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Soil Degradation in India: Challenges and Potential Solutions

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Department of SSAC, BHU, Varanasi

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Soil Degradation in India: Challenges and Potential Solutions

  1. 1. 1/10/2017 1
  2. 2. DEPARTMENT OF SOIL SCIENCE AND AGRICULTURAL CHEMISTRY INSTITUTE OF AGRICULTURAL SCIENCES BANARAS HINDU UNIVERSITY VARANASI-221005 DEPARTMENT OF SOIL SCIENCE AND AGRICULTURAL CHEMISTRY INSTITUTE OF AGRICULTURAL SCIENCES BANARAS HINDU UNIVERSITY VARANASI-221005 Soil Degradation in India: Challenges and Potential Solutions Course seminar
  3. 3. 3  Soil Degradation : Extent and Distribution in India  Principle types and mechanism of soil degradation  Causes of soil degradation in India  A case study on Cost estimation of soil erosion  A case study on management of soil erosion in Rajasthan desert  Strategies to mitigate soil degradation  Research results documenting to soil conservation  Drivers of soil erosion  Conclusion  Introduction
  4. 4. 4 • Of India’s (TGA 328.7 Mha), 304.9 Mha comprise the reporting area with 264.5 Mha being used for agriculture, forestry, pasture and other biomass production • Soil degradation in India is estimated to be occurring on 147 million hectares (Mha) of land (NBSS&LUP, 2004) out of which >94 Mha degraded by water erosion • India suffers from deleterious effect of soil erosion with an average soil erosion rate was ~16.0 ton ha−1 year−1, resulting in an annual total soil loss of 5.33 billion tons throughout the country (Pandey et al., 2007) • Nearly 29% of total eroded soil is permanently lost to the sea, while 61% is simply transferred from one place to another and the remaining 10% is deposited in reservoirs
  5. 5. 1/10/2017 5 “The nation that destroys its soil destroys itself.” Franklin D. Roosevelt (1882 - 1945)
  6. 6. 1/10/2017 6 "Soil degradation, decline in its capacity to support functions and provide ecosystem services, is caused by erosion, salinization, elemental imbalance acidification, depletion of soil organic carbon, reduction in soil biodiversity, and decline in soil structure and tilth” (Lal, 2012).
  7. 7. 1/10/2017 7 Soil degradation refers to the processes, primarily human induced, by which soil declines in quality and is thus made less fit for a specific purpose, such as crop production (FAO, 2011).
  8. 8. 1/10/2017 8 “Soil is a part of Land, thus any deterioration in it’s quality, mass or volume either singly or in combination, is also deterioration of Land”
  9. 9. 1/10/2017 9 “Soil degradation is closely linked to poverty in the sense that, as the degree of degradation increases, crop and animal yields decline and people have both less to eat and less to sell to support themselves.” Clark & Wallace,2002
  10. 10. 1/10/2017 10 INCREASE IN RURAL POPULATION LIMITED LAND RESOURCES LAND SHORTAGE LAND DEGRADATION POVERTY NON-SUSTAINABLE LAND MANAGEMENT PRACTICES
  11. 11. 1/10/2017 11 0 500 1000 1500 2000 2500 3000 Asia Africa South and central America Europe Oceania North America 2787 1663 1714 796 644 1131 747 494 307 218 104 96 MillionHectares Total land Degraded land
