Hriday Kamal Tarafder and Dr. P. K. Mani 1 Department of Agricultural Chemistry and Soil Science Faculty Of Agriculture Bidhan Chandra Krishi Viswavidyalaya Management of Crop Residue and Its Effect on Soil Quality in Rice Based Cropping System
Hriday Kamal Tarafderand
Dr. P. K. Mani
Department of Agricultural Chemistry and Soil ScienceFaculty Of Agriculture
Bidhan Chandra Krishi Viswavidyalaya
Management of Crop Residue and Its Effect on Soil Quality in Rice Based
Cropping System
Crop residue is defined as the vegetative crop material left on the field after a crop is harvested, pruned or processed.
The removal of crop residues leads to low soil fertility and thereby decreased crop production.
The straw of most cereal crop contains about 35,10 and 80% of the total N, P and K taken up by the crop.
(Barnard and Kristoferson,1985)
Crops Asia Africa S. America World
R-straw 771804 25968 24153 844782R-husk 154361 5194 4831 168956Wheat 379788 27395 25539 946734Barley 34097 6753 2141 208229
Sugarcane 53855 8561 41880 125227Cotton 6378 315 69 6801Oats 2424 342 1604 51604Corn 166205 38729 54626 604031
Table1: Residue production (x 103t) by rice and different crops grown in rotation with rice in the tropics in 1998
Global Availability of Crop Residue
Source: Larson et al., (1978), Bharday (1995), Beri and Sidhu (1996)
Crop Residue(mt)
Nutrients * (103) tones
N P2O5 K2O N+P2O5+ K2O
Paddy 225.9 1220 542 2417 4179
Wheat 98.9 534 237 1058 1824
Pearl millet 12.0 62 28 124 214
Maize 11.5 59 26 116 201
Sorghum 10.9 65 29 128 222
Barley 2.6 14 6 2747 47
Others 4.1 10 43 75
Table 2: Estimated cereal residues and nutrient present in the cereal residue of major crop of India
Availability of Crop Residue in India
Beri et al., (1998)
Residue burningBaling and removing the strawSurface retention and mulchingResidue incorporation
MANAGEMENT OF CROP RESIDUE
Advantage:It facilitate timely planting of the following crops.It clears the land quickly of residues before the next crop.It kills soil borne deleterious pests and pathogens.
Disadvantage:It cause significantly air pollutionKills beneficial soil
insects and micro- organismLoss of soil organic
matter (SOM).
Residue Burning
Baling and Removing the StrawUsed for livestock feed,
fuel,
building materials,
livestock bedding,
bedding for vegetables cultivation and
mulching for orchards and other crops.
Surface Retention and Mulching
It is a practice that leaves straw residues from a previous crop on the soil surface without any form of incorporation.
It helps to protect the fertile surface soil against wind and water erosion. This method is prevalent in no-till or conservation tillage practice where at least 30% of soil surface is covered with crop residue.
Crop Residue IncorporationCrop residue is incorporated completely or partially into soil mostly by ploughing.
Aboveground portion chopped into small size and can be incorporated by power-tiller.
Incorporation of straw increase soil organic matter and soil N,P and K content as compared to other management option.
Problem of Incorporation of Crop Residues in Relation to Crop Growth
Immobilization of mineral nutrients
Phytotoxicity associated with crop residue incorporation into the soil
Figure 1: Effect of pre-decomposition period of rice straw on mineral N (NH4 + N03) dynamics in soil
(Yadvinder-Singh et al., 2004)
How to overcome the problem of Immobilization?
Soil amended with 100 mg N kg-1 and incubated at 75% field capacity moisture regime at 30°C
Figure 2: Temporal changes in volatile organic acid concentrations in the soil solution collected at 100 mm soil depth as affected by added rice straw.
(Sharma et al., 1989)
How to overcome the problem of Phytotoxicity?
Effect of crop residue on
Soil quality
Soil quality is… “ the capacity of a specific kind of soil to
function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation.”
