting cultivation, improper crop rotations, imbalanced fertilizer use or excessive use of agro-chemicals, over-exploitation of ground water and improper management of canal water. The underlying causes are the factors indirectly responsible for land degradation such as population pressures, land shortage, tenancy

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rights, economic pressures and poverty. Land shortage and poverty together lead to non-sustainable land management and consequently land degradation.

A study in Western Himalayas indicated that 70% of the rainfed and 41% of the irrigated bench terraces were constructed on land slopes of 51-70% with 10% outward slope and 8% longitudinal slope and a riser batter of 0.5:1 to 0.25:1 thus leading to enormous runoff and soil loss (Juyal, 1987). In mountainous region of Nepal, common specifications are 12% outward slope, 8% longitudinal gradient, 50 m length of bench, vertical interval of 1-3 m with batter of 2:1 to 0.5:1 have been observed. In Bhutan, cultivation on terraces is being practiced on mountain slopes ranging from 25% to 100%. Clearing of vegetation for cultivation purposes on steep slopes and faulty management practices are the major factors contributing to severe land degradation problems in the hilly regions.

3.1. Water Erosion Dhruvanarayana and Ram Babu (1983) estimated that about 5334 million tonnes of

soil is lost annually which is equivalent to 16.35 t/ha/yr. About 10% of the total eroded soil gets deposited in the reservoirs thereby reducing their storage capacity by 1-2% every year. The data on 17 medium and small reservoirs under river valley projects in India have shown that the rate of inflow of sediments is about 3 times (9.17 ha-m/100 km2/year) as compared to the designed rate of 2.93 ha-m/100 km2/year, thus reducing the life expectancy and hydro-electric power generation to one-third of the planned capacity. Of the remaining, 61% is displaced from one place to another while 29% is permanently lost into the sea causing irretrievable loss of the soil resource.

Among different land resource regions, highest erosion rate occurs in the black soil region (23.7 – 112.5 t/ha) followed by Shiwalik region (80 t/ha), north-eastern region with shifting cultivation (27-40 t/ha) and the least in north Himalayan forest region (2.1 t/ha). Singh et al. (1992) reported that annual erosion rates vary from less than 5 t/ha/year for dense forest, snow-clad cold deserts and arid regions of Western Rajasthan to more than 80 t/ha/year in Shiwalik region. Sheet erosion affects red soils comprising alfisols, ultisols and oxidols (4-10 t/ha/year) and black soils constituting vertisols and vertic soils (11-43 t/ha/year). Gully erosion seriously affects hilly areas (> 33 t/ha/year) while hill slope erosion is more than 80 t/ha/year.

Recently, the Central Soil and Water Conservation Research and Training Institute, Dehradun, in collaboration with National Bureau of Soil Survey and Land Use Planning, Nagpur computed the potential erosion rates for different states of the country using 10 km x 10 m grid size data from the parameters of Universal Soil Loss Equation (USLE). Considering 10 t/ha as the permissible soil loss limit (Mandal et al., 2009), the analysis revealed that on the whole, about 39% area in India has potential erosion rate of more than the permissible limit while 11% area falls in very severe category with erosion rate of more than 40 t/ha (Fig. 3).


Fig. 3: Soil loss map of India (water erosion) (>10t/ha/yr)

The states of Nagaland, Meghalaya, Arunachal Pradesh, Assam, Chhatisgarh and Jharkhand have more than 60% of their total geographical area beyond the permissible rate of 10 t/ha. Similarly, more than 40% area in the states of Uttar Pradesh, Uttarakhand, Madhya Pradesh and Manipur is affected by erosion rate exceeding the permissible limit (Table 4) (Anonymous, 2008). About 125 Mha area in the country suffers from water erosion rate of more than 10 t/ha either exclusively or in conjunction with other land degradation problems like salinity, acidity etc.


Table 4: Area (%) affected by potential soil erosion rates in different states of India

TGA Moderate (10-15)

(t/ha/yr)

Moderate Severe (15-20)

(t/ha/yr)

Severe (20-40)

(t/ha/yr)

Very Severe (40-80)

(t/ha/yr)

Extra Severe (>

80) (t/ha/yr)

Total (>10)

(t/ha/yr)Sl. No. State

Area (sq km)

Area (%)

Area (%)

Area (%)

Area (%)

Area (%)

Area (%)

1 Andhra Pradesh 275045 13.16 7.54 12.50 6.53 0.00 39.73

2 Arunachal Pradesh

83743 5.10 5.42 23.65 27.31 11.17 72.65

3 Assam 78438 4.58 18.08 14.83 28.30 -- 65.79 4 Bihar 93979 6.23 3.43 2.73 0.58 -- 12.97 5 Chhattisgarh 134805 7.99 6.45 18.22 13.62 19.02 65.30 6 Delhi 1483 9.18 5.27 6.64 1.15 -- 22.24 7 Gujarat 196024 7.00 3.00 5.00 1.00 -- 16.00 8 Haryana 44212 2.57 1.25 1.83 0.95 -- 6.60 9 Himachal Pradesh 55673 5.43 3.75 7.40 5.74 10.08 32.40

10 Jammu & Kashmir

222236 0.63 0.53 1.66 2.73 10.21 15.76

11 Jharkhand 79898 15.55 11.44 20.95 12.20 4.63 64.77 12 Karnataka 191791 27.00 11.00 9.00 2.00 -- 49.00 13 Kerala 38863 10.21 2.59 2.36 0.09 -- 15.25 14 Madhya Pradesh 308641 12.92 9.53 18.93 9.31 8.56 59.25 15 Maharashtra 307713 9.77 5.74 8.19 4.90 5.61 34.21 16 Manipur 22327 15.25 11.43 26.61 0.00 -- 53.29 17 Meghalaya 22429 14.78 10.21 26.25 13.86 12.80 77.90 18 Nagaland 16579 4.09 3.80 15.96 28.48 34.94 87.27 19 Orissa 155707 10.28 6.69 9.54 4.22 1.04 31.77 20 Punjab 50362 2.52 0.90 1.79 1.48 -- 6.69 21 Rajasthan 342239 7.67 4.62 8.12 3.90 1.92 26.23 22 Sikkim 7096 0.90 1.19 7.82 10.93 16.02 36.86 23 Tamil Nadu 130058 10.78 4.65 4.15 0.15 -- 19.73 24 Tripura 10486 7.10 7.00 6.50 8.60 9.20 38.40 25 Uttar Pradesh 241046 27.58 9.95 8.26 13.44 -- 59.23 26 Uttarakhand 53365 7.71 7.04 9.24 34.23 -- 58.22 27 West Bengal 88752 11.89 4.24 3.67 0.39 -- 20.19

Total 11.22 6.46 9.92 7.14 3.99 38.73

Source: Anonymous, 2008


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As per harmonized area statistics on land degradation, an area of 73.27 Mha on arable land and 9.30 Mha under open forests (<40% canopy) is exclusively affected by water erosion of more than 10 t/ha/year (Table 3). In addition, salt-affected area of 1.20 Mha on arable land and 0.10 Mha under open forest is also affected by water erosion. Similarly, 5.72 Mha area on arable land and 7.13 Mha in open forest is affected by both acidity and water erosion. Thus, a total of 96.72 Mha (80.19 Mha on arable land and 16.53 Mha under open forest) area is affected by water erosion either exclusively or in conjunction with salinity/acidity which is about 80% of 120.72 Mha total degraded area in the country. The trend analysis indicated that the area affected exclusively by water erosion has declined from 148.9 Mha in 1994 to 93.68 Mha in 2005 and 73.28 Mha in 2007 at a rate of 3.91% (Fig. 4). Considering water erosion on arable lands in conjunction with open forest and salt-affected soils, the rate of decrease during 1994 to 2007 works out to be 3.33% (Table 5).

Fig. 4: Area (M ha) under salt affliction, 1976-2007

Table 5: Percent change over 1994 and 2005 in each category of land degradation Type of degradation Area (M ha)

1994 Area (M ha) 2005

Area (M ha) 2007

% change over 1994

% change over 2005

Water erosion 148.9 93.68 73.28 -50.78 (-3.91) -21.77 (-10.88)

Water erosion + open forest

148.9 - 82.57 -44.54(-3.42) -

Water erosion + open forest + salt affliction

148.9 - 84.41 -43.31(-3.33) -

Wind erosion 17.5 9.48 11.55 -34.00(-2.61) 21.83 (10.91)

Ravines 3.97 - 3.97 0.00(0.00) -


Type of degradation Area (M ha) 1994

Area (M ha) 2005

Area (M ha) 2007

% change over 1994

% change over 2005

Salt affected 9.4 5.94 8.22 -12.55(-0.96) 38.38 (19.19)

Waterlogging 11.6 14.30 14.3* 23.27(1.79) 0.0

Mining wasteland 2.53 - 0.26 -89.72(6.90) -

Shifting cultivation 4.9 - 1.88* -61.63(-4.74) -

Degraded forest 24.9 - 12.66* -49.15(-3.78) -

Values in the parenthesis are AGR(%); * = based on 2005 data

The reduction is largely attributed to massive integrated watershed development programmes launched in the country since 1991. Up to the end of Xth Five Year Plan (2002-07), 47% (56.54 Mha) degraded area has been treated under various watershed schemes and soil and water conservation programmes at an investment of about Rs. 19.5 billion (Sharda et al., 2008).

3.2. Wind Erosion Wind erosion is prevalent in arid and semi-arid regions of the country covering an

area of about 28,600 km2 in the states of Rajasthan, Haryana, Gujarat and Punjab. About 68% of the affected area is covered by sand dunes and sandy plains. It has been estimated that out of 208751 km2 mapped area of Western Rajasthan, 30% is slightly affected by land degradation, while 41% is moderately, 16% severely and 5% very severely affected (Narain and Kar, 2006). Decreasing rainfall gradient and increasing wind strength from east to west are responsible for the spatial variability in sand reactivation pattern. According to recent estimates, about 75% area of Western Rajasthan is affected by wind erosion hazard of different intensities (Table 6) (Narain et al., 2000) besides 13% area under water erosion and 4% under waterlogging and salinity/alkalinity. Fig. 5 presents the wind erosion map of the country with erosion rate of more than the permissible rate of 10 t/ha/yr.

Table 6: Wind erosion deposition in western Rajasthan

Erosion/deposition Area (km2)

% of total area

Very severe 5800 2.78

Severe 25540 12.23

Moderate 73740 35.32

Slight 52690 25.24

Negligible 50981 24.43

Total 208751 100.00


Fig. 5: Wind erosion map of India (>10t/ha/yr)

The spatial extent of the problem is increasing in the recent decades, especially due to increased cultivation and grazing pressures on the erstwhile stable sandy terrain (Narain and Kar, 2006) leading to depletion of vegetal cover. However, under desert development programme (DDP) and watershed development projects, affected areas are being rehabilitated along with stabilization of sand dunes through appropriate soil conservation measures. The harmonized area statistics on land degradation in the country shows that 12.4 Mha area on arable lands is affected by wind erosion of more than 10 t/ha/yr (Maji, 2007).

3.3. Waterlogging, Salinization and Acidification The problems of waterlogging and salinization in the irrigated command areas of arid

and semi-arid regions are a global phenomenon, mainly associated with canal irrigation systems. About 10-33 percent of irrigated lands in various countries are adversely affected by the problems of waterlogging and salinization. An area is said to be waterlogged when water table rises to such an extent that soil pores in the crop root zone become saturated, resulting in restriction of the normal circulation of air, decline in level of oxygen and increase in level of carbon dioxide. An area with water table within two metres is called waterlogged though safe limit is beyond 3 meter depth. The major factors


contributing to waterlogging and salinity include seepage from the canal distribution network, excessive irrigation of agricultural crops, impediments in natural drainage systems and topographical and climatic features.

Salt affected soils are grouped into two classes, namely saline and alkali soils depending upon nature of soluble salts, physico-chemical characteristics and management practices for their reclamation. Saline soils have EC higher than 4 dsm-1 but pH less than 8.5 and ESP below 15. Alkali soils, on the other hand, have pH higher than 8.5 and ESP >15 with variable electrical conductivity. The soils which are both waterlogged and salt affected are called waterlogged saline soils.

About 4.5 Mha area in India is affected by waterlogging, half of which occurs in canal commands and the remaining half in other regions (Anonymous, 2004a). Maximum area lies in Uttar Pradesh followed by Gujarat, Rajasthan, Andhra Pradesh and Bihar (Table 7). Similarly, salt affected soils occur in 8.55 Mha, out of which 41 percent lies in canal command areas. Though salt affected soils occur all over the country, they are mainly concentrated in arid, semi-arid and sub-humid regions (Fig. 6). The states most affected are Uttar Pradesh, Gujarat, Rajasthan, West Bengal and Andhra Pradesh (Singh, 1992). Area in the range of 1.5 to 20 percent of total irrigated area is affected by the problem of soil salinization in different states.

Table 7: Extent and distribution of waterlogged and salt affected soils in India (000, ha)

Waterlogged area Salt affected area State

Canal commands

Un- classified

Total Canal Commands

Outside canal

Coastal

Total

Andhra Pradesh 266.4 72.6 339.0 139.4 390.6 283.3 813.3

Bihar 362.6 NA 362.6 224.0 176.0 Nil 400.0

Gujarat 172.6 311.4 484.0 540.0 372.1 302.3 1214.4

Haryana 229.8 45.4 275.2 455.0 NA Nil 455.0

Karnataka 36.0 NA 36.0 51.4 266.6 86.0 404.0

Kerala 11.6 NA 11.6 NA NA 26.0 26.0

Madhya Pradesh 57.0 NA 57.0 220.0 22.0 Nil 242.0

Maharashtra & Goa 6.0 105.0 111.0 446.0 NA 88.0 534.0

Orissa 196.3 NA 19.3 NA NA 400.0 400.0

Punjab 198.6 NA 198.6 392.6 126.9 NA 519.5

Rajasthan 179.5 168.8 348.3 138.2 983.8 NA 1122.0

Tamil Nadu 18.0 109.9 127.9 256.5 NA 83.5 340.0

Uttar Pradesh 455.0 1525.6 1980.6 606.0 689.0 Nil 1295.0

West Bengal NA NA NA Nil NA 800.0 800.0

Total 2189.4 2189.4 4528.1 3469.1 3027.0 2069.1 8565.2

Source: Anonymous 2004a


Fig. 6: Salt affected soils in India

It is estimated that waterlogging and soil salinization is increasing at the rate of 3000 to 4000 ha per annum in various command areas. Rate of water table rise in Haryana has been 0.14 to 1.0 m/year and about 0.4 Mha area has water table within 3 m of soil surface. Similarly, in South Punjab and all irrigation commands of Gujarat, a steady rise in water table is reported with corresponding increase in salt affected area. Area affected by waterlogging in Tungbhadra Command in Karnataka increased from 16000 ha to 80000 during 1975 to 1997 (Fig. 7). Similarly, in Nagarjuna Sagar Project Command area, nearly 25000 ha of the 140000 ha under irrigation have been affected by waterlogging and salinity in a period of 14 years.


1645824475

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a)

Fig. 7: Increase in waterlogged area under Tungbhadra Project, Karnataka

Acid soils cover an area of 49 Mha in India out of which 25 Mha have pH below 5.5 and 24 Mha between 5.5 and 6.5 (Misra, 2004). These soils have been classified under soil orders Ultisol, Alfisol, Mollisol, Inceptisol and Entisol representing laterite, red, hill brown forest, alluvial and peat soils, respectively. They are found in Himalayan region, eastern and north eastern plains, peninsular India and coastal plains, covering states of north eastern region, West Bengal, Bihar, Orissa, Andhra Pradesh, Kerala, Madhya Pradesh, Karnataka, Maharashtra, Tamil Nadu, Himachal Pradesh, Jammu and Kashmir and Uttarakhand (Fig. 8). Table.8 presents percentage of total geographical area under acid soils in each state.

Fig. 8: Distribution of acid soils in India


Table 8: Extent of occurrence of acid soils

State % of TGA State % of TGA

Assam and North East 80 Karnataka 50

West Bengal 40 Kerala 90

Bihar 33 Maharastra 10

Orissa 80 Uttar Pradesh 10

Madhya Pradesh 20 Himachal Pradesh 90

Andhra Pradesh 20 Jammu & Kashmir 70

Tamil Nadu 20

Source: Misra, 2004

As per harmonized data base on land degradation in the country, an area of 5.09 Mha is exclusively affected in arable lands by acidity in addition to 5.72 Mha affected by acidity in conjunction with water erosion of more than 10 t/ha/year. An area of 7.13 Mha also suffers from acidity in the open forest lands (< 40% canopy). Thus an area of 17.94 Mha is degraded in India due to strong (pH < 4.5) and moderate (pH between 4.5 – 5.5) acidity either exclusively or in combination with water erosion on arable and non-arable lands.

3.4. Soil Physical Constraints: Compaction and Scaling Shallow depth, soil hardening, slow and high permeability, sub-surface compacted

layer, surface crusting, and temporary waterlogging are the major physical constraints of Indian soils. Soil compaction is a management problem resulting from movement of heavy machinery and repeated tillage operations accompanied with reduction in organic matter and destruction of soil aggregates. Soil is said to be compacted if resistance to penetration exceeds 2 Mega Pascal (Mpa). Compaction causes deterioration in soil structure and impedes root growth and biological activity besides generating high amount of runoff during intense storms.

Out of 141 Mha cultivated area, about 89.5 Mha suffers from one or another form of physical constraint in the country as shown in Table 9 (Painuli and Yadav, 1998). Maximum area is affected by shallow depth followed by soil hardening and the least by temporary waterlogging.


Table 9: Distribution of area (million ha) affected by various physical constraints in India

Physical constraint Area Main states affected

Shallow depth 26.40 Andhra Pradesh, Maharashtra, West Bengal, Kerala and Gujarat

Soil hardening 21.57 Andhra Pradesh, Maharashtra and Bihar

High permeability 13.75 Rajasthan, West Bengal, Gujarat, Punjab and Tamil Nadu

Sub surface hard pan 11.31 Maharashtra, Punjab, Bihar, Rajasthan, West Bengal and Tamil Nadu

Surface crusting 10.25 Haryana, Punjab, West Bengal, Orissa and Gujarat

Temporary waterlogging 6.24 Madhya Pradesh, Maharashtra, Punjab, Gujarat, Kerala and Orissa

Source: Painuli and Yadav (1998)

Soil scaling due to surface hardening and crust formation together affect 31.82 Mha area in the country. Major factors are construction of houses, roads and other land development activities and physico-chemical properties of the soil. They obstruct movement of rainwater into the soil thus leading to high runoff and soil losses. The deterioration in physical, chemical and biological functions of the soil due to compaction and scaling adversely affects the productivity of agricultural crops. The technologies for treating the soil affected by sub-surface mechanical impedance and compaction include chiseling, chiseling plus amendment application, construction of ridges and raised and sunken bed technology.

3.5. Floods and Droughts Occurrence of floods, droughts and other climatological extremes is a common

feature in many parts of the country. These natural disasters cause widespread land degradation apart from heavy monetary losses and a serious setback to economic development of the country. It has been estimated that 8 major river valleys spread over 40 Mha area of the country covering 260 million population are affected by floods. Besides environmental degradation, poverty and marginalization are other major factors which force the poor to live in threatened and exposed conditions. About 60% of total flood prone area in the country lies in Indo-Gangetic basin which supports 40% of India’s population with 60 Mha cultivable land. The Brahmaputra basin is also critical as it experiences frequent floods within the same year thus seriously affecting all developmental activities. The incidence of floods is not restricted to humid and sub-humid regions but have also caused extensive damage in the desert districts of Rajasthan and Gujarat in the recent years.


Drought occurs over an extended period of time and space, making it unpredictable and the losses are not quantifiable easily (Samra, 2002). Therefore, the impact of drought on the techno-economic and socio-economic aspects of agricultural development and growth of the nation is severe and results in huge production and monetary losses. It is estimated that about 68% of total sown area and 23% of total area of the country spread in 16 states, viz; Andhra Pradesh, Bihar, Chhatisgarh, Gujarat, Himachal Pradesh, Jammu and Kashmir, Jharkhand, Karnataka, Madhya Pradesh, Maharashtra, Orissa, Rajasthan, Tamil Nadu, Uttar Pradesh, Uttarakhand and West Bengal covering a total of 183 districts and 12% of population are accounted as drought prone (CESI, 2006). In a state like Rajasthan (arid), about 56% of the total area and 33% of the total population are chronic drought prone affected followed by Andhra Pradesh, Gujarat and Karnataka with corresponding figures as 30 and 22%, 29 and 18% and 25 and 22%, respectively. Except Kerala, Punjab and north-eastern region, every state has one or more drought prone areas. Drought is said to have occurred in an area when the annual rainfall is less than 75% of the normal in 20% of the years examined. Any Taluk or equivalent unit having 30% or more area under irrigation is considered to be reasonably protected against drought.

Apart from floods and droughts, cyclones frequently occur in the entire 5700 km long coast line of Southern and Peninsular India besides Islands of Lakshadweep and Andaman and Nicobar islands affecting 10 million population. Nearly 56% of the total area of the country is susceptible to seismic disturbances affecting 400 million people. Fig. 9 shows the areas affected by natural disasters in India (CPCB, 2005).

Fig. 9: Natural hazards in India


3.6. Vegetation Degradation The areas which are most affected by vegetation degradation include pasture lands

and open forests. The states which have considerable proportion of permanent pastures and grazing lands include Himachal Pradesh (32%), Sikkim (10%), Madhya Pradesh (including Chhatisgarh) (6%), Karnataka (5.1%), Rajasthan (5%), Gujarat (4.5%) and Maharashtra (4%). Madhya Pradesh and Chhatisgarh account for about 23% of all India acreage under pasture and grazing lands. The common grazing lands around the villages which include Gochar (cultivable waste), Oran (permanent pasture) and Agro (pasture around the pond) have been highly exploited and neglected. In India, with about 500 million livestock population, more than 50% of fodder demand is met from grasslands. The average grazing intensity in India is about 42 animals per ha of land against the threshold level of 5 animals per ha (Sahay, 2000). An estimated 100 million cow units graze in forest lands against a sustainable level of 31 million per annum (MoEF, 1999) affecting approximately 78% of India’s forests.

The land use statistics indicated that forests occupy 22.8% (69.67 Mha) area in the country which together with permanent pastures comes out to 26.2% (80.1 Mha) (DES, 2007). Though the area under forests increased significantly during 1950-51 to 1970-71 by about 7% to 63.91 Mha, the increase has been only marginal thereafter till 2004-05. The total perennial cover comprising of forests, permanent pastures and other grazing land, and miscellaneous trees and groves together has increased just by 0.5% since 1970-71 showing an annual growth rate of 0.017%. Per capita forest area in India is only 0.07 ha which is far below the world average of 0.8 ha. Dense forests are losing their crown density and productivity continuously, the current productivity being one-third (0.7 t/ha) of the actual potential. The combined availability of green fodder from pasture lands and grazing lands, agricultural lands and forest (899.33 Mt) is far short of the actual demand of 1820 Mt (DES, 2007). It causes indiscriminate grazing on forest lands leading to large scale degradation thereby seriously affecting natural regeneration of forests. The present forest cover of 20.6% (FSI, 2005) is far below the 33% cover recommended by National Forest Policy of 1988, the proportion being 60% in the hill regions and 20% in the plains. Out of this, 5.46 Mha (1.66%) is very dense forest (>70% canopy), 33.26 Mha (100.12%) is moderately dense (40-70% canopy) and the rest 28.99 Mha (2.82%) is open forest (<40% canopy) including 0.44 Mha mangroves. Including 3.85 Mha of scrub forest and 9.17 Mha under tree cover outside the recorded forest area, the total forest cover comes to be 76.88 Mha which is only 23.40% of the total geographical area of the country.

The net annual loss of forest areas is put at 74000 ha which is attributed to overgrazing and over-extraction of firewood from 78% of the forest areas and fire hazards in 71% of forest lands. The State of Forest Reports (SFR) 2001 and 2005 indicate that while the area under dense forest cover declined by 7.1% (from 416809 to 387216 sq km), the area under open forests increased by 12.0% (from 258729 to 289872 sq km) with overall increase of 0.2% during the 4 years period. The Joint Forest Management (JFM) programme launched in 1991 has the major objective of protecting, developing and managing forests particularly in degraded areas by bringing together State Forest Departments and village communities.


3.7. Nutrient Mining Excessive nutrient mining and inadequate replenishment of primary, secondary and

micro-nutrients are the major factors responsible for declining nutrient use efficiency, deterioration of soil health and consequently decline or stagnation in agricultural productivity. The decline in factor productivity and compound growth rates of major crops under intensive cropping systems and low nutrient use efficiency is attributed to deterioration of chemical, physical and biological functions of the soil due to imbalanced supply of plant nutrients (Lal, 2004). Most of the Indian soils are low in nitrogen, 65-70% are deficient in phosphorous content and 50% are either low or medium in potassium content. In addition, about 48, 30, 12, 4 and 3% soils are reported to be deficient in zinc, sulphur, iron, copper and manganese, respectively. Major crop rotations based upon cereal-cereal or cereal-legume cropping sequence remove more than 500 kg of NPK annually from the soil and/or added nutrients (Table 10).

Table 10: Nutrient uptake by some intensive cropping systems

Nutrient uptake kg ha-1 yr-1 Cropping system

Yield (t ha-1) N P2O5 K2O

Total

Maize-wheat 7.7 220 87 247 554

Pigeon pea-wheat 4.8 219 71 339 629

Soybean wheat 7.7 260 85 204 549

Pigeon pea-sorghum* 0.8+1.1 185 19 299 503

Pigeon pea-pearl millet* 0.7+1.3 203 14 336 553 Pigeon pea-urd bean* 0.9+0.2 154 26 132 312

* Intercropping systems

Similarly, annual removal of micro-nutrient is in the range of 287-744 g for Zn, 1224-7296 g for Fe, 488-2980 g for Mn, 144 – 710 g for Cu, 120 – 252 g for B and 16 g for Mo (Takkar, 1996).

In Indian agriculture, there is little resemblance between the pattern of NPK removal by crops and their addition through fertilizers (Tiwari, 2007). In general, nitrogen (N) is the dominant addition while potassium is the dominantly removed nutrient. Potassium is the lowest applied nutrient though it accounts for 55% removal of total NPK. Nitrogen contributes to only 31%, while P accounts for the remaining 14% of the total NPK uptake. Use of site specific nutrient management practice based on positive nutrient balance can yield about 15-17 t/ha/yr of grain production.

At the present level of crop production, crops remove 27 Mt of NPK against application of 16.8 Mt, thus resulting in a gap of 10.2 Mt. The gap is expected to increase up to 11 Mt by 2010 and 13.3 Mt by 2025 when the removal would reach a level of 31.7 Mt and 40 Mt, respectively. As a result of inadequate and imbalanced fertilizer


use, production response of chemical fertilizers has reduced from about 15 kg of food grains per kg of fertilizers in 1970 to only 5-6 kg per kg of fertilizer in 2005. Consequently, the annual compound growth rate of major crops has declined from 3.33% in 1981-85 to 0.11% in 2001-05, with a similar trend in pulses and oilseed crops also.

The fertilizer consumption in India is grossly imbalanced and is more inclined towards N followed by P. The imbalanced consumption ratio of N:P:K which was 6.2:4:1 in 1990-91 widened further to 7:2.7:1 in 2000-01 as against favourable ratio of 4:2:1. With the increase in foodgrain production, the number of elements deficient in Indian soils increased from one (N) in 1950 to 9 (Mo, B, Mn, S, K, P, Zn, Fe and N) in the year 2005-06 which may further increase due to imbalanced fertilizer use.

The gap between consumption and removal of nutrients by 2025 is expected to be bridged by use of crop residues, cattle dung, sewage-sludge and other organic sources. Crop residues offer most favourable alternative and have the capacity to supply 3.39 Mt of nutrients followed by cattle dung and human excreta (Table 11).

Table 11: Some projections on availability of plant nutrients from organic sources for agriculture in India during 2000-2025

N + P2O5 + K2O Resource

2000 2010 2025

Crop residue 2.05 2.34 3.39

Cattle dung 2.00 2.10 2.26

Human excreta 1.60 1.80 2.10

Total 5.50 6.24 7.75

3.8. Depletion of Soil Organic Matter The organic matter content in India varies with soil texture, climate, rainfall,

moisture, tillage, crop residue management, land use, application of fertilizers and cropping systems. The organic matter content is generally low under Indian conditions due to tropical and sub-tropical climate. Comprehensive data on status of organic matter during different time scales is largely missing. In Tamil Nadu state, organic matter reduced from 1.20 in1971 to 0.78 percent in 2002. In the cultivated fields, it rarely exceeds 1 percent except in few soils of hilly region (Table 12). High soil organic carbon (SOC) (> 1 percent) can be accumulated in red and laterite soils of humid tropical and hill and mountain soils having humid temperate climate. Desert soils are the poorest in SOC contents.


Table 12: Organic carbon in surface layer of important soil groups of India

Sl.No. Soil group Organic carbon (%)

1 Deep black soils 0.3 – 0.8

2 Red and laterite soils 0.7 – 6.5

3 Alluvial Soils 0.3 – 1.1

4 Hill and mountain soils 4.0 – 8.0

5 Desert Soils 0.3- 0.6

6 Coastal alluvial soils 0.5 –0.9

Bhattacharyya et al. (2000) reported that among the five physiographic regions of India (Fig. 10), the Northern Mountains cover 55.3 Mha area and have SOC reserve in the range of 7.89 to 18.31 Pg in first 30-150 cm depths. The Great Plains covering 72.4 Mha have SOC stocks of 3.2 to 10.53 Pg. For Peninsular India, The Peninsular plateau and Coastal Plains and Islands covering 54.7, 105.7 and 40.9 Mha area, SOC ranges from 3.64 to 13.34, 3.62 to 10.11 and 2.24 to 10.90 Pg, respectively.

Fig. 10: Soil organic carbon (SOC) stocks in different physiographic regions of India based on 1000 soil samples


It is estimated that 300, 375 and 16.5 Mt of crop residues, livestock dung and human excreta are available annually in India. Of this, about one-third of crop residues, half of the livestock dung and 80% of human excreta are available for use in agriculture. Every million tones increase in food grain production can produce 1.2 – 1.5 Mt of crop residues and every million increase in cattle population can provide additional 1.2 Mt of dry dung per annum. Thus NPK supply can be supplemented through all the wastes to the extent of 6.25 and 9.25 Mt by 2010 and 2025, respectively to sustain productivity and keep the fertilizer related pollution under control (IISS, 2007).

3.9. Over Exploitation of Ground Water The annual replenishable ground water resource in India has been estimated as 433

BCM, of which rainfall contribution is 67% (290 BCM) and the remaining 33% (143 BCM) is contributed by other sources that include return flow from canal irrigation, seepage from water bodies and artificial recharge from water storage structures (CGWB, 2006). Presently, about 53% (231 BCM) ground water resource has been developed which meets 70% of the irrigation and 80% of the drinking water needs of the country. Due to subsidized power and pump sets in rural areas and absence of any regulatory mechanism, the number of ground water abstraction structures has increased by more than 3 times since 1982-83, thus causing over-exploitation of ground water resource (Table 13).

Table 13: Growth of ground water extraction structures

Number of structures Type of structure

1982-83 1993-94 2000-01

Dug wells 5384627 7354905 9617381

Shallow tubewells 459853 3944724 8355692

Deep tubewells 31429 227070 530194

Total 5875909 11526699 18503267

About 70 percent area in Punjab, 50 percent in Haryana and a major part in lower Himachal Pradesh and Uttarakhand, Uttar Pradesh and Northern Rajasthan is being irrigated by tube wells. Over the last four decades, number of tube wells have increased twenty folds (6 lakhs) in Haryana and thirty folds in Punjab (14 lakhs) and still there are no legislative measures to control their numbers or regulate withdrawal of ground water. While area under canal irrigation has decreased from 1.3 to 1.0 Mha in Punjab, the area under tube well irrigation increased from 0.8 to 3.1 Mha during 1965-66 to 2003-04 (Fig. 11). Similarly, in Haryana area under tube well irrigation increased from 0.2 to 1.59 Mha (Fig. 12).


0

500

1000

1500

2000

2500

3000

3500

1965-66 1975-76 1993-94 1998-99 2003-2004Period

Are

a (0

00'h

a) ir

rigat

ed

CanalTube wells

0

200

400

600

800

1000

1200

1400

1600

1800

1965-66 1975-76 1993-94 1998-99 2003-2004Period

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a (0

00'ha)

irrig

ated

Canal

Tube wells

Fig. 11: Area (000’ha) irrigated by canals and tube wells in Punjab

Fig. 12: Area (000’ha) irrigated by canals and tube wells in Haryana

Due to declining ground water table, 90 percent farmers in rice-wheat cropping system of Punjab and Haryana are replacing centrifugal pumps with submersible pumps causing further exploitation of ground water (Kaledhonkar et al., 2006).

The Central Ground Water Board (CGWB) is monitoring ground water fluctuations in various blocks of the country which are classified as white, grey, dark and over-exploited depending upon the net draft as percentage of net recharge of <65, 65-85, 85-100 and >100 percent, respectively. The analysis of data indicates that out of 7928 blocks in the country, 425 fall in the dark/critical zone and 673 are over-exploited (Table 14).


Table 14: Groundwater development levels in India

No. of assessment units Over-exploited Dark/Critical Sl.

No. States Number of assessment

units No. % No. % 1. Andhra Pradesh 1157 118 10.20 79 6.83 2. Arunachal Pradesh 59 0 0.00 0 0.00 3. Assam 219 0 0.00 0 0.00 4. Bihar 394 6 1.52 14 3.55 5. Chhattisgarh 145 0 0.00 0 0.00 6. Delhi 6 3 50.00 1 16.07 7. Goa 12 0 0.00 0 0.00 8. Gujarat 180 41 22.78 19 10.56 9. Haryana 111 30 27.03 13 11.50 10. Himachal Pradesh 69 0 0.00 0 0.00 11 Jammu & Kashmir 69 0 0.00 0 0.00 12 Jharkhand 193 0 0.00 0 0.00 13 Karnataka 175 7 2.00 0 5.14 14 Kerala 151 3 1.99 6 3.97 15. Madhya Pradesh 312 2 0.64 1 0.34 16 Maharashtra 2316 154 6.65 72 3.11 17 Manipur 29 0 0.00 0 0.00 18 Meghalaya 39 0 0.00 0 0.00 19 Mizoram 12 0 0.00 0 0.00 20 Nagaland 52 0 0.00 0 0.00 21 Orissa 314 0 0.00 12 8.70 22 Punjab 138 81 58.70 48 33.76 23 Rajasthan 237 86 36.29 0 0.00 24 Sikkim 4 0 0.00 37 9.61 25 Tamil Nadu 385 138 35.84 0 0.00 26 Tripura 38 0 0.00 20 2.44 27 Uttar Pradesh & Uttarakhand 819 2 0.24 61 7.45

28 West Bengal 275 0 0.00 61 22.18 Total states 7910 671 8.48 424 5.36 Union Territories 18 2 11.11 1 5.56 Grand Total 7928 673 8.49 425 5.36


In Punjab, Haryana and Western U.P., the situation is really alarming as 40% of the total over-exploited and dark zones are located in these states. In Punjab and Haryana, there is steady decline of water table in areas having good quality aquifers while the water table is rising in regions having saline ground water. In fresh water areas of Haryana, water level has gone down by 2.5 to 11.0 m during thhe last two decades whereas it has increased by 0.5 to 6.0 m in saline ground water areas. Similarly, Punjab is experiencing fall of water level in 75% of the good quality water zones and rise in remaining 25% areas having poor quality. The ground water extraction in states experiencing decline in water table ranges from 98.3% in Punjab to 75.6% in Haryana, 72.1% in Rajasthan, 62.6% in Tamil Nadu, 49.3% in Gujarat and 41.9% in Uttar Pradesh.

The CGWB has drafted a model bill that can be adopted by various states to ensure sustainable and equitable development and use of groundwater resources. It envisages compulsory registration of bore-well owners, compulsory requirement of statutory permission to sink a new bore-well, creation of a groundwater regulatory body, restriction on the depth of bore wells, establishment of protection zones around drinking water wells and other measures. So far about 11 states and UTs have implemented the groundwater legislation based on the model bill of CGWB.

3.10. Use of Poor Quality Ground Water From management point of view, ground water may be classified into good, saline

and alkali water depending upon the restriction imposed (Table 15).

Table 15: Grouping of poor quality water

Water quality EC

(dSm-1) SAR

(mmol l-1)1/2 RSC

(meq l-1)

A. Good <2 <10 <2.5

B. Saline

i. Marginally saline 2-4 <10 <2.5

ii. Saline >4 <10 <2.5

iii.High SAR saline >4 >10 <2.5

C. Alkali waters

i. Marginally alkali <4 <10 2.5-4.0

ii. Alkali <4 <10 >4.0

iii High-SAR alkali Variable >10 >4.0

As per estimates of Ministry of Water Resources, Govt. of India, only 231 BCM (53.3%) of ground water has been utilized out of the 434 BCM annual utilizable ground water. About 31% of the utilized ground water is of poor quality particularly to meet the high irrigation demand. Maximum utilization of poor quality ground water in the range of 32 to 85% is in the arid and semi-arid regions of India. Fig. 13 presents the distribution of poor quality ground water in the country.


Fig. 13: Distribution of saline and alkali water in India

Based upon salinity alone, ground water is classified as good (EC < 2dsm-1), marginal (2-6 dsm-1) and poor (EC >6 dsm-1). A major portion of ground water is unfit for irrigation due to salinity (Table 16).

Table 16: Distribution of groundwater in different states based on ground water quality

Groundwater quality (%) State

Good Marginal Poor

Haryana 37 8 55

Punjab 59 22 19

Uttar Pradesh 37 20 43

Gujrat 70 20 10

Rajasthan 16 16 68

Karnataka 65 10 25

Source: Anonymous, 2004a


Rajasthan state has maximum area under high salinity followed by Haryana and Uttar Pradesh. Based upon ground water quality survey, a comprehensive ground water quality map of the country on 1:6 million scale has been developed (Fig. 14). The map provides distribution of different kinds of ground water quality, viz; good, saline, high SAR saline and alkali water.

Fig. 14: Ground water quality and quantity map of India

Poor quality alkali water zones occur in parts of U.P., Haryana, Punjab and Rajasthan. In Peninsular India, poor quality water is present in coastal belt and few isolated pockets. As per standards of Central Pollution Control Board (CPCB), a good quality irrigation water should have pH between 6-8.5, EC less than 2250 micro mhos cm-1, SAR less than 26 and Boron less than 2 mg/l.

Ground water quality is polluted either due to geological factors (arsenic, iron, fluoride etc.) or due to excessive use of agro-chemicals. The occurrence of arsenic in ground water is reported in West Bengal, Bihar, Chhatisgarh and Assam while high concentrations of iron have been observed mainly in Assam, West Bengal, Orissa, Chhatisgarh and in Karnataka. Similarly, high levels of fluoride occur in about 200 districts in India. Nitrate pollution occurs in intensively irrigated and high productivity regions due to excessive use of chemical fertilizers in India, especially in states like Punjab, Haryana and Western U.P. Use of agro-chemicals has increased from 56114 Mt in 1996-97 to 413,504 in 2004-05 (TERI, 2004-05) resulting in pollution of surface and ground water resources. Similarly, about 18.4 million m3 of waste water produced per day in India through sewage and industrial effluents is contaminating the water resources (Minhas and Samra, 2004). It is estimated that between 103 and 177 km3/year of waste waters that are discharged from municipalities, industries and irrigation can be recycled and reused after proper treatment for various purposes (Gupta and Deshpande, 2004).