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  14. 14. 1/10/2017 14 Table 1: Extent of land degradation in India, as assessed by different organizations Organizations Assessment Year Degraded Area (Mha) National Commission on Agriculture, New Delhi 1976 148.1 Ministry of Agriculture-Soil and Water Conservation Division, New Delhi 1978 175.0 Department of Environment, New Delhi 1980 95.0 National Wasteland Development Board, New Delhi 1985 123.0 Society for Promotion of Wastelands Development, New Delhi 1984 129.6 National Remote Sensing Agency, Balanagar, Hyderabad 1985 53.3 Ministry of Agriculture, New Delhi (20th ed.) 1985 173.6 Ministry of Agriculture, New Delhi (25th ed.) 1994 107.4 NBSS&LUP 1994 187.7 NBSS&LUP (revised) 2004 146.8 National Remote Sensing Agency, Balanagar, Hyderabad 2006 47.22 ICAR, New Delhi 2010 120.4
  15. 15. 1/10/2017 15 15 0.2 7.6 2.6 5.3 1.9 1.9 1.2 2.2 4.6 1 0.2 0.6 4.2 7 15.3 0.1 1.5 1.3 6.3 2.8 0.2 8.1 11.4 26.2 13.1 6.1 54.5 43.9 39.8 67.1 41 42.6 89.2 53.9 28.2 53.8 60 33 59.9 75 31.6 52 55.4 33.2 25.4 36.1 31 24.8 41.5 33.2 59.1 42.4 39.3 0 10 20 30 40 50 60 70 80 90 100 Total Degraded Area % of Degraded Area to TGA Fig. State-wise extent of degraded area in India (Mha), Source: NBSS&LUP, 2005 on 1:250,000 scale
  16. 16. 1/10/2017 16 Table 2. Estimates on the annual direct cost of land degradation in India Parameters NRSA (1990) ARPU (1990) Sehgal and Abrol (1994) Area affected by soil erosion (Mha) 31.5 58.0 166.1 Area affected by salinization, alkalinization and waterlogging (Mha) 3.2 - 21.7 Total area affected by land degradation (Mha) 34.7 58.0 187.7 Cost of soil erosion in lost nutrients (Rs billion) 18.0 33.3 98.3 Cost of soil erosion in lost production (Rs billion) 67.6 124.0 361.0 Cost of salinization, alkalinization and waterloggingin lost production (Rs billion) 7.6 - 87.6 Total direct cost of land degradation (Rs billion) 75.2 - 448.6
  17. 17. 1/10/2017 17 Area (Mha) affected by various erosion process in India 94 16 14 9 6 7 Water erosion Acidification Flooding Wind Erosion Salanity Combination of Factors Type of Erosion NBSS&LUP, 2004 (Total 147 Mha) ICAR, 2010 (Total 120.4 Mha) 94.9 0.9 3.7 17.9 2.7 0.3 Water and wind erosion Water logging Soil alkalinity/sodicity Soil acidity Soil salinity Mining and industrial waste
  18. 18. 1/10/2017 18 Classes Codes Area (in Mha) Water Erosion Loss of top soil Terrain deformation W Wt 83.31 Wd 10.37 Wind Erosion Loss of top soil Loss of top-soil/terrain deformation Terrain deformation/over blowing E Wt 4.35 Et/Ed 3.24 Ed/Eo 1.89 Chemical Degradation Salinization Loss of nutrients (En) – (Acid soils) C Cs 5.89 En 16.03 Physical Degradation Waterlogging P Pw 14.29 Others Ice caps/Rock outcrops/Arid mountain I/R/M 8.38 Total 147.75 Table 3: NBSS&LUP soil Degradation Classes, Derived From 1: 250,000 soil map (2004)
  19. 19. 1/10/2017 19 “Perhaps the most dominant soil degradation processes are soil erosion and organic matter decline.” B.A. Stewart, R. Lal, and S.A. El-Swaify. Sustaining the Resource Base of an Expanding World Agriculture. In: Soil Management for Sustainability. R. Lal and F.J. Pierce (eds.), 1991.
