Biodiversity and a Resilient Green Revolution: Lessons for a Changing Climate.

Climate uncertainty is increasing, putting food security at risk for millions of smallholder farmers. Mitigation of risk is fundamental to a re-vision of the green revolution. Monoculture cereal systems with improved genetics and high doses of agrochemicals are tremendously effective at producing hefty amounts of calories. It is not surprising then that simplified cropping systems have come to dominate African and Asian landscapes. There are biological and socio-economic reasons for this massive homogenization of species, but what are the consequences for cropping system resilience - how fast can these systems bounce back from drought, or flood? Resource conservation is another key concern, as subsidization of access to nutrients and pest control inputs has associated costs, and efficient, profitable use must be at the foundation of a greener revolution.   Experimental evidence from Malawi will be presented regarding biological and socio-economic performance and resilience over time of diversified versus simplified row crops.  In participatory research at multiple scales (n=990), a 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. Profitability under variable climatic conditions was evaluated, along with nitrogen conservation, nutrient-enriched grain production, and farmer assessment. Systems with enhanced biodiversity were associated with improved (16 to 50%) fertilizer use efficiency. Farmer preference was for legume-diversified maize systems (41 - 56%), compared to monoculture maize (6 to 8%). Farmer evaluation was consistent with economic assessment as the variable cost ratio of legume-diversified maize systems was two-fold higher (6.9-7.9) than monoculture maize (4.8-5.4). Overall, this is compelling evidence that biodiversity combined with integrated nutrient management can provide a basis for resilient production of food and protection of resources, in an increasing variable environment