Desertification in NW part of India : key issues - Vedas

Desertification in NW part of India : key issues

Pratap Chandra Moharana,Principal Scientist and Fulbright Fellow, [email protected]

Desertification, which is considered a major threat in the drylands of the world, is not

about advancing boundaries of the existing deserts, but about land degradation in the

arid, semi-arid and the dry sub-humid regions, which together form the drylands.

Desertification usually takes place

when the rates of natural geomorphic processes in the drylands

are accelerated by human action or through extreme natural events

like long term droughts, high-intensity rains, tectonic disturbances,

etc.

Our experiences :

• Terrain features can be used as state indicators of desertification, provided

we understand the spatial pattern of process-form interactions, and

vulnerability of the landscape.

• The occurrence of nebkhas in sandy plains is now recognized as a good

indicator of recent sand deposition (Nickling and Wolfe, 1994; Tengberg,

1995; Kar, 2006).

Great Rann of Kachchh

and Little Rann

Kachchh Mainland

Saurashtra upland

ARID

SEMI-

ARID

Thar Desert : Geomorphic Provinces

Agro-climatic Zones of western Rajasthan Morpho-edaphic Characteristics

IA Arid western plain Sandy plains and major dune fields, thick sand with CaCO3 horizon at varying depths, <250

mm rainfall zone

IB Irrigated north-western plain Canal irrigated leveled sandy plains, CaCO3 horizon, <300 mm rainfall zone

IIA Transitional plains of inland drainage Sandy alluvial plains, shallow to deep soils, irrigated with well/tube well, 300-450 mm zone

IIB Transitional plain of Luni basin Alluvial plains of Luni & its tributaries , 300 – 500 mm rainfall zone

Wind erosion and Aeolian activity in western part of Rajasthan : some key points

• Arid zone covers about 12% of the country's geographical area

• Western part of Rajasthan shares about 62% of hot arid region in India.

• Out of Country’s120 M ha degraded lands, Wind erosion affects 12.40 M ha area

• 3.76 M ha agricultural lands suffer from loss of top soil • ~ 71% area of western Rajasthan has been mapped under wind erosion

• Aeolian activity in this region is a measure of the strength and duration ofwind, sand supply, rainfall, vegetation cover and land surface conditions

• Aeolian activity is more effective during summer months due to persistentSSW & SW blowing of strong hot wind for days together that causes sandstorms.

• The wind and sand dynamics cease with the arrival of monsoon rains.

• Low and erratic precipitation (100 - 420 mm/year)

• High evapotranspiration (1500-2000 mm/year).

West

ern

Raja

sthan :

the r

egio

nal vari

abilit

y

• Human population trend (1961 – 2011) : +194%

( 37/ km2 – 108/ km2)

• Livestock population : 1961 – 2003 : +72%

(66/ km2 – 113/ km2)

• Human population

trend : 1961 – 2011 :

+194% ( 37 /km2 –

108/ km2)

• Livestock population :

1961 – 2003 : +72%

(66 /km2 – 113/ km2)

Western Rajasthan : Terrain & Rainfall pattern (Normal & Drought year)

High human pressure

Climatic variability

Water scarcity limits the production of crops, forage, wood

ANIMAL BASED AGRICULTURAL ECONOMY

(Crops-Trees/Grasses-Livestock)

Intensive cultivation

Overgrazing and Deforestation

Exploitation of resources

DESERTIFICATION

Landuse/landcover changes in Western Rajasthan

2005-06

Interpreted from FCCs of IRS-L3 satellite images of 2005-06Data used : FCCs of IRS-1C/1D satellite images of 1994-95

1996-97

Land use (2005-06)

Area (%)

Land use (in 90’s)

Area (%)

Croplands (Irrigated) : +8.69%

Wastelands : - 9.62%

Prosopis Cineraria : the mainstay of

Agro-forestry for rural livelihood

Tree , Fuel, Loong

Sand Dunes are croplands to the land owner

The future of Sandy uplands in western Rajasthan : Intensive vs Subsistence systems