  20. 20. 1/10/2017 20 SOIL DEGRADATION NATURALHUMAN -INDUCED URBAN LAND • Pollution • Compaction • Erosion INDUSTRIAL LAND • Soil Compaction • Soil Contamination • Acid Rain AGRICULTURAL LAND PHYSICAL • Pan formation • Hard-setting CHEMICAL • Leterization • Calcification • Leaching/ Illuviation BIOLOGICAL • Decline in soil diversity PHYSICAL • Compaction • Crusting • Water imbalance • Impeded erosion • Runoff CHEMICAL • Acidification • Nutrient depletion • Leaching • Nutrient imbalance • Salanization/alkanization BIOLOGICAL • Decline in soil organic C • Soil biodiversity reduced • Decrease in biomass C Principal types of soil degradation: (i) natural (ii)Human-induced
  21. 21. 1/10/2017 21 2 Primary drivers of soil erosion Water : non arid areas Gravity involved in both wind and water erosion (>94 mha area subject to wind and water erosion in India) Drivers Wind : arid and semi arid areas
  22. 22. 1/10/2017 22 Process involved in erosion
  23. 23. 1/10/2017 23 Forms of Water Erosion
  24. 24. 1/10/2017 24 soil
  25. 25. 1/10/2017 25 Table 4:Common soil stress and related degradative processes Stress Principal degradative processes Heavy load due to extensive mechanization (vehicular traffic) Physical degradation, eg., crusting, compaction, structural decline and poor soil tilth High intensity of rain and overland flow, high wind velocity Accelerated erosion by water and wind High evaporation demand and high salt concentration in the profile Drought, aridization or desertification, salinization or sodification Poor internal drainage, and slow surface drainage Soil wetness and anaerobiasis Intensive cropping Chemical degradation, nutrient imbalance and soil organic matter depletion Intensive use of agrochemicals and monoculture Biological degradation, acidification and reduction in soil biodiversity
  26. 26. 1/10/2017 26 1. Overgrazing 2. Deforestation 3. Industrialization 4. Overpopulation (Land Shortage, Land Fragmentation and Poor Economy) 5. Over exploitation/Mining of land 6. Agricultural activities leading to soil degradation i. Low and Imbalanced Fertilization ii. Excessive Tillage and Use of Heavy Machinery iii. Crop Residue Burning and Inadequate Organic Matter Inputs iv. Poor Irrigation and Water Management v. Poor Crop Rotations vi. Pesticide Overuse and Soil Pollution
  27. 27. 1/10/2017 27 Current position: Cattle population: 467 Million Area of pasture land: 11 Mha Implying an average of 42 animals per hectare Threshold level: 5 animals per hectare (Sahay, K.B. 2000) Too many grazing cattle, sheep, or goats, which can destroy vegetation and as a result, soil is exposed toerosion.
  28. 28. 1/10/2017 28 Current position: Per capita forest land in the country is only 0.08 ha compared to a requirement of 0.47 ha to meet basic needs. Average rate of soil loss due to wind and water erosion in India is 16.4 tons per hectare annually with an annual total loss of 5.334 billion tons [CSWCRTI Dehradun, 2010] and in US it was 1.725 billion tons in 2007. Deforestation is both, a type of degradation by itself, and a cause for othertypes of degradation, principally, water erosion
  29. 29. 1/10/2017 29 Underground tanks storage, application of pesticides, oil and fuel dumping, leaching of wastes from landfills or direct discharge of industrial wastes to the soil. In industrialized urban regions, pollution can harm the soil of farms and makethelandunstablefor farming
  30. 30. 1/10/2017 30 Current position: India has • Land area is about 2.5% of global land • Supports 16% of global human population and ~20% of livestock population • Average size of land holding declined from 2.3 ha to 1.3 ha during 1970–2000 with per capita land of 0.32 hectare in 2001 The needs also increase and utilize forests resources. To meet the demands of rapidly growing population, agricultural lands and settlements are created permanently by clearing forests
  31. 31. 1/10/2017 31 Negative effects of mining are water scarcity due to lowering of water table, soil contamination, part or total loss of flora and fauna, air and water pollution and acidmine drainage Mineral Production (Mt) Overburden/Waste (Mt) Estimated Land Affected (ha) Coal 407 1493 10,175 Limestone 170 178 1704 Bauxite 12 8 123 Iron ore 154 144 1544 Others 9 19 - Table 5. Mineral Production, waste generation and land affected in 2005-06 (Data source: Sahu and Das, 2011).