3.11. Degradation due to Urban and Industrial Wastes and Excessive Use of Agro-Chemicals

Rapid urbanization, industrialization and agricultural intensification are accompanied by generation of large amounts of solid and liquid wastes. Soil and surface bodies have become logical sinks for Urban Solid Waste (USW), sewage-sludge and industrial effluents (Minhas and Samra, 2004). The per capita generation of solid wastes in India varies from 0.2 to 0.6 kg per day depending upon population size of the city (MUD & PA, 2000). Thus over 450 class I and II cities in India are generating about 57 Mt of solid wastes which are expected to increase to 107 Mt per annum by 2030 (Anonymous, 2003) (Table 17).

Table 17: USW generation from urban areas and estimated quantity of compost production in India

Year Urban population (Million) USW (Mt/annum) Compost (Mt/annum)

2005 315 57.5 8.1

2010 355 64.8 9.1

2015 402 73.4 10.3

2020 456 83.2 11.7

2025 517 94.4 13.2

2030 586 107.0 15.0


The treatment of USW would not only clean the environment but also help in augmenting the supply of organic manures. As present, 8 Mt of compost can be generated from 57 Mt of urban wastes (Jewan Rao and Shantaram, 1999). The untreated compost has N, P2O5 and K2O contents in the range of 0.5 to 0.9 percent but the amounts of heavy metals are very high (Table 18).

Table 18: Heavy metal contents in USW (mg/kg dry weight)

Bangalore Nagpur Heavy metal Range Average Range Average

Fe 4291-22291 972.0 6634-100244 36539

Mn 34-161 98.4 210-3074 971.0

Cu 40-736 296.5 23.5-878 235.9

Zn 275-1341 808.0 29-3095 358.1

Pb 122-678 346.5 30.0-477.6 159.7

Cd 5-12 7.7 4.9-42.9 19.0

Ni 24-115 51.6 1.8-262.7 44.3

Cr 21-184 64.5 17.5-373.5 66.1


Sewage water and industrial effluents are the major sources of waste water. India produces 18.4 million m3 of waste water per day (Patnakar, 2001). Studies have shown that use of waste water in peri-urban areas has resulted in soil fertility and organic matter build up. However, harmful effects result from accumulation of heavy and toxic metals. Industrial effluents are even more harmful and pollute the surface water bodies. All the lakes around Coimbatore have been polluted by effluents produced from 30000 small, medium and large industries of textiles and foundaries. Surface water bodies loaded with effluents may ultimately pollute the ground water. Water samples collected from Hussain Lake, polluted by over 400 industrial units and also ground water samples collected from bore wells recorded higher degree of contaminations (Table 19). Heavy metal contaminations in ground water, 1-2 km away from the lake were many times less than those closer to the lake (Minhas and Samra, 2004).

Table 19: Metal contaminations in and around Hussain Sagar Lake (Hyderabad)

Zn Cd Pb Ni Source

Range Mean Range Mean Range Mean Range Mean

Lake water 48-271 181 4-8 5 38-62 42 16-31 24

Ground water from

0.2–1.0 km around lake 36-617 106 8-27 14 7-28 14 20-74 40

1-2 km from lake 0.35 17 1.7 4 1.9 7 0.20 11

Source: Minhas and Samra, 2004

The consumption of pesticides has increased from 2.35 thousand tonnes in 1950-51 to 37.95 thousand tonnes in 2006-07 and is still increasing (DES, 2007). Pesticides and heavy metals generally reduce soil respiration, microbial activity and enzyme activity, inhibit crucial processes such as ammonification and nitrification, reduce earthworm population and suppress algal population thus adversely affecting crop yields and quality. These pollutants may also enter the food chain and cause health problems like blood pressure, kidney problem, cancer etc. if threshold limit exceeds. Recent studies conducted by CCSHAU, Hisar (2003) have shown alarming levels of pesticide contamination in human food and water resources (Table 20).


Table 20: Pesticide residue persistence in food, fodder and irrigation waters as seen in 2001

Sl. No.

Commodity Samples (nos.)

Contamination Major residues

1. Feed & fodder 126 81.0 HCH, DDT, Chloropyri-phos, Endosulphan

2. Milk 537 52.0 HCH (94%), Endosulphan (9%) DDT residues

3. Butter 184 64.7 -do-

4. Irrigation waters

(a) General water 258 60.0 HCH, DDT

(b) Surface water 251 73.0 Endosulphan, Chloropyri-phos

(c) Canal water 10 100.0 -do-

(d) Pond water 11 100.0 -do-

Source: CCS Haryana Agricultural University (2003)

3.12. Coastal Erosion The coastline in India extends from Tamil Nadu to West Bengal in the east and from

Kerala to Gujarat in the west. The total coastal length has been reported to vary from 5708 km to 5996 km by various workers (Singh et al., 2004; Joshi, 1995; Ramachandran, 2001). The tidal waves in the Indian Ocean cause considerable soil erosion. Nearly 250 million people live within a distance of 50 km from the coast with a population density of about 880 persons per sq km.

In the west, about 80 percent (400 km) of the entire coast line of Kerala is affected by erosion while in Karnataka, about 73 km coastline is affected (Joshi, 1995). In some parts of coastal Kerala, erosion is so high that shoreline is receding at the rate of nearly 5 cm per year (Sundar, 2001). At some places, sea advances as much as 30 to 50 m during the monsoon and recedes by 25 to 40 m during the dry months thus resulting in a loss of 5 to 10 m of valuable land every year (KSLUB, 1996). Shoreline fluctuations over a period of 55 years (1910-1965) based on Survey of India toposheets shows a loss of 22 km2 through erosion (Thirvikramaji et al., 1983) and a gain of 41 km2 by accretion. Another study showed that about 600 m wide belt of land was lost during 120 years from 1850 to 1970 (KERI, 1971).

On the east coast, the region between Point of Climere and Vishakhapatnam has been identified as cyclone prone zone. Due to any storm of depression centered in the Bay of Bengal, whether it crosses the land or not, the equilibrium of east coast shoreline gets affected, resulting in sporadic coastal erosion of very severe nature (Natarajan et al., 1991). In Tamil Nadu, about 80 km coastline, in Orissa about 30 to 40 km and in West Bengal about 180 km coast stretching from confluence of river Hooghly in the west to confluence of river Jagdal in the east are affected. The rate of erosion is as high as 30 m per year (Joshi, 1995).


The coastline of Tamil Nadu is more affected by storms and depressions especially during November to January (north east monsoon). The state has lost many villages and towns in the past due to sea intrusions. A study of coastal processes indicated that a total extent of 158.52 acres of land has been lost to the sea on the coastal front of Tamil Nadu state during 1978 to 1988, within a stretch of 77 km. Therefore, the total erosion would amount to 1950 acres in 10 years period as a generalized estimate for the entire coastline of Tamil Nadu (Natarajan et al., 1991). By and large, cyclonic erosion and accretion is experienced along the entire east coast. The most vulnerable coastal erosion sites are presented in Fig. 15.

Fig. 15: Major coastal erosion sites

3.13. Gullies and Ravines Gullies result from continuous non-judicious use of the land and are defined as

advanced form of rill erosion. They generally originate on sloppy lands due to improper management and concentration of flowing water leading to severe erosion hazards. They are visible in the plateau region of Eastern India, along the foothills of Himalayas and in extensive areas of Deccan plateau. Ravines, on the other hand, are a network of gullies almost parallel to each other and generally associated with some river system. The major factors responsible for formation and development of ravines include severe misuse and management of rainwater and faulty agricultural practices in the upper river catchments resulting in heavy siltation rates and meandering of rivers and backflow of water from adjoining porous strata into the river system leaving behind a network of gullies.

In India, ravines (gullies) occur along the rivers Beas, Yamuna, Ganga, Chambal, Kalisindh, Mahi, Narmada, Sabarmati and their tributaries in the States of Punjab, Uttar Pradesh, Bihar, West Bengal, Rajasthan, Madhya Pradesh and Gujarat (Fig. 16).


Fig. 16: Extent of ravines in India

An area of about 3.7 Mha is affected by ravines in the country (Table 21). As already discussed, there is no change in the status of ravine area since 1985.


Table 21: Statewise distribution of ravines (Gullied area) in India

State Gullied area

(lac ha)

Uttar Pradesh 12.30

Madhya Pradesh 6.83

Rajasthan 4.52

Gujarat 4.00

Maharashtra 0.20

Punjab 1.20

Bihar 6.00

Tamil Nadu 0.60

West Bengal 1.04

Total 36.69


The CSWCRTI, Dehradun established three Regional Centres at Agra (U.P.), Kota (Rajasthan) and Vasad (Gujarat) during First Five Year Plan to tackle the problems of ravines and develop appropriate technologies for their reclamation and productive utilization in the Yamuna, Chambal and Mahi river systems, respectively.

3.14. Mass Erosion Problems Landslides, minespoils and torrents are the major mass erosion problems prevailing

in various regions of the country, especially in the hill and mountain agro-ecosystems covering Himalayas and Shiwalik region. Due to precipitous slope and high intensity rains, they lead to enormous sedimentation rates affecting productive lands besides loss to life and property. Apart from causing disruption to traffic, they also impair the quality of water resources and in turn the aquatic life in streams and reservoirs.

3.15. Landslides The hilly regions having steep slopes, fragile ecology, high seismic activity and

intense rainfall conditions are highly susceptible to landsliding. The problem gets further aggravated by excessive deforestation, unscientific cultivation on steep slopes and developmental activities like road construction, buildings construction, mining etc. Occurrence of landslides is a regular feature along nearly 44000 km roads constructed in the Himalayan region. National Highway No. 31A (Ranipur-Rangpur) in Sikkim state is a veritable live museum of landslides. Krishnaswamy and Jain (1975) identified 31 major landslides in northern and north-western Himalayas spread over 1,20000 km2. As many as 369 landslides have been recorded in the Alaknanda, Bhagirathi and Ganga basins of U.P. Himalayas by the Geological Survey of India.


A study conducted along the roads in Tehri Garhwal and Dehradun districts indicated that, on an average, there are about 10 medium size landslides in each kilometer of the road, each depositing about 500 hundred cubic metres of debris on the road (Bansal and Mathur, 1976). Small and medium size landslides (5-100 cubic metre) contributed 63 percent by number and 30 percent by volume of the debris clearance problem on Mussoorie-Tehri road (Haigh, 1979). The hill roads have been observed to suffer from about 4-10 landslides and 8-20 slumps per km, engulfing an area of about 15-20 ha (Saxena et al., 1995). Major landslides in Himalayas are estimated to cause an annual loss of more than 50000 man hours and 5000 vehicle hours per km on hill roads entailing an annual loss of Rs. 150 crores towards removal of debris for road clearance.

3.16. Minespoils Mining industry plays a vital role in Indian economy and is spread over an area of

9,43380 hectares covering 7365 mine leases (Anonymous, 1992). The Himalayas in India, covering an area of nearly 50 million ha, are bestowed with a large variety of mineral resources such as limestone, dolomite, phosphorite, magnesite, gypsum etc. An area of about 25000 ha has been estimated under mining activity, mainly limestone quarrying in the Himalayan region (Table 22) (Soni, 1994). Limestone mining has been found to reduce food production by 28%, water resources by 50% and livestock production by 35% in the upstream reaches of Doon Valley (Anonymous, 1988). The unscientific mining on steep slopes often using excessive explosives causes huge damage to the fragile ecosystem leading to environmental degradation due to heavy soil erosion, drying of water resources, loss of land area, disruption to communication systems, floods and consequent decline in food and milk production.

Table 22: Distribution of mined lands in Himalayas

State Mining area

(in ha) Mineral

Uttarakhand Garhwal region Kumaon region

6832 4820

610

Limestone, Phosphorite Limestone, Dolomite, Copper, Silica, Gypsum, Magnesite Chromite

Meghalaya, Assam & West Bengal

11471

Dolomite, Silica, Coal, Limestone, China Clay, Quartz, Mica

Jammu & Kashmir 886 Limestone, China Clay, Gypsum, Magnesite, Bauxite, Sapphire

Himachal Pradesh 438 Limestone

Total 25057


The sedimentation rate from unreclaimed minespoils of limestone mining in Doon Valley of North-West Himalayas has been recorded as 550 t/ha/yr (Katiyar et al., 1987). A reduction of about 50% in spring flow during the lean period has been reported due to mining activity in the Baldi valley (Katiyar et al., 1990). The torrents emanating from the mined headwater regions are damaging about 100 ha of forest land every year in the valley and destroying trees worth Rs. 10 million (Juyal et al., 1995). Due to communication failures, the Public Works Department was spending an amount of more than Rs. 1 lakh every year to clear the debris from a 64 ha limestone quarry at Sahastradhara, a tourist spot near Dehradun (Katiyar et al., 1987). The CSWCRTI, Dehradun has developed a bio-engineering technology for rehabilitation of degraded minespoil areas (Juyal et al., 2007).

3.17. Torrents Torrents are ephemeral streams characterized by flash flows accompanied with high

debris load during monsoon season. They originate from the hill slopes, descend to the mildly sloping foothills and valleys and finally drain into a river system. The area affected by seasonal torrents in Hoshiarpur district of Punjab increased from 192 sq km in 1852 to 286 sq km in 1886 to 2000 sq km in 1939 and to 3000 sq km in 1988 (Grewal, 1995). Latest estimates of Soil Conservation Division of Ministry of Agriculture, Govt. of India revealed that about 2.73 Mha area in the country is affected by the problems of torrents and riverine lands, a major part of torrents lying in the Shiwalik region (Mukherjee et al., 1985). The problem of meandering rivers is very acute in Bihar and Uttar Pradesh as many flood prone rivers flow through these states. The Kosi river alone has shifted over 167 kms from the east to the west over a period of over a century and a quarter (Das, 1985).

Recent studies have indicated that 1517 sq km area in the Shiwaliks lies directly under the course of torrents affecting about 7500 sq km area in the states of J&K, H.P., Uttarakhand, Punjab, Haryana and Union Territory of Chandigarh (Sharda et al., 2007). The torrent training measures include spurs, protection walls, embankments and biofences. A cost effective technology for training of torrents comprising of appropriate mix of engineering and vegetative measures has been developed by CSWCRTI, Dehradun (Juyal et al., 2005).

4. Impacts of Land Degradation Land degradation has both on-site and off-site impacts which apart from lowering the

productive potential also results in deterioration of soil health, impairment of water quality, pollution of surface and ground water resources, loss of storage capacity of reservoirs, loss of biodiversity, landlessness, poverty, food insecurity and several types of environmental hazards. A brief description of the impacts of various forms of land degradation is presented in the following sections:

Water Erosion: Erosion removes soil containing organic matter and other plant nutrients thus causing loss of productivity which has been estimated to vary from 5 to 50% depending upon type of soil and crop and the intensity of erosion (Sehgal and Abrol, 1994). It has been estimated that nearly 5.37 to 8.4 Mt of plant nutrients are lost every


year from Indian soils due to water erosion. The annual loss in production of major crops due to soil erosion has been estimated to vary from 7.2 Mt (UNEP, 1993) to 13.5 Mt (Bansil, 1990). The loss in production for 11 major crops varied from 1.7% to 4.1% of total production (Brandon et al., 1995). Experimental studies in lower Himalayan region indicated that removal of 1 cm of top soil caused 76 kg/ha reduction in maize grain yield and 236 kg/ha in straw yield (Khybri et al., 1988). The reduction was observed to be 103 kg/ha in Shiwalik region of Punjab (Sur et al., 1998). Vittal et al. (1990) recorded losses of 138, 84 and 51 kg/ha/cm removal of top soil for sorghum, pearlmillet and casterbean, respectively.

Recently, CSWCRTI Dehradun systematically computed the production losses of 27 major cereal, oilseed and pulse crops under rainfed conditions. The experimental data collected on loss of productivity in different agro-ecological regions was integrated with potential erosion rates in five categories, viz; <5, 5-10, 10-20, 20-40 and >40 t/ha/yr under three major soil groups i.e. alluvium derived, black and red by evolving a uniform procedure and methodology. From the analysis, it is concluded that in India, a loss of 1344.8 Mt occurs in cereal, oilseed and pulse crops due to water erosion which is equivalent to Rs. 111.6 billion. The cereals contribute 68.3% to total loss followed by oilseeds (20.9%) and pulses (12.8%). Among oilseed crops, groundnut and soybean occupying 26.5 and 36.5% of total area, contribute 12.3% and 10.4% to total monetary loss. Similarly, in pulse crops, gram (6.4%) and pigeonpea (2.9%) are the main contributors to total monetary loss as compared to other crops.

Apart from reducing productivity, sediment laden runoff water carries toxic substances and organic compounds such as pesticides which cause wide range of environmental hazards in the downstream reaches such as degradation of adjoining agricultural lands, meandering of river courses, smothering of crops and vegetation, pollution of water in streams, canals and rivers and flooding. Satellite imagery of Himalayan torrents shows that between 1990 and 1997, the width of torrents has increased by 106 percent and that of rivers by 36% resulting into flooding of downstream reaches.

The data on 17 medium and small reservoirs under river valley projects in India have shown that the rate of inflow of sediments is about 3 times (9.17 ha-m/100 km2/year) as compared to the design rate of 2.93 ha-m/100 km2/year, thus reducing the life expectancy and hydro-electric generation to one-third of the planned capacity. The loss of natural vegetation due to water erosion and deforestation is a major cause of natural disasters such as landslides and floods. In the Himalayan foothills, landslides killed more than 300 people within a week in August, 1999 (GoI, 1999). Occurrence of landslides has become a common feature due to clearance of forests for agriculture and road building. India is one of the top 10 countries in the world, which are highly vulnerable to droughts, floods, cyclones and earthquakes though landslides, avalanches and bush fires also occur frequently in the Himalayan region.

Wind Erosion: Wind erosion causes decrease in land productivity at both the sites from where the finer particles are blown away and at sites where they are deposited. Raina (1992) reported that decrease of organic carbon content in the soils of degraded sites was more in oran (50.7%) followed by cultivated (50.3%) and pasture lands (39.4%) while the decrease in potassium was more in cultivated soils (55%) followed by oran


(35.2%) and pasture land (12%). Maximum decrease in phosphorous was recorded in pasture soils (72.4%) followed by cultivated lands (52.9%). Deep ploughing of sand plains lost more than 3000 tonnes of soil per ha during a sand storm of 1987 while areas with 10-12% plant cover or with higher cloddy surface suffered negligible soil loss (Samra and Narain, 2006).

Waterlogging, Salinization and Acidification: Waterlogging causes reduction in oxygen supply to the root zone resulting in excess accumulation of toxic organic constituents and reduced forms of metallic ions such as iron and manganese thus causing complete failure of crops. It is estimated that India loses 1.2 to 1.6 million tones of food grain production every year due to waterlogging resulting from temporary submergence of soils by floods as well as rise in water table (Brandon et al., 1995). Reclamation of waterlogged saline soils is a costly affair and the progress is very slow. So far about 22000 ha barren waterlogged saline soils have been reclaimed (Table 23).

Table 23: Extent of salt affected and waterlogged saline soils reclaimed in different states

Salt affected area (m ha) State

Area affected Area reclaimed

Waterlogged saline area reclaimed

(ha)

Punjab 0.530 0.366 250

Haryana 0.700 0.547 1650

Uttar Pradesh 1.200 0.140 -

Rajasthan - - 15000

Karnataka - - 5000

Reclaimed waterlogged saline soils have the potential to produce 4.0 to 9.5 t/ha of wheat with a benefit cost ratio of 1.26 to 3.99, where nothing was growing (Anonymous, 2004a). Reclaimed area is contributing nearly 6 million tonnes of paddy and wheat annually in Punjab, Haryana and Uttar Pradesh.

The loss in productivity due to salinity in India is estimated to vary from 6.2 million tonnes (UNEP, 1993) to 9.7 million tonnes (Bansil, 1990). The difference is attributed to the fact that UNEP takes into account only the agricultural lands while Bansil includes other non-wasteland and other non-forest land as well. The annual loss in production of 11 major crops varied from 1.5% to 3% for UNEP and Bansil data, respectively. It is estimated that reclamation of 8.5 Mha salt-affected soils in India with suitable technology can produce additional 50-55 Mt of food grains annually with a benefit cost ratio of 4.6 without government subsidy on gypsum and between 6 and 7 with 50-70 percent subsidy (Yadav, 2007). The reclamation and management package for waterlogged, saline and alkali soils consist of land leveling and construction of bunds (field dykes), adequate drainage provision for removal of excess salt and horizontal sub-surface drainage to control


0

1

2

3

4

5

6

Control 100% NPK 100%NPK+lime

100%NPK+FYM

Gra

in y

ield

of m

aize

(t/h

a)

1973-82 1983-92 1993-01

water table, assured source of good quality irrigation water, application of amendments (gypsum/pyrite) in alkali soils, leaching of excess salts, selection of suitable crops and cropping sequences and nutrient and water management (Tyagi, 1998).

Depending upon level of acidity, type of soil, crop grown and climatic conditions, acid soils can reduce productivity by 10-50% (Velayutham and Bhattacharyya, 2000). The reduction is attributed to low base saturation (20-25%), deficiency of calcium, magnesium, molybdenum, boron and zinc, low cation exchange capacity of Kaolinitic clay and poor nutrient retention, poor organic matter build up and nitrogen availability, high P fixation and its low availability, and excess/toxicity of iron, aluminium and manganese. A long-term study conducted in Typic Hapudalfs acid soil for 29 years (1972-2001) indicated that even 100 percent application of recommended NPK fertilizer dose without amendments (lime or FYM) failed to check the decline in maize (Fig. 17) and wheat (Fig. 18) yields (Subehia et al., 2005). The higher yields of maize to the tune of 0.85 and 1.27 t/ha over 100% NPK were obtained with application of lime @ 0.9 t/ha and FYM @ 10 t/ha, respectively. Similarly, 100% NPK with FYM yielded highest wheat grain yield of 2.4 t/ha followed by 2.3 t/ha with 100% NPK + lime as against 1.6 t/ha with 100% NPK without amendments.

Fig. 17: Impact of nutrient and amendment on yield of maize in acid soil


0

0.5

1

1.5

2

2.5

3

3.5

4

Control 100% NPK 100%NPK+lime

100%NPK+FYM

Gra

in y

ield

of w

heat

(t/h

a)1973-82 1983-92 1993-01

Fig. 18: Impact of nutrient and amendment on yield of wheat in acid soil

Organic amendments like FYM, coir pith and press mud in conjunction with lime have been found quite effective. Depending upon their sensitivity to pH, high responsive crops (pigeonpea, soybean, cotton), medium responsive crops (gram, lentil, pea, maize and sorghum) and low responsive crops (paddy, small millet, mustard) can be grown.

5. Soil Physical Constraints The impact assessment of technologies developed for soils having sub-surface

mechanical impedance under field conditions show spectacular increase in production of major crops varying from 12 to 63% (Table 24) (Painuli and Yadav, 1998).

Table 24: Field evaluation of technologies for soils having sub-surface mechanical impedance

Technology Soil type (location)

Mode of evaluation

No. of years

Crop

Increase (%) in yield over

farmer’s practice

Chiesel technology (chiseling up to 45 cm at 50 cm interval)

Red soil (Coimbatore)

ORP- rainfed (8 acres) ORP irrigated (8 acres)

1 1 1 1 1

Sorghum (1 crop) Maize (II crop) Groundnut (1 crop) Tomato (II crop) Black gram (1 crop) Samai (II crop) Maize (I crop) Maize (II crop) Maize

18.6 21.6 62.7 26.9 64.1 28.9 55.7 28.2 34.4


Chiesel technology (chiseling up to 30 cm interval)

Black soil (Nizamabad)

Farmer’s field

1 Sugarcane 12.0

Chisel technology (chiseling up to 40 cm depth at 50 cm interval)

Sandy loam (Hisar)

Farmer’s field

- Wheat Cotton Raya

14.0 17.0 41.0

Chisel + amendment (gypsum @ 5 t/ha or FYM @ 25 t/ha) technology

Black soil (Nizamabad)

Farmer’s field

1 Sugarcane 25.4

Ridge technology Sandy loam (Hisar)

Farmer’s field

- Mustard 33.0

The raised and sunken bed (RSB) technology for vertisols having high clay content has been found to be highly remunerative on sustainable basis (Painuli et al., 2002). Soybean on raised bed produced 2.28 t/ha against 1.0 t/ha on flat bed while paddy yielded 2.6 t/ha in the sunken bed on net cropped area basis (Table 25). The technology is equally effective in sub-surface compacted soils as effective rooting depth is increased by 30 cm in raised beds. The technologies for checking sub-surface mechanical impedance and compaction also help in conserving soil and water besides increasing productivity.

Table 25: Productivity of soybean-rice cropping sequence in raised and sunken bed system of cultivation (t ha-1)

Soybean seed yield Selected year

Raised bed Flat bed

Paddy grain yield in sunken

bed

Annual rainfall (mm)

1980 2.96 2.23 5.10 1432

1985 2.25 1.00 2.50 1380

1990 2.43 0.58 3.00 1624

1995 1.76 1.11 4.47 1153

Mean of 16 yrs. 2.28 0.96 2.61 1397

Horti-pastoral system of aonla + hybrid napier was found to be more effective than pure aonla in reducing compaction in 10-30 cm soil depth from 1890 to 284 kpa (Yadav et al., 2005).

Poor Quality Ground Water : Long term use of poor quality water makes EC of top 60 cm of soil equal to that of irrigation water and high ESP in upper soil layer. It causes breakdown of structure in alkali soils and salt induced water stress in saline soils. The


strategies for minimizing the impact of poor quality water on crop productivity include the following: • Application of less amount of poor quality water • Conjunctive use with good quality water by blending alkaline/saline water with canal

water, rotational use of saline/fresh water and management of shallow saline water table

• Application of gypsum to neutralize RSC of irrigation water. Add 12 kg gypsum per hectare to neutralize 1 meg/l RSC for 1 cm of irrigation water.

• Appropriate water and nutrient management to prevent adverse impact of salts • Selection of suitable crops, varieties and rotations.

Pollution due to Urban Industrial Wastes and Excessive Use of Chemicals : The use of waste water from Nag river in India for 20 years was found to have no effect on morphological and physical properties of soil (Bhise et al., 2007). In fact it improved the availability of Ca, Mg, K, Zn, Cu, Mn and Fe under five land use systems tried. However, it had adverse impact on EC, ESP, soluble cation ratio (Na/K and Na/Mg) and heavy metal (Pb, Cd, Co and Ni) contents thus causing accumulation of toxic elements.

The impact assessment of wastes utilization in agriculture can be visualized in terms of soil quality, plant growth and human and animal health. Type of soil and organic matter contents play a crucial role in the amount of heavy metal that can be adsorbed. Detailed study on adsorption of Cd in sewage irrigated Haryana soils revealed that Cd adsorption was positively correlated with clay content, CEC, pH and organic matter (Lal and Minhas, 2005).

Use of solid and liquid wastes has risk of transfer of heavy metals and their accumulation in edible parts of vegetable and meat products. Sewage flowing through Musi river near Hyderabad has shown that Cd, Cr, Ni, Pb, Co, Zn, Cu, Fe and Mn get accumulated in milk produced by animals fed on fodder grown with sewage (Anonymous, 2004b). All these metals exceeded the safe limit in the milk produced (Table 26).


Table 26: Relationship between heavy metal contents in water, soil, plant and milch animals along Musi river draining Hyderabad city

Sewage Soil Plant Urine Serum Milk Element

Mean PSE Mean High PSE Mean High PSE Mean Mean Mean PSE

Cd 0.025

(5)

90 0.37

(0.7)

27.0 10 0.79 20 4 0.053 0.022 0.062

12.4

100

Cr Tr -- 1.32

(0.7)

12.2 -- 4.90

(2.5)

92 36 0.226 0.140 0.780

(15.6)

100

Ni 0.062

(1.3)

85 2.79

(1.4)

46.3 22 4.34

(2.2)

100 24 0.224 0.029 0.497

(3.9)

100

Pb 0.210

(1.3)

90 12.50

(2.5)

60.9 32 19.22

(3.9)

100 100 0.850 0.385 0.730

(14.9)

100

Co 0.053

(10.6)

100 0.52 4.9 -- 2.39

(1.2)

68 -- 0.345 0.077 -- --

Zn 0.003 Nil 10.96

(2.2)

87.8 -- 44.88

(2.2)

88 32 0.074 0.496 6.300

(1.3)

62.5

Cu 0.011 Nil 5.83

(3.2)

60.9 56 12.76

(2.1)

92 56 0.060 0.302 0.420 --

Fe Tr -- 75.9

(7.6)

92.7 65 4.59

(3.1)

84 60 0.370 24.16 11.900

(39.7)

100

Mn Tr -- -- -- -- 92.86

(1.8)

68 24 0.058 0.04 0.920

(9.0)

100

Source: Anonymous, 2004b

Figures in parentheses are number of times more than the normal limits; tr-traces; PSE- percent samples having excessive amounts than the prescribed limits.

The pesticides use in India may increase in the coming years due to intensification of modern agriculture which may have serious repercussions on soil and human health. Some of the negative impacts include excessive mortality and reduced reproductive potential in organisms, a reduction in number of species and diversity of ecosystems, deterioration of soil health and development of resistance to pesticides in the target and non-target species (TERI, 1998). Recent studies conducted by CCS HAU, Hissar (2003) have shown alarming levels of pesticide contamination in human food and water resources (Table 27).


Table 27: Pesticide residue persistence in food, fodder and irrigation waters as seen in year 2001

Sl. No.

Commodity Samples

(nos.) Contamination Major residues

1. Feed & fodder 126 81.0 HCH, DDT, Chloropyri-phos, Endosulphan

2. Milk 537 52.0 HCH (94%), Endosulphan (9%) DDT residues

3. Butter 184 64.7 -do-

4. Irrigation waters

(a) General water 258 60.0 HCH, DDT

(b) Surface water 251 73.0 Endosulphan, Chloropyri-phos

(c) Canal water 10 100.0 -do-

(d) Pond water 11 100.0 -do-

Source: CCS Haryana Agricultural University, 2003

Nutrient Mining: Studies have established that it is not possible to obtain economical yields of major crops in different regions of the country on long term basis (Swarup and Wanjari, 2000). Unfertilized exhausted soils can produce wheat, rice and maize yields only in the range of 0.8-1.1, 1.5 – 1.6 and 0.3 – 0.7 t/ha (Table 28). The yields can be increased and also sustained at higher levels of 4.0 – 5.0, 2.4 – 4.6 and 2.5 – 3.0 for rice, wheat and maize, respectively if deficient nutrients are brought to sufficiency levels through chemical fertilizers.

Table 28: Mean grain yield of crops under long term fertilizer application and manuring

Mean grain yields (t ha-1)

Location & Duration

Crops Unfertilized

100% NPK

100% NPK+FY

M

150% NPK

Barrackpore (27 yrs) Rice wheat

1.6 0.8

3.9 2.4

4.1 2.5

4.3 2.9

Bhubneswar (22 yrs) Rice Wheat

1.6 1.4

2.8 3.0

3.5 3.7

3.0 3.3


Coimbatore (28 yrs) Finger millet Maize

1.0 0.7

3.0 3.0

3.5 3.4

3.2 3.2

Ludhiana (29 yrs) Maize Wheat

0.4 1.0

2.6 4.8

3.2 5.0

2.5 4.9

Jabalpur (20 yrs) Soybean Wheat

0.9 1.1

2.1 4.2

2.2 4.6

2.1 4.4

Pantnagar (28 yrs) Rice Wheat

3.1 1.5

5.3 3.8

6.0 4.5

5.3 4.1

Palampur (26 yrs) Maize Wheat

0.3 0.3

3.2 2.5

4.6 3.3

4.0 3.0

Studies under Integrated Plant Nutrients Supply (IPNS) system proved that various types of organic sources of nutrients like FYM, crop residues and green manuring not only maintain the yield but also reduce input cost, enhance profit and improve soil health (Yadav et al., 2000). Nutrient studies for more than a decade have shown non-significant differences in yield of rice grown by 50 percent nutrient substitution by FYM, crop residues or green manure (Table 29). However, no nutrient balances need to be worked out to ensure the sustainability of the system. A system which is sustainable improves soil organic and fertility build up, increases yield and economic returns without causing adverse effect on environment.

Table 29: Grain yield (tha-1) for rice under long term application of NPK along or on substitution with organic sources

Location & Duration Control 50%

NPK 100% NPK

50% NPK + FYM

50% NPK + CR

50% NPK +

GN

Ludhiana (15 yrs) 2.05 3.95 6.08 5.57 5.06 6.05

Panthnagar (15 yrs) 2.80 3.39 4.56 4.03 3.84 4.29

Kanpur (13 yrs) 1.76 3.04 4.47 3.80 3.65 4.22

Faizabad (14 yrs) 1.66 2.91 4.20 4.03 3.78 3.88

Sabour (12 yrs) 1.58 2.78 4.11 4.08 3.87 3.90

Kalyani (13 yrs) 1.37 2.53 3.32 3.37 3.46 3.68

Jabalpur (12 yrs) 2.51 3.62 5.09 4.78 4.37 5.20

Mean 1.96 3.18 4.59 4.24 4.00 4.46

CD (P=0.05), Treatment (T) 0.21, Location (L) 0.21, Interaction(T x L) 0.53


RANCHI (ALFISOLS)

100%NPK 100%NPK+ FYM Control

0.5 0.4 0.3 0.2 0.1 0.0

1970 1980 1990 2000 2010 2020 2030

Years

Depletion of Organic Matter: Projection for 60 years (1970-2030) data showed that SOC could be maintained at the base level of 0.45 percent in Alfisols with conjunctive use of chemical fertilizers and FYM while it reduced to 0.30 and 0.36 percent under no fertilizer and chemical fertilizers treatments, respectively (Fig. 19) (Vision 2025, IISS, Bhopal).

Fig. 19: Projected level of soil organic carbon under different nutrient management practices under soybean-wheat rotation

The SOC can be improved through Integrated Nutrient Management (INM) by applying NPK in conjunction with FYM. Long-term studies in Mollisols indicated that INM helped in maintaining the SOC at the same level after 31 years of cropping cycles (Sharma et al., 2007). Addition of FYM with 100% NPK maintained the SOC at around 1.54 percent.

Land uses like agroforestry and agri-horticulture increased the soil organic content by about two folds compared to sole cropping within a short span of 6 years (Table 30) (Das and Itnal, 1994). Different species vary in their capacity to build up organic carbon under similar soil and climatic conditions. In salt-affected soils, organic carbon content increased many times in soil profiles under differet plant species, the maximum being under Prosopis juliflora and lowest under Eucalyptus tereticornis.

Table 30: Organic carbon content in soils after six years under different land uses

Organic carbon (%) Land use

0-15 cm 15-30 cm Sole cropping 0.42 0.37

Agro-foresry 0.71 0.73 Agri-horticulture 0.73 0.74 Agri-silviculture 0.38 0.56


The SOC in the degraded soils can be improved by adopting the following measures: • Conservation tillage utilizing crop residues • Growing leguminous cover crops to enhance biodiversity and produce quality residue

for incorporation in soils • Adding N, P, K and all deficient nutrients to accelerate the process of humification to

convert organic residues to humus besides optimizing production. • Adding organic manures (FYM, Compost and vermin-compost) under IPNS. • Adopting soil conservation measures, viz; contour cultivation, contour and graded

bunding, terracing etc. to hold humified organic residues along with the soil. • Maintaining microbial biodiversity which is inherently important to the concept of

soil health and transformation of soil organic matter through various soil processes.

Floods and Droughts: Average flood damage to houses, crops and public utilities during 1953-02 has been estimated as Rs. 13,760.8 million affecting an area of 7.38 Mha and a population of 32.97 million (CESI, 2006). Human and cattle loss has been put at 1560 and 91555 affecting 3.48 Mha of cropped area in the country (Table 31). The maximum damage to area, human and livestock population, crops and public utilities occurred during the years 1977, 1978, 1979, 1988 and 1998. Due to high erosion rates and excessive sedimentation, the storage capacity of major reservoirs is lost at the rate of 1-2% every year.

The ideal solution for flood control is the creation of adequate storages in flood prone river systems. The best example is the construction of storages in the Damodar river basin by DVC which have made the floods a matter of history in the region. Floods can be prevented or significantly moderated by watershed management in the catchment areas of river basins. For international rivers originating in Nepal and Bhutan, a joint mechanism for watershed management needs to be evolved. The total area reasonably protected against floods in India by the end of Tenth Plan (2002-07) is 18.22 Mha (Planning Commission, 2007).

Table 29: Flood affected area and flood damages

Sl. No.

Item Unit Av. flood damage during

1953-02

Maximum damage (with

year)

Damage during 2002 (tentative)

1 Area affected million ha 7.38 17.50 (1978) 2.87

2 Population affected

million 32.97 70.450 (1978) 22.41

3 Human lives lost Number 1560 11316 (1977) 640

4 Cattle lost Number 91555 618248 (1979) 3647

5 Cropped area affected

Million ha 3.48 10.15 (1988) 1.27


Sl. No.

Item Unit Av. flood damage during

1953-02

Maximum damage (with

year)

Damage during 2002 (tentative)

6 Value of damage to crops

Million Rs 5969.70 25109.00 (1988) 5471.30

7 Houses damaged Million 1.19 3.51 (1978) 0.45

8. Value of damage to houses

Million Rs 1891.00 13078.00(1988) 4551.70

9 Value of damage to public utilities

Million Rs 5662.40 31714.00 (1998) 4864.90

10 Value of damage to houses, crops and public utilities

Million Rs 13760.80 58459.80 (1998) 14887.90

Note: Figure for the years 1998, 1999, 2000, 2001 and 2002 are tentative and are being finalized in consultation with State Govt. Source: 1. Central Water Commission; 2. Compendium of Environment Statistics India, 2006, Central Statistical Organization, Ministry of Statistics and Programme Implementation, Govt. of India (Website: http://www.mospi.gov.in).

India has experienced 40 major droughts in the past 200 years (1801-2002) with 10 years under severe drought category (> 39.5% area affected) and 5 years under phenomenal drought (>47.7% area affected) (Subbareddy et al., 2008). Since Independence, India has experienced 15 droughts out of which 3 were of severe, 7 of moderate and 5 of slight intensity affecting 13.3 to 49.2% of total geographical area of the country (FAI, 2006-07). Drought prone areas are more vulnerable to land degradation. In a good or normal rainfall year, they substantially contribute to agriculture production particularly for groundnut, bajra and jowar crops where they account for one-third to one-fourth of the total national production. Similarly, one-sixth to one-tenth of other important crops like ragi, maize and cotton and 12% of rice production is realized from these areas besides sizeable contribution to the production of pulses and oilseeds.

The severe drought in 2002 was widespread affecting 14 states. In Andhra Pradesh alone, crop loss of Rs. 5227 crores was estimated. About 75% of the districts received rainfall less than normal till July and 64% till the end of monsoon. The late sowing resulted in significant reduction in production of crops like rice (-12.5 Mt), wheat (-6.5 Mt), coarse cereals (-7.52 Mt), oilseeds (3.37 Mt), cotton (-2.61 M bales) and sugarcane (-15.82 Mt) (Subbareddy et al., 2008).

