Widespread global land degradation affects over 2 billion hectares and supports around 1.5 billion people. Soil chemical degradation like nutrient loss accounts for over 40% of cropland degradation. Drylands, which comprise 40% of the world's total land area, have 47% of their rainfed cropland degraded. Watershed management and soil test-based fertilization have led to yield increases of 20-70% and have reduced soil loss. Increasing soil organic carbon can boost crop yields and enhance food production in developing countries by 30-50 million tons per year. Reversing land degradation through improved soil management practices is crucial for food security.

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