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Asia Regional Program Planning Meeting- Climate Change Impacts in Asia,Presentation by Dr Girish Chander: increasing-land-degradation

  1. Increasing Land Degradation Girish Chander, Suhas P Wani and Team/ Asia Regional Planning Meeting/ ICRISAT-Patancheru/04 May 2016)
  2. Widespread global land degradation ! • Land degradation - a temporary or permanent decline in the productive capacity of the land, or its potential for environmental management. • 2 billion ha (22.5%) out of 8.7 billion ha degraded; support ~1.5 billion people • Cost of land degradation – 300 billion USD per annum • Causes - Water & wind erosion, nutrient and or soil organic C depletion, waterlogging, compaction, salinization, acidification, pollution. • Soil chemical degradation like nutrient-loss accounts for >40% of cropland degradation. 1475 3212 4048 562 685 719 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Agricultural Land Permanent Pasture Forest and Woodland Millionhectares Million ha Total Land Degraded Land [38%] [18%][21%] 330 66 781 550 929 553206 121 197 243 344 130 0 200 400 600 800 1000 1200 1400 Agricultural Land - Asia Agricultural Land - Africa Permanent Pasture - Asia Permanent Pasture - Africa Forest & Woodland - Asia Forest & Woodland - Africa Million ha Non-Degraded Land Degraded Land [38%] [19%] [27%] [31%] [20%] [65%] A global perspective A regional perspective
  3. Land degradation in ‘Drylands’ • Drylands (arid, semi-arid, sub-humid) - 40% of world total land • 47% of rainfed cropland degraded • People affected – 40% of world population living in Drylands; ~1400 million (42% of region population) in Asia; ~270 million (41%) in Africa Drylands in the world
  4. Land Degradation & Implications 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Zambia Tanzania Kenya Uganda Ethiopia BurkinaFaso Niger Botswana Zimbabwe Vietnam Thailand India Iran Iraq Jordan Morocco Pakistan Syria Yemen Observed Yield Gap between Farmers’ Yield and Achievable Yields Long-term experiment at ICRISAT: Large untapped potential Provisioning services • Food, fibre, fuel supply • Productivity losses due to land degradation in drylands = US$13 billion to $28 billion year-1 Regulating services • Climate regulation (CO2, CH4, N2O emissions) • Water quality (Filtering, buffering substances) • Water supply (Infiltration, drainage) Supporting services • Primary production (medium for root growth) • Nutrient cycling (transformation of organic materials, retention/release of nutrients) Cultural services • Landscape diversity
  5. Nutrient mining or imbalances • Globally, chemical soil degradation mainly soil nutrient loss accounts for more than 40 percent of cropland degradation. • Infertile soils a major contributor to the yield gap. • Bhoochetana, watersheds findings on soil health mapping based management – 20%-70% yield increase, 3 – 14 : 1 B:C ratios for farmers. State % deficiency w.r.t. available nutrients in India N* P K S B Zn Karnataka 52 41 23 52 62 55 Andhra Pradesh 76 38 12 79 85 69 Madhya Pradesh 22 74 1 74 79 66 Rajasthan 38 45 15 71 56 46 Tamil Nadu 57 51 24 71 89 61 Jharkhand (Gumla) 33 23 27 100 93 73 Jharkhand (Saraikela) 45 80 58 69 98 71 *Deduced from % low levels of soil organic carbon; Organic C, Karnataka
  6. • Currently stresses in the nitrogen cycle, climate change are beyond safe operating ‘planetary boundaries’. Land management & N use efficiency NUpE (Nitrogen uptake efficiency) = Total plant N uptake/N supply [N-supply means sum of N applied as fertilizer and total N uptake in control] NUtE (N utilization efficiency) = Grain yield/Total plant N uptake; NUE (N use efficiency) = Grain yield/N supply; NHI (N harvest index) = N in grain/Total N uptake Treatment NUpE NUtE NUE NHI (kg kg-1 ) (kg kg-1 ) (kg kg-1 ) (%) NP 0.37 80.7 30.1 67 NP+SBZn-(every yr) 0.46 78.5 36 61 NP+50%SBZn-(every yr) 0.51 92.5 47.3 66 NP+SBZn-(once in 2 yr) 0.47 84.4 39.7 69 NP+50%SBZn-(once in2 yr) 0.42 80.8 34.1 67 LSD (5%) 0.11 17.4 8.85 11 Soil need based management at ICRISAT, Patancheru, Maize crop, rainy season 2010
  7. Watershed catchment management Year Rainfall Runoff Soil loss (mm) (mm) (t ha -1 ) Untreated Treated Untreated Treated CommunityWatershed Kothapally 2000 1161 118 65 4.17 1.46 2001 612 31 22 1.48 0.51 2002 464 13 Nil 0.18 Nil 2003 689 76 44 3.2 1.1 2004 667 126 39 3.53 0.53 2005 899 107 66 2.82 1.2 2006 715 110 75 2.47 1.56 2007 841 115 82 4.5 2.09 2008 1387 281 187 8.94 4.5 Mean 802 99.3 72.5 3.48 1.62 ICRISAT, Patancheru Mean ~800 220 91 6.64 1.60 • 114 M ha degraded lands in India – water erosion & Vegetal degradation with water erosion major factor • Watershed management is one of the most trusted and eco-friendly approaches to managing soil and rainwater resources • Reduced soil loss