Climate Change Impacts: The analysis of monthly rainfall data for all the 36 sub-divisions of the country indicates that contribution of June and August rainfall exhibited significantly increasing trend while contribution of July rainfall showed a decreasing trend (Guhathakurta and Rajeevan, 2006). Thus, a major shift in rainfall pattern both spatially and temporarily has been recorded in the recent years. Analysis of long-term rainfall data for over 1100 stations across India show pockets of deficit rainfall over eastern Madhya Pradesh, Chhatisgarh and North-east region in Central and Eastern India


(Subba Rao et al., 2007), especially around Jharkhand and Chhatisgarh. In contrast, increasing trends (+ 10 to 12%) in rainfall are observed along the west coast, northern Andhra Pradesh and parts of NW India (NAPCC, 2008). In the Southern Peninsular region, a shift in peak monthly rainfall by 20-25 days from September to October is recorded.

The intensification of hydrologic cycle due to global warming may result in more intense rains, frequent floods and droughts, shifting of rainy season towards winter and significant reduction in mass of glaciers causing more flow in the initial few decades but substantially reduced flow thereafter. Analysis of rainfall data with intensities of 10,100 and above 100 mm revealed that in the recent period, the frequency of rain events of more than 100 mm intensity have increased while the frequency of moderate events over central India has significantly decreased during 1951 to 2000 (Goswami et al., 2006). Thus high intensity storms would cause high erosion losses leading to severe land degradation problems.

The deforestation, desertification and soil erosion are also disrupting the carbon cycle between pedosphere and atmosphere resulting in decline of carbon stock especially of soil organic carbon thus deteriorating chemical, hydrological and biological environment of the soil. India is the lowest contributor of the GHG compared to North America and many other industrial and developed countries (0.29 tonnes per capita consumption compared to 5.37 and 4.63 by USA and Australia at 1996 level). However, with growing industrialization and economic development, India may become the second fastest growing GHG contributor in the world (increase in per capita consumption to 1.02 tonnes by 2004) next to China (NAPCC, 2008). While the CO2 emissions at 1997 level had been 237 Mt, it is projected to increase to 775 Mt by the end of the century if coal consumption continues at the present rate (Ravi Sharma, 2007).

The average increase in temperature in India during 1901 and 2005 has been 0.51oC compared to 0.74oC at global level. The increase was in the order of 0.03oC per decade during 1901-1970 while it was around 0.22oC per decade for the period from 1971 to 2004 indicating greater warming in the recent decades. The projected increase in the 21st century is expected to vary between 3 to 6oC with southern regions registering 2-4oC increase while the increase (> 4oC) would be more pronounced in the northern states and eastern peninsular region. The rainfall from the normal period (1961-1990) till the end of 21st century has been projected to increase in India by 15 to 40 percent by different models.

The climate change would have serious impact on agriculture, water resources, forests, national ecosystems, fisheries and energy sectors. The yields of both rabi and kharif crops are expected to be adversely affected due to deficient and erratic distribution of rainfall. Potential yields of major cereal crops especially wheat is likely to be reduced due to probable increase in minimum temperature during the reproductive period. A simulation study on the impact of high temperature on irrigated wheat in north India indicated that grain yield can decrease by 17% if the temperature increased by 2oC (Aggarwal et al., 2001).


The climate change would disturb the water balance in different parts of India and ground water quality would be affected due to intrusion of sea water. Thermal expansion of sea water due to global warming coupled with melting of glaciers and snowfields would result in the rise of sea level by 0.1 to 0.5 metres by the middle of 21st century (IPCC, 2001). It is expected that by the end of the century, 68 to 77 percent of the forest areas are likely to experience shift in forest types with corresponding reduction in forest produce and livelihood prospects. Coastal wetlands would have serious impact due to change in the composition of plant species and expected sea level rise. The marine and aquatic life would be significantly affected due to rise of sea water temperature and sea level resulting in their migration to favourable regions, thus affecting livelihood of coastal people. The energy requirements in summers in plains would increase more than being compensated by saving in energy due to increased temperature in winter in northern mountainous regions. The demand for energy would also increase for irrigation needs due to high evaporative demands in cropped areas.

6. Strategies for Arresting Land Degradation For evolving effective strategies to check land degradation, it is imperative to assess,

characterize and classify different types of degradation problems and develop appropriate technologies to reclaim the degraded areas for their productive utilization. In India, participatory watershed management has been accepted as a tool for all developmental activities with a focus on socio-economic aspects apart from biophysical attributes following ‘bottom up’ participatory approaches. Common guidelines for watershed development projects have been formulated and implemented since April 1, 2008 for all the concerned ministries. Under the guidelines, 50% of the total budget is earmarked for natural resource management with special emphasis on treatment of degraded/wastelands and water resource development. It involves adoption of appropriate resource conserving technologies on arable and non-arable lands for holistic development of rainfed areas and wastelands for sustained productivity and environmental security. The following issues need to be addressed on high priority for efficient management of natural resources: • Integrated land resource management policy is needed to meet the projected

phytomass/ biomass demand by accounting for the reclamation of degraded lands and involving all the concerned ministries.

• For sustainable land use management, methodologies need to be developed for optimal land use planning at different scales using modern tools and procedures.

• There is a need to develop and evaluate integrated farming systems in different agro-ecological regions of the country to maximize productivity and profitability, input use efficiency, cropping intensity, resource conservation, employment generation, environmental security and poverty alleviation. It would encompass optimal combination of various enterprises, viz; agriculture, horticulture, livestock, fishery, forestry etc. for different categories of farmers and farming situations to achieve efficient utilization of land and water resources and prevent over exploitation of land.

• For productive utilization of waste/degraded lands, location specific alternate land use systems, viz; agri-horti, horti-pastoral, agri-horti-silvi, agri-silvi-medicinal and silvi-pastoral need to be developed for scientific planning of land resources following watershed approach.


• Soil quality deterioration is attributed to wide gap between nutrient demand and supply, imbalanced fertilizer use and emerging deficiencies of secondary and micro-nutrients in soils. The nutrient use efficiency can be increased by integrating and balancing the nutrient dose in relation to nutrient status and crop requirements to achieve higher partial and total productivity. Soil health cards should be prepared based upon modern soil testing tools or test kits depicting fertility status of agricultural lands for balanced use of fertilizers.

• The problem soils such as saline and alkali soils should be managed by leaching of excess salts, improving drainage systems, application of gypsum, growing green manures or mulches and tolerant crops and trees as per packages developed and recommended by research organizations.

• Soils polluted by heavy metals or toxic substances and excessive use of agro-chemicals can be ameliorated through phytoremediation, bioremediation, manipulating microbial catabolic genes and growing resistant crops.

• To prevent land degradation, conservation agriculture should be promoted to ensure minimum disturbance to the soil, provide permanent cover to the land surface and select appropriate cropping systems and rotation to achieve higher profitability and environmental security. It would include zero-tillage, residue management, mulching, cover crops and various soil and water conservation measures.

• Soil management practices like residue incorporation, manuring, reduced tillage and mulching play a vital role in sequestering carbon in the soil and check CO2 emissions. Reclamation of degraded soils and ecosystems following watershed approach can enhance the terrestrial C pool, microbial population and soils net C sinks for higher and sustained productivity.

• Suitable soil quality indicators need to be developed to sustain hydrological, biological and production functions of the soil and prevent deterioration of land resource due to physical, chemical and biological factors.

• Enabling policy framework is essentially required by enacting suitable legislations to provide for remediation of damaged soils, trans-boundary impact of pollution and cost of land degradation to tax-payers. The polluters must pay for abuse of the land resource through dumping of industrial or domestic wastes, irrigation with poor quality water, excessive use of agro-chemicals, intensive use and over-exploitation of land especially the marginal and fragile ecosystems and non-adoption of appropriate conservation measures during mining and related activities.

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134 Land Degradation and Rehabilitation in Nepal

C o n t e n t Page 1. Introduction 135 2. Land Degradation 136 3. Causes of Land Degradation in Nepal 137

3.1 Geomorphology and Land form 137 3.2 Population Pressure 138 3.3 Land use 139 3.4 Soil Acidification and Soil Fertility Depletion 139 3.5 Shifting Cultivation 140 3.6 Torrential Rainfall and Glacial Lake 140 3.7 Livestock 140 3.8 Pressure on Forest 141 3.9 Infrastructural Development 141 3.10 Earthquake 141

4. Types of Land Degradation and Its Extent 142 4.1 Erosion 142 4.2 Flooding 143 4.3 Water logging 143 4.3 Stone Quarrying 143

5. Status of Land Degradation in Nepal 143 5.1 High Himalayas 144 5.2 Middle and High Mountains 144 5.3 Inner Terai/ Siwalik 144 5.4 Terai (Plain area) 144

6. Impact of Land Degradation in Nepal 144 7. Government Policy, Strategies and Programs 145

7.1 Agriculture 145 7.2 Forestry 145

8. Conclusion and Recommendations 147 9. References 149

Land Degradation and Rehabilitation in Nepal 135

1. Introduction Nepal is a mountainous country, sandwich between of China on the North and India

on the East, South, and West. It lies between 8004' to 88012' longitudes toward east and 26022' to 30027' latitudes toward north along the southern slope of great Himalayan between the Tibetan plateau in the north and Genetic plain in the south. The altitudinal variation of this country ranging from 67 meter in the south and 8848 meter amsl in north within less than 200 km distance. The country comprises of an area of 147,181 square kilometers. Nepal has divided into five physiographic regions, namely: the High Himalayas, the High Mountains, the Middle Mountains, the Siwalik and the plain Terai covering 22.7, 20.1, 30.1, 12.8, and 14.3 per cent of the total area of the country, respectively (LRMP, 1986).

Soil, water and vegetation, the basic natural resources of the life support system in Nepal, are under intense pressure due to natural and human accelerated factors. With different landform and climatic variation, different soils types prevail in Nepal. The hills soils are of medium to light texture with dominance of coarse-grained sand and gravel having very high permeability. The soils in the hills slopes tend to loss topsoil because of their erosive nature. The soil originating from weathered soft rocks are characterized by a high degree of porosity and poor slope stability is a common problem, particularly in the Siwalik. The soil reaction is moderately to strongly acidic. The organic matter, nitrogen, phosphorus and potassium content vary from low to medium, representing low to medium soil fertility (Joshy, 1997). The major soil orders of Nepal according USDA taxonomy system are Entisols, Inceptisols, Spodosols, Mollisols, Alfisols, and the soil orders occasionally found are Ultisols, Aridisols and Histosols (LRMP, 1986).

The major land use of Nepal namely agriculture, forests, grazing and shrub land covers about 26.8, 38.1, 11.9 and 4.7 per cent of the country, respectively. Similarly, perpetual snow, rock and sand, gravel and boulders cover about 3.5, 13.3 and 1.4 percent of the country and others cover 0.3 percent (LRMP, 1986). Land use distribution pattern in Nepal in different physiographic region is given in Table 1.

The country lies within the subtropical monsoon climate region, but because of its varied elevation and topography, it has a wide range of climates varying from Tropical to Arctic regions. About 60 to 80 percent of the total rainfall occurs in four months from June to September. With the wide range of temperature, altitude, slope and rainfall, Nepal has a rich in biodiversity. The distribution of vegetation generally follows the altitudinal zones.

Nepal has drained by three major river systems, the Koshi, Gandaki, and Karnali along with more than their 6000 tributaries (MoPE, 2004). All the rivers of the country ultimately flow to the Bay of Bengal.

Agriculture is the mainstay of the national economy, which accounts for about 40 per cent of the GDP and 70 per cent of the employment. Food grain production constitutes 82 per cent of the total agriculture production and among them cereal crops viz. rice, wheat, maize and millet occupy 61 per cent of that part. Total cultivated agricultural land is 2.97 millions hectare.


Table 1: Topographical Distribution of Land (Area ‘000 ha)

Agricultural Physical Condition Cultivated Non-

cultivated Grazing Forest Others Total

Hill Himalayas 7.7 1.7 884.4 221.5 2233.9 3349.2

High Mountain 244.8 146.9 509.9 1813.1 244.7 2959.4

Mid Mountain 1222.3 665.5 292.7 2202.4 60.7 4443.6

Siwalik 258.9 55.2 20.8 1476.6 74.3 1885.8

Terai 1234.3 117.5 49.7 592.9 116.0 2110.4

Percentage 21.1 6.7 11.9 42.8 18.5 100

Total 2968.0 986.8 1757.5 6306.5 2729.6 14748.4

Source: Rimal and Rimal, 2006

Steep hills and mountains comprise approximately 86 percent of the area. The rate of natural and anthropogenic erosion in the geologically young and seismically active mountains is high. The rapidly increasing infrastructural development like roads, irrigation canals, and dams create ecological disturbance provide the grounds to erosion and land degradation. Moreover, erosion and mass wasting in the high land and flooding and sedimentation in the lowlands have become a regular phenomenon in this region. Consequently, land degradation of mountain ecosystems is becoming increasingly widespread.

2. Land Degradation Land degradation has generally defined as the temporary or permanent decline in the

productivity capacity of the land (Stocking and Murnaghan, 2001). Land degradation may also be defined loss of utility or potential utility of land or to the reduction, loss, or change of features of land or organisms that cannot be replaced (Barrow 1991). Land degradation is one or more processes of reducing its current and potential capability to produce goods and services. It mainly reduces the biological productivity therefore the carrying capacity of the land. Thus, it reduces the production of fuel, fiber, food, and fodder thereby threat to the survival of the human kinds.

Land degradation is a serious environmental issue in Nepal leading to socioeconomic instability because the country is unable to supply adequate food and others basic requirements. In addition, the natural resources such as water, forest and land are also at declining state to support the livelihood of the hill and mountain people. Nepal is basically agricultural based whose important components are forestry, livestock and agriculture and the socio-economic status of the people determines the sustainable management of these resources. In recent year, government and other institutions and personnel involved in research and development have shown a great concern that there has been over exploitation and mismanagement of land resources. The hilly and


mountainous landscape itself is very vulnerable posing land degradation because of inherent geological and topographic properties. The climate and human pressure eventually further accelerate the land degradation processes. The ever growing population determines the sustainable management of these resources.

3. Causes of Land Degradation in Nepal Local geology, soil type, landform, land use, rainfall intensity, and human

activities/population pressure are root causes of the land degradation in Nepal (Figure 1). The causes of land degradation can be visualized as:

Fig. 1: Causes of Land Degradation and their Relationships, Nepal (UNEP, 2001)

3.1 Geomorphology and Land form Nepal is a diverse country with complex geomorphology, landform and climate with

a short span in width. Physiographically, Nepal has divided into five regions viz. High Himal, High Mountains, Middle Mountains, Siwalik and plain Terai. About three quarter’s of the Country’s topography is rugged comprising high Himal, High Mountains, Middle Mountains and the part of Siwalik region and remaining part is plain terai in south of the country (Figure 2). The rugged hills are geologically young and fragile

Less Manure Grassland Degradation

Fodder Deficit

Forest Degradation

Soil Erosion

Population Growth

Food Deficit Wood Deficit

Cultivation of Marginal Lands

Intensive Agriculture

Overgrazing Excessive Lopping of Fodder

Over Deficit

Reduced FertilityLand Degradation

Natural Causes


including Siwalik are more prone to landslide, mass movement, and soil erosion in the intense monsoon period. Consequently, frequent flooding in terai region causes loss of human life, agricultural product and washing away of infrastructure every year.

Fig. 2: Physiographic Division of Nepal

3.2 Population Pressure The population of the country reached 18.49 million in 1991 (CBS, 1994) with a

growth rate of 2.08 percent and in the fiscal year of 2005/06 the population has reached 26 million with a growth rate of 2.25 (CBS, 2009). The population density per square kilometers of total land is 176. Land has been one of the major natural resource available for economic development of the country. Agriculture has been basis in fulfilling basic needs for subsistence living of the major population of the country. Majority of the population deriving their livelihood from land resource is definitely not a favorable situation for the stability of hilly environment. The constant increase in the population depending on agriculture has many implications. One consequence is that the process of fragmentation of agricultural land parcels has continued because of an increase in the number of farming households, turning landholding parcels into uneconomic sizes in terms of modern agricultural practices. Secondly, there is a skewed distribution of landholdings among farmers, and this has hindered agricultural land development. The number of marginalized and small farmers with landholdings below one-hectare accounts for 69.4 % but these farms covers only 30.4 % of the total landholding area. Shifting cultivation has persistently existed in scattered form in the remote hills, encroaching upon forests. The impacts of land degradation such as landslides, soil erosion, and flash floods, are the most pressing problems particularly in Mid-hills of Nepal. These are every year phenomena that take place particularly during the rainy season. While landslides and soil erosion occur oven the hills and mountains, flash floods occur in the valleys and the Terai plains.


For the subsistence living, one family in the Mountain needs more than 1 hectare in

the Hills and 0.5 hectare in Terai. However, 43 percent of all land holdings were less than 0.5 hectare in size in 1991/92 (CBS, 1994). Therefore, those fraction of people are forced to seek additional land or other employment for their subsistence living. Since most of the arable lands are already under cultivation, the expansion of agriculture land will be mostly on fragile and marginal lands resulting land degradation. The farming of sloping areas especially in the hills and mountains without adequate conservation measures is another major cause responsible for the erosion of fertile topsoil.

3.3 Land use Land use beyond its capabilities or suitability is the root cause of land degradation in

Nepal. The soil conservation and watershed management plans prepared by the Department of Soil Conservation for some areas indicate that 19 percent of currently cultivated land should not be cultivated. Similarly 33 percent of forest, 51 percent of shrub land and 56 percent of grass land need permanent protection. Proper drainage is essential for 61 percent of agriculture lands and of which proper terracing is essential for 23 percent of agriculture land to continue cultivation. Land use beyond its capability or suitability and without due consideration of the conservation measures is the root cause of land degradation in Nepal.

3.4 Soil Acidification and Soil Fertility Depletion Topsoil degradation and loss are possibly the most serious processes affecting

sustainability of farming systems in the hills and mountains of Nepal. Throughout the hill regions, particularly at lower elevation where rainfall intensity is highest, erosion is a major contributor to the decline of soil fertility. Increased degradation of marginal upland soils results in the loss of nutrients. The estimated soil and nutrient loss are given for major production systems of Nepal below 1,000-m elevation in Table 2 (Carson, 1992).

Soil acidification degrades land, lower crop productivity and increase soil vulnerability to contamination and erosion. Soils are often initially acidic because their parent materials were acidic and initially low in the basic cations (Ca, Mg, K, and Na). Acidification occurs when these elements are removed from the soil profile by normal rainfall or the harvesting crops. The pH of the Nepalese soils usually ranges from 4.0-8.0. Most of the soils are formed from the acidic and neutral parent materials; they are slightly acidic to neutral in reaction. Soil of the middle and High mountains regions are acidic in reaction (Joshy, 1997). Continuous use of acidifying nitrogenous fertilizers like ammonium sulfate and urea has contributed to the development of high acidity in the agricultural land causing land degradation. It is even worse when there is unbalanced use of these fertilizers. Similarly, it has been reported that in the high mountain and mid hill area due to growing scarcity of broad leaf species intensive use of compost prepared from pine needles has helped in developing high acidity in the soils and thereby enhances the


land degradation.


Table 2: Estimated nutrient loss by rainfall erosion associated with different production systems

Rain fed Agriculture

Bench terrace Marginal land Grazing

(degraded)

Soil loss Depth in mm 0.4 1.0 8.0

Soil loss tons ha-1 yr-1 5.0 20.0 100.0

OM loss kg ha-1 yr-1 75.0 300.0 1500.0

Nitrogen loss kg ha-1 yr-1 3.8 15.0 75.0

Phosphorus loss kg ha-1 yr-1 5.0 20.0 100.0

Potassium loss kg ha-1 yr-1 10.0 40.0 200.0

Source: Carson, 1992

3.5 Shifting Cultivation Other forms of land degradation such as shifting cultivation whose extent and

coverage is not known clearly. Shifting cultivation is practiced in the mid-hills of Nepal in different intensity and is one of the causes of land degradation in many parts of the areas. Shifting cultivation had been a sustainable agro ecosystem in the past, but, it cannot serve as a model for the future. Regeneration of forests is crucial for the long-term productivity and sustainability of shifting practices. However, many farmers are no longer able to leave their fields fallow for the necessary period of time (Partap and Watson, 1994). Soil erosion during the monsoon due to high run-off is a serious problem and this process has further been accelerated due to the practice of shifting and sloping terrace cultivation in the hills and mountains of Central Nepal.

3.6 Torrential Rainfall and Glacial Lake Nepal being hilly and mountainous country with monsoon rain, major land

degradation is caused by the surface erosion, mass movement, river cutting and flooding. The hectic monsoon rains with localized cloud bursts pouring tremendous amount of rain in short period is one of the main reasons for the disastrous erosion with devastating damage to the land's quality therefore causing land degradation.

Glacial lakes are found above the snow line of the Eastern and Central Region of Nepal. Sudden breaks of these glacial lakes bring surges of debris laden floods and generally known as glacial lake outburst floods. The surge strips out the valley slopes causing unstable slopes to degrade.

3.7 Livestock Livestock, an integral part of agriculture production system are kept principally for

manure and all the draft power. Its milk, meat and wool production contributes as cash income for the owners. The cattle population of 7.36 million (2005/06) with its growth rate of 13 percent for the decade exerted tremendous grazing pressure on rangeland, grassland and forest. In addition, lot of fodder, bedding materials for cattle are collected


from the forest for the cattle feed, and biomass for the manure, which is the essential component for the subsistence farming system. There is a clear relationship between livestock, soil fertility and natural resources in the mountain farming system.

Livestock sector is a major performer in the agriculture. Therefore, sustainable management is an important aspect. The land available for raising livestock and feed availability according to the requirements is unbalance. The current stocking density is exceeding the carrying capacity except in the alpine meadows region. The situation is more alarming in the mid hills and open grassland (Tables 3), which are more vulnerable to land degradation.

Table 3: Stock density and carrying capacity in grassland in Nepal

Grass land Carrying capacity LU/ha Stocking density LU/ha

Mid-Hills 0.31 4.08

Steep grasslands 0.01 0.19

Open grass land 0.54 7.07

Alpine meadows 1.42 0.64

3.8 Pressure on Forest Heavy pressure on the forest for the additional agriculture lands and over-exploitation

of the fuel wood, timber and fodder to meet the demands of the fast growing population, the forest have been reduced and depleted the trees. Based on the aerial photographs the crown cover of the forest has been reduced at the rate of 2.1 per cent. For 1978/79 to 1990/91 period in the Terai districts, the annual deforestation rate has been estimated to be 1.3 per cent (FRISP, 1994). Resettlement program of the Government for hill migrants in Terai is also responsible for most of the deforestation in Terai. The rapid deforestation situation has increased soil erosion and mass movement in the hills and mountains and at the same time, there is widespread flooding and sedimentation in the plains and valleys. Because of rapid deforestation, it has become increasingly difficult for the people to meet their basic needs for forest products. Pressure on the remaining forests is further intensified, creating a vicious circle and aggravating the already serious problems of deforestation and therefore land degradation.

3.9 Infrastructural Development The rapidly increasing construction of infrastructures like roads, irrigation canals,

and dams residential house construction without due consideration of the conservation measures has encouraged soil erosion and landslides aggravating directly or indirectly land degradation.

3.10 Earthquake Nepal being seismically active, earthquake also aggravates land degradation by

setting the geology weak and triggering the mass movement. The earthquake in eastern Nepal occurred at the 6.7 Richter scale on 21 August 1988 took a heavy toll of 730 human lives and triggered several landslides.


4. Types of Land Degradation and Its Extent Almost all types of land degradation exist in Nepal. However, erosion, flooding and

water logging are the three major types of land degradation processes most prevalent in Nepal. Its extent has been broadly assessed as follows:- 4.1 Erosion

Erosion, mainly water, is one of the major land degradation processes most prevalent in Nepal due to its steep slopes and hectic monsoon. Almost all of Nepal is affected by water erosion mainly by surface erosion, mass movement (slumping, gulling, landslides and rock fall) and riverbank cutting, and some areas are affected by deposition and water logging (LRMP, 1986).

Table 4: Estimates of Soil Erosion Rates

Land use categories Soil erosion rate (tons/ha/yr)

Well-management forest land 5-10

Well-management paddy terraces 5-10

Well-management maize terraces 5-15

Poorly-managed slopping terraces 20-100

Degraded rangelands 40-200

Source: UNEP, 2001

The extent of area mainly affected by riverbank slumping and gulling is about 16398 sq. km., slumping and gulling is about 4244 sq. km. mass wasting (slumping, landslides rock fall and avalanches) is about 116566 sq. km. Expressing watershed condition at the district level, it is estimated that 5, 7 and 13 districts are under very poor, poor and marginal condition, respectively. There are 25 districts each under fairly good and good watershed condition (Shrestha et. al., 1983). The productivity of the land has been significantly reduced in 34 and 20 percent of the areas of Siwalik and the Middle Mountain region respectively.

Owing to the complex features of the mountain terrain, the nature of soil degradation varies greatly. However, information on soil degradation is scattered and sketchy. Table 4 provides information on the soil erosion rates for different lands-use categories. The soil erosion rate appears to be higher in the unmanaged land-use category and on steep slopes than in the managed land-use category.

The impacts of soil degradation are many and all are closely related to environmental degradation. One of the direct impacts of soil degradation is the loss of fine topsoil. There is also depletion of organic matter and plant nutrients along with the topsoil, which ultimately affects soil fertility. The average annual weight of sediment per unit area affected deposited by various rivers in Nepal is shown in Table 5.


Table 5: Sediment Yields from Some of the Main Rivers

River Location/Regions Rate (tones/ km2/yr) Tamor East 8,200 Sun Koshi Central and East 3,970 Bagmati at Chovar Kathmandu Valley, Central 3,030 Trisuli Betrawati, Central 2,750 Karnali Chisapani, Far West 5,100

Source: CBS, 1998

Landslides are another important factor in soil degradation. Landslides occur almost every year in every part of the country, resulting in the loss of land and lives. Several people’s life has loss and effect on land and families due to erosion, landslides, and flood in different years. Roads, trials, bridges, and property are also damaged or destroyed.

4.2 Flooding High intense rain has been main reason for the flooding during the monsoon in the

low-lying valleys and Terai plains. The floods can cause serious damage to infrastructure, houses, agriculture land and the environment along the flood path. The area affected by the floods accounts about 8977 square kilometers. These areas are flooded with different frequency damaging the fertile plains by scouring and sediment deposition.

4.3 Water logging Water logging is mainly problem during the monsoon period in depression of the

Terai region, where drainage has been disturbed due to some man made reasons such as embankment, dams, roads etc. Also, marshy land is observed in the Terai region, south of Bhabhar zone where two lithological units having different porosity and permeability meet along with the change of elevation resulting mainly spring lines, pond, lakes etc. The area affected by water logging during the monsoon is about 7297 square kilometers and has been mainly used for the rice cultivation.

4.3 Stone Quarrying Stone quarrying for construction materials has been one of the major causes of

landslides in the accessible areas. The flood and debris flow due to cloud bursts in 19-20 July 1993 were strongly influenced by unmanaged stone quarrying mainly along the high ways. In the year 2007-2010, the construction companies are quarrying stones and boulders from Siwalik range aggravating further land degradation.

5. Status of Land Degradation in Nepal Up to date status of the land degradation in Nepal has not well documented.

However, general remarks about the land degradation in the different physiographic zones can be stated as follows:-


5.1 High Himalayas In the High Himalayas, areas rockslides, avalanches and glacial lake outbursts are the

main erosion types resulting disastrous floods therefore land degradation.

5.2 Middle and High Mountains High population density, coupled with intensive land use and tourism enhanced

erosion in these regions. The predominant erosion processes in these regions are mass wasting and gully erosion. Surface erosion (rill and inter-rill) on sloping agriculture land is prevalent in the Middle Hills and to some extent in the High Mountains. A majority of the sediment load contribution to the rivers are derived from surface erosion. However, compared to mass wasting and gully erosion the contribution to in-stream sediment from erosion of agriculture land is considered to be less.

5.3 Inner Terai/ Siwalik This region lies at the foot of the Mahabharat range. In this region, there are several

inner valleys or Duns, which are densely populated. Because of the alluvial deposition by the rivers, these valleys are very fertile and are potential places for good agriculture. Siwaliks consists of weakly consolidated Tertiary sediments with gentle to strongly dipping slope. Its soils are unstable to retain high precipitation that frequently occurs resulting to flash floods in the river systems of the region. The Siwaliks areas are highly vulnerable to water erosion and flash floods occur frequently in the low-lying areas. The rivers flowing in the Siwalik region transport tremendous volumes of debris during the monsoon season causing land degradation by vast sedimentation of the fertile plains.

5.4 Terai (Plain area) This region is the flat plain area and is an extension of the southern Indio-Gangetic

Plain. The Terai regions are known as the granary of Nepal. Wherever irrigation water is available, the land is intensively cultivated. The Terai region, a gently sloping plain of alluvial deposits is subject to severe flooding, river shifting and riverbank cutting threatening the stability of agriculture in many areas of this region. The middle Terai is an undulating terrain with isolated pockets of water logging and marshy condition.

6. Impact of Land Degradation in Nepal The impact of land degradation are the loss of top soil and organic matter; plant

nutrients; landslides; siltation; loss of biodiversity and so on. It is estimated that a loss of soils at the rate of 5 tons per hectare, which is equivalent to loss of 75, 3.8, 10 and 5 kg per hectare of organic matter, Nitrogen, potassium and phosphorus, respectively (Carson, 1992). Similarly, Nepalese river systems drain thousand tons of soil per year, example of which is given in Table 5. Erosion estimated from some of the watershed indicated more than 70 tons per hectare of soil loss. Landslide is another example of land degradation in Nepal. As Nepalese landscape is relative young and rainfall pattern in Nepal is intense during summer monsoon period, event of landslide is higher during June to September. The loss of human life, agricultural land, livestock and soil have directly influence in the


ecology and economy in Nepal. Washing away of top soil and landslides in the hills cause frequent flooding in the terai region, which again temper national economy as well as life of human, livestock and other flora and fauna.

7. Government Policy, Strategies and Programs Extensive Land Degradation is caused mainly by the excessive land use. There are

numerous government and non-government sectors and agencies related with land degradation and working to rehabilitate degraded lands. Ministries of Agriculture, Forest and Soil Conservation and Water Resource are the three main line agencies and there are several non-governmental agencies involved in the land use and rehabilitation of degraded lands. However, agriculture, forestry and water resource are priority sectors of the government as well.

7.1 Agriculture Agriculture is mainly run by the private sector. Agricultural development is

determined by changes in prices, technologies, infrastructure and institutions. Role of government in the agricultural development is important for controlling agricultural land degradation. Government provides support service to ensure the delivery of the agriculture inputs and through extension provide the technical know how. In addition, government provides credits for the agriculture development through different banks. Due to duel, ownership and land tenure system in Nepal neither the landlord nor the tenants are willing to invest for land improvement.

The National Planning Commission in its 20 years Agriculture Prospective Plan (APP, 1995) has given top priority to soil fertility management for achieving increased agricultural productivity in Nepal which is not driven by physical targets, but is directed to meet Government's more general long term developmental goals of poverty alleviation, sustainable economic growth and resource conservation.

Ministry of Agriculture carry-out the upgrading of livestock by providing the basic inputs and technical services in different districts. It also provides extension services to carry out the agriculture development in integrated way. For the cultivation and rehabilitation of degraded lands, it also provides irrigation facilities. To mitigate the land degradation with perennial crops horticulture program has been extensively adopted at the district level activity.

Nepal Agricultural Research Council (NARC), a leader agricultural research in Nepal verified and promotes various technologies for achieving conservation agriculture. NARC promotes Sloping Agricultural Land Technology (SALT), Integrated Plant Nutrient Management System (IPNS), terrace and contour farming during past three decades in hills and terai of intensely cultivation region. However, adoption of these technologies is restricted and further dissemination is needed. 7.2 Forestry

Master Plan for the Forestry Sector (MPFS, 1988) emphasized on people participation in the forestry development through the implementation of community forestry, private forestry and leasehold forestry and prevention and control of erosion is


the main forestry policy of the government in order to manage the land and rehabilitation of degraded lands. Role of government in the management of forestland and rehabilitation of degraded lands through the people participation will be catalytic (community organization, mobilization and facilitating) and technical advisory. The strategic policy to manage forest and rehabilitate degraded lands is to produce basic needs for forest products with due consideration of soil conservation measures and promote alternative energy resource and energy efficient devices.

Under the guidance of the forestry development policies of the government, the Forestry Sector Master Plan has recognized four main programs related with the land use and rehabilitation of degraded lands. 7.2.1 Community and Private Forestry Program

Aims to develop and manage forest resources through the active participation of individuals and communities to meet their basic needs for fuel wood, timber, and fodder. The main components of the program are:

Mobilize, organize and support user groups to manage the scattered natural and or degraded forest, which is required to meet their basic needs within the communities. Government plays catalytic, advisory and technical supervisory roles in the management of the forest. The user groups prepare operational plans with the help of forestry field staff. District Forest Office hand over the forest to the user groups to protect, manage and get the total benefit from the forest as per the plans.

So far, there are more than 3000 user groups actively engaged in managing about 125000 hectares of the community forests. Impact of this program has shown encouraging results. Because of popularity of this program, there is high demand for the establishment of community forests. In Nepal, 61 percent (About 5.8 million hectares) of the national forest (5.5 million hectares) is potential for community forestry. About 27 percent of the total forest area is covered by grazing and barren lands. Planting trees is one of the main activities to rehabilitate degraded lands. 7.2.2 National and Leasehold Forest

Aims to develop and manage the national forests through government agencies and private sector lessees, and complement community and private forestry as a means to increase the supply of forest products. The main focus of the program is to establishment and management of national forests in suitable places to supply wood and timber to urban and wood deficit areas for development and leasing of forestland that is available and suitable for industrial plantations.

So far 34730 hectares of national forest has been under intensive forest management and about 165 hectares and 342 hectares of forest are under leasehold forest managed by industries/institutions and people below poverty level respectively. 7.2.3 Soil Conservation and Watershed Management Program

In continuing endeavor to mitigate land degradation and increase productivity through the mobilization of national and local resources, the Department of Soil Conservation and Watershed Management (DSCWM) has implemented four major sub-programs natural hazard prevention, land productivity conservation, development


infrastructure protection, and community soil conservation extension programs. The main roles of the department are to mobilize, organize and formulate user groups to manage the land resources against the degradation and implement conservation measures to rehabilitate the degraded lands for the betterment of the local peoples. Department plays catalytic, advisory and technical supervisory roles and provide constructional materials which are not locally available and skill labors.

Department of Soil Conservation had carried out rehabilitation of degraded lands of about 7000 hectares, on-farm conservation on 1335 hectares and about 1000 hectares of land had been planted with fodder, fruit, and or grass and 458 number of gullies, 169 number of landslides had been treated. Similarly, stream bank protection had been carried out in 16 kilometers and road slope stabilization in 58 kilometers. 7.2.4 Conservation of Ecosystems and Genetic Resources

In continuing endeavor to conserve the ecosystems, currently there are eight national parks covering 10,174 square kilometers, five reserves covering 2298 square kilometers and two conservation areas covering about 7830 square kilometers mainly managed by the Department of National Parks and Wildlife Reserve. 7.2.5 River Training Program

Department of Irrigation under the Ministry of Water Resource carry out the river training program regularly to check the damage to land and settlements from the river bank erosion and floods and to mitigate the land degradation caused by the flooding and river shifting. River training works are carried out by encouraging local people's participation. Local people will be involved from appraisal to implementation in the river training works. Main government role in river training will be to deliver the materials mainly galvanized crates at site and to provide the technical guidance and supervision in implementation.

8. Conclusion and Recommendations Land degradation is a serious problem in Nepal as Nepalese economy is based on

agriculture with about 70 percent of the population engaged in it. Land is the basis of subsistence, farm incomes and source of employment in Nepal. The root cause of land degradation in Nepal is the poor economic condition, lack of knowledge/awareness and inefficient government policies. Assessment of soil erosion and its associated factors is necessary for scientific planning and carrying out soil and water conservation land management practices for sustainable use of land. However, the findings on the assessment of erosion are very much inconsistent and difficult to draw conclusion. The main reasons are complex terrain, soils, and geology, climate and land management practices. At the same time the application of methodology to quantify the erosion rate and its extent vary greatly that make difficult task.

It is observed that there is a lack of study on land degradation at the national level. This could due to inadequate logistic support and trained human resources available or low priority of the government. However, to acquire information on land degradation in short period of time the application of remote sense technique could be an alternative which has been considered suitable for the difficult terrain and remoteness.


The program at watershed or sub watershed as a lowest management unit could be most appropriate. Both the combination of indigenous and modern management initiatives through people participation could be an ideal approach. Thus, the following measures are suggested for utilization of land resource sustainably:

Policies • Study on land degradation and its trends at the national and regional level • Awareness of land degradation and incorporation of environmental education in

school education • Implement integrated package programs that include vegetative, agronomic, and

water management measures to tackle soil erosion problems with watershed management approach

• Involvement and mobilize local people in the implementation of soil and land conservation activities

• Formulate the clear policy, strategies and programs, which should be given high priority to tackle the rehabilitation of degraded lands

• Formulate the proper land use policy, which direct people to use according its suitability

• Establish and maintain linkages and networking with all other related sectors such as forestry, agriculture, livestock, water resources, roads and so on

• Mobilize people’s participation in the implementation of soil conservation activities • Preparing a national action program to address the issues of land degradation and

desertification

Technical • Afforestation on degraded forest and establish and maintain linkages and networking

with all other related sectors such as forestry, agriculture, livestock, water resources, roads and other infrastructure

• Land gradation and land consolidation • Mulching on dry degraded lands • Liming on acidic lands • Integrated Plant Nutrient Management, conservation tillage, fallowing, and scientific

management techniques (such as use of legumes in the cropping systems, strip cropping, cover cropping etc.)

• Promotion of Sloping agricultural land technology (SALT) in sloping land • Promotion of erosion control techniques such as contouring, terracing or other

bioengineering approach in sloping land


9. References APP, 1995. The National Planning Commission (NPC), Twenty Years Agriculture Perspective

Plan (APP), Singhdarbar, Kathmandu, Nepal. Barrow, C.J. 1991. Land Degradation: Development and Breakdown of Terrestrial Environments.

Cambridge University Press, London. Carson, B. 1985. Erosion and Sedimentation Process in the Nepalese Himalaya, ICIMOD

Occasional Paper N. 1, Nepal. Carson, B. 1992. The Land, The Farmers and The Future, ICIMOD Occasional Paper N. 21,

Kathmandu, Nepal. CBS, 1994. National Sample Census of Agriculture Nepal (1991/92) Highlights. Central Bureau

of Statistics, Kathmandu, Nepal. CBS, 1998. A Compendium on Environmental Statistics: 1998. Central Bureau of Statistics,

Kathmandu, Nepal. CBS, 2009. Statistical Pocket Book, Nepal. Central Bureau of Statistics, Kathmandu, Nepal. FRISP, 1994. Deforestation in The Terai Districts 1978/79-1990/91. Forest Resource Information

System Project. Forest Research and Survey Centre, Kathmandu, Nepal. Joshy, D. 1997. Soil Fertility and fertilizer Use in Nepal. Soil Science Division, Khumaltar,

Lalitpur, Nepal. LRMP, 1986. Land System Report. Land Resource Mapping Project, HMG/N and Government of

Canada, Kenting Earth Science Limited. MoPE, 2004. Nepal: National Action Program on Land Degradation and Desertification in the

Context of the UN Convention to combat Desertification. Ministry of Population and Environment, Kathmandu, Nepal.

MPFS, 1988. Master Plan for the Forestry Sector (MPFS) Nepal. Ministry of Forests and Soil Conservation, Kathmandu.

Partap, T. and H. R. Watson, 1994. Sloping Agricultural Land Technology (SALT): A Regenerative Options for Sustainable Mountain Farming, Occasional Paper No. 23, ICIMOD, Kathmandu.