Tractorization : Disturbing the dune morphology for sand movement

0

50000

100000

150000

200000

250000

300000

350000

400000

Current fallowArea (ha)

1991 2001 2011

0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

1800000

Net area sown (ha)

1991 2001 2011

Comparative

statistics

For

1991, 2001

and 2011

Decline in land

fallowing in

almost all

districts

Increase in net

sown area in

ACZ-I & II

And

Negligible or no

change in

ACZ –III & IV

0

5

10

15

20

9.519.02 97.54

10.4312.17

14.09

2.41

16.3614.93

16.1916.61

Total Cropped Area

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

200000

Total_Irrigated_Area (ha)1992-2006

BRM : Barmer, JSM : Jaisalmer, BKN : Bikaner, CHU: Churu, JOD : Jodhpur, GNG: Ganganagar, HNG: Hanumangarh, NAG: Nagaur, JHU: Jhunjhunun, SIK: Sikar, JAL: Jalor, PAL: Pali

Agro-climate wise Distribution of Sand Dunes & Croplands in western Rajasthan

Sand Dunes : 48% area of western Rajasthan

20142005

Nov 2007Nov 2014

A Shift to

Irrigated

Agriculture

If water is

available

Ekalpar, SW of Ramgarh, Jaisalmer District

Changes : Sandy barren area to irrigated cropland

Irrigation advantage through IGNP canal , Tubewell & Khadin

Khadins

Tube well irrigation

IGNP canal system

2073 km network of canals in Mohangarh-Sadaru-Arjana-Sultana-Nachna

25.88 % area : ground water irrigationthrough 2,283 tube wells and pumpingsets

Cultivation on the conserved moisturethough ‘Khadin’. ~ 500 khadins in the

district.

Chandan-Sodakor-Lathi-SankraBharamsar-Roopsi

Total Irrigated Area:

1,91,796 ha

IGNP- 141674 ha

other sources-50123

ha

About 5000 ha area has been put under Pomegranate during 2010 – 2015 in

the above villages.

2009

2013

• Saline water irrigated crops : advantage over

sweet water for less insects,

• 8-10 irrigation/day,

• 500-800 trees/ha,

• 25-30 kg fruit/5 year old tree)

• Cost of input : 2 lakh / year,

• Tree spacing : 3 x 5 ft and also 12 x 15 ft,

• Anar as a fruit tree : 5-7 years good fruiting

• Seedlings provided from Gujarat traders : Rs.15/30

/tree

• Has replaced Arendi and Jeera

• Till 2009-2010, the area was a typical sandy

terrain with rainfed crops only

• Consultation fee : Rs. 15 / tree

• Indrana Jeera was a household name in the market

Changing

concept of

agriculture

in western

Rajasthan

Erosion/deposition

classArea (Km2)

Percentage of

total area

Very severe 5800 2.78

Severe 25540 12.23

Moderate 73740 35.32

Slight 52690 25.24

Negligible 50981 24.43

Source : CAZRI(2000).Wind erosion in western Rajasthan.

Croplands

Very

Severe

Severe Moderate Slight Negligible

Irrigated --- PokaranNawalgarh,

Sanchore

Chirawa,

Osiyan

Merta,

Degana

Rainfed

Jaisalmer,

Chohatan

Bikaner,

Phalodi

Nokha,

ShergarhJodhpur Nagaur

Wind erosion index:

a reliable measure for understanding the spatial pattern

of sand mobility based on threshold wind velocity and

PET for the period of strong sand shifting wind

(March to July).

