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Eco efficiency of Integrated Soil Fertility Management in Western Kenya Sommer et al 2014 presented at 20th World Congress of Soil Science

Eco efficiency of Integrated Soil Fertility Management in Western Kenya Sommer et al 2014 presented at 20th World Congress of Soil Science

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  • All percentages relate to the total emission worldwide. The data for Land Use Change are subject to significant uncertainties.

Eco efficiency of Integrated Soil Fertility Management in Western Kenya Sommer et al 2014 Presentation Transcript

  • 1. Rolf Sommer, John Mukalama, Job Kihara, Saidou Koala, Leigh Winowiecki and Deborah Bossio www.ciat.cgiar.org Eco-efficiency of integrated soil fertility management in Western Kenya
  • 2. What is eco-efficient agriculture? “Eco-efficient agriculture increases productivity while reducing negative environmental impacts. Eco-efficient agriculture meets economic, social, and environmental needs of the rural poor by being profitable, competitive, sustainable, and resilient. …, and generate benefits for the poor…taking into account the particular needs of women.” (CIAT Medium-Term Plan, 2009)
  • 3. Why is it important? • The need to feed a growing population and to improve the livelihoods of smallholder farmers • Gender equity / mainstreaming • Conservation of the natural resource basis • Adaptation to /mitigation of climate change  "More with less!"
  • 4. The need to feed a growing population • By 2050 the world’s population will reach 9.1 billion, 34 % higher than today. • About 70 % of the world’s population will be urban • In order to feed this larger, more urban and richer population, food production must increase by 70 %. • Annual cereal production will need to rise from 2.1 billion today to about 3 billion tons • Annual meat production will need to rise by over 200 million tons to reach 470 million tons. (FAO, 2009)
  • 5. Conservation of the environment • Maximizing the efficiency of inputs while minimizing their detrimental impact
  • 6. Nitrogen fertilizer use in sub-Saharan Africa 259 7.8 50 100 150 200 250 300 0 1960 1980 2000 Nfertilizerconsumption(kg/ha) China (1.26 M km²)* Sub-Saharan Africa (2.21 M km²)* *Arable land and Permanent crops (FAO data for 2010) Source: IFASTAT 2014
  • 7. Source: EcoFys 2013 World GHG emissions flow chart – data for year 2010 Nitrous oxide emissions – contribution to global warming Approximately 75 % of N2O emissions are from soils = 5 % of the global total GHG emissions Africa's share of the soil-related N2O emissions is ~30 % = 1.5 % of the total GHG emissions
  • 8. 22% 13% 7.0% 4.7% 4.2% 3.6% 2.4% 1.8% 1.7% 1.5% 1.4% 1.4% 1.3% 1.2% 1.2% 1.1% 1.1% 1.0% 0.98% 0.97% 0.96% 0.86% 0% 5% 10% 15% 20% 25% China USA India Russian Federation Indonesia Brazil Japan Canada Germany Iran, Islamic Rep. Mexico Australia United Kingdom Korea, Rep. South Africa France Saudi Arabia Pakistan Thailand Argentina Italy Malaysia Why bother? – because every bit counts Country contribution to total GHG emissions