Rimal, S. and R. Rimal, 2006. Nepal district profile. Nepal Development Information Institute (NIDI), Kathmandu

Shrestha, B.D, P. Van Ginneken and K.M. Sthapit; 1983. Watershed Condition of the Districts of Nepal. FO:DP/NEP/80/029, Field Document no. 9. Watershed Management and Conservation Education Project, Department of Soil Conservation, Kathmandu.

Stocking, A. M. and N. Murnaghan. 2001. Handbook for the Field Assessment of land Degradation. Earthscan Publication Ltd. UK.

UNEP, 2001. Nepal: State of Environment. United Nation Environment Program (UNEP), Regional Resource Center for Asia and the Pacific, Pathumthani, Thailand.

152 Strategies for Arresting Land Degradation in South Asian Countries – Sri Lankan Experience

C o n t e n t

Page 1. Abstract 153 2. Introduction 153 3. Severity of Land Degradation in Sri Lanka 158

3.1. Soil Erosion and Sedimentation 158 3.2. Coastal Erosion 162 3.3. Economic Estimations of Soil Loss 162 3.4. Soil Fertility Decline 163 3.5. Acidification 163 3.6. Salinity and Alkalinity 164 3.7. Iron toxicity 164 3.8. Leaching of Toxic Substances to Groundwater 165 3.9. Pollution 165 3.10. Gaps in the Knowledge Base 166

4. Policy Issues 167 5. Arresting Land Degradation: Some Recommendations 167 6. References 169

Strategies for Arresting Land Degradation in South Asian Countries – Sri Lankan Experience 153

1. Abstract

Sri Lanka consisting of a land area of 65,525 ha with a population of 19 million is ranked 19th in population density representing one of the densely populated countries in the world. Among SARRC countries it is ranked as no. 4 on population density. The land: man ratio for arable land is around 0.15 ha showing the pressure on land resources. With increasing pressure on land, population growth and slow growth rate of the economy, land degradation has become a major problem in the country. The land degradation factors identified are soil erosion and sedimentation, soil fertility decline, acidification, increase in salinity and alkalinity, accumulation of toxic substances, eutrophication due to over use of fertilizers, leaching of groundwater, iron toxicity, pollution and soil compaction. It is reported that the loss of land productivity due to degradation to be about US $ 36 /ha/yr while the loss due to nutrient depletion to be about US $ 51 /ha/y. The existing knowledge on land degradation is mostly limited to studies of soil erosion with less information available with other processes The knowledge gaps are mainly on the absence of a proper national data base on natural resources, specially on soil. Eventhough data on soil erosion and sedimentation are available, there is no data on fertility decline, salinity and eutrophication. A database should be developed in these lines and recommendations for arresting land degradation are highlighted in the paper.

Key words: Arresting Land Degradation, Sri Lanka

2. Introduction

The democratic socialist republic of Sri Lanka which was formally known as Ceylon comprises of one large island and several very small islets lying east of the southern tip of the Indian subcontinent. It stretches from 50 55’ to 90 50’ North latitude and from 790 42’ to 810 53’ East longitude. The maximum north-south length of the island is 435 km and its greatest width is 224 km surrounded by the Indian ocean. The coastline of the island is 1920 km long. The Bay of Bengal lies to its north and east and the Arabian Sea to its west. The country including adjacent small islands consist of a land area of 65,610 km2

(6,56 million ha) with a population of 20.2 million. For administrative purposes the country is divided by 9 provinces and 25 districts. The administrative structure extends to 319 divisional secretary/assistant government agent divisions and 38,259 villages. The country profile of socio economic data is shown in table 1.

Sri Lanka covers a land area of 65,610 km2 (6.56 million ha) with a population of 19 million. When compared with other countries in the world, Sri Lanka ranks 118th in area, 47th in population size and 19th in population density, making it one of the densely populated countries (Madduma Bandara. 2000). This is an indication of pressure on land


Table 1: The socio-economic data-country profile of Sri Lanka

2005 2006 2007(a)

Mid Year Population ('000 ) 19,668 19,886 20,010

Population Growth (%) 1.0 1.1 1.1

Population Density (persons per sq.km) 314 317 319

Labour Force ('000 persons) 8,141 7599 7,49

Employed Population ('000 persons) 6788 7,105 7,042

Unemployed Population ('000 persons) 524 493 447

Labour Force Participation Rate%) Male 67.3 68.1 67.8

Female 32.6 35.7 33.4

Total 49.3 51.2 49.8

Unemployment rate (% of Labour force) 7.2 6.5 6.0

Agriculture labour force employed (%) 30.7 32.2 3 \.3

Agriculture Contribution to GDP (% ) 11.8 1\.3 11.9

Real GDP growth rate (% ) 6.2 7.7 6.8

Per capita GDP at market price (US$) 1,241 1,421 1,617

Source: Central Bank of Sri Lanka

(a) Provisional resources creating human induced land degradation. The pressure on land will keep growing with the annual population growth rate of 1.1% where the total population is estimated to be 23 million by 2050 .The land area, population and population density in SAARC countries is given in table 2. (Survey Department, 2007). Among SAARC counties, Sri Lanka is ranked as 4th highest in population density. Topographically, the country has two distinct features, a central highland area rising above 2500 m and the lowland plains surrounding it extending to the coastal region. The climate is tropical and maritime, with two distinct monsoonal seasons, the southwest monsoon during May to September locally called Yala season and the northeast monsoon during October to January, the Maha season. The rainfall varies from 3175 mm per year in the wettest parts of the Wet Zone Up-country down to 500 mm per year in the driest parts of the Dry Zone Low Country. The variation of mean annual rainfall in Sri Lanka is shown in figure 1.


Fig. 1: Variation of mean annual rainfall (mm) in Sri Lanka (Domros, 1973)

Table 2: Land area, population and population density among SARRC countries

Country Land Area (km2)

Population (millions)

Population Density per km2

Rank

Pakistan 803,940 165.803 206.2 5

India 3,287,590 1,025.351 332.2 3

Maldives 300 0.359 1196.7 1

Sri Lanka 65.610 20.222 308.2 4

Nepal 140.800 28.287 201.0 6

Bhutan 47,000 2.273 46.5 7

Bangladesh 144,000 147.365 1021.4 2

Source: Survey Department, 2007

Based on the rainfall patterns three major climatic zones are identified. The Wet Zone covers the area where the mean annual rainfall > 2500 mm without any dry period while the Intermediate Zone is the area receiving mean annual rainfall of 1750-2500 mm with a short and less prominent dry season. The Dry Zone which covers more than 1/3 rd of the land area, receives <1750 mm rainfall per year with a distinct dry season from May to September. Even though the Dry Zone experiences a considerable total rainfall, the distribution is not even where more than 80% falls within a three months period. In addition to rainfall, the country is dividing to three physiographic regions based on the height from mean sea level as Low Country < 300 meters from mean sea level, Mid Country 300-900 m and Up country >900 m msl . In combination with the rainfall and physiographic regions the country is divided to 46 Agro-ecological regions. Each AER is denoted by a four character code consisting of letters and numbers (Example: WL1a). These denote the mean annual rainfall, elevation category


and distribution of rainfall. In addition the AER map gives information on the terrain and soil types

The total land area of Sri Lanka amounts to 65,610 km2 (6.56 million ha) where about 130,300 ha is covered by water bodies as irrigation and hydropower reservoirs which reduces the exposed surface area. According to the land balance sheet shown in table 1.7, only 1/3rd of the land area is used for agriculture while another 1/3rd is under forest and wild life conservations. Urban areas and areas of infrastructure development consist of the balance 1/3rd of the country (Somasekaram, 1996). The pressure on land which is shown by the land/man ratio (per capita land area) is a major factor contributing to land degradation. As shown in table 4 the land:man ratio of Sri Lanka in 1871 when the population was 2.4 million was 2.7 ha which reduced to 0.32 ha in 2007 with population

increasing to 20.2 million. This gross land:man ratio of 2.7 ha is misleading as it does not make an allowance for lands unsuitable for human use. When the topographically unsuitable lands and lands set apart for conservation are excluded the total land area available for agriculture decreases to 2.85 million ha decreasing the land:man ratio to 0.14 ha indicting the heavy pressure on agricultural land.

The first provisional soil map of Sri Lanka was compiled by A.W.R. Joachim (Joachim, 1955) and later revised by De Alwis and Panabokke (1972). This was the most used soil map in the past decade. This soil map which was at the scale of 1: 100,000 shows the soil mapping units. Soil mapping units of this map consist of soil associations, soil complexes and miscellaneous land units. When two or more Great Soil Groups occur in the same pattern in the centenary landscape they were called soil associations. When they do not occur in the same pattern the mapping unit is called a soil complex. The land pockets not suitable for agriculture as eroded remnants and rock knobs were called miscellaneous land units. A Great Soil Group was defined as a soil with similar sequences of genetic horizons, even though the depths of each horizon may vary. This map consist of a total of 31 mapping units, where 18 mapping units belongs to the soils of the dry zone and semi dry intermediate zone, 9 mapping units belonging to the wet and semi-wet intermediate zone and 4 were miscellaneous mapping units.

Table 3: Land balance sheet of Sri Lanka

Land Type Area (ha)

Reserved Land (Reservoirs, streams, roads, etc.) Forest and Catchment Areas Steep Lands Lands above 1500m (5000ft) contour Barren Lands Marshes and Mangroves Presently Used Lands Sparsely Used Land (Shifting cultivation, Patana etc.)

585,300 2000,000 380,000

76,400 77,000 70,000

2,635,000 728,800

Total 6,552,500


Table 4: Changes of the land/man ratio (per- capita land area) in Sri Lanka

Year Land area (million ha)

Population (million) Land/man ratio (ha)

1871 6.5 2.4 2.7

1900 6.5 3.5 1.8

1953 6.5 8.1 0.8

1986 6.5 16.5 0.4

2000 6.5 19.0 0.35

2007 6.5 20.2 0.32

With the advancement of Soil Science, to be at par with other countries, the need to classify and map the soils of Sri Lanka according to international systems in more detail was required. The Soil Science Society of Sri Lanka characterized the soils of Sri Lanka, classified them according to Soil Taxonomy and FAO-UNESCO legend under the SRICANSOL Project with assistance from Canadian Society of Soil Science. By this time, a transitional intermediate zone has been demarcated in-between the dry and wet zones which were identified mainly from proper interpretation of available climatic data. The most recent characterization, classification and mapping of soils were done in different stages for the three climatic zones. Wet zone, Intermediate zone and Dry zone, and maps in more detail scale were produced. The soil maps thus produced/consisted of the Wet Zone of Sri Lanka (Mapa et al, 1999) the Intermediate zone of Sri Lanka (Mapa et al., 2005) and Dry zone of Sri Lanka (Mapa et al., 2009). In addition, these soils were classified according to Soil Taxonomy (USDA, 2003) and FAO-UNESCO legend, and further to Soil Series level.

The United Nations Convention to Combat Desertification (UNCCD), defines land degradation as the reduction or loss of the biological or economic productivity and complexity of rain fed cropland, irrigated cropland or range, pasture, forest and woodlands resulting from land use or from a process or a combination of processes including processes arising from human activities and habitation patterns. Land degradation is the process that diminishes or impairs productivity of land which reduces its future capacity to support human life. When used in such a manner, 'Biological Potential of the Land' will decline irreversibly which ultimately reduce its ability to produce food and fibber, a process known as soil degradation. This can take place due to natural as well as human induced (anthropogenic) processes.

The reasons for soil degradation are reflected from the pressure on land resources of Sri Lanka. From the total land area of about 6.5 million ha, only about 3 million are arable due to unsuitable terrain, forest reserves and inland water bodies.The gross land/man ratio, which was 2.7 ha in 1871 with a population of 2.4 million, has been reduced to 0.35 ha with about 19 million people in 2000. According to Maddudma Bandara (2000), the arable land available for human use is estimated to be at 0.15 ha per


person. The pressure on land is also reflected from the forestry perspective where the forest cover declined throughout the years. The forest cover of the country which was 90% during 1900 when the population was 3.5 million, declined to less than 20% at present with the increase of population to 20.2 million. Out of this, only 9% are in the sensitive watershed areas showing the importance of relocating them with proper planning. Main reasons for soil degradation in Sri Lanka are listed as soil erosion due to water, fertility decline resulting from reduction of organic matter and plant nutrients, salinization resulting from improper water management and soil compaction.

Therefore, the objective of this study was to evaluate the extent of land degradation in Sri Lanka and the steps taken to arrest such degradation using available literature.

3. Severity of Land Degradation in Sri Lanka Nayekekorale (1998) reported soil erosion as the major soil degradation processes in

Sri Lanka where more than 33% of the land is exposed to erosion. The Central Environmental Authority of Sri Lanka, which is the major body dealing with environmental issues, listed soil erosion as the major cause of soil degradation in Sri Lanka. They documented that soil erosion resulted from encroachment of forests, disturbing the hydrologically critical areas, shifting cultivation, inadequate attention to lands higher than 1500 meters from mean sea level. They also highlighted that the fragmentation of responsibilities of soil conservation among different agencies is a drawback in controlling this problem.

3.1. Soil Erosion and Sedimentation Soil loss by sheet erosion and subsequent sedimentation are the major soil

degradation process as shown in figure 2. Even though the major cause of soil degradation is soil erosion, not much published data are found on erosion rates and related soil conservation. The tolerable soil erosion rate, which is the allowable soil erosion rate without declining the soil productivity was estimated by Krishnarajah (1984) and is given in table 5. These were estimated using the existing rooting depth, soil organic matter contents and soil formation rates and served as guidelines to understand the need for establishing soil conservation methods. Anandacoomaraswamy et al. (2001) documented that tea yields have an inverse relationship down to 350 mm of top soil depth


Fig. 2: Sheet erosion and associated reservoir sedimentation in Sri Lanka

and it is necessary to have at least 200 to 250 mm of top soil for successful tea cultivation. How the actual soil erosion rates exceeded the tolerable limit in most land use systems are given in table 6, as documented by Stocking (1992). These data also highlight the importance of simple agronomic conservation measures such as mulching and planting on the contour in decreasing the soil loss below tolerable limits. The lowest soil loss rates were observed in the mixed home gardens in Mid Country Wet zone which is a mixture of crops producing canopies at different levels in taking off the erosive power of raindrops at different heights. One of the major catchments of the up country Sri Lanka is the upper Mahaweli catchment area. This feeds the Mahaweli river which is the longest and most useful. The land use types and soil erosion associated with the upper Mahaweli watershed is given in table 7. As shown before, the highest erosion rates are associated with Tobacco cultivation, and slash and burn cultivation (shifting cultivation). Normally Tobacco is cultivated in fertile areas with high slopes and the open canopy type of the crop accelerates soil erosion.

Table 5: Estimated rates of tolerable soil loss for different soils of Sri Lanka

Agro-Ecological Region

Soil Order

Potential Rooting Depth (cm)

Tolerable Soil Loss t/ha/y

Up Country Wet Zone

Ultisols

180-240

13.2

Mid Country Wet zone

Ultisols

120-150

9.0

Low Country Dry Zone

Alfisols

90-150

6.7

The soil erodibility (K) factor, which shows the inherent susceptibility or resistance to soil erosion by water was worked out for selected soils by Joshua (1977). These


erodibility values are related to the clay and organic matter contents of soil, soil structural types and aggregate stability. These values are given in table 8. The Sandy Regosol great soil group which is classified as Entisols in Soil Taxonomy showed the highest susceptibility to erosion, while Reddish Brown Latosolic soils showed more resistance to erosion by water. This highlights the fact that soils with lower soil erodibility values could be cultivated with less hazards of soil erosion, while soils with high erodibility values need extensive soil conservation methods to be used for agricultural activity in a sustainable manner.

Most of the eroded soil causes sedimentation of reservoirs down stream causing siltation, while the finer particles interfere with power generating equipment. This water is subsequently released for irrigation in the dry zone where these finer particles causes many off-site environmental problems. It is documented that in the Mahaweli irrigation system the Polgolla reservoir has silted to 40% of its capacity in 12 years after its commissioning. Dhramasena (1991) reported that nearly 60% of the capacity is lost in most of the village tanks in the dry zone due to siltation by soil erosion. The sediment yields from selected sub catchments of the Upper Mahaweli watershed as reported by Wallingford (1995) are shown in table 9. As seen from these data, sediment yields are higher in lands which are disturbed annually for vegetable and potato cultivation than in permanent vegetation such as tea and home gardens.

Table 6: Soil loss in different land use systems in Sri Lanka

Agro-Ecological

Region

Location Land use Soil Loss (t/ha/y)

Mid Country Wet Zone

Peradeniya

Seedling tea without conservation Well managed tea in contour Mixed home gardens

40.00 0.24 0.05

Up Country Wet Zone

Talawakele Clean weeded VP tea VP tea with mulch

52.6 0.07

Mid Country Intermediate Zone

Hanguranketha Tobacco no conservation Capsicum no conservation Carrots no conservation

70.0 38.0 18.0


Table 7: Land use and soil erosion rates in the Upper Mahaweli catchment of Sri Lanka

Land Use Type Area (km2)

Soil Loss (t km-2 yr-1)

Bedrock Erosion Rate*

(mm k yr-1)

Dense Forest Degraded forest & shrubs Degraded grasslands Poorly managed seedling tea Seedling tea with conservation Vegetatively propagated tea Paddy Home gardens Shifting cultivation & Tobacco Market gardens

356.6 435.7 141.9 454.8 252.7 114.9 285.7 537.7 484.6 163.6

100 2500 3000 5200 1500 200 300 100

7000 2500

37 925

1110 1924 555 74

111 17

2590 925

These results give a clear picture of soil erosion in the country as the major soil degradation process. The worst affected area is the mid country, which ranges from 300-1,000 m elevation due to steep slopes, high rainfall intensities and more erodable soils. Not much work has been conducted in measuring soil erodibilities other than a value of 0.31 reported for tea soils by Greenland and Lal (1977) and the values reported by Joshua (1977) (Table 8).

Table 8: Soil erodibility values (K factor) for selected soils of Sri Lanka

Station Great Soil Group Soil taxonomic equivalent

Soil Erodibility Factor (K)

Ratnapura Katugasthota Katunayake Anuradhapura Kankasanthurai Batticaloa

Red Yellow Podzolic Reddish Brown latosolic Sandy Regosols Reddish Brown Earths Red Yellow Latosols Noncalcic Brown soils

Rhodudults Ultisols Entisols Rhodustalfs Oxisols Haplustalfs

0.22 0.17 0.48 0.27 0.33 0.35

(Soils with higher values show relatively higher susceptibility to erosion)


Table 9: Sedimentation of selected catchments in the mid county wet zone of Sri Lanka

Sub Catchment Area (km2) Land Use Sediment Yield (t ha-l yr -l)

Above Peradeniya 1,160 Tea, grassland 4.2 Above Plogolla 1,300 Tea, townships 3.4 Nilembe oya 61 Tea, home gardens 0.6 Victoria 1,800 Tea 3.4 Mahaoya 476 Vegetables 9.4 Uma oya 94 Vegetables 10.6

3.2. Coastal Erosion Sri Lanka also experiences severe coastal erosion as it is an island and the coastline

extends to 1920 km around the country. The coastline is shared by five provinces while covering urban areas and 33% of population in these areas. With the development of tourism the coastal areas will become more economically important in the future. The mean annual recession of the coastline of Sri Lanka is estimated as 1.1 m (Madduma Bandara, 2000). The most severe coastal erosion is in the coastal belt of 685 km extending from Kirinada to Kalpitiya.

Coastal erosion is of two types, seasonal in nature during monsoonal times and constant long term erosion. The erosion or deposition levels at the coast depend on the rates of sand deposition from the rivers and removal from the tide. In addition winds move sands off shore creatings and dunes. Coastal erosion is presently further aggravated by sand mining, due to shortage of river sand used for construction work.

As pointed out by many environmental economists the estimation of losses due to environmental degradation is a very complicated process (Gunathilaka, 2003). The most recent estimates about losses due to soil erosion in Sri Lanka is documented by Griggs (1999), where on site and off site add up to about Rs 3000 to 4000 million (Us $ 30-40 million) annually. The adverse impacts on irrigated agriculture mainly due to sedimentation are estimated to be equivalent to Rs 320 million (US $ 3.2 million) annually. These are only conservative estimates, as the intangible off site events as flooding, detrimental impacts on human health and recreation are not taken into account.

3.3. Economic Estimations of Soil Loss The National Report on Desertification/Land Degradation in Sri Lanka (Anonymous,

2000) estimated the on-site costs of soil erosion of the country as productive losses of Rs. 3529 (US $ 35) ha/y, loss of nutrients amounting to Rs 5068 (US$ 51) ha/y and estimated nutrient losses from the major watershed in Sri Lanka, the Upper Mahaweli watershed as Rs 953 million (US $ 9.5 m). The off site economic costs of soil erosion estimated were Rs. 3952 (US $ 40) ha/y, loss of nutrients as Rs 5481 (US $ 55) ha/y and loss due to reduction of hydropower and irrigation in the Upper Mahaweli watershed as Rs 15 million (US $ 1.5m) per annum.


The next level of soil degradation associated with edaphic changes is represented by transformation of the chemical composition of soil. This takes place in the form of depletion of soil nutrients, increase of the salinity and alkalinity of soil acidification and accumulation of toxic substances in the soil (Peiris, 2006).

3.4. Soil Fertility Decline Part of the soil fertility decline is associated indirectly with soil erosion as the most

active colloid particles are lost in the erosion process. The clay particles and organic matter affect the specific surface of soil effecting the nutrient and water holding capacity of soils. Fertility decline may take place due to reduction of soil depth, depletion of soil nutrients and organic matter. The removal of most fertile topsoil can reduce the yields of crops drastically. It is shown that removal of the first five cm of topsoil reduces the yield from 40% to 50% in many crops. Basnayake (1985) documented that during a five month observation period the N, P and K losses from a tea land on a 30% slope in the up country wet zone were 0.37, 0.87 and 0.045 kg /ha/t yr respectively.

The cation exchange capacity in some of the selected cultivated srilankar soils was found to be to mainly due to their highly weathered nature. Mapa (1992) showed that most of the soils of Sri Lanka have a kaolinitic and oxidic clay mineralogy and show low clay activity values. In such soils the only practical way to increase the CEC is by maintaining a higher amount of soil organic matter. The organic matter contents of cultivated soils are low due to its rapid decomposition in these tropical environments. In addition the soils in the wet zone are mostly acidic, affecting the availability of essential plant nutrients. Nayakekorala and Prasantha (1996) showed that the nitrogen content of most cultivated soils is within a range of 0.19% to 0.14% while the exchangeable K values varied from 27 to 75 ppm.

The ways to overcome the degradation of soils by fertility decline include application of fertilizers to replenish nutrients lost by plant uptake and leaching, and maintaining a healthy organic matter content together with application of soil amendments and liming material for the acidic soils. Maintaining a higher organic matter level is beneficial in increasing soil physical, chemical and biological properties. While providing a part of plant nutrient requirements, organic matter improves CEC and aggregate stability, reduces erosion by wind and water. Instead of application of organic matter from external sources as straw or compost, agro-forestry systems in which nitrogen fixing trees are grown alongside crops to enrich the soil have become sustainable farming systems in countries as Sri Lanka.

3.5. Acidification When rainfall is high, as in countries like Sri Lanka, the bases get leached from the

soil and H+ ion replace the sites occupied by the cations in the exchange complex. Soils in mid-country and up-country of Sri Lanka become acidic by natural leaching and applications of ammonium sulphate as N fertilizers to tea plantations (Wickramasinghe et al., 1985). Analyzing two degraded tea soil of Sri Lanka Botschek et al. (1994) showed that Al-saturation fluctuated between 61 and 74% where CEC and P-availability were extremely low and the soils were strongly acidic throughout the profile. They also


documented that the potential acidity of these soils were between 0.5 to 2.17 cmol/kg. The zero point of net charges fluctuated around 3, and in many soils is below the field pH. H showed that About 1-2 t ha-1 CaCo3 is required to reduce the Al-saturation of these topsoils by up to 30%.

Acid sulphate soils are found in poorly drained areas in the southwest of the low country Wet Zone. These are developed due to Dystrification whereby soil pH is lowered by increase of acidic compounds in soils. Tokutome (1970) reported that pH of these soils decreased on drying from 6.5 to 2.5. The occurrence of Typic Sulfaquents in Sri Lanka where the Sulphate-S is high as 3100 to 3900 mg/kg of surface soil have been reported by several workers. These soils are found in the Nilwala River flood plain close to the coastal sand plain where flooded rice is the main crop. Yellow coloured jarocite mottles could be easily observed along the cracks formed in the dry season due to oxidation of iron pyrite. These soils have high acidity and salinity, iron toxicity, hydrogen sulphide toxicity, aluminium toxicity and low P availability.

3.6. Salinity and Alkalinity Lathiff and Nayakakorala (1993) reported about 160,000 ha of salt -affected soils in

Mannar, Puttlam and Jaffna and around 15,000 ha in Galle and Kaluthara regions These are mainly the poorly drained areas along the sea cost consisting of Natraqualfs. In addition there are some inland salinity patches formed due to improper management of irrigation water. Most of the original drainage channels of major irrigation schemes are encroached by the farmers making drainage impossible. When drainage water is used to re-irrigate, this brackish water causes soil salinity. The available data for Sri Lanka indicates that large scale development of soil salinity is not a major problem due to high rainfall and sloping topography. Any soil salinity built-up during the dry season could be easily washed away using high rainfall water during the wet season if proper drainage is provided. Even though salinity is periodically flushed away by monsoon rains and cleaning of drainage channels, the rise of ground water level in irrigated areas of arid zone contributes to an upward movement of salts during drier periods.

3.7. Iron toxicity Iron toxicity is the major soil constraint in the wet zone paddy lands causing an

average yield loss of about 43 kg/ha (Herath et al., 1998). Iron toxicity causes bronzing, yellowing or orange colouration of the plant and is regarded as a major physiological stress. This is caused by higher solubility of iron compounds after submerging the soil. The standing water in paddy fields deprive the movement of oxygen into the soil where anaerobic conditions occur. These will reduce iron oxides ie ferric compounds are reduced to ferrous compounds, making them more soluble.

In soils with high organic matter content this condition may be more severe. According to Ponnamperuma (1972) the concentration of water soluble iron is around 20 parts per million (ppm) in a neutral well aerated soil and it may increase by 30 times to about 600 ppm, one to three weeks after submergence in an acid soil with high organic matter content. This higher solubility will result in higher uptake of iron by plants which will cause disorders that reduces the growth. When the soil is deficient in other nutrients


the iron toxicity is aggravated. Therefore, supplying the essential nutrients by fertilizer application, breeding for varieties of well developed root systems, higher oxidizing and nutrient extracting mechanisms has potential for the future. Liming of soils using dolomite to increase other ions as calcium and magnesium in soil solution also can reduce the ill effects of iron toxicity. Shallow submergence due to occasional flooding also effect paddy production in the internal lowland valleys. With prolonged submergence of soils with high organic matter content make them boggy, deficient in phosphorus as well as make tillage and water management difficult. Better flood protection mechanisms and drainage facilities have to be implemented to overcome the constraints due to flooding.

3.8. Leaching of Toxic Substances to Groundwater Leaching of plant nutrients and agro-chemicals to ground water can pollute water

resource and when this water is used for irrigation it causes land degradation. In Sri Lanka ground water is used for irrigation in the North and areas as in Kalpitiya in North Western Province. Jinadasa (1987) reported that in Red Latasols of the Northern region of Sri Lanka leaching rate of 10-28 kg N/ha during a 81 day period. In addition Nagarajah et al. (1988) reported that NO3-N in agricultural wells in iaffna and Kilinochchi districts were higher that the WHO drinking water standards of 11.3 mg/l. Kuruppauarchi et al. (1990) reported that the NO3-N levels of the ground water in Talawila, Kalpitiya area showed profound seasonal variation. The values increased to 70 mg/l in the wet season with the rise of the water table. He also documented that the potassium leached from use of higher doses of fertilizers increased the K concentration to about 60 mg/l in the ground water. Using such water for irrigation will definitely cause land degradation

3.9. Pollution Pollution leading to land degradation could be from effluents from industrial fields as

well as impurities in fertilizer as heavy metals. In addition extensive use of agro-chemicals lead to pollution of soils and water bodies. Soil pollution by toxic metals is one of the serious problems of the environment. In addition to the natural sources, the anthropogenic sources such as addition of fertilizers, agro-chemicals and manures are the major sources of heavy metals to the agricultural lands.

Sri Lanka is neither an industrialized country nor does it has any natural metal deposits. However use of chemical fertilizers, manures and pesticides more than the recommended doses as well as frequent and long-term cultivations could contribute to the heavy metal accumulations in soils. Jayathilake and Bandara, (1989) reported that most of Sri Lankan farmers apply two to eight times more fertilizer than the recommended dosage. Many researches have documented that, synthetic fertilizers and pesticides contain heavy metals as an impurity or as an active ingredient. Wood et al (1996) and Han et al. (2000) have shown that short and long-term applications of poultry litter increased Cu and Zn concentrations in soil especially in the top 5 to 10 cm. Hence, long term fertilizer and manure applied soils may accumulate these heavy metals over the time.

Heavy metal concentrations in Up Country and Low Country-Wet zone of Sri Lanka were determined by Premarathne (2006) in different vegetable growing soils, vegetables,


and in fertilizers and manures used in their agricultural activities. Crop, soil, and fertilizer/manure samples were collected from Kandapola, Sita-Eliya, Bogahakumbura, Haputale and Rahangala for the Up Country (Wellampitiya, Sedawatta, Welewatta and Kotuvila) and Bandaragama (Bandaragama and Kahathuduwa) selected as the Low Country areas. Soil, fertilizer and manure samples were analyzed for total heavy metals (Cd, Cu, Ni, Pb, and Zn). The Pb concentrations in the Low Country vegetable growing fields were similar to the control soil indicating either geological or non-agricultural activities as the source of Pb. Significant increase in Cd, Cu, Ni, Pb and Zn concentrations were observed in cultivated lands than the control. Values observed in Sedawatta fields were higher than the European Community Set Standards for Cd, Zn, Pb and Cu and was lower than that of the United State Set Standards. Farmers of these areas have been used higher amount of synthetic fertilizers and pesticides. It could also result from accumulation of heavy metal in soil as observed in many counties before (Williams and David, 1976). Fertilizers and pesticides contain some heavy metal as impurity or as an active ingredient. Therefore, fertilizers and pesticides could also be a source of heavy metals to the soils of the area. Further, the studied fields are located in flood plain of Kelani River and frequently subjected to flooding. Therefore, polluted water can enter in to these fields. thereby contributing to accumulation of heavy metals in these lands

Premaratne (2006) also measured the heavy metal contamination (Cd, Cu, Ni, Pb and Zn) of a range of phosphate fertilizers, manures and liming materials used by up country and low country vegetable farmers. The results indicated that rock phosphate mined from Sri Lanka (Eppawala rock phosphate) contains relatively low concentration of Cd and other heavy metals compared to imported rock phosphates and Triple super phosphate (TSP). Out of all fertilizers measured, the TSP contained the highest Cd concentrations and it was 23.5 mg/kg. Except for Cd in phosphate fertilizers, other heavy metals were well below the maximum levels of the standards setup by Sri Lanka Standard Institute (SLSI) for compost that can be applied to the agricultural lands. The standards for compost were used as at present there are no such standards imposed for heavy metals for commercial fertilizers. Application of TSP, poultry manure, and other amendments in high rates for a long period of time can increase soil Cd and other heavy metal concentrations significantly.

3.10. Gaps in the Knowledge Base The existing knowledge on land degradation is mostly limited to studies of soil

erosion with less information available with other processes of human induced land degradation. These data are available according to the regional elevation pattern as Up country, Mid country and Low country of Sri Lanka. Based upon spatial distribution of soil erosion index values for Sri Lanka showing the most sensitive areas for soil erosion, five areas were gazetted by the government as sensitive areas for soil erosion. In addition, soil erosion hazard maps constructed using soil erodibility and rainfall erosivity factor for districts in the central province are also available.

The knowledge gaps are mainly on the absence of a proper national data base on natural resources, specially on soil. Even though data on soil erosion and sedimentation are available, there is no data on fertility decline, salinity and eutrophication. Even in soil


erosion, field plots are used to monitor runoff and soil loss which give a set of process reflecting site condition, but they say little about whether the land use can be sustained and where the sediment depositsion will occur. In addition, the findings of these researches are limited to the soil type, slope and climatic zones and therefore, there is a need to study these factors covering all the soil types so as to increase the applicability of research findings.

Research should result in technologies that promote environmentally sound agricultural practices while increasing productivity, and policies that strengthen property rights, correct tenurial anomalies, discourage fragmentation, and promote land markets that operate more freely. The National Environmental Action plan proposed by the Government of Sri Lanka considering nine key sectors of the economy prioritizing the key issues related to land and water resource management provide guidelines to arrest land degradation due to each of these factors.

South Asian countries as Sri Lanka will have to manage their water resources on a long-term, integrated basis. The imperatives of such planning are particularly critical as withdrawals will increase to about 71 percent of available water. Seasonal water shortages can severely affect agricultural output. The use of water for agriculture in the region can be made more efficient through improved practices, such as water management regimes with user participation, and the application of new technologies, such as sprinkler irrigation. Incentives for economizing in the use of water must come from reasonable pricing policies. The pricing of irrigation water, however, remains a controversial issue in many Asian countries. The research and development initiatives should integrate in preventing land degradation resulting in increase of water quality and quantity.

4. Policy Issues The policy issues related to land degradation is strongly related to landlessness and

land tenure. If farmers do not own land they will be not interested or invest in long term sustainability but just mine the land until it is degraded. In Sri Lanka many land commissions have documented the historical aspects of land ownership. If some of the legislation related to land such as the Soil Conservation Act were properly implemented by the government, the land resource of Sri Lanka would have been more productive at present. Most of the policy for combating land degradation is prepared by the land Use Policy Planning Division (LUPPD) of the land Ministry while their implementation is done mostly through the Ministry of Environment and Natural resources.

Land use planning is the best long term tool to prevent land degradation. There are many sound land use planning examples as the Kandyan mixed home garden where the soil erosion is less as 0.05 t/ha/y.

5. Arresting Land Degradation: Some Recommendations The following recommendations are proposed to arrest land degradation of Sri

Lanka.


• There is a good understanding about human induced land degradation, especially the soil erosion and sedimentation problem. Still, the remediation measures are taken in ad-hoc basis by many different ministries and government departments. There should be coordination of these activities through a central body as a soil conservation authority.

• The long term arresting of land degradation depend on implementation of land use planning based on sound and long term land use policies formulated to fulfill national priorities. Crop zoning initiated by the Department of Agriculture is a good beginning. The lands best suited for selected crops have to be farmed intensively, while unsuitable lands have to be released for non-agricultural activities and for conservation.

• Rehabilitation of degraded land should be seen as an investment and Rs. 250,000/= (US $ 2500) per ha which is the approximate value loss due to complete degradation. This could be arrested by investing a fraction of this amount.

• Future land use policies should be developed on the basis that the population of Sri Lanka will which stabilize at 23 million by 2020 and out of this 70% will live in urban areas.

• Distribution of land for political reasons among the poor as an alternative for employment should be discouraged.

• Detailed information on soils is limited as well as scattered among many agencies. This data should be used to prepare a collective database and the data gaps should be identified and filled. A proper and complete database is a pre-requisite in making policies to arrest land degradation.

• Steps should be taken to stop slash and burn (shifting) agriculture and these lands should be made more productive by developing the soil organic matter levels using systems such as alley cropping and conservation farming techniques.

• A major shortcome in soil conservation programs is the laxity in respect of enforcement. Strict enforcement of regulations is necessary especially with the soil conservation act. In addition prohibition of cultivation of land exceeding 60% slope and above 1525 meters (5000 feet) contour line should be strictly enforced.

• New institutional mechanisms involving farmer organizations and the community should be developed at grassroots levels. Community based participatory approaches should receive high priority in future programs.

• Trade liberalization have positive effects on soil conservation. For example, trade restrictions for potatoes increase the price of potatoes which encourages cultivation in erosive upcountry lands. This is a large economic loss by degrading valuable land resource.

• New research programs emphasizing adaptive research should be initiated in collaboration with universities, and budgetary provision should be made for the research as well for dissemination of research findings. Farmers, plantation managements and the community should be closely involved in the exercise. Existing organizations such as the LUPPD, NRMC of the Department of Agriculture and the Tea Research Institute, already engaged in related activities should be strengthened by providing the required resources


• The Department of Agriculture should develop appropriate cropping systems incorporating ecological, social and economic goals for specific locations and landscapes. The Natural Resource Management Center of the Department of Agriculture has an important and leadership role to play for collecting available data and propose suitable of soil conservation measures to arrest land degradation in different agro-ecological regions of Sri Lanka.

• The Tea, Rubber, Coconut research institutes, departments of Forest, Export Agriculture and Coast conservation should be able to provide leadership in proposing and implementation of arresting land degradation with respect to their disciplines.

• The Central Environmental Authority is geared to provide leadership in arresting land and water degradation due to pollution from industries which can ruin these resources in a very short time.

• Soil conservation units of Provincial Councils need to be strengthened in implementing soil conservation measures in the provinces.

• Carefully targeted government assistance should be provided for land conservation. Land conservation should be made mandatory to qualify for government subsidies as fertilizer subsidies and subsidies for replanting perennial crops.

6. References Anonymous, 1998 National Environmental Action Plan. Ministry of Environmental and

Parliamentary Affairs, Government of Sri Lanka. Anandacoomrasamy, A, Ekanayake, A.A.B, Ananthacumaraswamy, S., Chishom, A.H. and

Jayasuriya, S. 2001. Effects of land degradation on tae productivity of Sri Lanka. Proc. International Symposium on soil erosion research for 21st century, ASAE publication 75-78.

Dharamasena, P.B. 1991. Present use of land and water resources in village tank farming. Journal of Soil Science Society, Sri Lanka 7, 1-17.

De Alwis, K.A.. and Panabokke, C.R. 1972. Handbook of Soils o Sri Lanka. Soil Sci. Soc. Sri Lanka 2:1-95

Domros, S. 1974. The Agro-Climate of Ceylon. Franz Steiner Verlag Gmbh. Griggs T 1998 Solutions to Sri Lankan erosion woes. Partners in Research for Development 11:

1-7. Gunathilake H.M., 2003 Environmental Valuation. Theory and Applications. 373 p Han, F.X.,

Kingery, W.L., Selim, H.M. and Gerard, P.D. (2000). Accumulation of heavy metals in a long-term poultry waste amended soil. Soil Science. 165(3): 260-268

Herath, B.R.M., Dhanapala, M.P., De Silva, G.A.C., and Hossain, M. 1998. Constraints to increase paddy production in Sri Lanka. Paper presented at the workshop on prioritization of rice research, IRRI, Phillipines, 20-22 April 1998.

Jayathilake, J., and Bandara, J.M.R.S. 1989. Pesticide management by the hill country vegetable farmers. Trop. Agri. Res.1:121-131

Joachim, A.W.R. 1955. The Soils of Ceylon. Tropical Agriculturist 111:161-172. Joshua, W.D. 1977. Soil erosive power of rainfall in the different climatic zones of Sri Lanka.

Proc. Symposium on deposition and soil matter transport in inland waters. Paris. AISI Publication no. 1222, 1977.