Western Rajasthan

Wind Erosion

Wind Erosion Index and distributional pattern of Aeolian bedforms

Aerosol Optical Thickness (AOT)

more is the AOT, greater is the dust concentration

AOT maps reveal dust aerosol was more active in the west of Jaisalmer

Source : MODIS aerosol level 2 product, MOD04_L2)

LocationWind erosioncategory

Annual soil loss

rate (t ha-1 yr-1)

Khuiyala Farmer’s field (Dune Covered)Jaisalmer district

Very severe 83.3

Bikaner Research Farm, CAZRI Severe 50.0

Jaisalmer Research Farm, CAZRI Moderate 12.2

Bhujawar Farmer’s field, Jodhpur Slight 1.3

Place / Terrain Measurement

Shergarh/Sand dune Erosion of 0.2 mm size sand grains @46 kg/m2 / hr Ramakrishna et al.1990

Pokaran/isolated barchan Movement of 2.25 m barchan by 1.70 m / 3 days /wind speed : 29 kmph (Kar, 1994)

Bikaner, Jodhpur &

Jaisalmer / cropland

Erosion from bare soil at Bikaner : 273.7 kg/ha/day,

Erosion from loamy sand soil with clod formation at Jodhpur : 15.6 kg/ha/day

Sandy soil at Chandan(Jaisalmer): 76.7 kg/ha/day during wind speed 29 kmph (Gupta, 1993)

Bikaner / cropland Soil loss during a prolonged sand storm

Bare soil : 1449 t/ha

Crop field (with 45 cm high Pearlmillet stubble): 22 t/ha (Gupta 1993)

Jodhpur / cropland

Chandan / sandy plain

Mean soil loss during 22 –day long sand storm, June 1985

Sandy plains, deep ploughed :: 2837 t/ha (3 sites)

Soils under 8-12 per cent natural vegetation cover) : 472 t/ha

Field cleared of vegetation : deflation of 15-18 cm (3100-3700 t/ha)

Dhir et al., 19

Rece

nt

Experi

ments

and F

indin

gs

Measu

red

so

il lo

ss d

ue t

o W

ind

ero

sio

n b

y C

AZ

RI sc

ien

tist

s

Erosion / deposition features Signature on satellite image FCCs

Sand sheets, fence line hummocks Uniform whitish or light pale brown color

Fresh sand deposits on old and stable sand dunes Bright white tone of reactivated sand and light yellow on stable surface

Fresh sand deposits on sand ridges Medium white tone with dull redness because of cultivation

Brachans or low dunes Bright white tone

TerrainAverage rainfall (mm)

Major FIELD indicators for assessment Severity

Flat sandy plains with dominantly loamy sand to sandy loam soil

100-550Fresh sand sheet ~ 30 cm thick; few scattered new fence line hummocks and nebkhas(~ 100 cm high)

Slight

Moderately sandy undulating plains and sand dunes with loamy sand soils; thickly sand sheeted plains

> 300Reactivated fresh sand ( 50 to 150 cm thickness on stable dunes) , sandy plains and fence line hummocks; recently formed nebkhas

Moderate

Moderately sandy undulating plains and sand dunes with sand to loamy sand soils

< 300

Reactivated and fresh sandy hummocks (nebkhas) sand ridges of 90-300 cm height; sand sheets of 60-150 cm thickness between undulations; reactivated stable dunes with fresh sand deposits of 70 to 200 cm thickness;

Exposed plant roots to a depth of 40 to 100 cm in the sandy plains indicate erosion

Moderate

Moderate to strongly undulating sandy plains with closely spaced hummocks and high sand dunes with sand to loamy sand soils

100-550

Closely spaced sandy hummocks and sand ridges of 1 to 4 m height with fresh sandcover; sand deposits of 100-300 cm thickness usually present between undulations;highly reactivated sand dunes with fresh sand and superimposed crescent bedformsof 2 to 4 m height

Severe

Barchan dunes and very thick sandy plains with loose sand throughout the profile

100-550Areas of drift sand, especially as fields of barchans of 2 to 5 m height, which encroach upon roads, settlements and agricultural fields; also areas with very closely spaced nebkhas of 2-5 m height

Very severe

INDICATORS

Dust Catcher

(fixed type)

Wind Erosion Sampler

(freely rotating type)

Shelterbelts have varied effects in reducing wind velocity depending upon plant species, structure, height, length and density. However,

studies (CAZRI, 2006) indicates improved mico-climate, soil quality and increased crop productivity in irrigated area covered with

shelter belt plantation.