(Karlen et al., 1997)
Soil Quality Indicators
PhysicalChemicalBiologicalOrganic Matter
Chemical
PhysicalBiologicalOM
Monitoring of Trends
Soil
Qua
lity
Time
Aggrading
Sustaining
Degrading
Base
line
(Seybold et al., 1998)
AggregationPorosityHydraulic ConductivityInfiltrationBulk Density
Effect on Physical Quality
Figure 3: Soil aggregates stabilization by various sources of organic matter.
(Dalal and Bridge, 1996)
Effect on Aggregation
Table 3: Effect of crop residues on soil aggregation in 23 years old rice-wheat cropping system
(Bandyopadhyay et al., 2009)
TREATMENT WSMA(%)
AR AS(%)
MWD(mm)
GMD(mm)
Fallow 76.8 3.31 76.75 1.57 1.14
Control 41.0 0.69 39.3 0.60 0.70
NPK 63.2 1.72 63.20 0.01 0.73
NPK+PS 74.2 2.88 73.24 0.89 0.89
Table 4: Effect of straw application on Bulk density, Hydrolic conductivity,WSA and Porosity
Bellakki et al.,1998
Treatment To Sumer Rice
Bulk Density (Mg/m3 )
Hydraulic Conductivity
(cm/h)
Water Stable Aggregate
(%)Porosity
(%)
NPK 1.43 1.18 37.6 46.0
Rice Straw To Meet 50% N
1.26 1.93 51.3 52.0
Rice Straw To Meet 25% N
1.27 1.78 49.6 52.0
Soil ReactionRedox Potential and Electrical ConductivitySoil Organic matterSoil Macronutrient and Micronutrient
Effect of Crop Residues on Chemical Quality
Crop residues influence soil pH through accumulation of CO2 and organic acids during decomposition
A sharp decrease in soil pH of flooded soils due to application of rice straw has been recorded by Murty and Sing (1976).
Soil Reaction
Redox Potential and Electrical Conductivity
Straw incorporation hastened and intensified soil reduction and also increase pH and E.C of acid soils
(Beye et al.,1978)
Decreased soil pH and E.C of alkaline soils under submergence
(Yodkeaw and Datta,1989)
Yadvinder-Singh et al. (2004) reported that rice residues incorporation increased organic carbon content of sandy loam soil more significantly than straw burning or removal after 7 years.
Table 5: Effect of crop residue management on organic carbon content of soil
*Beri et al.,1995,;**Yadvinder-Singh et al.,2004
Type of Crop Residue and Soil
Duration (Yr)
Residue Management
Organic Carbon(%)
Rice Straw in Wheat And Wheat Straw In Rice ; Sandy Loam* 10
Removed 0.38
Burned 0.43Incorporated 0.47
Rice Straw in Wheat Wheat in Rice In Rice-wheat Rotation ; Sandy Loam**
7
Removed 0.38Burned 0.39
Incorporated 0.50
Soil organic matter(SOM)/ Soil organic carbon(SOC)
Within 3 years of incorporation of rice straw at 6-7 t ha-1, total N content in soil increased by 0.021% over the straw removal treatment.
Table 6: Effect of straw management on the nutrient status of Mahaas clay of five cultivars
(Ponnamneruma.1984)
Treatment Organic C (%)
Total N(%)
Olsen P(Mg /Kg)
Exchangeable K
(Mg/Kg)
Removed 1.81 0.167 9 10.5
Burned 1.94 0.173 11 12.5
Incorporated
2.17 0.182 12 11.6
Soil Macro and Micronutrient
Table 7: Effect of crop residues on soil chemical indicator
SS: Sorghum Stover; GL: Glyricidia Lopping NR: No Residue(Sharma et al.,2005)
Treatment
pH OC N P K Ca Mg S Zn Fe Cu Mn B
SS 6.3 6.2 216 46 208 4.5 1.4 8.8 1.2 10.1 0.8 25.3 0.9
GL 6.2 6.4 251 46 247 4.7 1.4 6.9 1.3 9.6 0.7 27.4 1.3
NR 6.1 4.0 227 38 201 4.6 1.4 6.1 1.2 9.5 0.8 24.6 1.3
Microbial PopulationEnzymatic ActivityMicrobial Biomass C and NCarbon and Nitrogen mineralization
Biological Quality
Table 8: Microbial population as affected by residue management in Rice-Wheat rotation
Population Burning Removal Incorporation
After rice
Bacteria(*105) 59.6 15.6 115.4
Fungi(*103) 69.0 13.5 143.0
After wheat
Bacteria(*105) 16.2 13.9 126.6
Fungi(*103) 34.5 33.2 133.6
Sidhu et al., (1995)
Microbial Population
The enzyme activity in the soil environment is considered important in contributing the overall soil microbial activity and soil quality. (Jordan et al.,1995)
Enzymes are involved in the dynamics of soil nutrient cycling and energy transfer.