Kabir,W. and Akter, N. 2007. Statistical data book for agricultural research and development in SAARC countries. SAARC Agricultural Centre, Dhaka, Bangladesh. 403

Krishnarajah P.1984. Erosion and degradation of environment. Proc. Annual Sessions of the Soil Science Society of Sri Lanka

Lathiff, M.A. and Nayakekorale, H.B. 1993. Problem soils of Sri Lanka. SAARC Workshop on Problem Soils, 23-24 Nov. Kandy, Sri Lanka.

Madduma Bandara, C.M. 2000. Land Resources: Conditions and Trends. (Ed.) PG Cooray. Natural Resources of Sri Lanka. National Science Foundation of Sri Lanka 53-73

Mapa RB 1992 Clay mineralogy of six Sri Lankan soils in relation to weathering sequences. J. Geological Soc. Sri Lanka 4:41-49.

Mapa, R.B. ,Somasiri, S. and Dassanayake, A.R. 2007. Soils of the Dry Zone of Sri Lanka. Morphology, Characterization and Classification. Special Publication No. 9. Soil Science Society of Sri Lanka. 357 pp

Mapa, R.B., Dassanayake, A.R. and Nayakekorale, H.B. . 2005. Soils of the Imtermediate Zone of Sri Lanka. Morphology, Characterization and Classification. Special Publication No. 4. Soil Science Society of Sri Lanka. 225 pp

Mapa, R.B., Somasiri, S. and Nagarajah, S. 1999. Soils of the Wet Zone of Sri Lanka. Morphology, Characterization and Classification. Special Publication No 1, Soil Science Society of Sri Lanka 191 pp

Nagarajah, S and Hindagala, C.B. 1993. Report of the SAARC Workshop on problem soils. 23-24 November 1993, Kandy Sri Lanka.

Nayakekorale HB 1998 Human induced soil erosion status in Sri Lanka. J. Soil Sci. Soc. Sri Lanka 10: 1-35.

Nayakekorala, H.B. and Prasantha, B.O.R. 1996. Physical and chemical characteristics of some eroded soils in the mid country of Sri Lanka. Journal of Soil Science Society, Sri Lanka 9, 16-31.

Ponnamperuma, F.N. 1972. The chemistry of submerged soils. Advances n Agronomy Premarathne, H.M.L.P. 2006. Soil and Crop Contamination by Toxic and Trace Elements, M.Phil. Thesis, Postgraduate Institute of Agriculture, University of Peradeniya, Sri

Lanka Somasekaram, T. 1996. Facts About Our Land. Arjuna Consulting Co. (Ltd.) Dehiwala. Stockings M. 1992. Soil erosion in the upper Mahaweli catchment. Technical report No. 14,

Report submitted to the environment and forestry division of Mahaweli authority of Sri Lanka.

Survey Department. 2007. National Atlas of Sri Lanka. Published by the Survey Department of Sri Lanka pp

USDA. 2003. Keys to Soil Taxonomy. 9th Ed. Natural resources Conservation Service, United States Department of Agriculture. 325 p

Wood, B.H., Wood, C.W., Yoon, K.H., and Delancy, D.R. (1996). Nutrient accumulation and nitrate leaching under broiler litter amended corn fields. Commun. Soil Sci. Plant Anal. 27: 2875-2894.

172 Acid Soil Management in India-Challenges and Opportunities

Acid Soil Management in India-Challenges and Opportunities

D. Jena Professor IFFCO Chair & Former Head

Department of Soil Science & Agriculture OUAT, Bhubaneswar-751003

Email: [email protected]

Acid Soil Management in India-Challenges and Opportunities 173

Abstract Acid soils are base unsaturated soils developed under drastic weathering, influenced

by hot and humid climate and heavy precipitation. Acid soils constitute about 30 % of the total cultivated area in India. The productivity of acid soils is low due to low pH, presence of toxic levels of Al, Fe and Mn, nutrient imbalance, deficiency of Ca, Mg, S, P, B and Mo and poor microbial activity .Amelioration of acid soil by liming enhances availability of several plant nutrients and increases crop yield. Agriculture can not afford to use industrial grade lime as it is cost prohibitive. Alternative sources of lime like paper mill sludge, steel mill slag, blast furnace slag, pressmud are recommended for acid soils. Amending soil with full dose of lime should be replaced by 0.10 to 0.20 LR dose. Phosphorus management in such soils is done economically by using powered indigenous rock phosphate mixing with highly active imported rock. Deficiency of Ca and Mg can be corrected by using dolomite or other liming materials. Modest dose of lime should find a place in integrated nutrient management system for acid unbunded and bunded uplands. Balance use of lime and micronutrients is recommended for vegetables, cereals, pulses and oilseeds in acid soils. Growing acid tolerant species and cultivars is the alternative. Keyword : Acid soil, liming material, lime requirement, nutrient availability, acid tolerant crop.

Acid soils are base unsaturated soils constitute about 30% of the total cultivable area in India. They occur in the Himalayan region, the eastern and north-eastern plains, peninsular India and coastal plains under varying topography, geology, climate and vegetation. Most of these soils belong to the soil orders, Ultisols, Alfisols, Mollisols, Spodosols, Entisols and Inceptisols. The acid soils are mostly distributed in Assam, Manipur, Tripura, Meghalaya, Mizoram, Nagaland, Sikkim, Arunachal Pradesh, West Bengal, Jharkhand, Orissa, Madhya Pradesh, Himachal Pradesh, Jammu & Kashmir, Andhra Pradesh, Karnataka, Kerala, Maharastra and Tamilnadu. Acid soils of Himalayan region are occupied by acid podozols in association with brown forest soils. Acid soils of alluvial region occur in West Bengal, Bihar, Assam and Orissa.

Acid soils in marsh areas are found in Assam, Kerala, West Bengal, Coastal districts of Orissa,south-east coast of Tamilnadu, tarai regions of Utter Pradesh, Bihar and West Bengal. Acid sulphate soils are found in Sunderban area of West Bengal and Kuttand area of Kerala. The extent of occurance of acid soils in different states of India is given in table 1. It is estimated that about 12% soils are strongly acidic (pH < 5.0), 48% moderately acidic (pH 5.0-5.5) and 40% mildly acidic (pH 5.6-6.5).

Formation of Acid Soils Acid soils in India are formed due to drastic weathering under hot humid climate and

heavy precipitation. Laterization, podzolization and accumulation of undecomposed organic matter under marshy conditions contribute to the development of soil acidity.

Acid soils are formed mainly due to acidic parent materials (granite) and leaching of bases from the surface soils due to high rainfall. Nitrogenous fertilizers like ammonium sulphate, mmonium nitrate, ammonium chloride and urea create soil acidity.


Table 1: Acid soils regions

State Area under acid Soils (m ha)

Percent Cultivated area (mha) with pH < 5.5

Assam and Northeastern states 20.0 80 3.5

West Bengal 3.5 40 2.0

Erstwhile Bihar 5.2 33 0.4

Orissa 12.5 80 1.8

Madhya Pradesh 8.9 20 -

Andhra Pradesh 5.5 20 -

Tamilnadu 2.6 20 -

Karnataka 9.6 50 -

Kerala 3.5 90 2.1

Maharastra 3.1 10 0.3

Erstwhile Uttar Pradesh 2.9 10 -

Himachal Pradesh 5.0 90 0.1

Jammu & Kashmir 15.5 70 -

Source: Mandal (1997), Sarkar (2005)

Chemistry of Acid soils In acid soils, the concentration of H+ ions exceeds that of OH- ions. For the long

time, it has been considered that the soil acidity is owing to exchangeable H+ ions only. Mukherjee and Chatterjee (1942, 1945) found the dominance of Al in the soil acidity in early thirties. Most of the clay particles interact with H+ ions. Hydrogen saturated clay undergoes a spontaneous decomposition. In the octahedral layer, hydrogen ions replace the Al ions. The Al released is then absorbed by the clay complex and a H-Al-Clay complex is formed rapidly. The trivalent aluminium hydrolyses to monomeric and polymeric hydroxy-aluminium complexes (Chernov 1947) and contribute to soil acidity.

Soil acidity is of three kinds (i) Active acidity refers to H+ ions soil solution (ii) Exchange acidity includes exchangeable H+ and Al3+

(iii) Non-exchange or residual acidity comprising of weak acids caused by organic matter and bound Al. The total acidity estimated by BaCl2 – TEA comprises of pH – dependent or residual and exchange acidity. Different types of soil acidity in different soil orders is presented in table 2.


Table 2: Forms of acidity [c mol(p+) kg-1] in soils under different soil orders

Location Total acidity

pH dependent

acidity

Total exchange

acidity

Acidity due to H+

Acidity due to Al3+

Inceptisols

West Bengala 5.98 5.50 0.48 0.19 0.29

Orissab 2.29 2.19 0.10 0.08 0.02

Mizoramc 12.50 11.08 1.41 0.23 1.18

Alfisols

West Bengala 3.20 3.1 0.10 0.03 0.07

Orissab 10.3 8.7 1.60 0.45 1.15

Entisols

West Bengala 5.15 4.93 0.22 0.11 0.11

Orissab 10.76 10.65 0.11 0.11 -

Mizoram 12.24 11.63 1.64 0.32 1.32

Ultisols

Orissab 5.30 4.70 0.60 0.30 0.30

Mizoramc 13.19 11.67 1.52 0.29 1.23

Source: a- Chand & Mandal (2000) b- Misra et al. (1989) c- Misra & Saithantuaanga (2000)

Studying different forms of acidity in major soil groups of India, Sharma et al (1990) reported that exchangeable H+ and exchangeable Al 3+ comprises 21 and 79% of exchange acidity, whereas pH dependent and exchange acidity accounted for 71% of the total acidity. The acidity unaccounted for were probably due to hydrolysis of Fe and Mn on the exchange sites of the soil complex. The important soil factors that control the different kinds of soil acidity are pH organic matter, exchangeable and extractable Al.

Crop Production constrains in Acid Soils The upland acid soils have coarse soil texture with high infiltration rate, low water

holding capacity, high permeability, soil crust formation, excessive leaching of nutrients and high bulk density. Seed germination is affected by surface soil crust. Application of organic matter (Biswas and Khosla 1971), tank slit, conservation tillage, contour and strip


cropping, intercropping of cereals with legumes or oilseeds and insitu rainwater harvesting are some of the suitable methods for crop yield in such soils.

Common problems of acid soils in respect of chemical properties are low pH, low CEC (due to dominance of 1;1 type of clay),low level base saturation percentage, high Fe, Al, and Mn saturation percentage, a high P fixing capacity, clay fractions consisting of rather low surface active minerals. These problems could be managed by amelioration with liming which improve soil pH, base status and CEC, inactivates Fe, Al and Mn soil solution, reduce acidity and P fixation in soil (Panda and Koshy 1982, Misra et al. 1989, Sahu and Patnaik 1990, Jena 2008 (Fig.-).

Acid soils are deficient in Ca. Exchangeable Mg content of such soils is also poor. High concentration of Fe and Al results in Fe and Al toxicity. Sulphur deficiency is common in upland coarse textured soils. Micronutrients such as B and Mo are often deficient in acid soils. Acid soils of India have generally low organic carbon and nitrogen status.

Crop production in acid soils suffer due to poor availability of plant nutrients, toxicity of Fe and Al, poor biological activity and low and imbalanced fertilizer use. Ameliorating these soils with liming materials, using balanced nutrients, organic manure, growing acid tolerant crops and crop species, use of biofertilizers will definitely increase crop productivity in acid soil regions of the country.

Liming- Source, Efficiency, Response and Limitations Liming is a widely accepted practice for ameliorating acid soils. It decreases

exchange acidity and increases soil pH. It improves base saturation percent of soils, inactivates Al, Fe and Mn, reduces P fixation and stimulates microbial activity leading to the mineralization of organic nitrogen. Availability of major, secondary and micronutrients due to liming of acid soils have been reported.

Among the naturally occurring lime sources, calcite, dolomite and stormatolitic lime stones are important. Since calcite and dolomite have industrial use, its application in agriculture is not economical. In India, the total reserve of all categories of lime stone is about 76,446 million tones (mt) out of which 11,562 mt are under proved category, 16,463 mt under probable category and 48,419 mt under possible category (Panda 2007). Deposits of lime stone in North-Eastern states are in the order of 4522 mt in Meghalaya, 703 mt in Assam, 309 mt in Nagaland, 140 mt in Arunachal Pradesh and 46 mt in Manipur. Orissa has a reserve of 1683 mt. Deposits of about 40 mt of stormatolitic lime stone, a poor grade lime containing 28-32% CaO, 12% MgO and 0.5% P2O5 is found in Orissa. Its use in acid soils needs detailed study.

Several industrial wastes such as paper mill sludge (PMS) from paper mills, basic slag from steel industry, pressmud from sugar mills using carbonate process have been tested successfully in acid soil regions of India as amendments which are ecofriendly. Depending on the availability and cost of the materials, several types of liming materials are used in acid soil regions of India (Table 3). Liming material must be locally available, properly ground and should have high neutralizing value and low cost for use by small and marginal farmers. Although huge amount of basic slag (100 mt per annuum) is


generated from steel mills located in Bhilai, Rourkela, Bokaro, Durgapur Burnpur, its use is limited due to high grinding cost. On an average Indian slag contains 1 to 7 of P2O5, 24 to 50% CaO and 2 to 10% MgO.

Table 3: Availability of liming materials in India

Acid soil region/state Liming material Quantity available (million tones)

Assam Lime stone 15.0

Himachal Pradesh Marketable lime -

Jharkhand Lime stone/basic slag* 1.0

Kerala Lime shells 4.0

North-Eastern Hill region Lime stone 14.0 Orissa Paper mill sludge/ basic slag*/

stromatolytic / lime stone* 0.2

West Bengal Basic slag 0.3

Others Basic slag 3.0

*prices not available Source: Sharma and Sarkar (2005)

Crop Response to Liming and Fertilization Effect of lime on crop yield in acid soil regions has been reported by several workers.

Based on past studies on liming (Table 4), the crops have been grouped into (a) High response group (pigeon pea, soyabean, cotton), (b) Medium response group (gram, lentil, groundnut, maize, sorghum, wheat, pea) (c) Low response group (barley, minor millet and paddy). Generally the crops

responded to liming are legumes, cotton, maize, sorghum, wheat and linseed etc.

Table 4: Relative response of different crops to liming

Crop Control Lime alone NPK alone NPK + lime

Group-I High Response

Arhar 100 1133 394 1927

Soyabean 100 503 207 788

Cotton 100 1083 2270 3887

Group II- Medium Response

Gram 100 223 256 606

Lentil 100 266 301 627


Groundnut 100 304 197 333

Maize 100 202 429 660

Sorghum 100 196 139 346

Wheat 100 109 215 267

Pea 100 295 313 596

Group III- Low Response

Barley 100 102 265 327

Minor millet 100 132 283 319

Paddy 100 173 280 266

Source: Sharma and Sarkar (2005)

Sharma and Sarkar (2005) reported that application of lime @ 2-4 q/ha increased the yield of rape seed mustard, wheat, green gram, maize, pigeon pea, field pea, black gram, groundnut by 14 to 52% over farmer’s practice. The recommended application of fertilizers (100% NPK) increased yield by 15 to 99% over farmer’s practice at different places. On the otherhand application of lime with 100% NPK resulted in 49-189% higher yield over farmer’s practice. The response to combined application of lime and fertilizers was more than fertilizer or lime alone, indicating synergy or complementarity between fertilizer use and liming. The yields recorded with 50% NPK + lime @ 2-4 q/ha were equal or slightly higher to the yield with 100% NPK (Table 5).

Jena (2008) studied the effect of different levels of lime (calcite) on pH, exchangeable Al+3 and H+ in an acidic laterite soil of Dhenkanal. The data revealed that application of lime @ 0.2 LR increased the pH from 5.1 to 6.9 (Fig 1) and decreased exchangeable Al+3 from 0.62 to 0 cmol(p+) kg-1 within seven days of incubation (Fig 2). Based on the study, several field trials were conducted in farmer’s field covering several crops and soil types 5.5 6 6.5 7 0 7 15 22 30 3 Incubation Period (Days) P.

Fig. 1: Effect of Lime application on soil pH


Fig. 2: Effect of Lime application on Exch. Al

Table 5: Yield (q/ha) of crops in acid soils with recommended fertilizer and half the recommended fertilizer + lime

State Crop 100% NPK 50% NPK + lime

Yield deviation (%)

Assam

Rapeseed Summer green gram

9.7 4.4

10.1 5.2

+ 4.1 +18.1

Himachal Pradesh

Maize wheat

34.0 27.9

33.1 23.7

- 2.6 - 15.0

Jharkhand

Maize + pigeon pea (maize equ. yield) Pea

69.0 38.4

65.0

50.8

- 5.8

+ 32.3

Kerala

Cowpea Blackgram

8.6 6.4

10.6 8.1

+ 23.2 + 26.6

Meghalaya

Maize Grundnut

30.5 14.2

30.3 21.3

- 0.7 +50.0

Orissa Groundnut Pigeonpea

22.5 12.0

23.6 12.2

+ 4.9 + 1.7

West Bengal

Mustard Wheat

8.2 16.7

8.4 17.1

+ 2.4 + 2.4

Source: Sharma and Sarkar (2005)

The data revealed that liming @ 0.2 LR through PMS (paper mill sludge) increased the yield of groundnut by 17-36%, green gram 5-21 %, cabbage 15-16 %and cauliflower 22% over farmer’s practice (Table 6).


Organic amendments reduce exchangeable Al in soils due to precipitation of Al ions by OH ions released from exchangeable ligand (Hue 1992; Lyamuremye et.al 1995). Several workers have suggested for application of organic amendments (FYM) either alone or in combination with lime for controlling the acidity as well as nutrient availability (Table 7). Liming also stimulates microbial activity leading to mineralization of organic N and fixation of N2 (Raychaudhuri et al 1998).

Table 6: Response of different crops to liming in red and laterite soils of Orissa Yield (q/ha)

Crop

District pH FP FP +lime Yield Response (%)

Groundnut

Dhenkanal Mayurbhanja Nayagarh Ganjam

4.0-6.3 4.8-5.2 5.5-5.7 5.6-6.1

8.40 15.05 10.70 19.05

11.43 17.55 12.70 23.87

36 17 19 25

Greengram Khurda Dhenkanal

5.5-6.5 3.8-6.0

8.10 8.20

8.95 9.90

5 21

Cabbage Kandhamal Koraput

5.9-6.6 5.8-7.3

111.70 224.00

130.00 256.90

16 15

Cauliflower 6.0-6.1 99.50 121.0 22

Source: Jena (2008)

Table 7: Effect of lime and FYM on soil properties after 30 days of application in acid Inceptisols of Bhubaneswar

Acidity (cmol (p+) kg-1) Available (kg ha-1) Treatments

pH Total Exch. Al N P K

Control 5.8 3.0 0.17 0.06 349 50 138

Lime 6.9

1.9 0.16 0 359 66 148

FYM 5.9 2.4 0.16 0 384 70 160

Lime + 6.8 1.9 0.14 0 370 60 160

FYM - - - - - - -

Source: Mohanty (2000)

Lime requirement value of varies with soil properties. Lime requirement of acid soils of India varied from 2.6 to 24.0 t CaCO3 ha-1 and was significantly related to soil pH and organic matter content (Sharma and Tripathy 1989). But liming at @ full LR dose is


often not economical. For laterite soil of Bhubaneswar 0.5 LR was enough for maize (Pradhan 1978), although exchangeable Al was neutralized with 0.25 LR. Application of lime @ 10-20% of LR in furrows increased the yield of greengram, groundnut, blackgram, soyabean, lentil, pea and gram over ‘no lime’ control (Mathur et al. 1985, Mathur 1997). In an experiment on direct and residual effect of liming in different cropping system conducted in acid sandy loam soil at G. Udayagiri in Orissa, grain yield of mustard, wheat and cowpea increased by 41, 28 and 21%, respectively due to direct effect of liming @ 0.25 LR and maize yield increased by 7-13% under residual condition (Table 8).

Result of long-term experiment conducted in acid soil regions at Ranchi, Bhubaneswar, Palampur and Bangalore over a period of 9-24 revealed that soil pH was decreased by 0.2-0.9 units with application of chemical fertilizer (NPK) but the pH was almost maintained or increased by 0.3-0.6 units with NPK + lime (Table 9). Average crop yield of soyabean, wheat, rice and maize increased by 0.3-0.7 t ha-1 due to application of NPK + lime over NPK. The crop response to lime application at Bangalore was negative because the initial pH was higher than 6.

Table 8: Effect of liming on field pea, wheat and mustard and its residual effect on succeeding maize crop

Direct effect (t/ha) Residual maize (t/ha) B:C Ratio Crop

L0 L1 L0 L1

Field pea F1 1.02 1.30 2.00 2.21

F2 1.34 1.56 2.16 2.21

Mean 1.18 1.43 2.08 2.21 4.25

Wheat F1 0.75 0.90 1.00 1.02

F2 0.89 1.15 1.09 1.35

Mean 0.82 1.02 1.04 1.18 1.33

Mustard F1 0.18 0.24 1.18 1.27

F2 0.29 0.34 1.14 1.31

Mean 0.23 0.29 1.16 1.29 1.68

L0: No lime, L1: 0.25 LR F1: 50% RDF, F2: 100% RDF (Recommended dose of fertilizer) Source: Jena (1996)


Table 9: Long term effect of liming on soil pH and crop yield in acid soil regions

Soil pH after 9-36 years

Grain yield (t/ha)

Location/cropping system

Initial

NPK NPK+Lime NPK NPK+Lime Response Ranchi Soyabean Wheat

5.3

4.8 5.8 1.6 3.4

1.9 3.7

0.3 0.3

Bhubaneswar Rice Rice

5.6 5.4

5.5

2.8 3.0

3.3 3.4

0.5 0.4

Palampur

Maize Wheat

5.8

5.3

6.4

3.5 3.0

4.1 3.3

0.6 0.3

Bangalore Finger millet Maize

6.1

5.2

6.4

4.0 2.1

3.7

2.0

-0.3

- 0.1

Source: Singh & Sarkar (1998); Sahoo et al (1998); Sharma et al (1998); Sudhir et al (1998)

Agro-techniques for Reducing Phosphate fixation and Improving Fertilizer use Efficiency

Attempts have been made by several workers to reduce the cost of P fertilizers in acid soils by direct use of rock phosphate or rock phosphate and single super phosphate mixture in 1:1 ratio. The total phosphate rock deposit in India is estimated as 200 million tones of which only 18.5 m ton can be rate as high grade (> 30% P2O5). Crop response to phosphate is strongly dependent upon the rate of dissolution of rock. Partial acidulation of phosphate has been reported to be the possible means for economic and efficient utilization.

Panda et al. (2007) reported North-carolina rock phosphate of 35 mesh was superior to 100 mesh size of Indian phosphate rocks such as Udaipur, Musoorie, Hirapur, Kasipatnam, Maton and Purulia. Udaipur rock phosphate containing dolomite and calcite was found economical for maize-mustard cropping system in alfisol. (Jena et al 2004). Mixture of imported phosphate rock with indigenous phosphate rocks works good for crops in acid soils since former one could act as a starter dose. The effectiveness of low reactivity phosphate rock can also be increased by applying it to green manure crop preceeding the main crop or by inoculation of the field with either phosphate solubilizing micro-organisms or Mycorrhiza (Misra 2004). Rice grown in iron toxic soils can be benefited from application of Udaipur rock phosphate containing substantial amount of dolomite and calcite. (Misra 2004).


Management of Secondary Nutrients in Acid Soils Most of the acid soils are deficient in Ca, Mg and S except acid sulphate soils which

contain high amount of S. Soils having Ca saturation less than 25% of the total cation exchange capacity require Ca application to most of the crops. Deficiency of Ca and Mg can be corrected by using lime or liming materials @ 4-5 q/ha.

Coarse textured acidic upland soils low in organic matter show S-deficiency. Sulphur deficiency of 17-87% was recorded in acid soil regions of the country (Singh 2007). Results of long term fertilizer experiments on maize-wheat sequence of Palampur (pH 5.8), soyabean-wheat sequence in Ranchi (pH 5.6), and finger millet-maize sequence in Bangalore (pH 6.0) showed the necessity of S application. Continuous depletion of S lead to significant decline in crop yields compared to the yields achieved in NPK + S treatment. Deficiency of S can be corrected by use of various S sources such as gypsum (15-18% S), SSP (12%S), ammonium sulphate (24% S), ammonium phosphate sulphate (15% S), sulphate of potash (18%), gromor sulphur bentonite (90% S) in acid soils. The efficiency of gromor bentonite S pastille can be compared with SSP on yield of rice-cowpea sequence in alfisol of Bangalore and rice-groundnut and hybrid rice-potato sequence in acid soils of Bhubaneswar (Jena et al 2006).

Phosphogypsum is a byproduct of diammonium phosphate factory located at Paradip of Orissa state. When rock phosphate is treated with sulphuric acid, gypsum and phosphoric acid is produced. Phosphogypsum contains 16% S and 20-21% Ca. It also contains about 0.2 to 1.2% phosphorus. Since Ca in phoshogypsum can leach down faster as compared to lime in light textured soils, sub-soil acidity could be ameliorated with resultant reduction of aluminium toxicity and calcium deficiency. Jena (2008) reported that about 10 million tones of phoshogypsum is dumped around fertilizer industry at Paradip and it has been found equally efficient source for correcting S deficiency in various crops. Table 10: Crop response to phoshogypsum application in Orissa

Yield (q/ha) % Response Crop Soil

NPK NPK + S Groundnut laterite 5.08 6.95 36.8 (kharif) Rice laterite 25.50 29.73 16.6

Hybrid rice laterite 43.13 52.33 21.3

Rice alluvial 52.30 63.30 21.0

Potato laterite 178.00 212.70 19.5 Greengram laterite 6.30 8.53 35.4

Groundnut (Rabi)

alluvial 17.50

29.50 68.6

Source : Jena (2008)


Management of Micronutrients in Acid Soils Data complied by Singh (2007) for different states representing mostly acid soils

indicate the deficiency of Zn, Cu, Fe and Mn is 31, 3, 4, and 3% samples, respectively in comparison to 47, 4, 14 and 6% for non-acidic soils of India. Taking DTPA extractable micronutrient levels as 0.6 ppm Zn, 0.2 ppm Cu, 4.5 ppm Fe, 2 ppm Mn, 0.5 ppm hot water soluble B and 0.15 ppm ammonium oxalate extractable Mo as the critical levels, out of 33000 and 4268 soil samples 45 and 12% samples were found to be deficient in B and Mo, respectively. Wide spread Zn deficiency ranging from 23 to 54% has been reported from the states like Assam, Jharkhand, Chattisgarh, Uttarakhand, Orissa and West Bengal. The deficiency of Zn and B may be attributed to a number of factors such as high rainfall, high acidity, coarse texture, low oxidation of organic matter etc.

Deficiency of B can be corrected by applying various boron fertilizers like borax decahydrate (Na2B4O7.10H2O; 10.5% B), boric acid (H3BO3, 17% B), granubor II (Na2B4O7.5H2O; 14.6% B). Boron is generally applied through broadcast and mixed properly prior to sowing or transplanting of crops @ 0.75 to 1.5 kg/ha. Band placement 1-2 kg B/ha was superior to broadcasting in increasing cud yield of cauliflower (Singh 2007). Productivity of cereals, chickpea, pigeonpea, groundnut, sunflower, sesame, linseed and mustard increased significantly with application of 12.5 kg B/ha (Sakal and Singh 1995). Application of granubor significantly increased the yield of caulifliower in Kullu, Himachal Pradesh (Sharma 2006) and alfisols of Tamilnadu, maize and cauliflower in Alfisols of Ranchi (Mohapatra 2006), maize-groundnut in acid soil of Srikakulam (Bhupalraj et al 2005) and rice-groundnut laterite soil of Bhubaneswar (Jena et al 2006).

Recovery of applied B in acid soils is about 36-54% due to higher precipitation with hydrous oxide of Al and Fe ( Mandal and Mandal 1992). Mandal (1995) and Jena (2008) found that combined application of B with lime together had significant effect on increasing the yield of wheat and cauliflower, respectively. Singh (2007) reported that the soil application of B @ 2 kg/ha was superior to foliar spray of 0.2% borax + lime twice for increasing tuber yields of potato in acid soils of Garhwal, but for crops like soyabean both soil and foliar spraying were equally efficient.

Zinc deficiency is wide spread in Assam and North-Eastern hill regions due to high organic matter content. In terai soils, the deficiency was about 49-51% as compared to 20-46% in red and laterite soils. Zinc deficiency has been reported from tea orchard soil of north-eastern hill region soils. Basal application of ZnSO4 is the common practice to correct Zn deficiency. Application of ZnSO4 @ 25 kg/ha in coarse textured soils and 37.5 kg/ha in fine textured soils was found optimum for rice, wheat, maize and other field crops. If soil application is missed at sowing/planting, top-dressing up to the pre-flowering stage in rice, wheat and other crops is recommended. The spraying of ZnSO4 @ 0.5% neutralized with lime @ 0.25% on standing crops correct Zn deficiency in cereals, pulses, oilseeds and plantation crops.

Seed treatment with teprosyn zinc phosphate (slurry containing 300g Zn + 200g P2O5 per litre at the @ 8 mL/kg seed) increased the yield of maize, groundnut, sunflower and was comparable to that of basal application of Zn @ 5 kg/ha (Singh 2003). Seed treatments to the crops having smaller size was found ineffective.


Organic manures raise the use efficiency of synthetic materials due to higher chelation and subsequently slow release (Singh 2007, Jena et al. 2006). Zinc @ 2.5 kg/ha was thoroughly mixed with 200-300 kg of fresh cowdung or well decomposed FYM and incubated for 20-25 days under optimum moisture condition to facilitate chelation of Zn. At the end, the material was dried under shade, finely ground for uniform distribution on the field. The result revealed that Zn-enriched organic manure @ 2.5 kg Zn/ha recorded similar yield of groundnut, mustard, sesame, bengalgram, pea as compared to 5 kg Zn/ha. Thus the Zn-enriched organic manure increased the use efficiency of Zn by saving 2.5 kg Zn/ha without causing any loss in crop productivity.

Limited information is available on rate and method of application of Mo fertilization. Among Mo sources, molybdic acid (80%), ammonium molybdate (54%) and sodium molybdate (39%) were equally efficient in correcting Mo deficiency in groundnut, lentil, cauliflower and other crops (Singh 1993). Pre-soaking of potato tubers in 0.01% ammonium molybdate solution increased the tuber yield by 2 t/ha in hill, 1.3 t/ha in red and lateritic and 0.2 t/ha in alluvial soils (Grewal and Trehan 1990).

Integrated nutrient management The basic principle of integrated nutrient management (INM) is the maintainace of

soil health, sustenance of agricultural productivity and increasing farm profitability through judicious use of chemical fertilizer, organic manure, green manuring, residue recycling and biofertilizers. Though biofertilizers are ecofriendly and can increase farm productivity in economically backward acid soil regions, their benefit is limited. Rhizobium is beneficial for pulses and oilseeds crops like soyabean, groundnut. But their growth in acid soils is affected due to poor availability of nutrients. Blue green algae perform poorly when the soil is highly acidic. Azolla could not be popularized due to poor management of water in high precipitation regions. Azospirillum is good for cereals, where as Azotobacter can benefit crops like sugarcane, cotton, potato etc. A good amount of organic manure like FYM or paddy straw are not available because a large proportion of cattle dung is used for fuel. There is no escape to accept a small dose of lime as a component in acid soils. Integrated application of lime and FYM further improves in yield of several crops. Mishra (2002) reported the yield of cowpea, groundnut, pigeonpea and maize in Alfisols of Bhubaneswar significantly increased with application of lime @10% LR and FYM @5 t/ha.

Long term experiment conducted at Ranchi, Bhubaneswar, Palampur and Bangalore over a period of 9-24 years showed that average grain yields of crops such as soyabean, wheat, rice and maize increased by 0.4 to 1.5 t/ha due to application of NPK + FYM over NPK (Panda et al 2007). Integrated use of chemical fertilizer with lime and organic manures has shown higher nutrient use efficiency compared to inorganic sources alone. In acid soils, crop response to liming was more than chemical fertilizers and liming along with NPK fertilizer imparted sustainability to the crop yields. Green manuring with fertilizers use have shown excellent results in rice-based cropping systems in the irrigated areas.

In a long term experiment conducted over more than 10 years in an acidic red soils of G-Udayagiri, Orissa with rice-horse gram cropping system, Jena et al (2000b) observed


that, water stable aggregates, porosity, available water capacity, organic C, available P and K content of the soil were higher with Gliricidia green leaf manure or FYM application either alone or in combination with 50% RDF over control or 100% RDF. While full dose of NPK gave higher yield in years of favourable distribution of rainfall, the INM practice recorded higher yield in the years of uneven distribution of rainfall, suggesting the sustainability of crop production with INM in rainfed acid soil regions. Combined application of chemical fertilizer, FYM @ 5 t/ha and lime @ 0.25 LR to maize crop in acid red sandy loam of Phulbani district of Orissa gave significantly one (Jena et al 2000 ).

Management of Iron toxic soils Iron toxicity occurs in hill bottom red and lateritic soils (Alfisol, Oxisol, Ultisol)

under undulating topography and impeded drainage condition. These soils are characterized with poor base saturation and limited supply of available nutrients like K, Ca, Mg, P, Zn and Cu. Iron toxicity symptoms in rice is seen as bronzing symptoms when Fe2+ concentration in soil solution goes up to 250-500 mg/kg due to reduce conditions under prolonged submergence (Jena et al. 2008). The concentration of Fe2+ further increases due to lateral flow of Fe from an adjacent upland to low land rice fields during rainy season (Sureshkumar 1999). In most of the rice soils the concentration of Fe2+ increases upon flooding and attains peaks after 2-5 weeks (Mandal 1961).

In iron toxic soils, substantial amount of iron is oxidized and get deposited on the active roots making physical barrier for absorption of plant nutrients from soil solution. Under extreme conditions, more number of roots become blackish in colour and only a few remain as whitish to brownish in colour. Plants get stressed and forced to produce more new roots at the expense of shoot growth. Production and decay of roots continue throughout the plant growth period. Iron toxicity in plants promotes sterility and the grain yield is reduced by 20-80% depending upon the situation.

Iron toxicity can be corrected by providing intermittent drainage. It reduces uptake of iron and increases availability of other plant nutrients. Liming of soils @ 1-2 t/ha along with K application had beneficial effect on alleviating Fe toxicity in rice by 27% over lime control in soils of Orissa (Mitra and Sahu 1992). Application of fresh cowdung @ 5 t/ha increased grain yield by 9.31 q/ha over control (19.04 q/ha). Application of lime @ 0.5 LR or potash @ 40 kg/ha or Zn @ 10 kg/ha increased grain yield by 8.25, 11.41 and 11.63 q/ha, respectively over control (Jena et al 2007). Foliar application of MnSO4 @ 0.6% had no beneficial effect on rice in iron toxic soil. Balanced fertilization helps in alleviating iron toxicity in rice. Singh et al (1993) reported application of 90 kg P2O5 /ha to iron toxicity soil at Barapani farm of Meghalaya resulted in reduction of Fe2+ from 3.60 to 1.63 mg/kg. Dipping rice seedling in boronated SSP and FYM slurry before transplanting helped to increase rice yield by reducing Fe toxicity.

Jena (2007) evaluated several rice genotypes in iron toxic laterite soils of Bhubaneswar over three consecutive years and reported rice genotypes like Kalinga III, Udayagiri, Panidhan and Tulasi are good tolerant to iron toxicity and IR 36, Konark, Birupa, Gajapati, Samalai and Indrabati are moderately tolerant to iron toxicity. Savithri and Sree Poongodevi (1980) evaluated rice varieties in iron toxic acid soils (pH 4.7;


DTPA Fe- 31 ppm, Aquic Hapludalf) in Kanyakumari district. Genotypic difference in the degree of susceptibility to excess Fe was confirmed by changes in the content of metabolically active Fe2+, chlorophyll and enzymatic activity in plant parts. Metabolically-active Fe2+ contents in the leaves, stems and roots of tolerant genotype (ASD-16) was 212, 392 and 4674 ppm as compared to highly susceptible rice genotype (ADT36) having 281, 442 and 5933 ppm Fe content, respectively. Genotypic differences in degree of susceptibility to excess Fe were attributed to leaf tissue tolerance of high level of Fe, reduced translocation from root to shoot and ability of roots to resist its entry inside the plant system.

Epilogue Acid soils are formed due to drastic weathering accompanied by hot humid climate

and heavy precipitation. Inherent soil characteristics pose macro, secondary and micronutrient deficiency as well as toxicity problems. These soils have poor physical properties, low pH, poor base saturation and high sesquioxides contents which affects the transformation and availability of nutrients. These soils are generally deficient in Ca, Mg, S, B, Zn and Mo and adequate in Fe, Mn and Cu. These soils have not been considered problematic and hence neglected.

Deficiency of Ca and Mg can be corrected by using locally available low cost liming materials at the rate of 0.1 to 0.2 lime requirement. Phosphorous management in such soils is done economically by using powdered indigenous rock phosphate by mixing with highly active imported rock. Partial acidulation is also recommended. Locally available phosphogypsum offers a cost-effective and cheaper option for correcting Ca and S deficiencies. Application of 25kg zinc sulphate/ha in coarse textured soils efficiently corrects the Zinc deficiency and leaves residual effect for 3-4 crops. Seed treatment with Zinc phosphate is beneficial for bold and big-sized seed crops like maize, sunflower etc. Application of 0.5-1.5 kg B/ha corrects the boron deficiency in most of the crops. Application of 0.5 kg sodium molybdate /ha annually has been found to be optimum in maize, niger, groundnut, rice and vegetable crops. Balance use of lime and micronutrients produces higher response than either lime or micronutrient application alone. Integrated use of lime and FYM @ 5 t/ha is beneficial in ameliorating Zn, B and Mo deficiencies as well as correcting Al and Fe toxicities in acid soils. Toxicity of iron can be alleviated by using lime, high dose of P, K and Zn fertilizers, FYM and pressmud etc.

Several crops and cultivars tolerant to acidity has been suggested. Horticultural and plantation crops suffering from micronutrients deficiencies can be benefited by foliar spraying of micronutrients. The technology generated requires to be operationalized on about 25 mha of cultivated acid lands having pH < 5.5. About 10 mha of cultivated lands have been identified for amelioration in the agriculturally-important districts of states in the first instance. The central and state Governments should facilitate the availability, marketing and distribution of locally available liming materials to the farmers at cheaper rates. The participation of KVKs and ATMAs in this regard would go a long way in popularizing the technology in the acid soil regions.


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Issues and Strategies for Managing Degraded Lands in Rainfed Ecosystem in India

B. Venkateswarlu and J.V.N.S. Prasad

Central Research Institute for Dryland Agriculture, Hyderabad 500 059, India Email: [email protected]

192 Issues and Strategies for Managing Degraded Lands in Rainfed Ecosystem in India

Abstract Land degradation is steadily increasing due to the growing pressure on land and

unsustainable land use in India. Land degradation and the associated loss of soil productivity and quality is of great concern both from food production perspective and environmental conservation. Land degradation due to water erosion is the most widespread, the extent of the area affected is to the tune of 82.5 m ha. constituting about 78 % of the total degraded area of the country. Water erosion is prevalent in all the agroecological zones of the country. Various technologies for arresting land degradation have been tested across the country in research stations and farmers fields through a large number of developmental programmes. Some of the most effective technologies for arresting water erosion induced land degradation in rainfed agro-ecosystems are discussed in this chapter. Keywords: land degradation, water erosion, engineering measures, agroforestry, vegetative measures, rainfed agro-ecosystem.