  • 9. Adaptation & mitigation of climate change • Climate smart agriculture – increased production – increased system resilience – reduced greenhouse gas emissions • year-2030 aspirational mitigation targets to meet the +2 °C goal: "The agricultural sector needs to achieve emission reductions of about 600 Mt CO2eq./yr from 2010 to 2030 to achieve this target and avoid dangerous climate change." (CCAFS, 2014)
  • 10. Eco-efficient agriculture in Africa • Integrated Soil Fertility Management (ISFM) – stepwise adoption – maximize fertilizer and organic resource use efficiency and crop productivity – include appropriate fertilizer and organic input management in combination with improved germplasm Resourceuseefficiency Responsive soil Poor, less responsive soil Germplasm & Fertilizer Germplasm & Fertilizer + Organic resource mgmt. Germplasm & Fertilizer + Organic resource mgmt. + Local adaptation Movement towards resource integration ISFM Current practice • The long-term sustainability / eco-efficiency of ISFM has not been studied in great depth
  • 11. CIAT ISFM long-term trial in West Kenya ("INM3") • Since 2004 • Near the village of Madeya, 50 km northwest of Kisumu • Humid tropical climate, at 1331 m above sea level • Acric Ferralsol (>70 % clay, low CEC, pH 4.9-5.5, topsoil SOM 3.4 %) • Each year has a long- and a short-rainy season • Test the impact of: – Application of farm yard manure (FYM) – Maize stover residue retention – Maize mono-cropping vs. intercropping (with soybean) and maize- rotation with Tephrosia candida – various levels of N and P fertilizer application • split-split-split plot design
  • 12. Maize yields • Average and standard deviation of all plots 0 2 4 6 8 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Maizeyield(Mg/ha) Year
  • 13. Maize yields by treatments • significant effect of FYM application min. rep max-min max. rep LSD 0 1 2 3 4 5 6 Intercr M-M M-T Intercr M-M M-T Intercr M-M M-T Intercr M-M M-T R- R+ R- R+ Minus FYM Plus FYM Maizeyield(Mg/ha) N0_P0 N0_P60 N30_P60 N60_P60 N90_P60
  • 14. Maize yields by treatments • significant effect of P-fertilizer application – less though when FYM is applied min. rep max-min max. rep LSD 0 1 2 3 4 5 6 Intercr M-M M-T Intercr M-M M-T Intercr M-M M-T Intercr M-M M-T R- R+ R- R+ Minus FYM Plus FYM Maizeyield(Mg/ha) N0_P0 N0_P60 N30_P60 N60_P60 N90_P60
  • 15. Maize yields by treatments • N-fertilizer application above 30 kg/ha has no significant effect min. rep max-min max. rep LSD 0 1 2 3 4 5 6 Intercr M-M M-T Intercr M-M M-T Intercr M-M M-T Intercr M-M M-T R- R+ R- R+ Minus FYM Plus FYM Maizeyield(Mg/ha) N0_P0 N0_P60 N30_P60 N60_P60 N90_P60
  • 16. Maize yields by treatments • highest maize grain yields per season under M-T rotation; but not high enough to match maize double-cropping annual yields min. rep max-min max. rep LSD 0 1 2 3 4 5 6 Intercr M-M M-T Intercr M-M M-T Intercr M-M M-T Intercr M-M M-T R- R+ R- R+ Minus FYM Plus FYM Maizeyield(Mg/ha) N0_P0 N0_P60 N30_P60 N60_P60 N90_P60
  • 17. In-depth studies on eco-efficiency Goals: • assess the eco-efficiency of current farmers practices and ISFM as a potential climate smart, eco-efficient farm intensification option; – quantify the GHG footprint / climate change mitigation potential of these systems; – Crop modeling (CropSyst) of N-dynamics • describe tradeoffs between eco- efficiency, climate change mitigation potential and food security needs