  8. Soil & Carbon-cycle Biota 600 Pg C Atmosphere 750 Pg C Soil (to 2-m depth) 2500 Pg C (billion tons) 100 Pg Yr-1 100 Pg Yr-1 Respiration Photosynthesis • Climate change - more people and larger areas of land in drylands to be affected • A global loss of 70 to 90 billion tons C through land misuse and soil degradation • 2.1 billion t C year-1 global potential of C-sequestration in soil • 10% increase in soil organic C pool in world soils over the 21st century implies a drawdown of about 110 ppm of atmospheric CO2
  9. Depleted soil organic C 57 24 61 66 49 43 17 45 35 11 43 39 56 43 76 39 34 51 57 83 55 65 89 57 61 44 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% SoilorgCinpilots,AP Sufficient Deficient Soil org C in pilots in AP Low levels of soil organic C – major stumbling block for enhancing productivity and livelihoods
  10. Soil Management & C-Sequestration  Additional 7.3 t C ha-1 (335 kg C ha-1 yr-1) sequestered under IM over 24- year period  CaCO3 content of IM decreased from 6.2 % under FM system to 5.7 %  C inputs increased with continuous cropping and soil test-based balanced fertilizers application and when legumes were included Properties System Soil depth (cm) 0 to 60 60 to 120 Organic C (t C ha-1 ) Improved 27.4 19.4 Traditional 21.4 18.1 Long term study at ICRISAT  An increase of 1 ton of soil carbon pool of degraded cropland soils may increase crop yield by 200 to 400 kg ha-1 for maize, 20 to 70 kg ha-1 for wheat, 20 to 30 kg ha-1 for soybean, 5 to 10 kg ha-1 for cowpeas, 10 to 50 kg ha-1 for rice, 50 to 60 kg ha-1 for millets and 20 to 30 kg ha-1 for beans.  An increase in the soil organic C pool within the root zone by 1 t C ha-1 year-1 can enhance food production in developing countries by 30 to 50 Mt year-1.
  11. Management for Soil Health Properties System Soil depth (cm) 0 to 60 60 to 120 Microbial biomass C (kg C ha-1 ) Improved 2676 2137 Traditional 1462 1088 Organic C (t C ha-1 ) Improved 27.4 19.4 Traditional 21.4 18.1 Microbial biomass N (kg N ha-1 ) Improved 86.4 39.2 Traditional 42.1 25.8 Total N (kg N ha-1 ) Improved 2684 1928 Traditional 2276 1884 Olsen-P (kg P ha-1 ) Improved 6.1 1.6 Traditional 1.5 1  Soil microbial biomass C serves as a surrogate for soil quality  Soil microbial biomass C responds more rapidly than soil organic C to changes in management  Higher (10.3 vs. 6.4%) biomass C as a proportion of soil organic C (up to 120 cm soil depth) under improved management  Biomass N comprised about 2.6% of total soil N in the improved system, whereas in the traditional system it constituted only 1.6%. Long term study at ICRISAT
  12. • Best entry point activity for harnessing low hanging fruits – Bhoochetana (Karnataka, AP), watersheds - >7 million ha; 5million families. • Use of microbial consortia and earthworms for enriched composts for soil C-building and to cut cost of chemical fertilizers • Cultivating post-rainy fallows – Jharkhand example of cultivating chickpea (KAK-2; JG-11) (1520-1340 kg ha-1 yield) • Cultivating rainy fallows – MP example of cultivating soybean (1400-2500 kg ha-1 yield) • For exploiting varietal potential – Rajasthan case: 40% increase with var but 140% with var+BN • Shifting to high value agriculture – Karnataka case, 2011: Rs 20000- 50000 additional returns with BN • Enhancing rainwater use efficiency – soybean in MP, 2010: 1.48-3.45 kg mm-1 ha-1 improved to 2.07-4.38 under INM. • Resilience-building - Benefits of balanced fertilization particularly micronutrients observed in 3 succeeding seasons in crop yields • Soil Test-Based Fertilization for Nutrition and Produce Quality Scaling-out/up land rejuvenation in drylands
  13. Conclusions & Way Forward • Minimize further degradation of soils and restore the productivity of soils that are already degraded in regions where people are most vulnerable • Stabilize global stores of soil organic carbon and soil organisms • Stabilize or reduce global use of nitrogen and phosphorus fertilizer, while increasing fertilizer use in regions of nutrient deficiency • Improve our knowledge about the state and trend of soil conditions o “Soils are the foundation of food production and food security, supplying plants with nutrients, water, and support for their roots. o Soils function as Earth’s largest water filter and storage tank; o Soils contain more carbon than all above-ground vegetation & atmosphere, hence regulating emissions of carbon dioxide and other greenhouse gases; o Soils host a tremendous diversity of organisms of key importance to ecosystem processes.”
  14. Thank you! ICRISAT is a member of the CGIAR Consortium
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