Introduction Land degradation can be defined as lowering of land productivity due to the

deterioration of land’s physical, chemical and biological condition. Physical land degradation is due to water erosion, wind erosion, compaction, crusting and water logging and chemical degradation is due to the processes of salinization, alkalization, acidification and nutrient depletion. Biological degradation is due to the reduction of soil biota and organic matter, degradation of vegetation and impairment of activities of micro-flora and fauna. Worldwide about 1,900 M ha of land is suffering from various forms of land degradation.

In India, land degradation assessment has been undertaken by various organizations in the past. Recently, efforts were made to harmonize the data bases of different categories of degraded lands estimated by various organizations. The total degraded area in India is about 120.72 M ha of which 104.19 M ha is under arable land use and 16.53 M ha is under forest land use with less than 40% canopy (Table 1). Among the different types of land degradation, water erosion (with soil loss of more than10 t/ha/yr) is the predominant form of degradation affecting an area about 73.27 M ha in the arable land and 9.30 M ha in the open forest. About 78% of the total degraded area in the country is due to water erosion (ICAR, 2010). As the country’s burgeoning population places multifarious demands on the land for food, fodder and fuel, besides the growing demands on land for habitat, industries, infrastructure development including roads and other public amenities, the pressure on the land is growing continuously. Due to the growing pressure and the unsustainable use, land degradation is continuously on rise. Land degradation and the associated loss of soil productivity and quality is thus a great concern not only from the perspective of food production but also for protecting the environment.

Issues and Strategies for Managing Degraded Lands in Rainfed Ecosystem in India 193

Table 1: Harmonized area statistics of degraded and wastelands of India (M ha)

Degradation type Arable land (Mha)

Open forest (<40% canopy) (Mha)

Data source

Water erosion (>10 tonnes/ha/yr)

73.27 9.30 Soil Loss Map of India CSWCRT&TI

Wind erosion (Aeolian)

12.40 - Wind erosion map, CAZRI

Sub total 85.67 9.30 Chemical degradation Exclusively Salt Affected Soils

5.44 -

Salt Affected and Water Eroded Soils

1.20 0.10

National Salt Affected Soils Map, CSSRI, NBSS&LUP, NRSA and others

Exclusively Acidic Soils (pH< 5.5)

5.09 -

Acidic (pH < 5.5) and Water Eroded Soils

5.72 7.13

Acid Soil map of India NBSS&LUP

Sub-total 17.45 7.13

Physical degradation Mining and Industrial Waste

0.19

Waterlogging (permanent surface inundation)$

0.88

Wasteland Map of the NRSA

Sub-total 1.07

Total 104.19 16.53 Grand Total (Arable land and open forest)

120.72

Source: ICAR (2010)

Water Erosion Land degradation due to water erosion is the most widespread in India and occurs

widely in all the agro-climatic zones. Soil displacement by water can result either in loss of top soil or terrain deformation or both through the processes of splash erosion, sheet erosion, rill erosion and gully erosion. Soil erosion starts with the falling of the raindrops onto the bare soil surface. The impact of the raindrops breaks-up surface soil aggregates and splashes particles into the air. On sloping land, detached soil material flows with runoff down the slope, resulting in soil loss. The extent and the severity of erosion is a function of the intensity of rainfall, land slope, soil types and land use.


Water erosion is the most predominant form of degradation affecting a large number of states. Madhya Pradesh is the worst affected state owing to water erosion, consisting of 16% of the total geographical area, followed by Uttar Pradesh, Andhra Pradesh, Maharashtra, Rajasthan and Karnataka covering 15%, 10%, 11%, 10% and 9% of the total area of these states (Table 2). Orissa, with 4% affected area ranks seventh and Jharkhand with 3.8% ranks eighth in terms of the area affected by water erosion. Water erosion in agricultural and open forest areas has affected almost all agro ecological regions (AERs) of the country. The AERs affected by water erosion are those regions which are primarily semi arid and where rainfed agriculture is predominant. AERs where large areas affected by water erosion are: AER-4 (13.1 M ha), AER-6 (10.6 M ha), AER-5 (7.4 M ha), AER-12 (6.4 M ha), AER-14 (5.0 M ha), AER-7 (4.8 M ha) and AER-8 (4.8 M ha, Table 3). Apart from the above, AER-9, AER-10and AER-11s has substantial area affected by water erosion. The nine above mentioned areas have about 56.5 M ha. area affected by water erosion which constitutes about 76% of the total area affected in the country (Table 3). Severely degraded lands are mostly inhabited by marginal farmers and tribal populations, who are poor and less literate. They are devoid of land-based amenities and infrastructure in comparison with the other farmers who cultivate better lands. Besides, soil erosion and land-degradation processes lead to nutrient depletion thus reducing soil quality. Studies have been carried out to examine implications of land degradation in terms of the resulting economic losses. The total economic losses to the country at current prices have been estimated to be a staggering sum of over Rs 285 billion, which is about 12% loss as per the total value productivity of these lands (Vasisht et al., 2003). Conservation of natural resources and rejuvenation of the degraded and the wastelands, therefore, offer a potentially enormous means of poverty alleviation and sustainable livelihoods (Srivastava et al., 2002).

Table 2: State wise area statistics of water eroded lands of India

State Water erosion (000'ha)

(>10 t/ha)

Total geographical area

of the state (%)

Total degraded area of the state

(000'ha)

Madhya Pradesh 11,881 16 14,095

Uttar Pradesh 12,370 15 14,405

Andhra Pradesh 8,050 11 9,193

Maharashtra 8,400 11 9,728

Rajasthan 7,436 10 20,424

Karnataka 7,450 9 8,093 Orissa 2,176 4 3,722 Jharkhand 2,825 4 3,943 Chhattisgarh 2,347 3 4,786 Asom 1,929 3 4,571 Tamil Nadu 2,063 3 2,997

Source: ICAR (2010)


Table 3: Area affected by water erosion under different AERs of India

AER no.

Description of the AER Area affected (,000 ha)

Total degraded

area (,000 ha)

4 Northern plain and central highlands including Aravallis, hot semi-arid eco region, with alluvium derived soils 12,109 14,961

5 Central (Malwa) highlands, Gujarat plains and Kathiawar peninsula, hot semi-arid ecoregions, with medium and deep black soils 6,455 7,700

6 Deccan plateau, hot semi-arid eco regions, with shallow and medium (with inclusion of deep) black soils 10,374 11,270

7 Deccan (Telangana) plateau and Eastern Ghats, hot semi-arid eco regions, with red and black soils 4,376 4,986

8 Eastern Ghats, Tamil Nadu uplands and Deccan (Karnataka) plateau, hot semi-arid eco regions with red loamy soils 4,412 5,685

9 Northern plain, hot sub-humid (dry) eco regions with alluvium derived soils 3,122 4,271

10 Central Highlands (Malwa, Bundelkhand and Eastern Satpura), hot sub-humid eco regions, with black and red soils 6,934 8,289

11 Eastern plateau (Chattisgarh), hot sub humid eco region, with red and yellow soils 3,843 5,925

12 Eastern (Chhotanagpur) plateau and Eastern Ghats, hot sub humid eco region, with red and lateritic soils 4,917 8,194

Total of the 9 AERs 56,542

(76%)

Total area 74,020 120,410

Source: ICAR (2010)

Technologies for controlling of water erosion and improving soil productivity Based on the outputs from various research institutes and experiences from watershed

development programs in India, technologies for arresting water erosion have been identified for different agro climatic zones of India. The details are furnished in Table 4.


Table 4: Soil and water conservation measures for various rainfall zones in India

Seasonal rainfall (mm)

< 500 500-750 750-1000 >1000

• Contour cultivation with Conservation furrows

• Ridging • Sowing across

slope • Mulching • Scoops • Tied ridges • Off season

tillage • Inter row water

harvesting system

• Small basins • Contour bunds • Field bunds • Khadin

• Contour cultivation with conservation furrows

• Ridging • Sowing across slope • Tied ridges • Mulching • Zingg terrace • Off season tillage • Broad bed furrow • Inter row water

harvesting system • Small basins • Modified Contour

bunds • Field bunds • Khadin

• Broad bed furrow (vertisols)

• Conservation furrows

• Sowing across slope

• Tillage • Lock and spill

drains • Small basins • Field bunds • Vegetative bunds • Graded bunds • Nadi • Zingg terrace

• Broad bed furrow (vertisols

• Field bunds • Vegetative bunds • Graded bunds • Choes • Level terraces

Source: Pathak et al. 2009

The choice of measures to be implemented depends on the predominant problems and resource endowments of the region. Earlier, efforts were concentrated on the construction of mechanical structures like bunds across the slope in various soil and water conservation programs. They helped in controlling erosion and reducing soil loss rather than increasing crop yields through moisture conservation. Current emphasis is more on improving moisture through various field and community based moisture conservation practices (Pathak et al. 2009) and contribute towards improvement of crop yields. Some of the promising soil and water conservation interventions for improving the productivity and reducing the land degradation are described below.

Broad bed and furrow (BBF) This technology is suitable for the rainfall range of 700 - 1300 mm and for medium

to deep black soils (Vertisols) with slope up to 5%. The BBF system consists of a relatively raised flat bed or ridge approximately 95 cm wide and shallow furrow about 55 cm wide and 15 cm deep. The BBF system is laid out on a grade of 0.4 - 0.8% for


optimum performance. It is important to attain a uniform shape without sudden and sharp edges because of the need to plant rows on the shoulder of the broad-bed. The BBF formed during the first year can be maintained for the long term (25-30 years). The raised bed portion acts as an in-situ 'bund' to conserve more moisture, ensures soil stability and the shallow furrows provides good surface drainage to promote aeration in the seedbed and root zone and prevents water logging of crops on the bed. It is suitable for many crops and cropping systems and mechanized operations and reduces the water erosion and conserves moisture effectively.

Conservation furrows This technology is suitable for the rainfall range of 400-900 mm for alfisols and

associated soils with a slope of 1-4%. This practice is highly suitable for soils with severe problems of crusting, sealing and hard setting where early runoff is quite common. In this practice, a series of furrows are opened on contour or across the slope at 3-5 m apart. These furrows harvest the local runoff water and improve the soil moisture to the adjacent crop row, particularly during the period of water stress. To improve its effectiveness further it is recommended to use this system along with contour cultivation or cultivation across the slope (Rao et al. 1981). The spacing between the furrows and its size can be chosen based on the rainfall, soils, crops and topography. The furrows can be made either during planting time or during interculture operation using a country plough. Two to three passes in the same furrow may be needed to obtain the required furrow size.

Modified Contour Bunds This technology is suitable for the rainfall range of 500-900 mm for alfisols and

moderate to deep black soils with slope of 1-8%. The modified contour bunds with gated-outlets have shown good promise because of the better control on ponded runoff water. Modified contour bunding involves constructing embankments on contours with gated-outlet at the lower end of the field. This gated-outlet allows the runoff to be stored in the field for a desired period and then released at a predetermined rate through the spillway, thus reducing the time of water stagnation behind the bund, which will have no adverse effect on crop growth and yield and also facilitates the water infiltration into soil to its optimum capacity.

Contour cultivation A simple practice of farming across the slope has many beneficial effects. The ridges

and the rows of the plants placed across the slope form a continual series of miniature barriers to the water moving over the soil surface. The barriers are small individually, but as they are large in number, their total effect is great in reducing run-off, soil erosion and loss of plant nutrients. Apart from conserving the water and soil, contour-farming conserves soil fertility and increases crop yields. This technology is suitable for the rainfall up to 1000 mm for almost all soil types with a slope of 1.5-4.0%. Contour cultivation or cultivation across the slope are simple methods of cultivation, which can effectively reduce the runoff and soil loss on gentle sloping lands (Figure 1). In contour cultivation, all the field operations such as ploughing, planting and inter-cultivation are


performed on the contour. It helps in reduction of runoff by impounding water in small depressions and reduces the developments of rills. In some situations it is desirable to provide a small slope along the row (cultivation a cross the slope), to prevent runoff from a large storm breaking over the small ridges formed during the contour cultivations. On long slopes, where bunding is done to decrease the slope length, the bunds can act as guidelines for contour cultivation. On the mild slopes where bunding is not necessary, contour guidelines may be marked in the field (Rao et al. 1981).

Fig. 1: Contour farming using vegetative hedge

Community-based Water Harvesting and Soil Conservation Structures The community-based soil and water conservation are playing a key role in

improving surface and groundwater availability and controlling soil erosion in the watershed programs in India. Some of the most promising community based soil and water conservation measures are discussed.

Masonry Check Dam These structures are popular in watershed programs in India. Masonry check dams

are permanent structures used for controlling gully erosion, water harvesting and groundwater recharging. The cost of construction is generally quite high. These structures are preferred at sites where the velocity of runoff water flow in gullies/streams is very high and stable structure is needed to withstand the velocity. Proper planning and design are needed for construction of masonry check dam. The basic requirements for designing the masonry check dams are: hydrologic data, information on soils and geology, the nature and properties of the soils in the command area and profile survey and cross-sectional details of the stream or gully. A narrow gorge should be selected for erecting the dam to keep the ratio of earthwork to storage at minimum. Runoff availability for the


reservoir should be computed on the basis of rainfall runoff relationship. Depending upon the assumed depth of structure and the corresponding area to be submerged, suitable height of the dam may be selected to provide adequate storage in a given topographic situation (Katyal et al. 1995). The cross-section of dam and other specifications are finalized considering the following criteria: there should be no possibility of the dam being over-topped by flood-water, the seepage line should be well within the toe at the downstream, the upstream and downstream faces should be stable under the worst conditions, the foundation shear stress should be within safe limit, proper spillway should be constructed to handle the excess runoff and the dam and foundation should be safe against piping and undermining (Pathak et al. 2009).

Low-cost earthen check dam Earthen check dams are those water harvesting structures that have an embankment

constructed across the waterway. The size of the dam depends on the site conditions. Earthen check dams are very popular in the watershed programs in India for controlling gully erosion and for harvesting runoff water. These are constructed using locally available materials. The cost of construction is generally quite low. This technology is suited for all soil types in the rainfall range of 350-1300 mm. In some cases, the stone pitching may be required to protect the bund from scouring. The earthen check dams are used for multiple purposes. They are used as surface water storage structures as well as for recharging groundwater.

Khadin System Khadin is a land-use system developed centuries ago in the Jaisalmer district of

western Rajasthan. This system is practiced by a single larger farmer or by group of small farmers. It is highly suitable for areas with very low and erratic rainfall. This technology is suitable for sandy and other light soil types in the rainfall range of 250-700 mm. In khadin system, preferably an earthen or masonry embankment is made across the major slope to harvest the runoff water and prevent soil erosion for improving crop production. Khadin is practiced where rocky catchments and valley plains occur in proximity. The runoff from the catchment is stored in the lower valley floor enclosed by an earthen/stone 'bund'. The water stands in the khadin throughout the monsoon period. It may be fully absorbed by the soil during October to November, leaving the surface moist. If standing water persists longer, it is discharged through the sluice before sowing. Wheat, chickpea or other crops are then planted. These crops mature without irrigation. The soils in the khadins are extremely fertile because of the frequent deposition of fine sediment, while the water that seeps away removes salts. The khadin is, therefore, a land-use system, which prevents soil deterioration. This practice has a distinct advantage under saline groundwater condition, as rainwater is the only source of good quality water in such area.

Farm Ponds Farm ponds are very age old practice of harvesting runoff water in India. These are

bodies of water, either constructed by excavating a pit or by constructing an embankment across a water-course or the combination of both. Farm pond size is decided on the total


requirement of water for irrigation, livestock and domestic use. If the expected runoff is low, the capacity of the pond will only include the requirement for livestock and domestic use. Once the capacity of the pond is determined, the next step is to determine the dimensions of the pond. High-storage efficiency of the farm pond can be achieved by locating the pond in a gully, depression, or on land having steep slopes. This design will considerably improve the storage efficiency of the structure. Reduction in seepage losses can be achieved by selecting the pond site having sub soils with low saturated hydraulic conductivity. As a rough guide, the silt and clay content of the least conducting soil layer is inversely linked with seepage losses. Therefore, it is best to select the site having subsoil with higher clay and silt and less coarse sand. Also, reduce the pond wetted surface area in relation to water storage volume. This can be achieved by making the pond of a circular shape or close to circular shape.

Gully checks with loose boulder wall Loose boulder gully checks are quite popular in the watershed program for

controlling gully erosion and for increasing groundwater recharge. These are very low cost structures and quite simple in construction. These gully checks are built with loose boulder and may be reinforced by wire mesh, steel posts, if required for stability. Often it is found on the land and thus eliminates expenditure for long hauls. The quality, shape, size and distribution of the boulders used in the construction of gully checks affect the life span of the structures. Obviously, boulders that disintegrate rapidly when exposed to water and atmosphere will have a short structural life. Further, if only small boulders are used in a dam, they may be moved by the impact of the first large water flow. In contrast, gully checks are constructed of large boulders that leave large voids.

Important vegetative measures for controlling water erosion Crops and vegetation cover the ground surface substantially and have extensive root

system to prevent soil erosion. Plant canopy protects the soil from the adverse effect of rainfall. The grasses and legumes produce dense sod which helps in reducing soil erosion. The vegetation provides organic matter to the soil. As a result, the fertility of soil increases and the physical condition of soil is improved which will enhance infiltration. Following are some of the key technologies which can be used for arresting the water erosion at field level.

Intercropping systems Intercropping systems are intensification of cropping systems in space and time.

These systems cover the soil during the early crop growing season and continue to cover the soil for longer period unlike the normal cropping pattern. Due to the differential canopy, these systems provide vegetative cover for longer periods than the mono cropping system. A good intercropping system should include densely planted small grain crops, spreading legume crop etc. which will check soil erosion. Integration of legumes in to the intercropping systems will supply nitrogen to the associated crop resulting in better growth and economic benefits. Different types of intercropping systems with various row ratios were developed for rainfed situations in the country. The best performing intercropping systems and their adoption for rainfed situations in different agro climatic regions was reported by Rao and Khan (2003).


Mulching Mulches of different kinds such a leaves, straw, stubbles, etc. minimize evaporation

and increase the infiltration of moisture and protect the surface of the land against the beating action of rain drops and reduces the erosive velocity. Later on they decay to form humus which improves the physical condition of soil. Mulches involving the leguminous materials provide substantial quantities of nitrogen for the crop growth. Various types of mulches are used and plastic mulches are being used for high value crops.

Strip Cropping It consists of growing erosion permitting crop (e.g. Jowar, Bajra, Maize etc.) in

alternate strips with erosion checking close growing crops (e.g. grasses, pulses etc.). Strip cropping employs several good farming practices including crop rotation, contour cultivation, proper tillage, stubbles mulching, cover cropping etc. It is very effective and practical means for controlling soil erosion, especially in gently sloping lands. It may be of different types such as contour strip cropping, which is growing of erosion permitting and erosion resisting crops alternately in strips across the slope and on the contour line. This practice is useful as it checks the flow of run-off, increases the infiltration and prevents soil erosion. In buffer strip cropping, the eroded portion of land is permanently kept under grass and contour strip cropping is practiced in the rest of the area.

Vegetative hedges or strips Vegetative barriers or vegetative hedges or live bunds are effective in reducing soil

erosion and conserving moisture. In several situations the vegetative barriers are more effective and economical than the mechanical measures viz. bunding. This technology is suitable for alfisols, vertisols, vertic-inceptisols and associated soils with slope more than 2.5%. Vegetative barriers can be established either on contour or on moderate slope of 0.4 to 0.8%. The vegetative hedges act as barriers to runoff flow, which slow down the runoff velocity resulting in the deposition of eroded sediments and increased rainwater infiltration. These hedges can increase the time for water to infiltrate into the soil, and facilitate sedimentation and deposition of eroded material by reducing the carrying capacity of the overland flow. It is advisable to establish the vegetative hedges on small bund. This increases its effectiveness particularly during the first few years when the vegetative hedges are not so well established. If the main purpose of the vegetative barrier is to act as a filter to trap the eroded sediments and reduce the velocity of runoff then the grass species such as vetiver, sewan (Lasiurus sindicus), sania (Crotolaria burhia) and kair (Capparis aphylla) could be used. But if the purpose of vegetative hedges is to stabilize the bund then plants such as Glyricidia or others could be effectively used. Afforestation and grassland management

Sod forming crop such as lucern (Medicago sativa L), Egyptian Clover, Berseem (Trifolium alexandrinum), ground nut (Arachis hypogea L), Sunhemp (Crotolaria juncea), etc. cover the surface of the land and their roots bind the soil particles to form


soil aggregates, thus preventing soil erosion. Growing of trees in areas which are devoid of vegetative cover substantially contributes towards the reduction of erosion. Infiltration of water is favoured due to high porosity of soil under vegetation. Surface accumulation of organic matter increases the water holding capacity of the underground soil. Root system of vegetation holds the soil mechanically and provides stability of the underground soil. The highly degraded soils can be brought under vegetative cover for arresting further degradation.

Agroforestry Agroforestry is a land-use systems in which trees or shrubs are grown in association

with agricultural crops, pastures or livestock, and in which there are both ecological and economic interactions between the trees and other components. It is a traditional form of dryland management and soil conservation measure that has been practiced in various parts of the world. Agroforestry practices provide vegetative cover which reduces the impact of rain drop and provide protection to the soil, enhance soil productivity and contribute towards sustainable land management. There is experimental evidence that soil loss can be greatly reduced by maintenance of a good ground surface cover (Young, 1989). Agroforestry systems are more effective in erosion control through supply of litter to the ground surface than through the effects of the tree canopy. Reduction of runoff and soil loss with tree species of leucaena and eucalyptus was reported when grown alone or in combination with grass than growing of subabul or eucalyptus along with maize (Narain et al., 1994). Based on research various agroforestry models suitable for different regions of the country have been evolved (Figure 2). Important agroforestry options for degraded lands in key agro climatic regions are furnished in Table 5.

Fig. 2: Different agroforestry systems for degraded lands


Table 5: Agroforestry systems for rainfed conditions in various agroclimatic regions of the country

Arable land Non arable lands S No

Agroclimatic region Agrisilviculture Agri horticulture Silvi pasture Hortipasture Block

plantation 1. Eastern

plateau and hills region

• Acacia nilotica + coarse cereals

• Tectona grandis + oilseeds

• Gmelina arborea+ soybean/lentil

• Annona squamosa + coarse cereals

• Emblica officinalis + pulses

• Psidium guava + soybean

• Azadirachta indica + Panicum maximum

• Acacia nilotica + Pennisetum pedicellatum

• Hardwickia binata + Setaria

• Tamarindus indica/ Annona squamosa + Stylosanthes hamata

• Leucaena leucocephala,

• Casuarina equisetifolia,

• Eucalyptus sps.

2 Central plateau and hills region

• Azadirachta indica+ sorghum

• Acacia ni/otica + Groundnut/ Sorghum

• Hardwickia binata + coarse cereals

• Zizyphus mauritiana +Mustard • Anona squamosa

+ Groundnut/ Sorghum

• Citrus/ Pomegranate+ Pigeon pea/Gram

• Albizia lebbeck + Cenchrus

ciliaris • Hardwickia

binata+Sehima nervosum/

Dichanthium annulatum

• Zizyphus mauritiana + Stylosanthes hamata

• Psidium guajava +Panicum maximum

• Emblica officinalis + Stylosanthes hamata

• Leucaena leucocephala

• Acacia nilotica

• Acacia tortilis

3 Western plateau and hills region

• Azadirachta indica/

Acacia nilotica + oil seeds

• Hardwickia binata /Leucaena leucocephala

+ Sorghum/ pulses /soyabean

• Zizyphus mauritiana+ Groundnut/

Sorghum /Pigeonpea • Anona squamosa

+ oil seeds • Emblica

officinalis / Citrus /

Pomegranate + Lentil Mustard

• Albizia lebbeck/ A. amara/ A.

procera+Cenchrus ciliaris /Sehima nervosum

• Hardwickia

binata +Dichanthium

annulatum /Panicum maximum

• Zizyphus mauritiana /Psidium guajava+ Stylosanthes hamata

• Emhlica officinalis+ Stylosanthes hamata / Panicum maximum

• Citrus + Stylosanthes

hamata / Panicum

maximum


• Acacia nilotica

• Acacia tortilis

4 Southern plateau and

• Tamarindus indica+

• Tamarindus indica/ Syzygium cumini

• Acacia leucophloea/

• Citrus • Cocos nucifera

• Prosopis juliflora/


Arable land Non arable lands S No

Agroclimatic region Agrisilviculture Agri horticulture Silvi pasture Hortipasture Block

plantation hills region Tomato

/Chilli,/Curry leaf

• Ailanthus excelsa + Cowpea/, Sesamum/ Sorghum /,PearmiIlet

• Albizia lebbeck+

Cowpea/ Sesamum /Sorghum /Pearl miIlet

+Tomato/chilli • nona squamosa / Emblica officinalis + Tomato/curry leaf

+Cenchrus ciliaris / Cenchrus setigerus /

Local grasses

• Nutmeg

• A. planiormis/

ferruginea

• Borassus flabellifer

5 Gujarat plains and hills region

• Azadirachta indica+ groundnut

• Acacia nilotica + cotton/ pulses

• Hardwickia binata /Dalbergia sissoo + castor /onion

• Zizyphus mauritiana+ groundnut

• Emblica officinalis +pulses,

• Punica granatum +cotton,castor

• Prosopis cineraria

• Ailanthus excelsa

• Acacia tortilis • Acacia nilotica

• Mangifera indica+ Cenchrus ciliaris

• Zizyphus mauritiana +Stylosanthes hamata

• Emblica officinalis

+Sehima nervosum

• Casuarina equisetifolia


• Prosopis juliflora

• Eucalyptus hybrid


Community–based biomass production for improved soil health This practice emphasizes on community approach for increasing the biomass

productivity and utilising the biomass produced for improving the fertility of the soil. Trees such as Gliricidia are grown either on degraded lands or on bunds for producing the biomass and the biomass thus produced is either used as mulch or incorporated in to the soil. This practice contributes for arresting the water erosion through arresting the impact of rain drop and increases the infiltration in to the soil and thus reduces the water erosion. The tree has high coppicing ability and twigs and leaves are rich in nitrogen (about 3%). Biomass production during the second year is about 1.3 kg dry matter/m2, which will increase to 2.6 kg/m2 during the third year and about 3.6 kg /m2 during the fourth year. The biomass production can reach up to 30 t/ ha from third onwards, which has potential to contribute substantial quantity of nitrogen besides contributing towards carbon sequestration and improvement in soil physical properties.

Tank silt as an organic amendment for rehabilitating degraded land Tank silt is an important amendment which can be used for the development of

degraded lands affected by water erosion. Continuous exposure to water erosion leads to loss of silt fraction which can be remedied by tank silt application. The tank silt by virtue of higher silt and clay content retains substantial quantities of moisture and improves the crop growth and yield. This is especially effective in light textures soils. The on farm evaluation of silt application in various field crops under rainfed conditions at six centers, viz. Anantapur (AP), Nalgonda (AP), Warangal (AP), Kolar (Karnataka), Solapur (Maharashtra) and Bhilwara (Rajasthan) for two years was presented in Table 6. Silt application has improved the crop yields, water productivity and profitability per millimeter of water used [Osman, (2010), Figure 3].

Table 6: Water use efficiency of different crops as influenced by tank silt application

WUE (kg ha-1 mm-1)

2008-09 (year I) 2009-10 (year II)

Sl. No.

District Crop

With silt Without silt With silt Without silt

1. Anantapur Groundnut 1.86 0.74 3.34 2.07

2. Nalgonda Castor 0.48 0.14 *3.89 *1.74

3. Warangal Cotton 2.57 2.17 3.35 2.00

4. Kolar Mulberry 0.52 0.50 0.33 0.29

5. Solapur Rabi sorghum 6.30 4.24 8.08 6.01

6. Bhilwara Maize 6.89 5.57 5.28 3.93

Note: * indicates yield accrued from cotton crop, castor was substituted with cotton during the second year


a) With tank silt application b) without tank silt Fig. 3: Effect of tank silt application in Maize at Bhilwara (Rajasthan)

Issues involved in arresting land degradation due to water erosion Continued practice of unsustainable land use and management practices is

contributing towards the land degradation due to water erosion. The growing pressure on land is leading to bringing more land under intensive use resulting in further degradation. Any comprehensive program or action to arrest water erosion should be based on assessment of the current land use, ownership and the severity of erosion. As watershed development program is being implemented by the government in large scale throughout the country effective implementation of the program will greatly contribute towards arresting the further degradation. As the extent of area affected by water erosion is large and difficult to cover the entire area, it is appropriate to inventorize the already treated lands and their current status and prioritization of the remaining degraded lands needs to be done for effective targeting of the program.

However, in recent years, large scale distribution of land to the weaker sections for cultivation is being done without providing support for their improvement. As these lands require substantial investments to control water erosion, suitable provision should be made for providing resources for arresting degradation of such lands. Besides issues such as overlapping jurisdiction of ministries, shortage of trained staff for implementation of the watershed development programme, rampant encroachment, lack of control on open grazing and lack of effective supervision and monitoring and evaluation inbuilt in the program are contributing for the lack of desired impact of the program. There should be a proactive approach for convergence among relevant programs, separate cost norms for treatment depending on the severity of degradation and effective use of GIS and remote sensing are necessary for the effective implementation of the watershed related development programs aimed at arresting land degradation.


Conclusions There is a need for convergence of different programmes aimed at land and water

resources development to tackle the problems of land degradation in arable and non-arable lands. A consortium approach in planning, implementation and monitoring of the program is essential. There is a need for generating a sense of awareness and building of ownership of the program by PRIs/SHGs/UGs and besides hand-holding by NGOs and line departments.

References ICAR (Indian Council of Agricultural Research) (2010). Degraded and wastelands of India.

Status and spatial distribution. ICAR, New Delhi. Katyal, J.C., Shrinivas Sharma, Padmanabhan, M.V., Das, S.K. and Mishra, P.K. (1995). Field

manual on watershed management. Central Research Institute for Dryland Agriculture, Santoshnagar, Hyderabad, India, 165pp.

Narain, P., Chaudary, R.S., and Singh., R.K.( 1994). Efficacy of conservation measures in north eastern hilly regions. Indian journal of soil conservation, 22:42-62.

Osman, M. (2010). Final report on Tank silt as an organic amendment for improving soil and water productivity. FPARP, Ministry of Water Resources, New Delhi, 98pp.

Pathak, P., Mishra, P, K., Rao, K.V., Wani, S.P. and Sudi, R. (2009). Best best options for soil and water conservation. In: Best best options for integrated watershed management. (Ed. Wani, S.P., Venkateswarlu, B., Sahrawat, K.L., Rao, K.V. and Ramakrishna, Y.S.). Proceedings of the comprehensive assessment of watershed programs in India, 25-27 July 2007, ICRISAT, Patancheru 502324.

Pathak, P.S. and Solanki, K.R. (2002). Agroforestry technologies for different agro-climatic regions of India. ICAR, New Delhi, India, 42 pp.

Rao, J.V. and Khan, I.A. (2003). Research gaps in intercropping systems under rainfed conditions in India, An On farm survey. CRIDA, Hyderabad, 132 pp.

Rao, M.S.R.M., Chittaranajn, S., Selvarajan, S. and Krishnamurthy, K. (1981). Proceedings of the panel discussion on soil and water conservation in red and black soils, 20 March 1981, UAS, Bangalore, Karnataka; Central Soil and water Conservation Research and Training Institute Research Center, Bellary, Karnataka and University of Agricultural Sciences, Bangalore, India, 127 pp.

Srivastava, S.K., Bandopadhyay, S., Meena Rani, H.C., Hedge, V.S. and Jayaraman, V. (2002). Incidence of poverty, natural resources degradation and economic policies and interventions: A study based on wasteland mapping. IAPRS & SIS, Vol. 34, Part 7, Resources and Environmental Monitoring, NRSA, Hyderabad, India.

Vasisht, A.K., Singh, R.P., Mathur, V.C. (2003). Economic implications of land degradation on sustainability and food security in India. Agropedology, 13:19-27.

Young, A. (1989). Agroforestry for soil and water conservation. CABI, 318 pp.

Land Degradation due to Selenium: Causes, Implications and Management

K. S. Dhillon and S. K. Dhillon Department of Soils, Punjab Agricultural University, Ludhiana, India

Email: [email protected]

Land Degradation due to Selenium: Causes, Implications and Management 209

Abstract Selenium (Se) is not an essential element for plant growth, but its concentration in

plant tissues is important for animal and human health. Plants vary considerably in their physiological response to Se. Intensive screening of cultivated agricultural plant species have revealed that Se accumulation was the greatest in oilseeds followed by legumes and cereals. The soils containing > 0.5 mg Se kg-1 are often associated with vegetation accumulating > 5 mg Se kg-1 - the critical level for animal consumption and thus are designated as Se-degraded or seleniferous soils. The presence of Se-degraded soils has been reported from Haryana, Punjab, West Bengal, Assam and Meghalaya states of India. The problem of selenium toxicity has been studied in detail during the last two decades in Punjab where >1000 ha of Se-degraded land has been identified. This paper reports about the sources of selenium, distribution in soil – plant system, toxicological impacts on animal and human health and the management of seleniferous environments.

Introduction Selenium (Se) was discovered by Jöns Jacob Berzelius and J. G. Gaham in 1817

while working with sediments of a sulphuric acid plant at Gripsholm, Sweden. The element isolated from the red deposits on the walls of lead chambers was given the name of ‘Selenium’ after the moon Goddess ‘Selene’. Since its discovery, Se continued to be known as an environmental toxicant till it was discovered as an essential nutrient for animal and human health (Schwarz and Foltz, 1957). In 1985, the United States Environmental Protection Agency postulated that Se should receive closer scrutiny as a potential contaminant of the food chain.

Perhaps, Marco Polo was the first to come in contact with probable Se poisoning while traveling in the remote parts of Western China and eastern Turkestan in 13th century. However, the first documented report describing Se poisoning in animals (horses), as known to today’s scientists, was penned in 1856 by an army surgeon Dr. Madison stationed at Fort Randal, South Dakota, USA. Loss of hooves and hair from horses grazing on the “poisoned lands of Meath” was reported from Ireland as early as 1890. Later on, Se toxic areas were identified in Columbia, Ireland, Israel, Australia (Rosenfeld and Beath, 1964). More recently, accumulation of Se in toxic levels in food chain has been observed in San Joaquin valley of California, USA (Ohlendorf, 1989) and northwestern India (Dhillon and Dhillon, 1991a). Selenium is increasingly becoming an environmental threat and often has been described as the element with two faces of toxicity and deficiency existing side by side. Selenium occurs naturally in soils varying from 0.005 mg kg-1 in a deficient area in Finland to 8000 mg kg-1 in the Tuva area of Russia.

Recently, a great loss of animal wealth due to some mysterious disease was reported from some locations in northwestern India. The basic reason for this health problem was identified in 1984-85 when chemical analysis of plant samples showing snow-white chlorosis revealed the presence of excess selenium. Further investigations revealed the presence of large amounts of Se in samples of soil, water, plant, animal and human tissues collected from the affected area. Selenium is not an essential element for plant

210 Land Degradation due to Selenium: Causes, Implications and Management

growth, but its concentration in plant tissues is important for animal and human health. The nutritional minimum level for animals and humans is about 0.05 to 0.10 mg Se kg-1 dry fodder / food. Toxic effects of Se may appear in animals and humans consuming feed containing 2 to 5 mg Se kg-1 or more. A number of greenhouse and field experiments were conducted to study the impact of selenium in soil - plant - animal - human system and to develop a suitable technology for mitigating the toxic effects of selenium in animal and human health. The results are discussed in the following sections.

Location of Se-degraded soils Interpretation of data in terms of probability of occurrence of a particular

concentration of Se in soil-plant system (Dhillon et al., 1992a) has revealed that soils containing > 0.5 mg Se kg-1 are, in fact, associated with vegetation accumulating Se more than the maximum permissible level (MPL) of 5 mg kg-1 dry matter for animal consumption. Thus, presence of 0.5 mg Se kg-1 soil was considered as the critical level and the soils containing Se above the critical level were designated as Se-degraded or seleniferous soils. The plant species, however, differ appreciably in their Se absorbing capacity and thus the critical limit should be used cautiously in differentiating seleniferous from nonseleniferous soils.

The presence of Se-degraded land has been reported from four different locations in India: i) Initially, Se toxicity problem was reported from Haryana state (Arora et al., 1975). A lot of research work was undertaken at National Dairy Research Institute, Karnal and Haryana Agricultural University, Hissar; but the relationship of Se toxicity in soil-plant-animal system was established only at one site near Karnal. The soils containing excess Se were highly saline in nature. The problem of Se toxicity disappeared when the affected soils were subjected to the process of reclamation; ii) In 1984-85, Se toxicity problem was reported from Punjab (Dhillon and Dhillon, 1991a). Since then detailed investigations have been undertaken and the results are discussed in the present manuscript; iii) Selenium toxicity in cattle were reported from Jalpaiguri, West Bengal by Ghosh et al., (1993); iv) Dey et al. (1999)) have reported that the dead remains of wild animals collected from the forest areas of Assam and Meghalaya states contained Se many times more than the normal level. Scientists concluded that the wild animals could have died due to accumulation of excess Se in their body tissues. Forages containing deficient as well as toxic levels of Se have been reported from different countries including America, Canada, Australia, New Zealand, China, India, Israel, United kingdom, Sweden, Finland.

Extent of Se-degraded Soils in Punjab, India Periodic surveys were conducted to assess the status of Se in soils, grasses, forage

and grain crops commonly grown in Punjab and Se-related disorders in animals and human-beings. In a survey conducted in 1970-72, only 1% of plant samples collected from different blocks of Punjab contained Se in toxic levels and the toxic site was located in Saroya block of Hoshiarpur district (Dhillon et al., 1977). The follow-up survey undertaken in 1984-85 lead to the identification of selenium toxic areas in a number of villages namely Panam, Nazarpur, Simbly belonging to Hoshiarpur and Barwa, Jainpur, Mehindpur, Rakkara Dhahan, Jadla and Bhan Majara villages of Nawanshahar districts of


Punjab (Dhillon and Dhillon, 1991a and Dhillon et al., 1992a). The Se-contaminated region that has been subjected to detailed investigation is enclosed by Garhshankar – Balachaur road on the eastern side, Bist Doab Canal on the western side and Nawanshahar – Balachaur road on the southern side. On the basis of Se content of soil and plant samples, the soil maps have been prepared depicting highly toxic and moderately toxic locations in Hoshiarpur and Nawanshahar districts (Fig 1). During a recent survey of whole of the Kandi region of Punjab (Dhillon et al., 2004), some additional Se-contaminated sites were identified and the comprehensive list is reported in Table 1. There is need to undertake detailed investigations so as to ascertain the extent of Se toxicity problem at the new locations also. Selenium-contaminated soils as shown in Fig 1 constitute about 1000 ha and are sporadically distributed in different villages (Table 2).

Fig 1: Map showing severely and moderately Se-contaminated areas in Punjab


Table 1: Comprehensive list of seleniferous sites located in the Kandi region of Punjab

Distric Block Village

Garhshankar Simbly, Nazarpur, Dhamai, Panam, Binjon and Behbalpur Hoshiarpur

Mahilpur Todarpur and Jandoli

Saroya Jainpur, Mehindpur, Rakkar Dhahan, Bholewal, Bharapur, Chandpur Rurki, Karimpur Chawala, Karimpur Dhianai, Thandupur, Bachhauri, Kulpur and Katwara

Nawanshahar Barwa, Bhan majara, Kishanpura and Daulatpur

Nawanshahar

Balachaur Rurki khurd, Phirni majara, Karawar, Mazari and Ghamour

Ropar Anadpur Sahib Lodhipur

Table 2: Selenium-contaminated area (acres) at different locations in Punjab as shown in Fig 1.

