Wednesday, August 4, 2010
Exhibit Hall A, David L Lawrence Convention Center
Background/Question/Methods . Simplified systems of cereal and cash crops are coming to dominate many African landscapes. There are biological, political and socio-economic reasons for this massive homogenization of species, but what are the consequences for farmer resilience and resource conservation in the face of climate change? Experimental evidence from Malawi is presented regarding ecosystem services generated, and biological and socio-economic performance of diversified versus simplified plantings. In a country wide trial (n=990), the staple maize crop was grown as a sole crop or in various combinations with legumes of variable growth habit, and small doses of nitrogen were applied. Economic yield under variable climatic conditions was evaluated over two years, along with nitrogen conservation, nutrient-enriched grain production, and farmer assessment.
Results/Conclusions . Systems with enhanced biodiversity were associated with improved (16 to 50%) nitrogen efficiency. Farmer preference was for legume-diversified ‘rotation Plus’ systems (41 - 56%), compared to monoculture maize (6 to 8%). Farmer evaluation was consistent with economic assessment as the variable cost ratio of ‘rotation Plus’ systems was two-fold higher (6.9-7.9) than monoculture maize (4.8-5.4). Overall, biodiversity combined with integrated nutrient management provided a basis for food security and protection of resources, in an increasing variable environment.