  32. 32. 1/10/2017 32 Current position: India has • Imbalanced consumption ratio of (N:P:K fertilizers) • 6.2:4:1 in 1990–1991 has widened to • 7:2.7:1 in 2000–2001 and • 5:2:1 in 2009–2010 compared with • Target ratio is 4:2:1 Agricultural activities and practices can cause land degradation in a number of ways depending on land use, crops grown and management practicesadopted i. Low and Imbalanced Fertilization
  33. 33. 1/10/2017 33 In India, ~500 Mt of crop residues are generated every year and ~ 125 Mt are burned. Crop residue generation is greatest in Uttar Pradesh (60 Mt) followed by Punjab (51 Mt) andMaharashtra (46Mt) Ministry of New andRenewable Energy (2009) ii. Crop Residue Burning and Inadequate Organic Matter Inputs Residue generation by different crops in India (MNRE, 2009) Burning of rice residues, a prevalent practice in northwest India
  34. 34. 1/10/2017 34 Excessive tillage coupled with use of heavy machinery for harvesting and lack of adequate soil conservation measures causes a multitude of soil and environmental problems iii. Excessive Tillage and Use of Heavy Machinery Less CO2 leaves soil when no-tilled Compaction due to use of heavy machinery and others
  35. 35. 1/10/2017 35 Expansion of canal irrigation (like the Indira Gandhi Nahar Project, for instance) has been associated with widespread waterlogging and salinity problems in areas, such as in the Indo-Gangetic Plains. iv. Poor Irrigation and Water Management Waterlooging and salinity due to poor irrigation management
  36. 36. 1/10/2017 36 Improper crop rotation coupled with lack of proper soil and water conservation measures are important reasons contributing to soil erosion in lands under cultivation v. Poor Crop Rotations Table 6: Effect of crop rotation on soil organic matter in soils
  37. 37. 1/10/2017 37 Overuse of chemical fertilizers and pesticides have effects on the soil organisms that are similar to human overuse of antibiotics. Indiscriminate use of chemicals might work for a few years, but after awhile, there aren’t enough beneficial soil organisms to hold onto the nutrients” (Savonen, 1997) vi. Pesticide Overuse and Soil Pollution Consumption pattern of pesticides (Aktar et al., 2009) Once they has been sprayed, it does not disappear completely. Some of it mixes with the water and seeps into the ground. The rest of is absorbed by the soil and plant itself.
  38. 38. 1/10/2017 38 The major outcomes of land degradations are as follows: Decline in the productive capacity of the soil (temporary or permanent) Decline in the soil “usefulness”. Loss of biodiversity Increased vulnerability of the environment or people to destruction or crisis Accelerated soil erosion by wind and water Soil acidification and the formation of acid sulphate soil resulting in barren soil Soil alkalinisation owing to irrigation with water containing sodium bicarbonate leading to poor soil structure and reduced crop yields Soil salinization in irrigated land requiring soil salinity control to reclaim the land Soil water logging in irrigated land which calls for some form of subsurface land drainage to remediate the negative effects. Destruction of soil structure including loss of organic matter.
  39. 39. 1/10/2017 39 A case study on Cost estimation of soil erosion and nutrient loss from a watershed of the Chotanagpur Plateau, India (Area- 14 square km, slope - 1% to 5%, annual rainfall – 1300–1500 mm, soil texture -Sandy clay loam) Gulati and Rai, 2014 1. It was observed that overland flow was greatest in orchard (30.73%) and lowest in vegetable field (15.84%). 2. Soil loss from the field plots ranged between 9 and 37 tonnes/ha during the monsoon months. 3. Nutrient leaching was highest in paddy fields. A strong positive correlation was observed between organic carbon and soil loss (P < 0.01). 4. On an average, 590 kg of macro-nutrients (N, P and K) were lost per hectare during the monsoon season. Approximately INR 8,893 ha–1 (US$ 137 ha–1) would be required to replace this loss through inorganic fertilizers. 5. Agricultural practices in mountain areas should be strengthened with more agroforestry components to promote conservation of soil, water and nutrients.