District Block Village Highly toxic

(>2 mg Se kg-1 soil)

Moderately toxic (0.5 - 2 mg Se kg-1

soil)

Total

Simbly 180 488 668 Nazarpur 25 56 81

Hoshiarpur Garhshanker

Total 205 544 749 Barwa 175 355 530 Bhan Majara 16 45 61 Baghouran 21 60 81 Jadla 30 45 70

Nawanshahar

Total 242 505 742 Jainpur 150 310 460 Mehindpur 25 60 85 Rakkar Dhahan

65 130 195

Nawanshahar

Saroya

Total 240 500 740 Grand

Total 687 1549 2231


Genesis of Se-degraded soils in Punjab The factors responsible for the development of Se-degraded soils in Punjab are -

Parent material, Irrigation water and Adoption of rice based cropping sequences. Parent material: The most important factor controlling the level of Se in geo-

ecosystems is the parent material (Rosenfeld and Beath, 1964). Accumulation of Se in toxic levels is a direct consequence of geological origin of soils. The soils that tend to be seleniferous have developed like the normal soils as a result of so called active and passive factors of soil formation. Change in topographical features and leaching / erosion processes have played an important role in the development of seleniferous soils. Areas containing toxic, adequate or deficient Se levels exist side by side in many parts of the world. Most of the seleniferous soils lying in arid and semi-arid areas of the western states of USA have developed in situ from weathering of underlying rocks. Toxic soils are derived from Cretaceous sedimentary deposits of the Niobrara and portions of Pierre shale. The chalky and calcareous marls and shales of Niobrara formation are the most persistent seleniferous beds of the Great Plains region of USA.

In Punjab, Se-toxic sites are located at the dead ends of seasonal rivulets (Choes) originating from the Shiwalik ranges (Fig 2). Identification of Se contaminated soils at the dead ends of seasonal rivulets (choes) provides a valid reason to believe that Se-rich material could have been transported through these rivulets along with flood water and repeatedly being deposited at their endings. Exact nature of parent material of seleniferous soils is not known, but it might resemble that of upper Shiwalik rocks. These rocks are mainly composed of polymictic conglomerates of variable composition containing many unstable materials (granite, basalt, limestone etc.) and derived from metamorphic terrain of Himalayas (Karunakaran and Rao, 1979). In addition to this, Se absorbed by natural vegetation from lower layers of soil got deposited in the surface layer following countless cycles of growth and death. Under increasing population pressure, when these sites were brought under cultivation, movement of Se in appreciable quantity from soil through plants to animal and human system has resulted in serious health hazards.

Selenium content of rock samples collected from Shiwalik range is reported in Table 3. Among the sedimentary rock samples, majority of the samples belonged to sandstone. Selenium content of rock samples is also quite low and thus may not be considered as Se-rich materials at present. It is most likely that instead of transporting Se-rich materials as such, the flood water moving through the materials in the Shiwalik range dissolved Se from the materials which moved down stream along with water and got repeatedly deposited at the dead ends. It is a well known fact that Se is highly soluble in water. According to Krauskopf (1955), the processes responsible for enrichment of Se in geological materials are: mechanical enrichment, precipitation, adsorption, substitution and presence of organic material in deposits. Among the sedimentary rocks, shales commonly contain more Se than sandstone, limestone and phosphate rocks. Sandstones are usually more permeable than limestones and shales and their gross composition is more variable. Local enrichment of sandstone may occur because of precipitation of Se from ground waters moving through beds long after their deposition. Of the total Se in


sandstones, >80% is water soluble, whereas in pyritic phosphoric rocks only 0.6% is water soluble (Rosenfeld and Beath, 1964). In Se-toxic regions of China, the leaching conditions controlled by microtopography features are mainly responsible for the distribution and redistribution of Se in soils and plants (Zhu and Zheng, 2001).

Fig 2: The lines depict the choes originating from the Shiwalik ranges and

transporting alluvial material along with flood water to the low lying araes. ● – Indicate location of Se-contaminated soils at the dead ends of choes

Table 3: Selenium content of rock samples collected from lower and upper Shiwalik ranges

Se content (µg kg-1)

Sampling period

No. of sample

s

Location Type of rocks

Range Mean±SD November 2003

5 Cluster of rocks near Pojewal, Distt Hoshiarpur

Clay stone, Salt and pepper sandstone, Yellowish brown sandstone and Light grey sandstone

1864 -2754

2341± 336

December 2004

25 Upper Shiwalik hills along roads from Hoshiarpur to Gagret, Nurpur Bedi and Una

Shale, Sandstone, Claystone, Siltstone, Limestone, Conglomerates

11 - 847 242± 190

April 2005

9 Along Chandigarh– Basathu– Solan road

Sandstone, Claystone, Siltstone, Wood coal

46 - 644 247± 211


Irrigation water: Wide variation in Se concentration of underground water was observed in the affected region. In general, Se content of water samples ranged from 0.25 to 69.5 g L-1 with an average value of 4.7 g L-1 (Fig 2). However, the samples collected from tubewells located at or near the toxic sites contained 2.5 to 69.5 g Se L-1 with an average value of 24.6 g Se L-1. On the basis of the guidelines recommended by the NAS-NAE (1973), 88.9% of water samples contained Se in the safe range, 11.1% of the samples were not suitable for drinking purposes; 4.4% of the samples exceeded the irrigation water guidelines of 20 g Se L-1. Total Se in ground water, in the present investigation, was higher than that observed by Robberecht and Grieken (1982) in ground water from Italy, Australia, Belgium, Russia and Sweden and was 1 to 8 times lower than that observed in France, Argentina and USA.

Adoption of rice based cropping sequences: The affected region was traditionally a maize-wheat growing area. With the availability of electric power, the farmers installed tubewells for pumping out underground water. Wherever the land was suitable, rice-wheat system being more profitable was adopted by the farmers. After about 8-10 years of regular cultivation of rice, Se toxicity symptoms started appearing on wheat crop that followed rice. Underground water, the only source of water available for irrigation purposes, was found to be contaminated with Se at certain locations. Depending upon the amount of irrigation water required and the extent of Se contamination in water, Se additions through water may range from 6 to 1155 g ha-1 under different crops. Obviously, Se additions through the irrigation water were the highest in the case of rice. Selenium inputs in soil through underground water under different cropping sequences (Table 2), revealed that regular cultivation of crops with excessive requirements of water is leading to significant accumulation of Se in the soil and is further accentuating the Se toxicity problem.

Characteristics of Se-degraded soil Se-degraded soils were alkaline in reaction ranging in pH from 7.3 to 9.4 and

electrical conductivity from 0.2 to 5.2 dS m-1. Except a few samples, all the soil samples were calcareous in nature having free calcium carbonate 0.1 to 6.2%, organic matter 0.1 to 2.7% and cation exchange capacity 2.6 to 36.7 cmol kg-1. Soil texture varied between silty loam to silty clay loam. Seleniferous soils did not differ significantly from nonseleniferous soils with respect to their physical and chemical characteristics except in calcium carbonate content. Average CaCO3 content of toxic soils (1.7± 1.01%) was almost double than that of non-toxic soils (0.9± 0.83%). There was no difference in the productivity potential of both the soil groups except that the farm produce obtained from toxic soils is rich in selenium and is thus not fit for animal and human consumption.


Fig. 3: Se content of underground water - the only source of irrigation and drinking water in the seleniferous region of Punjab, India

Table 4: Selenium additions in soil after irrigating different cropping sequences with underground water in the seleniferous region of northwest India

Se addition through underground water after one year (g ha-1)

Crop rotation

Range Mean

Se addition through underground after after 10

years (g ha-1)

Rice - Wheat 50.6 – 1417 498 4980

Rice-Berseem 63.7 – 1785 627 6270

Rice -Sunflower 59.9 – 1680 590 5900

Maize-Wheat 18.8 – 525 184 1840 Sugarcane 22.5 – 630 221 2210

Rice - Oryza sativa; Wheat - Triticum aestivum; Berseem - Trifolium alexandrinum; Sunflower - Helianthus annuus; Maize - Zea mays; Sugarcane - Saccharum officcinarum.

In a survey extended over whole of the Kandi region and its adjoining areas in Punjab, Dhillon et al. (2004) have reported that total Se content in the surface soil ranged from 0.02 to 4.55 mg kg-1 with an average value of 0.41±0.68 mg kg-1 (Table 5). Out of 184 soil samples, 18% of the samples contained Se more than the critical level of 0.5 mg Se kg-1. On the basis of average values, maximum level of Se was present in soils from Nawanshahar block followed by that from Garhshanker, Saroya, Anandpur Sahib, Nurpur Bedi, Balachaur and Mahilpur blocks. Total Se content exhibited significant and positive relationship with hot water soluble Se (r = 0.83**), Se content of plants (r = 0.78**),


CaCO3 content (r = 0.42**), electrical conductivity (r = 0.39**) and silt content (r = 0.31**) of soils. Fractionation of native Se in seleniferous soils of Punjab, from where chronic selenosis in animals has been reported, revealed that KCl extractable Se (selenate) constitutes 6-14% of total Se, KH2PO4 extractable (selenite) 11-19%, 4M HCl extractable Se 2-7% and residual Se ranged from 67-76% (Dhillon and Dhillon, 1999).

At the seleniferous sites, Se was present in the soil profile up to 2 m depth, but its distribution in different layers of the soil profile did not follow any specific pattern (Table 6). At all of the toxic sites, surface layer was found to be rich in Se as it contained 1.5 to 6.0 times more Se in comparison to the lower layers. Among the surface soil layers at different sites, Se content was the greatest in Simbly followed by that from Nazarpur, Barwa II, Jainpur and Barwa I sites. On the basis of physico-chemical characteristics of surface and profile samples, it may be concluded that seleniferous soils belong to Order - Inceptisol, Great group - Haplustept and Subgroup - Fluventic.

Among other states of India, soils with as high as 10 mg Se kg-1 exist in Haryana (Singh and Kumar, 1976); but no relationship has been reported between high Se levels and health of animal and humans. Only at one location near Karnal at village Chamar Khera, symptoms resembling Se toxicity were observed by Arora et al. (1975) on some buffaloes (Bubalus bubalis) feeding on fodders containing 0.9 to 6.7 mg Se kg-1. In the sub-Himalayan region of West Bengal, Se content of soils from the toxic pastures ranged from 1.45 to 2.25 mg kg-1. Se-rich soils have been identified in many parts of the world. Selenium content of surface soils ranged from 1.5 to 20 mg kg-1 and a maximum of 98 mg Se kg-1 have also been recorded in the toxic region in Western United States (Rosenfeld and Beath, 1964). In China, soils containing total Se >3.0 mg kg-1 and water-soluble Se >0.02 mg kg-1 are associated with Se poisoning and are located in Sangliao, Weihe and Hua Bei plains (Tan et al., 1994). Acute poisoning and chronic selenosis has been reported from the regions where total Se content in surface soils ranged from 0.3 to 0.7 mg kg-1 in Canada, 0.3 to 20 mg kg-1 in Mexico, 1 to 14 mg kg-1 in Columbia, 1.2 to 324.0 mg kg-1 in Ireland and up to 6.0 mg kg-1 in Israel (Rosenfeld and Beath, 1964).

Table 5: Selenium content (mg kg-1) of surface soil (0-15 cm depth) from different locations in the Kandi region of Punjab

Selenium content (mg kg-1) District Block No. of samples Minimum Maximum Mean + SD

Hoshiarpur Garhshankar 35 0.09 2.92 0.69 0.76 Mahilpur 12 0.08 0.42 0.20 0.11

Nawanshahar Saroya 69 0.02 4.55 0.41 0.68 Nawanshahar 16 0.08 2.41 0.83 0.84

Balachaur 25 0.06 0.74 0.25 0.16

Ropar Anandpur Sahib

14 0.15 0.80 0.46 0.29

Nurpur Bedi 13 0.07 0.49 0.31 0.22


Table 6: Distribution of Se in the soil profiles representing different seleniferous sites in the Kandi region of Punjab

O C CaCO3 Total Se HWS-Se Profile locations

Depth (cm)

pH E C (dS m-1) (%) (mg kg-1)

Nazarpur 0-24 8.22 0.27 0.65 0.87 2485 70.7

24-87 8.08 0.15 0.46 0.75 1056 31.8

87-120 7.89 0.18 0.43 0.50 1695 10.9

120-157 7.73 0.28 0.41 0.50 593 12.0 157-170 8.55 0.20 0.37 7.50 402 15.5

Simbly 0-27 8.45 0.25 0.63 2.25 3247 98.0

27-90 8.23 0.14 0.41 0.50 1044 30.8

90-146 8.59 0.17 0.34 9.92 1171 14.8

146-195 8.67 0.16 0.36 12.5 1235 8.9 Barwa I 0-22 8.78 0.23 0.53 2.65 1432 31.0

22-61 8.50 0.16 0.40 0.75 698 18.2

61-89 8.35 0.21 0.41 0.35 1104 9.8

89-111 8.41 0.18 0.33 0.30 859 11.9

111-166 8.70 0.20 0.31 9.30 1319 13.3 Barwa II 0-24 8.58 0.30 0.53 4.87 2322 26.8

24-62 8.56 0.23 0.39 1.75 1742 12.7

62-126 7.84 0.31 0.33 0.52 1012 10.1

126-163 7.89 0.34 0.32 0.35 507 5.6

Jainpur 0-17 8.56 0.27 0.58 4.75 1729 35.7

17-65 8.80 0.23 0.55 2.87 1091 13.9 65-124 8.10 0.30 0.40 0.32 294 9.6 124-155 8.06 0.32 0.39 0.40 460 8.3

Impact of selenium toxicity on plant, livestock and human health Plant health: Typical symptoms of Se poisoning in plants i.e. snow-white or papery-

white chlorosis with pink colouration at lower side of leaves and sheath of wheat (Triticum aestivum) were, at first, observed by Hurd-Karrer (1934) in a sand culture experiment. But in the recorded history of Se research, similar symptoms have been recorded for the first time on wheat growing under field conditions on naturally occurring seleniferous soils of Punjab, India (Dhillon and Dhillon, 2003) and on lentil (Lens culinaris) plant under greenhouse conditions at a level of 2.5 mg selenate-Se kg-1 soil. The red colour indicates that excess Se has accumulated in elemental form. The above


ground portion of wheat plants showing varying degrees of toxicity symptoms may contain Se ranging from 100 to 450 mg kg-1. Plant responses to different levels of selenate -Se were recorded under greenhouse conditions. Progressive restriction in growth was observed in all the plant species with increasing level of Se in the soil. Among oilseed crops, complete mortality was observed in all the crops except toria (Brassica compestris var toria) at a level of 5 mg selenate-Se kg-1 soil. Taramira (Eruca sativa) proved the most sensitive and toria highly resistant to the presence of selenate-Se in the soil. Among vegetables, only spinach (Spinacea oleracea) and potato (Solanum tuberosum) plants could withstand the toxic effect of Se when applied as selenate up to 5 mg kg-1 soil. Complete mortality was observed in case of radish (Raphanus sativus) and turnip (Brassica rapa) and fruit development did not take place in case of tomato (Lycopersicum esculentum), brinjal (Solanum melongena), peas (Pisum sativum) and cauliflower (Brassica oleracea var. botrytis). Tuber / bulb formation did take place to some extent in potato, garlic (Allium sativum) and onion (Allium cepa). All the weed plants proved very sensitive and their growth pattern was seriously affected due to the presence of selenate-Se in soil. In some species flowering was delayed by about a week and in others colour of leaves changed to light green. In case of wild oats (Avena sativa), burning of tips and leaf margins was observed at 2.5 mg selenate-Se kg-1 soil. While studying the impact of Se accumulation on consumability of leafy vegetables, it was observed that Se uptake adversely affected the dietary parameters like total proteins, vitamin C and crude fiber content (Sagoo et al., 2004a).

Animal health: Animals consuming Se-rich fodders and cereal straws grown on seleniferous soils exhibited typical symptoms of Se poisoning (Dhillon and Dhillon, 1990, 1997a; Dhillon et al., 1992c). The most consistent clinical manifestations indicated by all the affected animals were: loosing body condition and loss of hair, necrosis of the tip of tail reluctance to move, stiff gate, overgrowth of hoof followed by cracks gradually leading to detachment from the main hoof, abnormalities in horn growth and shedding of horn corium. The animals may die depending on the severity of symptoms. Some of the animals were showing hair loss from switch of tail and bilateral cataract. Complaints of delayed onset of estrus, anestrus and premature abortion were also recorded. Farmers also reported that animals brought from nonseleniferous areas start disliking even the succulent green fodders within a short period of even 4-5 days. As a result of garlic like smell emanating from toxic fodders, animals are able to differentiate between Se-toxic and healthy fodders. There are cases where animals suffering from chronic selenosis have recovered when fed with fodders brought from Se-free areas.

Epidemiological studies conducted on animals showing varying degrees of chronic selenosis in the seleniferous region of Punjab (Atwal et al., 2003) have revealed that anestrus condition was prevalent in all the age groups of buffaloes and was observed in more than 50% of the animals. Delayed puberty was a prominent sign in 32% of the heifers. Majority of anestrus animals in selenotic areas were found to be in low to medium plane of nutrition and may be designated as major cause of reproductive failure in seleniferous areas of Punjab. The animals affected with chronic selenosis had 35% less haemoglobin and 15% less TEC and thus were also suffering from macrocytic and hypochromic anaemia (Dhillon et al., 1992b). Further investigations on pathophysiology


of affected animals revealed that chronic selenosis results in chronic hepatitus and impairment of hepatic and renal functions (Randhawa et al., 1992; Singh et al., 2002). Selenium content in tissues of diseased animals was significantly higher than the critical levels reported by Blood and Radostitis (1989) in cattle and thus confirming Se toxicity. Average Se content of hair, hoof and blood samples of animals showing typical symptoms of Se toxicity was 311 to 643, 34 to 37 and 38 to 83 times higher than that of healthy animals feeding on plants grown in nonseleniferous areas of the state.

Human health: Selenium toxicity in human beings resulting from dietary intake of Se was considered ‘unobserved’ up to as late as 1980 (FNB, 1980). The best evidence of chronic Se toxicosis as a result of excessive dietary intake of Se was at first reported from China by Yang et al. (1983). The authors have reported that a disease characteristic of Se poisoning in human population occurred in some villages of Enshi County of Hubei province. Corn containing markedly elevated levels of Se was identified as the main toxic dietary constituent. Daily dietary intake of Se in the affected individuals ranged from 3.20 to 6.69 mg with an average value of 4.99 mg compared with 0.116 mg in Se adequate areas. The population suffering from chronic selenosis exhibited prominently the loss of hair and nails. In the affected individuals, hair was found to be brittle, easily broken and the new hair lacked pigment. Nails were also brittle with white spots and longitudinal streaks and eventually broke-off. Eruptive skin lesions occurred with reddish pigmentation that frequently remained after the lesions have healed. Tooth mottling was evident in approximately 1/3 of the affected population. Numerous neurological signs, frequently accompanied by gastrointestinal disturbances were observed in one village that had a particularly high prevalence of selenosis.

Humans residing in the seleniferous areas of Punjab and consuming Se-rich grains and vegetables (Table 9) produced at their farms have developed typical symptoms of Se poisoning (Dhillon and Dhillon, 1997a). Out of 20 humans studied, 55% showed loss of hair from the body, particularly head, malformation of finger as well as toe nails and progressive deterioration in general health. Others complained of occasional severe headache and nausea. In some of the affected humans, fingernails got completely detached and blood kept oozing out from the fingertips. Humans of all ages were affected by Se poisoning. Selenium content of hair and nails of affected persons was 8 - 9 and 6 - 8 times, respectively, higher than the healthy persons (Dhillon and Dhillon, 1997a). In addition to the symptoms described above, majority of the human population suffering from chronic selenosis also exhibited tooth decay, black / brown stains on teeth and nails showing longitudinal streaks, black stains and brittleness (Hira et al., 2003). Farmers in the seleniferous region did observe that even leaving the region temporarily for 3 - 4 months resulted in a remarkable recovery from Se poisoning. Similar observations have also been reported by Yang et al. (1983). Obviously, when source of food was changed from seleniferous to nonseleniferous regions, intake of Se was reduced.

In a recent survey, Hira et al. (2003) compared the general growth pattern of humans residing in endemic and nonendemic areas of Punjab. Data on anthropometric measurements of 40 families from each region indicated that the height of men and women in both areas was comparable, while the weight and body mass index (BMI) calculated as weight/ (height)2 of men and women in nonendemic (low selenium) area was significantly higher (P ≤ 0.01) than that of their counterparts in the endemic (high selenium) areas.


Management of Se-degraded soils The main thrust of the technology for the management of seleniferous soils is on the

production of forages/cereals containing the amount of Se which is safe for animal/human consumption. This can be achieved either by reducing the movement of Se from soil through plants to animal/human system or by lowering the level of Se in toxic soils to safe levels. Efforts have been made to develop suitable technology for the remediation of seleniferous soils and the results are discussed below:

Application of Gypsum: Selenium accumulation by plants is significantly influenced by the presence of sulfate ions in the growth medium. The antagonistic interaction between sulfate and selenate for plant uptake was initially observed by Hurd-Karrer (1934) under greenhouse conditions. Recently, this relationship has been confirmed under actual field situations in sugarcane (Dhillon and Dhillon, 1991b) and rice - wheat cropping sequence (Dhillon and Dhillon, 2000). Reduction in Se absorption by 60-70% in a number of crops has been achieved by application of gypsum in alkaline calcareous seleniferous soils of northwestern India. Farmers of the region have adopted this practice as a practical measure for reducing transfer of Se from soil to food chain crops.

Selecting plants with low Se absorption capacity: In order to reduce the movement of Se into the food chain, plants absorbing the least amount of Se may be recommended for cultivation in seleniferous regions (Dhillon and Dhillon, 1997b). Investigations on the Se absorption capacity of fodder crops commonly grown in the seleniferous region revealed that the differences in the Se content of fodders was negligible up to a level of 0.25 mg Se kg-1 soil. At higher Se levels, the differences in Se accumulation became apparent. Oat (Avena sativa) and sorghum (Sorghum bicolor) among cereals and senji (Melilotus parviflora) among leguminous fodders absorbed the least amount of Se compared to other fodder crops. In case of multi-cut fodders like berseem (Trifolium alexandrinum) and lucerne (Medicago sativa), the first one/two cuts contain 2-3 times more Se than the following cuts. The farmers are advised to avoid feeding of the first cut of berseem and the first two cuts of lucerne to animals.

Cultivation of crops requiring less water: Excessive use of Se-contaminated underground water for irrigation of crops in the seleniferous region, especially rice, has contributed significantly to the development of seleniferous soils. Therefore cultivation of crops requiring less water should be preferred over other crops in this region. The farmers are advised to discontinue the cultivation of rice based cropping sequences.

Role of organic amendments: Application of sugar cane press mud at 15 to 20 t ha-1 and poultry manure at 10 to 15 t ha-1 proved equally effective in reducing Se content in grain and straw of wheat and rapeseed. Reduction in Se content varied from 73 to 92% in wheat and 45 to 96% in rapeseed. In case of wheat, Se content of grains and straw got reduced to the levels considered safe for animal and human consumption. Positive residual effect of these manures was also observed on the following crops of maize and rice.

Phytoremediation: Although concept of phytoremediation is not new, yet it has become the topic of extensive research only recently. Phytoremediation has been defined as the use of green plants to remove pollutants from the environment or to render them


harmless. Chaney (1983) introduced the idea of developing a “Phytoremediation crop” to decontaminate polluted soils emphasizing that value of metals in the biomass might off-set a part or all of the cost of cleaning up the toxic site. Linking birth defects in waterfowl to excessive Se build-up in Kesterson reservoir in California (Ohlendorf, 1989), provided a strong incentive to the scientists to establish phytoremediation as a new technology for the clean up of Se polluted soil and water. The development of technology and the increased knowledge of the phytoremediation processes have led to the identification of important mechanisms by which plants are believed to remove, degrade or stabilize the environmental contaminants. The possible mechanisms are: Phytoextraction - Plant uptake and assimilation of contaminants Phytovolatilization - Use of plants to volatilize contaminants absorbed from soil Phytodegradation - Use of plants to make volatile chemical species of contaminants Rhyzofilteration - Use of plant roots to remove contaminants from flowing water Rhyzodegradation - Biodegradation of environmental contaminants by plant

exudates Phytost - Use of plants to transform soil metals so as to reduce their

bioavailability and prevent their entry into the food chain

Selenium hyper accumulating plants are known to exist even before the problem of Se toxicity was recognized (Rosenfeld and Beath, 1964). However, the practicality of including Se accumulators in remedial strategies is limited, because they are i) genetically poor, ii) susceptible to pests and diseases ii) not responsive to fertilizer application and iv) seed is not commercially available. In fact the plants that are the best Se accumulators are small in size and thus do not produce high biomass. The ideal plant species for phytoremediation of Se must be able to accumulate and volatilize large amounts of Se; grow rapidly and accumulate large biomass on the contaminated soil; tolerate salinity and other toxic conditions. Intensive screening of different cultivated agricultural plant species (Dhillon and Dhillon, 2009a, 2009b)) under greenhouse (Fig 4) and field conditions revealed that Brassica spp. have most of the desired attributes compared to others and notable among them were Indian mustard (Brassica juncea czern. L.) and canola (Brassica napus). As soon as plant roots absorb Se, it is translocated to shoots and the harvested biomass can be removed away from the site; thus leading to reduction in Se levels in the soil.


Fig. 4: Selection of crops for phytoremediation purposes

Selenium removal efficiency of different cropping systems: i) Biomass production and Se content of different crops:

Field experiments were conducted at two different locations in the seleniferous region of northwestern India from 2000-06. Cropping systems selected for the experiment were: a) rapeseed (Brassica napus) (locally known as gobhi sarson) – arhar (Cajanus cajan); b) rapeseed (Brassica napus) – sunn hemp (Crotalaria juncea), c) rapeseed (Brassica napus) - cotton (Gossypium arboretum) and d) wheat (Triticum aestivum) – rice (Oryza sativa). Total biomass (straw + grain) of all the crops at maturity (Table 7) was greater than that at the peak flowering stage throughout the period of phytoremediation experiments at both the sites (Dhillon and Dhillon, 2009c). At maturity, the greatest biomass was obtained from rice followed by wheat and rapeseed, arhar, cotton or sun hemp. At the peak flowering stage, the leaves of different crops contained greater amounts of Se than stems (Table 8). By the time the crop matured, more Se was translocated to grain than stems in leguminous and oilseed crops, but the reverse was true for cereal crops. For the different crops, seeds of rapeseed contained the greatest amount of Se at both sites. In the first year of phytoremediation experiments at site I, rapeseed grains contained the greatest amount of Se (108.6±10.4 mg Se kg-1) followed by cotton (67.5±7.7 mg kg-1), wheat (33.9± 4.1 mg kg-1), arhar (16.1±1.3 mg kg-1) and rice (12.7±5.1 mg kg-1) (Table 8). The order of Se content in the straw portions of different crops slightly changed with the highest value (70 mg Se kg-1) in rapeseed followed by wheat, rice, cotton and arhar straw. These results are in line with those of Bañuelos et al. (1997) who reported that among different plant species, Indian mustard absorbed the highest amount of Se in comparison with other crops. Nevertheless shoots of different crops evaluated by Bañuelos et al. (1997) absorbed only 0.36-2.15 mg Se kg-1 as compared to 15-129 mg Se kg-1 in the present study. The biomass of different crops was, however, comparable in the two studies.


Table 7: Total biomass accumulation by crops (q ha-1) in a year under different cropping systems*

Site I Site II

Cropping systems

Crops G S I G S II Cropping systems Crops G S I G S II

Rapeseed 76.5±5.4 96.8±7.4 Rapeseed 78.6±5.6 87.0±9.8 Rapeseed - Cotton Cotton 59.5±1.6 63.2±2.4

Rapeseed-Sunn hemp Sunn hemp 52.8±3.4 76.7±9.5

Rapeseed 74.2±6.6 94.0±9.8 Rapeseed 69.5±4.5 83.5±8.2 Rapeseed - Arhar Arhar 64.4±4.7 69.6±6.0

Rapeseed - Arhar Arhar 103.8±20.3 123.8±25.6

Wheat 85.0±12.1 103.6±3.5 Wheat 61.4±8.2 98.0±7.3 Wheat –Rice Rice 95.7±6.5 129.7±3.7

Wheat –Rice Rice 83.8±18.2 123.1±8.9

*Growth stage I (GS I) refers to peak flowering for rapeseed, Cotton, Sun hemp and Arhar; or Ear initiation in wheat, or panicle initiation in rice and growth stage II (GS II) refers to maturity. Values are mean±SD.

Table 8: Representative contents of Se (mg kg-1 DM) in plant parts at different growth stages of crops

Site I Site II

Growth stage I

Growth stage II Growth stage I Growth stage II Cropping systems

Crops

Shoots Stem Grains

Cropping systems

Crops

Shoots Stem Grains

Rapeseed 131±6 69±6 109±9 Rapeseed 153±19 70±18 185±21 Rapeseed - Cotton

Cotton 105±35 19±1 67±8

Rapeseed-Sunn hemp

Sunn hemp 44±10 27±6 48±8

Rapeseed 129±7 68±4 107±20 Rapeseed 177±22 62±19 201±18 Rapeseed - Arhar

Arhar 19±2 11±1 20±1

Rapeseed -Arhar

Arhar 44±10 16±8 68±11

Wheat 43±7 29±7 19±4 Wheat 60±7 46±5 53±7 Wheat - Rice

Rice 15±5 17±6 11±5

Wheat – Rice

Rice 27±14 20±13 3±10

Selenium removed by Brassica based cropping sequences at the peak flowering stage was 2-3 times more than that removed by the wheat-rice rotation (Dhillon and Dhillon, 2009c) (Table 9). The amount of Se added to the soil through leaf fall at maturity was relatively more in the case of rapeseed-cotton than for the rapeseed-arhar sequence. Selenium removal by different crops was higher at maturity than at the peak flowering stage at site II compared to site I where redeposition of Se in soil through leaf fall was almost twice that at site II. In a field experiment conducted for 4 years with different crop rotations, Se removal ranged between 4 to 13 g ha-1 yr-1 (Bañuelos et al., 1997). In contrast, Se removal by different crop rotations was many times higher in the present investigation and varied between 435 to 1374 g Se ha-1 yr-1 at the peak flowering stage and between 370 to 949 g Se ha-1 yr-1 at the maturity stage at the two experimental sites. In both situations, Brassica based cropping sequences could remove 2 to 3 times more Se than others.


ii) Net Se change in soil profile under different cropping sequences: At site I, cumulative Se removed from seleniferous soil in two years by different crop

rotations (Table 9) varied from 984 to 2749 g Se ha-1 at the peak flowering stage (Dhillon and Dhillon, 2009c). When harvested at maturity, the total amount of removed Se decreased by 25 to 39% compared to that at the peak flowering stage. The amount of Se removed by different crops at maturity was only 1.7 to 5.1% of total Se present in soil down to 120 cm. Losses of soil Se under different crop rotations was 18.5 to 24.5% of the total Se present as indicated by soil analysis after two years of experiment.(Table 9). Similarly, different crop rotations at peak flowering removed 1306 to 2527 g Se ha-1 in 3 years at site II. When harvested at maturity, Se removal varied from 1551 to 2846 g Se ha-1 and was equivalent to 4.8 to 13.2 % of total soil Se. But the results from soil analysis indicate that Se loss varies from 21 to 33 % of total soil Se. Thus at both sites 15-20 % of total Se lost from the soil cannot be explained. Appreciable differences between the two estimates indicate that besides plant uptake, some other processes are responsible for soil Se losses. These may include Se volatilization by plants (Terry et al., 1992) and soil microorganisms (Frankenberger and Karlson, 1994), Se entrapped in the plant root system (Dhillon and Dhillon, 2009d), leaching of Se below the sampling depth and spatial variability of soil Se.

Selenium removal efficiency of different Agroforestry farming systems Different agroforestry farming systems were evaluated for their Se absorption

capacity under greenhouse and field conditions in the seleniferous region of Punjab (Dhillon et. al., 2008; Banuelos and Dhillon, 2010). Among different trees, poplar (Populus deltoides) proved more efficient than eucalyptus (Eucalyptus hybrid) and shisham (Dalbergia sissoo). Total removable biomass of poplar trees, when harvested after 7 years of growth, was recorded as 272±2.34 Mg ha-1 y-1 (Table 10). Poplar trees get completely denuded during winter season and thus 15 to 20 Mg ha-1 of leaf biomass was re-deposited in the soil during its growth period of 7 years. Selenium removal through poplar- sugarcane (Saccharum officcinarum) /wheat system was 1.5 times more than that of poplar- menthe (Mentha viridis) /wheat system (Table 10). Including sugarcane as intercultural crop improved the efficiency of Se removal by agroforestry farming systems. Comparing Se removal efficiency of different farming systems in one year, the Brassica-based cropping systems was 1.1 to 1.4 times more efficient than poplar-sugarcane/wheat; 1.5 to 2.1 times more efficient than poplar-mentha/wheat system and 2.6 to 3.7 times more efficient than the cultivation of poplar alone. Cultivation of agroforestry trees yielding 40 t ha-1 yr-1 dry matter containing 3.5 mg Se kg-1 can help in removing 140 g Se ha-1 yr-1 (Cervinka, 1994). In addition to Se removal through biomass, hybrid poplar can volatilize significant amounts of Se and the volatilization rates are dependant upon the form of Se present in soil (Pilon-Smits, et al., 1998).


Table 9: Selenium balance in soil profile under different cropping systems after the completion of phytoremediation experiments

Selenium balance in the soil profile (0-120 cm) at Site I On the basis of Se removed by harvested biomass in 2 yrs

On the basis of soil analysis before &after 2yr

Se lost from soil Se removed in 2 yrs (g ha-1)

Se removed in 2 yras % of initial soilSe

Cropping Sequence Initial Se level (g ha-1)

G S I G S II G S I G S II

Se left in soil (g ha-1)

Total Per (g ha-1) cent

Rapeseed - Cotton 32627 2749 1665 8.43 5.10 24633 7994 24.5 Rapeseed - Arhar 48195 2083 1473 4.32 3.06 37448 10747 22.3 Wheat - Rice 42891 984 740 2.29 1.73 34957 7934 18.5 Selenium balance in the soil profile (0-120 cm) at Site II

On the basis of Se removed by harvested biomass in 3 yr

On the basis of soil analysis beforeafter 3 yr

Se lost from soil Se removed in 3 yrs (g ha-1)

Se removed in 3 yr as % of initial soil Se

Cropping Sequence Initial Se level (g ha-1 )

G S I G S II G S I G S II

Se left in soil (g ha-1) Total Per

(g ha-1) cent

Rapeseed- Sunn hemp 30830 2149 2665 6.97 8.64 20625 10205 33.1 Rapeseed - Arhar 21564 2527 2846 11.72 13.20 15181 6383 29.6 Wheat - Rice 32076 1306 1551 4.07 4.84 25407 6669 20.8

Table 10: Biomass and Se accumulation from Se-degraded soils by agroforestry farming systems

Note: The intercultural crops grown in poplar plantation are: mentha / sugarcane was grown for the initial 2 yrs followed by wheat for the next 5 yrs.

Se balance in soil Cropping system

Trees/ Crops

Plant parts Se content (mg kg-1)

Total biomass

(mg ha-1 y-

1)

Initial Se in soil

(g ha-1)

Se removal through biomass (g ha-1)

Se removal through

biomass as % of initial

Se Leaves 32.6 ±3.79 17.2

Stem 5.2±1.25 220.7 Branches 7.3±2.13 34.5

Poplar

Roots 18.7±2.35 29.3 Shoots 32.1±2.45 3.6±1.4 Mentha Oil 2.3±0.44 - Straw 38.4±7.24

Poplar - Mentha/ Wheat

Wheat Grain 44.3±9.87

6.5±0.5

17350 1959+ 226+ 1335 = 3520

20.3

Cane 7.8±0.9 81.2±6.2 Green leaves 21.8±6.2 13.7±1.2 Dry leaves 13.4±2.2 3.0±0.5 Baggasse 9.5±1.9 -

Poplar - Sugarcane/ Wheat

Sugar- cane

Juice 0.11±0.03 -

17350 1959+ 2006+ 1335 =5300

30.5


Managing seleniferous soils through cultivation of flowers/fiber crops Greenhouse and field experiments were conducted to quantify Se uptake by different

flowering and fiber plants (Banuelos and Dhillon, 2010). The flowering plants evaluated under both the situations were able to absorb significant amounts of Se. On the basis of the amount of Se accumulated per pot, different flowering plants can be ranked as: Gaillardia > Kotchia > Dimorpothica ≥ Cosmos > Rose > Coreopsis > Holicrism. In the field experiment conducted in the seleniferous soil containing 4.2 mg Se kg-1 in the surface layer, Se removal was found to be the greatest in case of gaillardia followed by calendula, African marigold, French marigold, coreopsis, dimorpothica and holicrism (Table 11). Thus, cultivation of gaillardia, calendula and African marigold should be encouraged in Se-degraded soil. Among the cultivated agricultural crops, sunn hemp - the only cultivated fiber crop, does not constitute food item for animals/human consumption. When grown in the seleniferous fields in the affected region, sunn hemp crop could remove up to 240 g Se ha-1 when harvested at maturity.

Table 11: Efficiency of different flower / fiber crops for Se accumulation under field conditions

Se content (mg kg-

1) Total Se Removal Flower/ Fiber crops Dry matter

yield (g m-1) Flowers Straw (µg m-2) (g ha-1)

Flower crops

Calendula (Calendula officinalis) 966 24.0 21.6 18828 188

Gaillardia (Gaillardia aristata) 364 26.2 59.6 23784 238

Coreopsis (Coreopsis gladiata) 102 57.6 30.1 2656 27

Dimorpotheca (Dimorpotheca pluvialis) 123 17.4 24.7 2707 27

Helichrysum (Helichrysum orientale) 250 13.8 10.3 2198 22

French marigold (Tagetes patula) 463 20.5 22.7 9982 100

African marigold (Tagetes erecta) 364 30.6 38.0 12760 128

Fiber crops

Sunn hemp (Crotalaria juncea) 767 48.2* 27.4 23930 239

Conclusions More than 1000 ha of Se-degraded land has been characterized and mapped in

northwestern India. Consumption of plant based products grown on Se-degraded land is seriously affecting health of animals and humans in the affected region. Phytoremediation using Brassica or agroforestry based farming systems seem to be an important tool for managing selenium affected soils. Brassica based systems can remove 0.8-1.0 kg Se ha-1 y-1 and agroforestry farming systems can remove 4-5 kg Se ha-1 in a growth period of 7 yrs. Selenium removal can further be increased by 1.5-2 times if Se-rich leaves after


senescence and root biomass are also removed away fom the soil. If this practice is adopted as a regular strategy in the seleniferous region, it may require regular cultivation of about 20-35 cycles of rapeseed -arhar sequence or 4-8 cycles of poplar based farming systems to lower the level of Se in contaminated soils to < 0.5 mg kg-1 which is considered safe for producing forages and grains without any potential danger to animal and human health. The time needed for effective remediation becomes less important if Se-rich biomass (grain + straw) produced by the process of phytoremediation is considered as harvestable resource of economic value.