  • 18. In-depths studies on eco-efficiency Rotation FYM application Maize stover retention N-fertili- zation (kg/ha) P-fertili- zation (kg/ha) Description M-M + - 0 60 resource-poor livestock farmer T-M + + 30 60 best-bet ISFM T-M - - 0 0 no fertilizer M-M - + 90 60 intensive maize farmer Selected treatments
  • 19. Simulation results: yield and biomass 0 2 4 6 8 10 12 14 N0 N0 N90 N30 T-M M-M M-M T-M R- R- R+ R+ Minus FYM Plus FYM Minus FYM Plus FYM Mg/ha Observed Yield Simulated Yield Observed AGB Simulated AGB
  • 20. 0 0.1 0.2 0.3 0.4 0.5 0.6 0 50 100 150 200 250 300 01/Sep/13 01/Oct/13 31/Oct/13 30/Nov/13 30/Dec/13 Soilmoisture(m/m) N2Oflxu(gN/ha/d) N2O flux, simulated observed Soil moisture, 0-14 cm 0 0.1 0.2 0.3 0.4 0.5 0.6 0 50 100 150 200 250 300 01/Sep/13 01/Oct/13 31/Oct/13 30/Nov/13 30/Dec/13 Soilmoisture(m/m) N2Oflxu(gN/ha/d) N2O flux, simulated observed Soil moisture, 0-14 cm 0 0.1 0.2 0.3 0.4 0.5 0.6 0 50 100 150 200 250 300 01/Sep/13 01/Oct/13 31/Oct/13 30/Nov/13 30/Dec/13 Soilmoisture(m/m) N2Oflxu(gN/ha/d) N2O flux, simulated observed Soil moisture, 0-14 cm 0 0.1 0.2 0.3 0.4 0.5 0.6 0 50 100 150 200 250 300 01/Sep/13 01/Oct/13 31/Oct/13 30/Nov/13 30/Dec/13 Soilmoisture(m/m) N2Oflxu(gN/ha/d) N2O flux, simulated observed Soil moisture, 0-14 cm Plus FYM, R-, M-M, N0 Plus FYM, R+, T-M, N30 Minus FYM, R-, T-M, N0 Minus FYM, R+, M-M, N90 Simulation results: N2O fluxes 0 0.1 0.2 0.3 0.4 0.5 0.6 0 50 100 150 200 250 300 01/Sep/13 01/Oct/13 31/Oct/13 30/Nov/13 30/Dec/13 Soilmoisture(m/m) N2Oflxu(gN/ha/d) N2O flux, simulated observed Soil moisture, 0-14 cm
  • 21. Simulation results: N2O fluxes and N-uptake 0 50 100 150 0 1 2 3 4 5 6 7 17 70 106 162 N-uptakeIkg/ha) N2Oemission(kgN/ha/season) Total N applied (kg/ha) • Total N applied to the system does not explain well N2O emissions! Minus FYM Plus FYM Minus FYM Plus FYM R- R- R+ R+ T-M M-M M-M T-M N0 N0 N90 N30
  • 22. N-balance (short rainy season 2013) FYM Minus FYM Plus FYM Minus FYM Plus FYM Maize stover retention R- R- R+ R+ Rotation T-M M-M M-M T-M N & P level N0, P0 N0, P60 N90, P60 N30, P60 Total N uptake (kg N/ha) 81 94 154 108 N-conc. AGB (%) 1.67 1.00 1.83 0.99 N2O emissions (kg N/ha) 2.2 5.7 3.4 2.9 N-leaching (kg/ha) 3.2 2.9 3.2 2.9 Fertilizer N (kg/ha) 0 0 90 30 Organic N (kg/ha) 17 70 16 132 Total N applied (kg/ha) 17 70 106 162 Loss of applied N as N2O 12.7% 8.2% 3.2% 1.8% N-balance (kg/ha) -64 -24 -61 49 Apparent N-recovery 4.6 1.3 1.5 0.7 kg crop yield per kg nutrient applied 116 59 37 30
  • 23. 0 4 8 Long-term dynamics 0 5 10 15 20 LR SR LR SR LR SR LR SR LR SR LR SR LR SR LR SR LR SR LR SR 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 Mg/ha Plus FYM, R-, M-M, N0 YIELD simulated AGB simulated 130 135 140 145 150 1/1/04 1/1/05 1/1/06 1/1/07 1/1/08 1/1/09 1/1/10 1/1/11 1/1/12 1/1/13 1/1/14 MgC/ha SOC, 0-1.1 m N2O losses (kg N/ha)
  • 24. Preliminary conclusions • Negative N-balance in three out four tested treatments • Observed and simulated SOM depletion  FYM application alone is not a guaranty for sustainability • "Chaotic" N2O fluxes – does Tephrosia application reduce emissions? (Further research required!) • Eco-efficiency assessment also requires consideration of tradeoffs (e.g. loss of annual maize yields with inclusion of green manure cover crop)
  • 25. Thank you!