  40. 40. 1/10/2017 40 Case study :Management of soil erosion in the Rajasthan Desert What is the Issue?= Desert and semi-desert conditions occur in Rajasthan and there has been advance of the desert and encroachment of sand on fertile lands due to desertification and soil erosion. There has been a programme of action which includes: 1. Creation of a vegetation belt—five miles wide—along the western border of Rajasthan. 2. Improvement of land-use practices, especially the creation of shelter belts of trees by cultivators 3. A Desert Research Station is being set up at Jodhpur to investigate the problems of desertification. Research on soils, land-use and afforestation practices would be undertaken at this station. Planning Commission, GOI
  41. 41. 1/10/2017 41 • Soil Erosion • Nutrient runoff loss • Waterlogging • Degradation • Acidification • Compaction Negative • Crusting • Organic matter loss • Salinization • Nutrient depletion by leaching • Toxicant accumulation • Conservation tillage • Crop rotation • Improved drainage • Residue management • Water conservation • Terracing Positive • Contour farming • Chemical fertilizer use • Organic fertilizer use • Organic fertilizer (Green manure) • Improved nutrient cycling • Improved system to match soil climate and cultivars Soil Productivity Soil Degradation Processes Soil Conservation Processes The relationship between soil degradation processes and soil conservation practices
  42. 42. 1/10/2017 42  Soil Erosion Control  Water Harvesting (Watershed Approach), Terracing and Other Engineering Structure  Landslide and Mine-spoil Rehabilitation and River Bank Erosion Control  Intercropping and Contour Farming  Integrated Nutrient Management and Organic Manuring  Reclamation of Acid and Salt Affected Soils and Drainage (Desalinization)  Water Management and Pollution Control  Vegetative Barriers and Using Natural Geotextiles, Mulching and Diversified Cropping  Agro forestry  Conservation Agriculture (CA)  Disaster (Tsunami) Management
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  44. 44. 1/10/2017 44 Figure 1. Soil organic C (SOC) stabilization in the 0 to 45 cm soil layer as affected by 32 years of continuous annual fertilization under soybean-wheat cropping in a sandy clay loam soil of the Indian Himalayas Figure 2. Ratios of labile and recalcitrant pools of total SOC and applied C stabilized in soils by depth after 32 years of cropping with different fertilization (error bars indicate SEm Source: Bhattacharyya et al. (2011)
  45. 45. 1/10/2017 45 Table 7: Effects of balanced fertilization (NPK and NPK + FYM or compost) on C build up in soils under different cropping systems Build-up = [(NPK//NPK + FYM – Control)/Control] × 100; Build-up rate = [(NPK//NPK + FYM – Control)/year]; R-M-S, rice-mustard-sesame; R-W-F, rice-wheat-fallow; R-F-B, rice-fallow-berseem; R-W-J, rice-wheat-jute; R-F-R, rice-fallow-rice, FYM, farmyard manure. (Data source: Mandal et al. [2007]). Cropping System C Build-Up (%) in Treatments over the Control Plots C Build-Up Rate (Mg C ha−1 year−1 ) over the Control Plots NPK NPK + FYM NPK NPK+FYM R-M-S 51.8 a 55.7 a 1.91 a 2.05 a R-W-F 16.8 c 23.4 c 0.27 b 0.37 c R-F-B 9.3 d 24.7 c 0.13 c 0.36 c R-W-J 14.9 c 32.3 b 0.11 c 0.25 d R-F-R 33.5 b 54.8 a 0.28 b 0.45 b