Although Se removal by flower and fiber crops is quite low as compared to the cereal and oilseed crops; yet it is considered to be the highly remunerative system. The major advantage of cultivation of flowers or fiber corps lies in the fact that these crops do not constitute food items for animals and humans. Thus, adoption of floriculture or fiber crops will help in achieving the ultimate objective of the phytoremediation technology, i.e. a complete ban on the entry of Se in the food chain and thereby avoiding any potential dangers to animal and human health.

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234 Strategies for Arresting Land Degradation In South Asian Countries

Appendix-A

Strategies for Arresting Land Degradation in the South Asian Countries

1. Background and justification 1.1. Importance of the land resources

LAND is Nature’s most precious gift to mankind. Some 12000 years ago, an ancient man (or, probably, a woman), the first “farmer”, consciously sowed seeds on a piece of land. It was a unique incident, the most important turning point in human history that marked the beginning of agriculture, and, with this, mankind’s first step, or more precisely put in, the first leap toward civilization. Land with all its attributes as a versatile resource base played the key role here. For about ten thousand years now, farmers, a most hardworking and productive section of the human population, have been working up land to produce food, the most basic necessity of life, not only for themselves but also for their fellow human beings.

With time, human needs increased in diverse ways. Demands for a mix of cereals, vegetables, fruits, meat, fish, etc. instead of a simple cereal in the food bowl grew. The need for plant fibre for clothing instead of crude animal hide was felt. The caves were abandoned as people moved into huts and finally to today’s multistoried buildings to live in. Land, in some way or other, provided all of these, food, feed, fibre and shelter, for the human race and its civilization to thrive on this planet. As civilization progressed, great advances in the art and science of agricultural production came about — the “Green Revolution” consisting of quality research-derived seed-fertilizer-pesticide-irrigation technology could be cited as a good example. Farmers were able to reap increasingly better harvests, cautious optimism about wiping out hunger and poverty from the planet was there.

However, while the Green Revolution was doubling or tripling the food output from the land resources, an undesirable development was taking place — the human population boom. This threatened to negate the gains from the Green Revolution. Population experts now estimate world population had doubled four times within the first 10000 years following the advent of agriculture. The population growth rate increased fast so that the time taken for the doubling of the population was becoming shorter for each doubling. It took about 2000 years for the doubling of the world population from 250 million in 350 B.C. to about half a billion (500 million) in the year 1650 A.D. With ever increasing population growth rates, it took only 325 years for the world population to reach a figure of 4 billion in 1975. The estimate is that, the world will have more than 8 billion people in the year 2020 (IUPAC/IRRI, 1983). The population growth rate was high, around 2% per annum in the impoverished, developing nations of Asia. For

Concept Note

Strategies for Arresting Land Degradation In South Asian Countries 235

example, in the SAARC countries, the total population was 1418.5 million in 2004 which is estimated to be about 1800 million by the year 2020 (SAARC Statistical Data Book, 2006-2007). About 22% of the world’s human population live in the eight SAARC countries. Obviously, pressure on land resources intensified to meet increasing demands for food by a burgeoning population.

The food demand and internal supply situations in most SAARC countries have not been satisfactory as the scope of horizontal expansion of agriculture almost exhausted and crop yields began to stagnate or even decline in many cases. The recent food price hikes and limited availability of food in the international markets have further complicated the issues related to achieving food security in the SAARC countries and at the same time maintaining the pace of their socio-economic development. The implication, then, is that, countries must produce enough food for their present populations and check population growth rates to ensure that food shortages do not occur in the future. Virtually all of the food increase will have to come from land. It is now time, therefore, for policy makers, researchers, farmers and the general public to pay attention to these crucial points: (1) Land is a FINITE resource, (2) No science or combination of sciences related to agriculture offers infinite prospects for increasing the supply of food (IUPAC/IRRI, 1983), (3) Population growth rates must be substantially and quickly checked, and (4) Quality of land resources, especially when under pressure from natural processes and phenomena and indiscriminate human interventions, WILL deteriorate.

It is in the above context that the issue of land degradation has to be addressed. Land degradation as an issue is not something new, but recent developments in the food sector do not bode well for the South Asian countries striving to provide food security and improve the quality of life for their teeming millions. A fresh assessment of the status of the land resources and evaluation of the land degradation processes to close the knowledge and awareness gaps and develop ways and means for SAARC national and regional technological and policy level interventions to halt, and wherever possible, reverse land degradation are necessary. This Concept Note seeks to attract the attention of policy makers and agricultural scientists to the issues stated above.

1.2. Land degradation: Causes, processes, extent in South Asia Land is a complex, multi-component natural entity that becomes a resource base

when used for a specific purpose or purposes. In light of this, land degradation has been defined as “The reduction in the capability of the land to produce benefits from a particular land use under a specified form of land management” (Blaikie and Brookfield, 1987). Thus, when agricultural use of land is concerned, land degradation would essentially mean losses in production of crops, plantations, livestock and inland fishery. There are a number of interrelated land degradation components, as follows, all of which may contribute to a decline in agricultural production (FAO, 1999): • Soil degradation: Decline in the productive capacity of the soil


• Vegetation degradation: Decline in the quantity and quality of the natural biomass and loss of vegetative cover (A very recent example from Bangladesh: The hurricane “Sidr” caused a 5% loss of the Sundarbans, the largest mangrove forest of the world, Bangladesh lost a portion of the “green wall” against cyclones)

• Water degradation: Decline in the quantity and/or quality of the surface and groundwater resources

• Climate deterioration: Changes in climatic conditions that increase the risk of crop failure

A big difficulty in studying these components of land degradation and their impacts on agricultural production separately is that, they are caused by both natural factors and human interventions mostly in overlapping ways. For example, soil degradation may occur due to fertility decline caused by loss of nutrients through erosion (natural cause) and simultaneously, intensive cropping without appropriate fertilization (human factor) and if some adverse climatic condition (e.g., too little or too much rain) sneaks in, what expectedly would result is a huge crop loss, the ultimate impact. Here, while the crop loss could be measured, it would be almost impossible to determine exactly which factor contributed how much in causing yield loss! Such attempts would not be practical either. For the practical purpose of assessment of land degradation in SAARC countries and determination of the needs for technological and policy interventions, the following list showing the causes of land degradation, natural or human induced, should suffice: 1. Natural hazards e.g flood, drought, tidal surge, snow melt, etc. (some or the other

in all SAARC countries---e.g., floods and tidal surges in Bangladesh, drought in Pakistan and India, snow melt and landslides in Nepal and Bhutan)

2. Erosion by water and wind (e.g. serious land erosion from riverwater currents in Bangladesh during recurrent floods, wind erosion in the semi-arid regions of India and Pakistan)

3. Salinization and acidification (natural and anthropogenic e.g tidal flooding, shrimp culture in crop land in Bangladesh, faulty irrigation and drainage in India and Pakistan, arid and semi-arid conditions in India and Pakistan, draining and drying of potentially acid sulphate soils, etc.)

4. Formation of hardpan, compaction and waterlogging (mostly human induced in all SAARC countries)

5. Deforestation, shrinkage of vegetation cover on land, overgrazing (natural and/or human induced----in India, Pakistan for example)

6. Inappropriate management in cultivation of land on steep slopes (human induced---e.g., in Nepal)

7. Nutrient mining and inadequate nutrient replenishment (human induced----all SAARC cpountries)

8. Soil organic matter depletion (mostly human induced----e.g., serious problem in Bangladesh)


9. Over-exploitation of ground water in excess of natural recharge capacity (faulty irrigation practice, human induced)

10. Use of poor quality irrigation water (e.g. use of groundwater containing high arsenic concentrations for irrigation in Bangladesh and West Bengal of India, risk of toxic levels arsenic accumulation in soils and foodstuff)

11. Pollution of soil and surface water bodies (rivers, ponds) by urban industrial waste, excessive use of agrochemicals, oil spills etc. (human induced----e.g., in India, the most industrialized SAARC country)

12. Global warming and consequent sea level rise, an impending calamity? (mostly human induced, mainly responsible are the industrialized countries of North America and Europe, but the SAARC are under the of severe consequences).

An important question is: What is the status of the latest information and statistics about the nature and extent of the different land degradation components in the SAARC countries? There are limited data, varying in content and precision from country to country. However, what is known to date may be largely qualitative and not always precise but these do provide food for thought for policy makers and agricultural scientists of the region for future action plans to protect the region from the ill effect of land degradation.

Some statistics gleaned from various sources (SAARC Statistical Data Book, 2006-2007) are given below as references: 1. Water erosion and chemical degradation are the most devastating land degradation

pathways in the SAARC region. Erosion risk is the highest (53% of the total area) in Bhutan, followed by 42% in Sri Lanka, 31% in Nepal, 29% in India, 15% in Bangladesh and 13% in Pakistan.

2. Soil salinity/sodicity are problems in Pakistan (20% of the total area), India (8%) and Bangladesh (6%).

3. Land with shallow soils (poor fertility and physical properties): 24% in Pakistan, 21% in Nepal, 13% in Bhutan, 10% in Sri Lanka, 9% in India and 1% in Bangladesh.

4. Soil fertility decline due to organic matter depletion is a growing problem in all countries. In Bangladesh about 60% of the soils have a low organic matter content, often less than 1%.

5. In India 41% of the land area is without major soil constraints, the figures for Sri Lanka, Bangladesh, Nepal, Bhutan and Pakistan are 37%, 29%, 26%, 22% and 9%, respectively.

6. On a SAARC regional basis, only 24% of the total land area is without major soil constraints.

An irony is that, while farmers toil hard to increase production and as countries struggle to eradicate hunger and alleviate poverty, land degradation is accelerated. “Land mismanagement, whether for crop, livestock or tree production purposes, consists usually


of removing too much, returning too little, and cultivating, grazing or cutting too often. Such mining of land beyond its limits results in degradation with decreasing productivity, and is not sustainable” (FAO, 1999). Estimates of human induced land degradation in the SAARC countries are rather disquieting. Land degradation through human activities is progressing at a fast pace in all South Asian countries. Human induced land degradation in India is the highest (58% of the total degraded area) followed by Sri Lanka 54%, Bangladesh 27%, Nepal 27% and Pakistan 24%. It is in this aspect of land degradation, i.e., human induced land degradation, where there is the greatest scope and necessity to intervene with national and regional policy measures and technological innovations.

1.3. Impacts of land degradation Estimating the impacts of land degradation is a very difficult task as this would

involve not only the biophysical and agro-ecological issues but also socio-economic and development issues. However, this is very important since policy makers, donor agencies and international development partners would be more interested in quantitative estimates of the impacts of land degradation than just qualitative statements about what could happen. A concerted effort by agricultural and social scientists is very much needed. A study of the effect of land degradation in south Asia concluded that land degradation was costing countries in the region an economic loss of the order no less than US$ 10 billion, equivalent to 7% of their combined agricultural GDP (FAO 1994). The current figures could be much higher.

An estimate of losses from land degradation in Bangladesh is given in Table 1 below:

Table 1. Estimates of economic losses from different types of land degradation in Bangladesh.

Type of degradation

Degraded area

(million ha)

Degree of degradation

Loss estimate (million ton/year)

Financial loss (million US$/yr)

Water erosion (mostly floods and riverbank erosion)

1.70 Light to Strong Cereal production loss: 1.06 Nutrient loss: 1.44

140.72 544.18

Fertility Decline

3.20 Light to Moderate

Cereal production loss: 4.27 Additional input need : 1.22

566.84 461.04

Salinization 3.10 Light to Strong Total production loss: 4.42

586.75

Source: Z. Karim and Anwar Iqbal, 2001


A more recent estimate-projection on the impact of land degradation in Bangladesh is quite frightening (Kholiquzzaman, 2007) : • Loss of 180 ha arable land/day, 7.5 ha/hr due to building of homes, industries, roads

and other structures. • Loss in food production estimated at 5000 t/day or 1.6 million t/yr. • At this rate of loss of arable land, not even a sq inch would be available for

agriculture 50 years hence. • In 1974, 59% of the net land area of the country was under agriculture; decreased to

53% in 1996. During the period 1983-1996, the rate of decrease in arable land area was 87,000 ha/yr.

• During 1983-1996, food production suffered a loss of about 2.1 million t/yr due to continuously decreasing arable land area

• Since 1996: o In 10 years the number of families increased by 5.015 million, an additional 0.18

million ha arable land was lost for housing, at the rate of 18,200 ha/yr o For other purposes, additionally, 0.05 million ha arable land was lost every year o In total since 1996, the loss of arable land over the next 10 years was 0.65 million

ha/yr. Bangladesh faces another hazard, that from sea level rise due to global warming. The

losses could be really colossal: • Inundation of the whole coastal belt • Displacement of some 30 million people who will become refugees in their own

country

• Huge loss of agricultural production will result in widespread hunger and poverty

• More than 10% of the GDP could be lost.

The above are some examples of the present and potential impacts from one SAARC country only (Bangladesh). Land degradation in almost all its known forms is in progress in all other SAARC countries. The extent and intensity of the various land degradation processes would differ, however, from country to country. For example, arsenic contamination of the irrigation water-soil-crop systems is known to be quite a serious water quality/soil degradation problem in Bangladesh and West Bengal of India, but this is not much of a problem in Pakistan, other parts of India and other SAARC countries. Again, sea level rise due to global warming could be a very serious threat to Bangladesh and Maldives, but Nepal and Bhutan are not supposed to be directly affected. Since no generalization can be made regarding the causes and effects of land degradation, it is imperative that dependable data for each country be available so that scientists, policy makers and farmers can take appropriate measures to face the problem nationally and regionally. This Concept Note calls for relevant information generation.


2. Benefits of the proposed project Considering the importance and urgency related to land degradation, the Governing

Board of SAC at its very first meeting approved to undertake a study on “Strategies for arresting land degradation in the South Asian Countries”. It is expected that, this important study findings would help to (a) formulate policy issues (b) draw strategies and (c) undertake joint projects and also national programs projects in order to address the issues of major concern and collectively find out measures to minimize the impact of land degradation on the millions of affected people in the SAARC nations.

The purpose of this concept note is to initiate an assessment and review of the land degradation situations in the different SAARC countries, collect and sort out information and following this prioritize strategies and actions for the SAARC countries individually and identify needs and scopes of regional collaboration to tackle the problem of land degradation.

3. Target beneficiaries Beneficiaries will include policy makers in the governments of the SAARC

countries, agricultural and social scientists, environmental scientists, NGOs, donor agencies and ultimately the farmers.

4. Goal Understand and quantify the impacts of natural and anthropogenic land degradation

on agriculture and socio-economic development in SAARC countries and develop strategies to prevent further land degradation at national and regional levels.

5. Objectives The objectives of the project/programme will be to:

a. Collect information on the factors and processes and nature and extent of land degradation in each SAARC country.

b. Assess the impacts of land degradation on agriculture and socio-economic development at the SAARC national and regional levels.

c. Review existing technical knowledge and evaluate knowledge gaps in the field of management of land degradation.

d. Prioritize R&D initiatives to address the specific needs of the SAARC countries and suggest “optimal option” guidelines.

e. Review policy issues, examine existing laws and regulations to combat land degradation in order to provide appropriate policy support to agricultural and social scientists, field level workers and farmers themselves to prevent further land degradation and rejuvenate degraded land wherever possible.

• Strengthening knowledge and awareness among the government policy making officials about the problem of land degradation and its impact on agriculture and the national economy.


• Foster inter-government collaboration on the prevention of land degradation at SAARC national regional levels.

• Government and inter-government regular monitoring of the implementation of policy decisions, identify shortfalls and take necessary measures as and when needed the fields of – Environmentally friendly land use, agricultural enterprises, agribusiness – Agricultural production practices beneficial for the land resource base (e.g. IPNS,

ICM, contour cropping, etc.) – Housing, settlement and structures

• Increasing public awareness about the ill effects land degradation through formal education and media campaigns.

• Review organizational capacities, modes of operation, HR needs to undertake the gigantic task of leadership and coordination both at national and SAARC regional levels.

6. Participating organizations/institutions • SAARC Agriculture Centres • SAARC NARES institutions and agencies • Relevant national government regulatory offices • Relevant international institutions and agencies • International Agricultural Research Centres in SAARC countries • NGOs

7. Approach and Methodology a. Preparation of country reports: As per existing practice, SAC through its GB

members in the respective countries will identify subject/area related focal agency/scientists, and they will be mainly responsible for gathering information and preparing the country status papers.

b. A workshop/expert consultation will be organized to present the country reports and discuss and review information and suggestions.

c. A compilation containing all aspects of land degradation and corrective measures will be prepared and distributed to all participants to develop future action plans.

d. The action plans will be submitted to national governments and the SAARC Secretariate to develop policy formulation and implementation plans for specific land related issues.

e. SAC will provide leadership and coordination of the activities under the guidance of the SAC Governing Body.


8. Outputs a. SAARC country position papers covering all aspects of land degradation. b. Compiled study report on ‘Strategies for Arresting Land Degradation in the South

Asian Countries’ c. Priority program/projects development, both national and SAARC regional, and steps

towards their implementations. d. Short- and long-term impacts of measures against land degradation — ultimately

manifest in prevention of land degradation, reversal of the adverse effects, increased land productivity without risk of further resource degradation.

References Blaikie, P. and Brookfield, H. 1987. Land Degradation and Society. Methuen London and New

York. FAO 1999. Poverty Alleviation and Food Security in Asia: Land Resources. FAO Regional Office

for Asia and the Pacific (RAP), Bangkok. RAP Publication 1999/2. IUPAC (International Union of Pure and Applied Chemistry) and IRRI (International Rice

Research Institute). 1983. Chemistry and World Food Supplies: Perspectives and Recommendations. G. Bixler and L.W. Shemilt (eds) Proc. Conf. on Chemistry and World Food Supplies, Manila, Philippines, 6-10 December, 1982.

K. Kholiquzzaman. 2007. Report in the daily Bengali newspaper “Janakantha”, July 08, 2007, Bangladesh.

SAARC Statistical Data Book, 2006-2007, Volume 5, 2006/2007. SAARC Agriculture Centre, Dhaka, Bangladesh.

Z. Karim and Anwar Iqbal (Eds) 2001. Impact of Land Degradation, BARC Soils Pub. No. 42, Dhaka, Bangladesh.


Appendix-B

Recommendations of the Regional Consultation on Strategies for Arresting Land Degradation

in South Asian Countries

Date: 21-23 June, 2010 Kolkata, West Bengal, India

SAARC Agriculture Centre BARC Complex, Farmgate, Dhaka-1215

Bangladesh


A Regional Consultation on “Strategies for Arresting Land Degradation in South Asian Countries” was organized by SAARC Agriculture Centre (SAC), Dhaka Bangladesh in collaboration with National Bureau of Soil Survey and Land Use Planning (NBSS & LUP), ICAR, West Bengal, India during 21-23 June 2010 at Kolkata. Mr. Narendra Nath De, Minister In-Charge Agriculture and Consumer Affairs, Govt. of West Bengal inaugurated the Consultation Meeting. Dr. Anil Kumar Singh, Deputy Director General (Natural Resource Management), ICAR, New Delhi; Dr. Md. Rafiqul Islam Mondal, Director, SAC, Dhaka; Mr. AZM Shafiqul Alam, Additional Secretary (PPC), Ministry of Agriculture, Bangladesh; Dr. Zahurul Karim, Former Secretary and Executive Chairman, Bangladesh Agricultural Research Council; Dr. Saroj Kumar Sanyal, Vice Chancellor, Bidhan Chandra Krishi Viswavidyalaya and Dr. Dipak Sarkar, Director, NBSS & LUP, Nagpur, India were present in the inaugural occasion. A good number of related senior scientists from SAARC member states attended in the consultation. Professionals from SAC and NBSS & LUP also attended in the meeting.

The Consultation was completed with five technical sessions followed by plenary session on 22 June, 2010. Dr. Prithish Nag, Director, National Atlas and Thematic Mapping Organization, DST, Govt. of India was the Chief Guest on the concluding session. The third day was kept exclusively for a visit to ICAR Institutes located in and around Kolkata, West Bengal.

During consultation, representatives of SAARC countries, one each from Bangladesh, Bhutan, India, Nepal and Sri Lanka and twelve resource persons from ICAR institutes, ISRO, Government of India and State Agricultural Universities from the host country participated in the two days deliberations. A total number of nineteen research papers were presented in the Meeting. Dr. Anil Kumar Singh, DDG (NRM), ICAR, presented the Key note paper in the Meeting. During consultation meeting, SAC and NBSS & LUP displayed their products and services

The aim of the consultation meeting is to formulate policy issues, strategies to undertake joint projects and national programs in order to address the issues of major concern and collectively find out measures to minimize the impact of land degradation on the millions of affected people in the SAARC nations, identify needs and scopes of regional collaboration to take the problem of land degradation.

Extend and trends of land degradation in South Asian countries, processes responsible for degradation such as erosion, salinization and sodification, acidification, nutrient mining, imbalanced fertilization, inappropriate land use planning and lack of an appropriate land use policy in different SAARC countries, were elaborated in the consultation. The expected influence of climate change on land degradation was also highlighted.

The influence of various agro-techniques including soil erosion preventive measures, moisture conservation, correcting water quality, integrated nutrient management, diversification of agriculture, conservation tillage and gene mining for drought avoidance, alternate land use planning, inclusion of legumes in crop calendar, legume based forage production, silvipasture and silviculture based agriculture on degradation were extensively discussed in the technical sessions.


At the end of the group discussion, following recommendations have been emerged. Researchable issues in South Asia for arresting land degradation • Extensive research should be done for developing and framing versatile and robust

database on GIS platform. • Focus on developing decision support system (DSS) for integration of land use

technology and planning environment on different scale. • Appropriate mapping techniques should be evolved for the delineation of problem

areas including the areas affected with erosion, salinity and sodicity, acidity and nutrient mining alone or in combination.

• Research efforts should focus upon studying the temporal and spatial monitoring of the type and severity of land degradation under different agro-ecological conditions, using remote sensing and GIS techniques.

• Delineation and mapping of areas affected with heavy metal pollution should be taken up at the top of the research agenda; and the impact of heavy metals on human and livestock after entering into food chain should be investigated.

• Screening and breeding of crop varieties tolerant to soil acidity, salinity and sodicity, using conventional and biotechnological methods; evaluation of locally available alternate mitigation options including several soil ameliorates; amelioration through phytoremediation and bioremediations; and water management covering in situ and ex situ water harvesting techniques should be given top priority.

• Development of multi-storied agro-forestry (including alley cropping) practices for sustainable natural resource management.

• Integrated Farming System models to be developed for sustainable agricultural production, enhancing livelihood options and building resilience against adverse impact of climate change.

• Impact of climate change on land degradation should be monitored, using modern techniques of remote sensing and GIS.

• Collaborative research effort among the SAARC member countries may be considered to address the land degradation problem. SAARC Agriculture Centre may be taken initiatives to exchange of views, interactions among the scientists and exchange visits as well as sharing of technologies among SAARC member states are urgently needed with this regards.

Policy issues for arresting land degradation in South Asia • Policy investment should be made in research and development for solving land

degradation problems to ensure food security, poverty alleviation, natural resource conservation and address climate change issues at the nationally, regionally and globally. SAC may address issues of concern and collectively identify measures to reduce impact of land degradation in South Asia.


• All member states and development partners working in the region may revisit their development agenda in view of intensity of land degradation problems

• SAARC countries should have their own land use policies pertaining to land degradation, diversion of agricultural land for non-agriculture uses and these should be implemented strictly.

• Policy makers need to be sensitized about the seriousness of the land degradation problem and the urgency to implement remedial measures.

• Web based database on land degradation issues including problems and available mitigation measures should be established. SAC may be developed web based database for the SAARC member states.

• Preparedness and capacity building of all stake holders to combat land degradation should be ensured.

• Rapid up-scaling of mitigation to technologies of arsenic, selenium, fluoride etc. may be taken up to reduce public health hazards.

Extension and development issues • Inventorization of type and severity of various forms of soil degradation in the

SAARC countries should be made on temporal and spatial basis, using modern tools and techniques.

• Development of technology modules for addressing each kind of land degradation and remedial measures that is easily understandable and adoptable by the implementing agencies.

• Action plan/road map for implementation of recommended technologies should be chalked out following participatory approach on watershed scale.

• Assessment of impact of technologies at the farmer’s field should be taken up and appropriate mechanism should be ensured for their up-scaling at state and regional levels.

• Sharing of experiences related to utilization of the degraded lands for the productive purposes by using potential technologies. SAC may be taken up program in this regard for SAARC countries.

Impact of land degradation on crop productivity • Site specific data on impact of different land degradation processes on productivity of

different crops/ land uses/soil based nutrient loss should be collected and documented and shared amongst all stakeholders for effective refinement in technologies. SAC can collect data on the topic and share among member states in South Asia.


Appendix: C

Program of Regional Consultation on Strategies for Arresting Land Degradation

in South Asian Countries During 21-23 June, 2010

Jointly organized by SAARC Agriculture Centre (SAC), Dhaka, Bangladesh &

National Bureau of Soil Survey and Land Use Planning, NBSS & LUP (ICAR), Kolkata, West Bengal, India

Programme Day-1: 21 June, 2010 (Monday)

Venue: IndiSmart Hotel, International Tower Salt Lake, Kolkata

0830 Registration Inagural Session

0930 - 1100

Chief Guest Sh. Naren De Minister-in-charge, Agriculture, Govt. of West Bengal

Chairperson Dr. A.K. Singh Deputy Director General (NRM), ICAR, New Delhi, India

0930 Guests take their seats

0935 Invocation song 0940 Welcome address

Dr. Rafiqul Islam Mondal, Director, SAC, Dhaka Dr. Dipak Sarkar, Director, NBSS&LUP (ICAR), Nagpur

0950 Address Prof. S.K. Sanyal, Vice Chancellor, BCKV West Bengal, Guest of Honour

1000 Address by the Guest of Honour :

Mr. AZM Shafiqul Alam, Additional Secretary (PPC), Ministry of Agriculture, Government of Bangladesh

1010 Remarks by the Chief Guest

1020 Address by the President

Dr. A.K. Singh, Deputy Director General (NRM) ICAR, New Delhi

1030 Vote of thanks

Dr. S.K. Singh, Head, NBSS&LUP(ICAR) Reg. Centre, Kolkata

1040 Tea Break


R&D EFFORTS AND EXPERIENCES ON LAND DEGRADATION IN SOUTH ASIA

TECHNICAL SESSION I

1115-1350 Chairperson Prof. S.K. Sanyal, Vice Chancellor, BCKV, West Bengal

Rapporteurs Ms. Nasrin Akter, Sr. Programme Officer (Crops), SAC and Dr. A.K. Sahoo, NBSS&LUP, Kolkata

1115 Presentation of the Keynote paper “Strategies for Arresting Land Degradation in the South Asian Countries”

Dr. A.K. Singh Deputy Director General (NRM) ICAR, New Delhi.

Presentation of Country Status Report

1145 Status Report from Bangladesh presented

Dr. M. Shahabuddin Khan, Bangladesh Agriculture Research Institute (BARI)

1200 Status Report from Bhutan presented Ms. Karma Dema Dorji, Ministry of Agriculture & Forest, Bhutan

1215 Land degradation status in South East Asian Countries with special reference to India

Dr. Dipak Sarkar, Director, NBSS&LUP(ICAR), Nagpur

1225 Management of salt affected soils Director, CSSRI (ICAR), Karnal /representative.

1235 Status Report from India Dr. V.N. Sharda, Director, CSWCR&TI(ICAR), Dehradun (Title to be obtained)

1245 Issues and strategies for arresting land degradation in Arid Ecosystem

Director CAZRI Jodhpur/ Representative

1330 Open discussion on the papers presented

1340 Remarks by the Chairperson

1350 – 1445

Lunch

TECHNICAL SESSION II

1500-1520 Chairperson

Professor Dr. Zahurul Karim, Former Secretary and Executive Chairman, BARC, Government of Bangladesh

Rapporteurs Dr. S.K. Pal, Dy. Director (Agri.), SAC and Dr. K. Das, NBSS&LUP, Kolkata

1520-1645 Presentation of papers

1520 Status Report from Maldives presented Dr. Mohamed Ali, Honourable Minister


of State for Fisheries and Agriculture, Republic of Maldives

1530 Water Policy in India: Issues and priorities

Dr. B.M. Jha, Chairman, Central Ground Water Board, Faridabad

1540 Issues on Cropping Strategy in Degraded Lands – Indian context

Dr. B.S. Mahapatra, Director, CRIJAF(ICAR), Barrackpore, West Bengal

1550

1600 Issues and Strategies for Managing Degraded Soils of Rainfed Agro-Eco System in India

Dr.B.Venkateshwarlu Director , CRIDA Hyderabad / representative

1600 – 1630

Open discussion on the papers presented


1645 – 1700

Tea

1700 - 2100

Non-formal Session and Activities

1700 - 1745

Poster demonstration and free discussion among participants

1745 - 1900

Sight seeing tour - if approved

1930 - 2100

Consultation Dinner

Day-2: June 22, 2010 (Tuesday)

TECHNICAL SESSION III

0900-1200 Chairperson

Dr. Rafiqul Islam Mondal Director, SAC, Dhaka

Rapporteurs Dr.Nurul Alam, Sr. Programme Specialist ( PS&PD), SAC and Dr. D.C. Nayak, NBSS&LUP, Kolkata

0900 – 1155

Presentation of papers

0900 Status Report from Nepal presented Dr. Y. G. Khadka Nepal Agricultural Research Council

0920 Land degradation caused due to Selenium content in Soil-Plant-Animal System

Dr. K.S.Dhillon, Retd. Prof., Deptt. of Soil Science, PAU, Ludhiana

0940 Application of remote sensing and GIS in monitoring and arresting land degradation

Dr. P.S. Roy, Dean, & Assoc. Director, (Capacity Building) NRSC, ISRO, Dehradun


1000 Status Report from Sri Lanka presented

Professor Ranjit Mapa University of Peradeniya

1020 Use of Geo-textiles for arresting Land Degradation in varied eco-system

Dr K. K. Satpathy, Director, NIRJAFT(ICAR), Kolkata / Dr. Gautam Bose, Principal Scientist, NIRJAFT (ICAR), Kolkata

1020 – 1045

Tea

1045 Land use planning for arresting land degradation-

Dr. S.K.Singh, Head NBSS&LUP, Regional Centre Kolkata

1105 Issues and strategies for arresting land degradation in coastal agro-ecosystem

Dr. B.K.Bandhopadhyay CSSRI (ICAR), Canning Town West Bengal

1105-1125 Strategies of managing acid soils for sustainable agriculture in Asian countries

Dr. D. Jena, Ex-Head Department of Soil Science and Agricultural Chemistry, OUAT Bhubaneshwar, Orissa

1125-1145 Soil site nutrient management as a tool for preventing soil degradation in irrigated agro-ecosystem

Dr. Biswapati Mondal, Prof. of Soil Science, BCKV, Nadia

1145 - 1225

Open discussion on the papers presented

1225-1240 Remarks by the Chairperson

1240 - 1320

Lunch

TECHNICAL SESSION IV

1320-1340 Arsenic Pollution in South East Asia with special reference to India and Bangladesh

Prof. S.K.Sanyal, Vice Chancellor, BCKV, West Bengal

1340 - 1420

Thematic Group Work

Facilitator Dr. A.K.Singh, DDG (NRM) / Prof. S.K. Sanyal, VC, BCKV

1340 Introduction to the Group Exercise by the Facilitator

1340- 1515

Group work (4 parallel groups)

Group 1: Research Issues

Co-Facilitator Dr. Dipak Sarkar, NBSS&LUP

Rapporteur Dr. Pradip Sen, Jt. Director (Res.), Govt. of West Bengal

Group 2: Extension and Development issues


Co-Facilitator Dr. Paritosh Bhattacharya Addl. Director, Research, Dept of Agriculture,Govt of West Bengal

Rapporteur Dr. A.K. Sahoo, Pr. Scientist, NBSS & LUP

Group 3: Policy Issues

Co-Facilitator Any Suitable Delegates from other SAARC country/Director CRIDA/ Director CSWCRTI / Jt. Director (Res), Govt. of West Bengal

Rapporteur Dr. S.K. Pal, Dy. Director (Agriculture), SAC, Bangladesh

Group 4: Impact of land degradation on crop production in South Asia

Co-Facilitator Dr. M. Shahabuddin Khan, Bangladesh Agriculture Research Institute

Rapporteur Ms. Nasrin Akter, Sr. Programme Officer (Crops), SAC and Dr. Pradip Sen, Jt. Director (Res), Govt. of West Bengal

1515 – 1535

Tea

Technical Session V

1535 – 1615

Presentation and discussion on group reports

Chairperson Dr. Pradeep Sen, Jt Director, (Research), Dept of Agriculture Govt. of West Bengal

Rapporteurs Dr. S.K.Pal, Dy. Director (Agri.), SAC, Dr. T.H.Das, Pr. Scientist, NBSS&LUP (ICAR), Kolkata

1535 Group -1 (10 minutes for presentation and 10 minutes for discussion)





1615 - 1630

Drafting of recommendations by the Rapporteurs of Session-V, facilitated

Dr. T.H. Das, Dr. K. Das, NBSS&LUP and Ms. Nasrin Akter, SAC


CONCLUDING SESSION

1630 – 1730

Chairperson

Dr. A.K. Singh, DDG (NRM), ICAR, New Delhi

Co-Chairperson Dr. Dipak Sarkar, Director, National Bureau of Soil Survey and Land Use Planning, NBSS & LUP, (ICAR), Nagpur

Rapporteurs Dr. S.K.Singh and Ms. Nasrin Akter, SAC

1630 Presentation draft Workshop Recommendations

1640 Remarks Prof. S.K. Sanyal, Vice-Chancellor, BCKV

Remarks Professor Dr. Zahurul Karim, Former Secretary and Executive Chairman, BARC, Government of Bangladesh

1650 Remarks Director of Agriculture, Govt. of West Bengal / Dr. Pradip Sen, Jt. Director (Res.), Govt. of West Bengal

1700 Remarks Chief Guest (to be nominated)

1710 Remarks by the Chairperson Dr. A.K. Singh, DDG, NRM, New Delhi

1720 Vote of Thanks Dr. Rafiqul Islam Mondal, Director, SAC, Dhaka

1720 - 1740

Refreshment

Day 3: 23 June (Wednesday)

0930-1045 Visit to NBSS&LUP (ICAR), Regional Centre, Kolkata

1045-1245 Visit to NIRJAFT (ICAR), Kolkata

1245-1500 Visit to CRIJAF (ICAR), Barrackpore followed by Lunch at same venue

1500 Back to Hotel


Appendix-D List of Participants of the Regional Consultation on Strategies for Arresting Land degradation in South Asian Countries

21 -23 June, 2010 IndiSmart Hotel, International Tower

Salt Lake, Kolkata

Sl. No. Name Designation Address

1 Sh. Naren De Minister-in-charge Ministry of Agriculture and Consumer Affairs, Government of West Bengal, India

2 Dr. V.N. Sharda Director Central Soil & Water Conservation Research and Training Institute 218, Kaulagarh Road, Dehradun-248195, India

3 Dr. M. Shahabuddin Khan Ex-Head, Soil Science Division

Bangladesh Agriculture Research Institute (BARI) Joydebpur, Gazipur

4 Ms. Karma Dema Dorji Programme Director National Soil Services Centre, Department of Agriculture, Ministry of Agriculture & Forest, Thimphu, Bhutan

5 Dr. Ranjit Mapa Senior Professor Department of Soil Science Faculty of Agriculture University of Peradeniya Peradeniya-20400 Sri Lanka

6 Dr.Y. G. Khadka, Ph.D. Chief, Soil Science Division

Nepal Agricultural Research Council (NARC), Khumaltar, Lalitpur, Nepal

7 Dr. Md. Rafiqul Islam Mondal

Director SAARC Agriculture Centre BARC Complex, Farmgate, Dhaka-1215

8 Dr. S. K. Pal Deputy Director (Agriculture)

SAARC Agriculture Centre BARC Complex, Farmgate, Dhaka-1215

9 Mrs. Nasrin Akter Senior Programme Officer (Crops)

SAARC Agriculture Centre, BARC Complex, Farmgate, Dhaka-1215

10 Dr. Nurul Alam Senior Programme SAARC Agriculture Centre, BARC


Sl. No. Name Designation Address Specialist (PSPD) Complex, Farmgate, Dhaka-1215

11 Dr. Biswapati Mandal Professor Bidhan Chandra Krishi Viswavidyalay Kalyani, dist. Nadia West Bengal, India

12 Dr. A.M. Puste Professor Bidhan Chandra Krishi Viswavidyalay Department of Agronomy P.O. Krishi Viswavidyalaya, Mohanpur Nadia, West Bengal, India

13 Prof. Dr. Zahurul Karim Chairman, CASEED Former Secretary, Government of Bangladesh & ex-Executive Chairman, Bangladesh Agricultural Research Council (BARC)

14 Mr. AZM Shafiqul Alam Additional Secretary (PPC)

Ministry of Agriculture, Government of Bangladesh

15 Prof. S.K. Sanyal Vice Chancellor BCKV, West Bengal, India

16 Dr. K. Das Principal Scientist NBSS & LUP (ICAR), Regional Centre, Kolkata, India

17 Dr. D. Jena Ex-Head Department of Soil Science and Agricultural Chemistry, OUAT Bhubaneshwar, Orrisa, India

18 Dr. B.K. Bandhopadhyay Head CSSRI (ICAR), Canning Town, Dist. 24-Parganas, West Bengal, India

19 Dr. K.K. Satpathy Director NIRJAFT (ICAR), Kolkata, West Bengal, India

20 Dr. P.S Roy Dean & Assoc. Director (Capacity Building)

NRSC, ISRO, Dehradun, India

21 Dr. K.S Dillon Retd. Profeesor Department of Soil Science, PAU, Ludhiana, India

22 Dr. D.C. Nayak Principal Scientist NBSS & LUP, Kolkata, India

23 Dr. B. Venkateshwalu Director CRIDA, Hyderabad, India

24 Dr. B.S. Mahapatra Director CRIJAF (ICAR), Barrackpore, West Bengal, India

25 Dr. B.M. Jha Chairman Central Ground Water Board,


Sl. No. Name Designation Address Faridabad, India

26 Dr. S.K. Singh Principal Scientist & Head

NBSS & LUP (ICAR), Reg. Centre, Kolkata, West Bengal India

27 Dr. Dipak Sarkar Director NBSS & LUP (ICAR), Nagpur, India

28 Dr. A. K. Singh Deputy Director General (NRM)

ICAR, New Dehli, India

29 Dr. Pradip Sen Jt. Director (Research)

Govt. of West Bengal, India

30 Dr. T.H. Das Principal Scientist NBSS & LUP (ICAR), Regional Centre, Kolkata, West Bengal, India

31 Dr. A. K. Sahoo Principal Scientist NBSS & LUP (ICAR), Regional Centre, Kolkata, West Bengal, India

32 Dr. Amal Kar Principal Scientist & Head

Natural Resource and Environment Division.CAZRI, Jodhpur

33 Dr. Mohammed Osman Principal Scientist Central Research Institute for Dryland Agril.(ICAR), Santoshnagar, Hyderabad, India

34 Dr. Pradip Dey Principal Scientist CSSRI, Karnal, India

35 Dr. Ajoy Kr. Misra Superintending Geohydrologist,

Central Ground Water Board, Kolkata, India

36 Dr. Gautam Bose Principal Scientist, NIRJAFT, Kolkata, India



Appendix-E: Consultation Photo Album







ii - SAARC Agriculture Centreof legumes in crop calendar, Legume based forage production, Silvipasture and silviculture based agriculture, Agro-forestry, Strategies for arresting land

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