Increasing and Sustaining Dryland Agricultural Productivity in Africa: Challenges, Experiences, Principles

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Presentation by Mike McGahuey (Sustainable Agriculture and Natural Resources Management Advisor, USAID) and Jerry Glover (Senior Sustainable Agricultural Systems Advisor, USAID) at the May 15, 2013 event "Natural Resource Management and Food Security for a Growing Population". For more information visit: http://www.wri.org/event/2013/05/natural-resource-management-and-food-security-growing-population

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Increasing and Sustaining Dryland Agricultural Productivity in Africa: Challenges, Experiences, Principles

  1. 1. Increasing and Sustaining Dryland Agricultural Productivity In Africa Challenges, Experiences, Principles World Resources Institute Roundtable May 15, 2013 Mike McGahuey and Jerry Glover, USAID
  2. 2. Agricultrual Productivity: Drivers of Progress • Where have yields increased and to what degree? • Where has resilience been strengthened? • What problems did they overcome? • What practices and principles did they use?
  3. 3. Key Challenges: Low Rainfall-use Efficiency • “(Experts) estimate that only 10–15% of the rainfall is used by the vegetation.”* • Rainfall Characteristics – Intensive rainfall events « 25-50% runoff rates** – Long intervals between events « Frequent need to replant « Shortened Season – Periodic droughts « Crop failure for annual staples *Doumbia, M. (2008) Sequestration of organic carbon in West African soils by Aménagement en Courbes de Niveau Agron. Sustain. Dev., 2008 **Stroosnijderi, L., & Hoogmoed, W. (1984). Crust formation on sandy soils in the Sahel, Il Tillage and its effect on the water balance. Soil & Tillage Research, 4, 321-337.
  4. 4. Key Challenges: Weathered Soils and Loss of Coping Strategies 1. “Africa is the world's most ancient land mass.”* – “Only 10 percent of the soils are relatively young and still have nutrient-rich sediments.” – “The soil organic matter content is low.”* 1. Soil are Characterized as – Nutrient poor « Requires external inputs – Low inherent capacity to retain nutrients applied in fertilizers (low fertilizer-use efficiency) « Fertilizers often not economical unless soil organic matter content is amended 1. Demographic Pressure has reduced options for soil regeneration and coping with drought and pushed people to the margin Breman, Henk, et.al. (2005). THE LESSON OF DRENTE'S 'ESSEN‘: SOIL NUTRIENT DEPLETION IN SUB-SAHARAN AFRICA AND MANAGEMENT STRATEGIES FOR SOIL REPLENISHMENT. International Center for Soil Fertility and Agricultural Development
  5. 5. Soil Organic Matter (SOM) and Fertilizer-Use Efficiency • “in the Sudano-Sahelian zone, the effective cation exchange capacity (ECEC) is more correlated to organic matter than to clay,”* • Recovery of N-fertilizer as related to SOM:* – Infields (high SOM): 34% - 37% – Outfields (low SOM): 17% - 23% • ”in the surface horizons of tropical African soils, soil organic matter contains practically all of nitrogen and about 20±80% of phosphorus.” Bationo, A., F. Lompo, S. Koala (1998) Research on nutrient Flows and balances in West Africa: state-of-the-art; Agriculture, Ecosystems and Environment 71 (1998) 19±35 *Bationo, A, et.al., 2006. African Soils: Their Productivity and Profitability of Fertilizer Use. Background paper prepared for the African Fertilizer Summit. The International Fertilizer Development Center.
  6. 6. Returns to Fertilizer as a Function of SOM Estimated marginal value product of nitrogen fertilizer (Kshs/kg N) conditional on plot soil carbon content* *Marenya, P.P. and C.B. Barrett (2009) State-conditional Fertilizer Yield Response on Western Kenyan Farmers; Amer. J. Agr. Econ. 91(4) (November 2009): 991–1006 *Marenya, P. P., C. B. Barrett (2009) Soil quality and fertilizer use rates among smallholder farmers in western Kenya; Amer. J. Agr. Econ. 91(4) (November 2009): 991–1006
  7. 7. Addressing Biophysical Challenges Producers use practices and systems that do the following: 1. Reduce rainfall run-off and increase infiltration 2. Build up soil organic matter – Increases soil’s moisture retention capacity in crop’s root zone (retains up to 90% of its weight in moisture)* – Increases soil’s fertilizer-use efficiency 1. Use fertilizers and improved seed in tandem with above 2. Diversify farming systems to include crops less vulnerable to drought and other shocks (e.g., tree crops in a mixed annual-perennial system) and avoid selling productive assets in order to eat!! *Wood, Sebastian, Scherr (2000) Pilot Analysis of Global Ecosystems—Agroecological Systems; World Resources Institute
  8. 8. Soil Organic Matter By Continents “Africa is the world's most ancient land mass.” Breman While Increasing Fertilizer Use in Dryland Africa is Essential, increasing SOM is Essential for FUE