  46. 46. 1/10/2017 46 Table 8: Runoff and soil loss under different crops on varying slopes at research farm, Bellary (Karnataka) (Source: CSWCR&TI Annual Report [2009]) Treatments Runoff (mm) Soil Loss (ton ha−1 ) Sorghum Chickpea Sorghum Chickpea 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 0.5 1.0 2.0 Slope (%) With fertilizer 52.3 66.78 94.8 48.71 64.45 84.56 2.45 4.04 5.67 2.01 2.72 4.79 Without fertilizer 63.16 66.85 101.79 49.06 65.64 92.99 2.72 4.79 6.08 2.19 3.31 5.35
  47. 47. 1/10/2017 47 Year Rainfall (mm) Runoff (mm) Soil Loss (ton ha-1 ) BBF FOG BBF FOG 2003 1058.0 163.0 (15.4%) 214.9 (20.3%) 2.0 2.9 2004 798.2 124.0 (15.5%) 183.3 (23.0%) 0.7 1.5 2005 946.0 177 (18.7%) 246 (26.1%) 1.4 3.1 2006 1513.0 502 (33.2%) 873 (57.7%) 3.5 6.4 Table 9: Seasonal rainfall, runoff and soil loss from different land configuration, broad-bed and furrow (BBF) and flat on grade (FOG) Note: Values within parentheses indicate the percent of total rainfall [Data source: Mandal et al. (2013)]
  48. 48. 1/10/2017 48 Table 10. Ameliorative effects of tree plantation on salt affected soils of India Region Tree Species Soil Depth (cm) Original After References pH EC (dSm−1) pH EC (dSm−1) Karnataka Acacia nilotica (Babul) (age 10 years) 0–15 9.2 3.73 7.9 2.05 Basavaraja et al. [2010] Karnal Eucalyptus tereticornis (age 9 years) 0–10 10.06 1.90 8.02 0.63 Mishra et al. [2003] Lucknow and Bahraich in north India Terminalia arjuna (Arjun) 0–15 9.60 ±0.42 1.47±0.45 8.40±0.27 0.31±0.07 Singh and Kaur [2012] Prosopis juliflora (Kikar) 8.70±0.33 0.42±0.06 Tectona grandis (Teak) 6.15±0.23 0.06±0.006
  49. 49. 1/10/2017 49 Fig. Impacts of conservation agriculture (CA) on soil aggregation in the 0–5 cm layer in the upper IGP (Source: Bhattacharyya et al. [2013])
  50. 50. 1/10/2017 50 Patchwork ploughing: Australian farmer creates huge geometric artwork to fight soil erosion
  51. 51. 1/10/2017 51 Contour Trenches in Himalayan region
  52. 52. 1/10/2017 52  Appropriate mitigation strategies of the nearly 147 Mha of existing degraded land in the sub-continent of India are of the utmost importance  With changing climate, land degradation is expected to only increase due to high intensity storms, extensive dry spells, and denudation of forest cover.  Combating further land degradation and investing in soil conservation is a major task involving promotion of sustainable development and nature conservation  Sustainable agricultural intensification using innovative farming practices have tremendous potential of increasing productivity and conserving natural resources, particularly by sequestering SOC and improving soil quality.  Novel CA practices include: permanent broad bed with residue retention under maize/cotton/pigeon pea-wheat cropping systems and seasonal tillage alterations under rainfed and rice-based agro-ecosystems.
  53. 53. 1/10/2017 53  For sure, the non-edible (to animals) agricultural residues must not be burnt and should be used for mulching along with growing of cover crops, preferably legumes.  Improved grazing practices, irrigation management, control on urban sprawl and control and management on mining are a few other solutions for preventing land degradation.  Domestic and municipal wastes, sludges, pesticides, industrial wastes, etc. need to be used if possible to close nutrient cycles, but with caution to avoid the possibility of soil pollution.  Future research should focus on enhancing nutrient and water use efficiencies and reduction in the pesticide use under CA.  A well-defined integrated land use policy to include rural fuelwood and fodder grazing is urgently needed at the implementation level Cont......
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