Improving Soil Fertility and Nutrient Management in Developing Countries

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Fertilizer use and crop production worldwide,Green revolution & fertilizer,Soil organic matter build-up & fertilizer,Fertilizers and the environment,Soil Fertility in Asia,Soil Fertility in Africa,Future needs for research and outreach

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Improving Soil Fertility and Nutrient Management in Developing Countries

  1. 1. Improving Soil Fertility and Nutrient Management in Developing Countries K.F. BronsonTexas A&M and Texas Tech University
  2. 2. Outline• World fertilizer consumption/crop production – 1961-2002/malnutrition• Green revolution & fertilizer• Soil organic matter build-up & fertilizer• Fertilizers and the environment• Nut mgt in Asia -- Central Asia -- South Asia -- SE Asia• Nut mgt in Africa -- West Africa• Future needs for research and outreach
  3. 3. Fertilizer use and cropproduction worldwide
  4. 4. World cereal production and total fertilizer 2500 160 consumption, 1961-2002 (FAOSTAT) 140 2000 Fertilizer consumption (mill Mt) 120 Cereral production (mill Mt) 100 1500 80 Cereal production 1000 Fertilizer consumption 60 40 500 20 0 0 1961 1964 1967 1970 1973 1976 1979 1982 1985 1988 1991 1994 1997 2000Africa is an exception Year
  5. 5. Productionper capitaandProductionArea percapita
  6. 6. Percent of population malnourished for 1990-2001 45 40 35Percent of pop undernourished 30 1990-1992 25 1999-2001 20 15 10 5 0 Devg Asia India Bang China Indo Sub-Africa Niger Mali S.A. Brazil Colum Countries
  7. 7. Calories/person/day for 1990-2001 3500 3000 1990-1992 1999-2001 2500 Calories/person/day 2000 1500 1000 500 0 Devg Asia India Bang China Indo Sub-Africa Niger Mali S.A. Brazil Colum CountriesNote: World avg 2700-2800 cal, USA avg 3500-3800 cal
  8. 8. Fertilizer and the green revolution
  9. 9. Response of tall, traditional rice and semi-dwarf rice to N fertilizer, Philippines, 1968 10.00 9.00 8.00 7.00Grain yield (t/ha) 6.00 5.00 Tall, native variety IR8 4.00 3.00 2.00 1.00 0.00 0 20 40 60 80 100 120 Nitrogen rate (kg/ha)
  10. 10. “African Exception” (Avery, 2000)• Africa has been low population with low input/low yield bush fallow. 25 % good cropland not used• Green revolution efforts targeted Asia, were not transferable to Africa• Poor record keeping• Poor governance
  11. 11. Why hasn’t the green revolution been successful in Africa? (Evenson&Gollin)• No elite germplasm for cassava, beans sorghum, millet• Crops are more diverse & mostly dryland• Large landholdings for cash crops
  12. 12. Fertilizer and soil organic matter
  13. 13. Total soil organic C and total soil N in 0-15 cmInceptisol after 30 yr of rice-wheat-jute cropping, West Bengal, India (Manna et al., 2006) Nutrient Total organic C Total N management g/kg mg/kg Control 5.1 c 422 f N 5.7 d 660 d NP 6.3 c 750 c NPK 7.4 b 867 b NPK + FYM 7.9 a 927 a
  14. 14. Crop residue removal
  15. 15. Advantages of organic manures• Boost yields, retard yield declines• Provide N, P, micronutrients• Fortify seeds with micronutrients• Build-up soil organic matter• Improve soil physical properties• Improve soil water relations
  16. 16. Limitations of organic manures• Availability/transport costs• Nutrient imbalance (i.e. manure is about 2:1 N:P2O5, plants need 5-7:1 N:P2O5)• Variability in composition• Potential for polluting surface waters• Limited nutrient availability in 1st year• Pathogens