August 2009 January 2012

November 2009 November 2013

Sh

elt

er

Belt

Str

ate

gy t

o c

heck b

low

n s

an

d a

cti

vit

ies

San

d D

un

e S

tab

iliz

ati

on

/ W

ind

Bre

aks

• Fencing of the area• Establishment of micro-wind breaks on the wind ward side (5 m chess board or in 5 m parallel

strips)

• Sowing of grasses and transplanting of trees and shrubs with onset of monsoonLocal shrubs / bushwood materials : Khimp (Leptadenia pyrotechnica), Pala (Ziziphus numularia), Sania

(Crotalaria burhia and Murah (Panicum turgidum)

Tree species : Acacia tortilis, Acacia senegal, Tamarix articulata

Grasses : Lasirus sindicus, Cenchurus ciliaris

Creepers : Citrullus colocynthis

KHARDA

• Croplands degraded due to Industrial

effluent along the Bandi river (1-2 km

extent) : 1880 ha (15 % of study area)

• No crops in all the seasons, croplands

infested with P.Juliflora

• Land degraded due to salinity developed

around reservoir : 1124.67 ha (9% of study

area)

Zaid

Rabi

Khar

if

Com

bati

ng D

ese

rtif

icati

on

Mic

ro W

ate

rshed o

f K

akniN

adi,

west

of

Jais

alm

er

Lodorv

a-M

uls

agar-

Jiy

ar-

Kuld

hara

-Dam

odara

Legend

Rocky Structural Plains/Hamada

Rocky Uplands/Ridges

Rocky Pediments Dissected with Gullies

Rocky Gravelly Plains

Desert Pavements with Shallow Soil

Shallow Allluvial/Colluvial Plain

Flat Depressions/Khadins

Low Lying Plains

Sandy Uplands/Sand Dunes

Highly Eroded Mines Area

Settlements

Ephemeral Streams

Major Land Units for

Combating Desertification

At a Micro catchment scale

Manpiya

The Landscape, 2007

CROPLAND

S ROHILI R.

KAWAS

The Lignite Landscape 2013

MINING

The Mining at Kapoordi: Morphology

A DRY EPHEMERAL CHANNEL

LINKING RIVER ROHILI

ROHILI R

Climate change, Environment,

Implications

• More short duration high

intensity rain events

• warming trend

• increased dryness

• higher wind speed

• and higher evaporative

demands by the plants

Possible Implication

Would make

the desert and its eastern margin

more vulnerable to accelerated

wind erosion,

And other desertification

processes.

• Symbiotic relationship between natural environment and arid agriculture

• Research methodologies for development of wastelands that constitute ~30% of

the arid zone, wilh viable technologies, to be implemented in village situations to

demonstrate their potentials for employment and resource generation.

• Pressurized irrigation for efficient use of water and other inputs to conserve

water will receive a high priority.

• Conservation agriculture will be a crucial tool in countering the negative impacts

of climate change.

• Plant biodiversity of the arid region has to be maintained and harnessed

scientifically for improving the livelihood of the rural people.

• Watershed management, with appropriate mix of different components of the

agri-horti-silvo-pastoral system, crop diversification and better utilization of

rainwater.

• Replacement of conventional low-yielding crop varieties with improved high-

yielding ones, and by optimizing agro-techniques commensurate with the changing

crop calendar.

• Systematic harnessing of solar and wind energy for their for agricultural and

domestic uses.

symbiotic relationship between natural environment and arid agriculture

Possible Approach for

ML-LUP

• Village level /

cadastral level

Resource information

• Technological help

and intervention at

village level

• Aggregation of

information at ACZ

units for planning

• DSS for sustainable

agriculture

Botto

m to

top a

ppro

ach

Strategy for Micro-level Land Use Planning for combating desertification

Thanks

&

Questions