Different crop residues incorporation were significantly higher the enzymes activity than the no residues. (Bandick and Dick, 1999)
Enzyme activity
Table 9: Changes of soil enzyme activities after I5 years of cultivation with rice-wheat copping sequence
(Ghosal, 2004)
Treatment Dehydroge
-nage
Acid
Phosphatase
Alkaline
phosphatas
e
Urease Arylsulph-
atase
Control 22.87 75.69 54.49 9.04 7.76
NPK 20.34 76.08 47.11 10.42 9.52
NPK+PS 24.82 85.01 57.45 12.14 9.96
Fallow 30.40 69.02 56.44 14.43 9.32
Microbial biomass is a small (1-5% by weight) but active fraction of soil organic matter.
Soil microbial biomass acts as a reservoir of plant nutrients (like N,P and S) and its availability .
After straw incorporation MBC increase by 2-5 fold in 10 days and reached highest by 30 days.
MBC increased by 45 % and N by 60% in residue retention over residue removal. (Kushwaha et al.,2000)
Microbial biomass C and N
Table 10: Carbon, Nitrogen and biomass C in surface soil under different residue management
(Monneveux et al.,2006)
Treatment Organic C(%) Total N(%) Biomass
C(µg/g)
No residue 1.92b 0.14b 47.4c
Maize residue 2.01a 0.13a 71.5
Maize and Jackbean residue
2.01a 0.16a 114.9
Table 11: Microbial biomass C (MBC), mineralizable C (minC), basal soil respiration (BSR) and microbial quotient (MQ) in soils
Treatments at P ≤ 0.05 by Duncan’s multiple-range testMajumder et al., 2008
Treatment MBC Min C(0-24 days)
BSR( 10-24 d) MQ
(g C Kg-1) g CO2-C kg-1C d-
1
Kg minCKg-1 TOC
Control 0.28d 1.15c 0.21c 0.023c
NPK 0.41c 1.65b 0.31b 0.029b
NPK+PS 0.48ab 1.76ab 0.31b 0.032a
Carbon and Nitrogen mineralization
At soil depth of 0 to 0.2m under different treatments after 19 yr of rice-wheat cropping
1. Crop residue for reclamation of salt affected soil
2. Biological N₂ Fixation3. Weed Control
Some special effects of crop residue management
Rice straw incorporation decreased the precipitation of Ca and carbonate
Increased removal of Na in drainage water
Decreased the pH and EC of soil
1. Crop residue for reclamation of salt-affected soil
(Yoo et al.,1990) reported that surface application of rice straw increased flood water pH to an optimum level for N2-fixing organism, and thereby increased the N2-fixtion by heterotrophic bacteria and blue green algae.
Roper(1983)observed that a positive correlation between(r=+0.98) between nitrogenase activity and wheat straw decomposition.
2. Biological N2 fixation
Crop residues can suppress weeds in many ways reported by Kumar and Goh (2000) for example.
Through there physical presence on the soil surface as mulch and by restricting solar radiation reaching below the mulch layer.
By direct suppression caused by allelopathy.
By controlling N availability. Burning of residue can help in effective
removal of weed seed and weeds.
3. Weed control
Crop residue incorporation improve physical, chemical and biological properties of soil.
In long-tem incorporation of crop residue increased the productivity.
Overall, incorporation of crop residues appears to be a better management option.
Incorporation should be done at least 10 d and preferably 30 d before the establishment of succeeding crop.
CONCLUSION
Thank You