  17. 17. Fertilizer and the environment
  18. 18. Nitrous oxide fluxes in irrigated rice as affected by N fertilizer source and mid-season drainage, 4 Los Banos, Philippines, 1993 dry season. 3.5 3 2.5N2O (mg N/m2/d) 2 1.5 Urea Ammonium sulfate 1 0.5 0 0 20 40 60 80 100 120 -0.5 Days after transplanting
  19. 19. Methane fluxes in irrigated rice as affected by N fertilizer source and mid-season drainage, Los Banos, Philippines, 1993 dry season. 40 35 30CH4 flux (mg C/m2/d) 25 20 Urea Ammonium sulfate 15 10 5 0 0 20 40 60 80 100 120 -5 Days after transplanting
  20. 20. Cadmium content of phosphate rock mg /kg mg/kg P2O5 Igneous Deposits South Africa 1 3 Former USSR 1 3 Sedimentary Deposits China 2 7 Morocco 26 80 Senegal 87 241 North Florida 6 20 North Carolina 38 128 Western US 92 292
  21. 21. Other environmental issues• Eutrophication of surface waters• Nitrate contamination of surface and ground waters• Arsenic contamination of groundwater• Aral Sea crisis
  22. 22. Soil Fertility in Asia
  23. 23. Fertilizer use and grain production in India 160 20 18 140Rice and wheat production (milln Mt) 16 Fertilizer cionsuption (milln Mt) 120 14 100 12 80 10 8 60 6 40 Rice production Wheat production 4 20 Fertilizer consumption 2 0 0 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 19 20 20 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 01 03 Year
  24. 24. Chlorophyll meter and leaf color chart for in- season N monitoring in Asia
  25. 25. Rice grain yields as affected by chlorophyll meter-based management, Ludhiana, India, 1997N Total N Cultivarmanagement applied kg N/ ha PR-106 PR-111 ---------- Mg ha-1 -----------Well-fertilized 240 5.80 a 7.02 areferenceChlorophyll 90 6.08 a 6.51 ameter-basedFixed-timing 120 6.14 a 6.54 aZero-control 0 4.42 b 4.72 b
  26. 26. Urea and singlesuperphosphate fertilization in Eastern Uzbekistan
  27. 27. Uzbek farmers fertilization survey• What is your cotton seeding rate (kg/ha)? 60• What is your seedcotton yield goal (t/ha)? 2.9• How much total urea do you apply (kg/ha)? 488• How much superphosphate do you apply (kg/ha)? 421• How much potash do you apply (kg/ha)? 32
  28. 28. Uzbek farmers’ survey for wheat• What is your wheat seeding rate (kg/ha)? 250• What is your yield goal (t/ha) ? 4.3• How much urea do you apply (kg/ha)? 452• How much superphosphate do you apply (kg/ha)? 419• How much potash do you apply (kg/ha)? 3• How often is your soil sampled and tested at the local lab? No (100%)
  29. 29. Soil test results from three districts in Ferghana valley, March, 2003 Quva (11) Bagdod (12) Okhunboboev (12) Low Med High Low Med High Low Med HighNitrate 100% 100% 66% 34%P 55% 45% 100% 34% 34% 34%K 18% 82% 100% 100%1:1 pH 7.7 (0.4) 8.1 (0.2) 8.0 (0.2)ECa 6.0 (0.6) 2.0 (0.2) 1.8 (0.3)(mmo/cm)a irrigation water
  30. 30. Establishment of N and P fertilizer rate trials in 2005• Three locations (Quva, Ristan, and Bagdod)• Soil tests (LaMotte) done 0-15 cm• RCB design, N x P factorial, three reps• Plot size 15 M x 8 (0.09 m rows)• Urea-N rates of 0, 80, 160, and 240 kg N/ha• Single superphosphate rates of 0, 45, and 90 kg P2O5/ha
  31. 31. Nutrient managementrecommendations forUzbekistan• Farmers are applying ~ 2 X the N and P fertilizer needed for the yield levels.• Fertilizer timing can probably be simplified. Phosphorus can be applied just once, pre- plant. Urea applications might be reduced to two splits (pre-plant and squaring).• Recommend N and P fertilizer rate trials.