  9. 9. Reducing Runoff and Reclaiming Land at Scale Central Plateau, Burkina Faso: 200,000 ha. Tahoua Region, Niger 100,000 ha Reij, C., G. Tappan, M. Smale (2009) Agroenvironmental Transformation in the Sahel: Another Kind of “Green Revolution; IFPRI Discussion Paper 00914, November 2009; Prepared for the Project, Millions Fed: Proven Successes in Agricultural Development Djenne, Mali, Chris Reij, 2008
  10. 10. Sorgho “Sustainable Intensification”: Microdose in Tandem with Zai’s Millet: One week after seeding— Early establishment correlated to higher yields Sorghum Treatment Yields Control 0 to 400 kg/ha Zai + microdose 900 kg to 2000 kg/ha SAWADOGO H. and Barro, A. POLITIQUES DE RECUPERATION DES TERRES DEGRADEES AU BURKINA FASO: BILAN ET PERSPECTIVES ; Power Point Presentation, Février 2012 ; INRAN, Burkina Faso
  11. 11. Ridge Tillage in Mali: Increasing Rainfall-use Efficiency Increased: •Infiltration by 66% •Average Soil moisture by 17% but 39% in the 20-40 cm zone at end of season •Soil C by 12-26% •Fertilizer-use Efficiency by 30% « • 30-50% yield increase • Water table recharged -Doumbia, M. (2008) Sequestration of organic carbon in West African soils by Aménagement en Courbes de Niveau Agron. Sustain. Dev., 2008 -Kablan, R. et.al, (2008) '"Aménagement en courbes de niveau," Increasing Rainfall Capture, Storage, and Drainage in Soils of Mali', Arid Land Research and Management, 22:1, 62 – 80
  12. 12. Dry Season Gardens: A Dividend of Rainwater Management • Higher water table allows dry season irrigation; • Higher prices for counter-season produce; • New and additional sources of revenue and nutritious foods. • Resilience Strengthened Sorofin Diarra irrigates her garden while daughters Batama, Youma and Nieba observe. Currently, 80% of Siguidolo households have gardens compared to one before ACN was introduced12 years ago . (ACN Brochure, Soils Management CRSP)
  13. 13. REJUVENATED LAND: Dr. Doumbia (left) and farmer Zan Diarra observe a baobab tree that regenerated following the establishment of ACN. High-Value Field Trees: Additional Dividend of Rainfall Management
  14. 14. Weathered Soils & Integrated Soil Fertility Management (ISFM) ISFM: “combined use of locally-available organic resources and the judicious use of mineral fertilizer …” Farmers’ practices After 4 yrs of ISFM Cereal Yield* VCR** Fertilizers Cereal Yield VCR Fertilizers Maize; outlying field 750 --*** 2,750 4 Maize; compound 3,000 --*** 4,600 12 Sorghum 1,000 --*** 2,000 8 Cotton 1,150 5 2,000 8 *kg/ha; **Incremental value/fertilizer cost; ***No fertilizer used H. Breman, A. Gakou, A. Mando and M. Wopereis (2004) Enhancing Integrated Soil Fertility Management Through the Carbon Market to Combat Resources Degradation in Overpopulated Sahelian Countries; Regional Scientific Workshop on Land Management for Carbon Sequestration; Bamako (Mali), February 27-28, 2004
  15. 15. ISFM Principles Applied Over Time *Source: Sedogo (1993); Bationo, “Technologies for sustainable management of sandy Sahelian soils,” in FAO, “Management of tropical sandy soils for sustainable agriculture.” **Wopereis, M., A. Mando, B. Vanlauwe Agro-ecological principles of integrated soil fertility management – a guide with special reference to sub-Saharan Africa;mIFDC Technical Bulletin Series •“Treatments using only inorganic fertilizer often show a decline in yield after time….” •Acidification •SOM decline • Soil organic matter improves • Cation exchange (CEC) • Water retention capacity • Soil structure.** Sorghum grain yield as affected by mineral and organic fertilizers over time.*
  16. 16. ISFM: Challenges of Soil Organic Matter Nyankpala region (Northern Ghana): Compost heap (after a practical class by researchers from SARI and development workers from MoFA)
  17. 17. Mature Faidherbia albida Parkland: Peanut Basin, Senegal (Tappan) •Soil Carbon: Increase between 40% and 269%* •Cation-Exchange Capacity (CEC): 120% increase •Soil-water Holding Capacity: Significant Increase •Microbial activity: Significant Increase •Yields: Increased from 500 (+/- 200) to 900 kg/ha (+/- 200) “State of the Art: Acacia albida,” Peter Felker, 1974 FMNR: Source of Soil Organic Matter and Other Benefits
  18. 18. Diversified Systems to Sustain Productivity and Build Resiliency Animal fattening operation based primarily on pods from field trees
  19. 19. Diversified Systems to Sustain Productivity and Build Resiliency Fuel Wood and Construction Poles
  20. 20. A Conclusion • Based on current evidence, many farmers in dryland Africa can double or triple yields, in a cost-effective and sustainable manner, and can strengthen resilience by – Investing in fertilizers and improved seeds in tandem with practices that increase rainfall and fertilizer-use efficiencies and – Diversifying their production systems to include crops and sources of livelihoods that are less vulnerable to climatic and market shocks than annual staples.
  21. 21. Doubled-up legume systems
  22. 22. Multiple benefits from perennial pigeonpea (P.P.) shrub-diversified maize Snapp et al. 2010 PNAS P.P. + ½ F

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