  32. 32. Soil Fertility inAfghanistan • Soil pH ranges from 7.5-8.8 (Mean 8.2) • CaCO3 ranges 3-42% (Mean 23%) • Phosphorus and deficiencies are widespread. • 46 % soils < 10 ppm Olsen-P • 66 % soils < 0.5 ppm DTPA-Zn • Potassium is generally adequate
  33. 33. Fertilizer use• Only on irrigated fields, mainly wheat• Average of 152 kg diammonium phosphate (18-46-0) (27 kg N/ha, 70 kg P2O5/ha)• Average of 150 kg urea/ha (70 kg N/ha) in two splits• Infrequent response – reasons?• Little manuring
  34. 34. Cereal production in Afghanistan, 1964-2003 (FAO, 2003)
  35. 35. Challenges for future of agriculture in Afghanistan – Soil & Crop Mgt• Cash crop replacement for opium poppy• Research no-till wheat for dryland• Inexpensive implements to band P fertilizer• Access to Zn fertilizer• Rebuild cotton gins for cotton production• Training of agric. Scientists (undergraduate and graduate level)
  36. 36. Soil Fertility in Africa
  37. 37. Productionper capitaandProductionArea percapita
  38. 38. Agronomically, what has changed in 40-50 years?• SoilP levels have probably decreased overall if~5 kg P/ha is removed per year•Expansion into more marginal lands•Yield has decreased•Fallow frequency and duration have decreased•Other problems associated with land degradation,e.g. soil crusting, wind and water erosion, etc.,increase.
  39. 39. Soil nutrient depletionin Africa,Smaling et al., 1997
  40. 40. Consumption, production, export, and import of mineral fertilizer in Sub-Saharan Africa 1988-1999 (IFDC Website) 1988/89: 1,182,000 mt 1998/1999: 1,282,000 mt Totals for 1990- 1991- 1992- 1993- 1994- 1995- 1996- 1997- 1998- 1999- 2000- Sub-Saharan 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 Africa (x 1000 mt N + P2O5+K2O) Consumption 1246 1267 1287 1341 1212 1073 1305 1252 1232 1303 1230 Production 547 543 573 539 376 348 327 272 314 296 167 Exports 207 190 179 171 134 110 95 117 157 103 83 Imports 1058 933 1096 1090 1026 827 1216 1162 1160 1146 1164Despite recognition of acute P and other nutrient deficiencies for ~ 50 y, no realsign of progress in fertilizer consumption
  41. 41. Improving Crop Production under low soil P fertility• Regional Phosphate Rock• Partially acidulated PR• Water soluble P fertilizers (SSP, TSP) -- Regional SSP/TSP production -- Import SSP/TSP/DAP• Genetic Approach• Agroforestry/VAM
  42. 42. Geologic IronyBationo,Christianson, andMokwunye, 1989.
  43. 43. Grain yields as affected by Kodjari phosphate rock (PR) and TSP, Burkina Faso (Frederick et al., 1992) Millet Sorghum MaizePhosphorus ------------------------ kg/ha -------------------------TreatmentsControl 596 916 2219PR 698 (68) 1006 (39) 2464 (35)PAPR 728 (88) 1103 (81) 2839 (88)TSP 745 1146 2919RAE (relative agronomic effectiveness are in parentheses)
  44. 44. Grain and seedcotton yields as affected by Tilemsi phosphate rock (PR) and SSP, Mali, 1989-1992 (Bationo et al., 1997) SSP Tilemsi PRSougoumba ------------- kg/ha ---------------Sorghum 1.43 (11)a 1.52 (27)aCotton 1.42 (33) 1.39 (55)TinfoungaMaize 2.61 (22) 2.26 (27)Cotton 1.61 (33) 1.41 (55) aP source rates in kg P/ha/yr are in parentheses
  45. 45. Agroforestry Faidherbia albidaAfrican winterthorn/Mimosa –VAM&Bradyrhizobium
  46. 46. Soil available P as affected by distance from Faidherbia albida 30 Payne et al Crop Soil depthBRAY I P (mg kg-1) Sci. 38:1585-1591. 20 100 cm 50 20 10 0 0 5 10 15 DISTANCE (m)
  47. 47. Needs for soil fertilityresearch/education/capacity building
  48. 48. Research/extension education/capacity building needs for improving soil fertility & nutrient management• India/South Asia – More balanced fertilization, more manure and residue• Afghanistan – Cotton, hort crops, P, micronutrients• Uzbekistan – more efficient irrig., rationalize N and P, i.e. less application/more for export• Southeast Asia – improve NUE in rice w/LCCs, urea briquettes, green manures, P, animal manure• West Africa – PAPR, N, lime, HYVs, animal waste• Training of agric. Scientists (undergraduate, graduate/post-docs/visiting)

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