Evaluating conservation agriculture for small-scale farmers in Sub-Saharan Africa and South Asia

This introductory paper provides an overview of the contributions to this special issue, addressing four key questions related to conservation agriculture (CA) in Sub-Saharan Africa and South Asia: What is the impact of CA on yields? What is the impact of adopting CA on farmers’ profits? What are the environmental impacts of adopting CA? How well does CA fit with wider agricultural, social, economic and political contexts for small-scale farmers? Papers in this special issue find that yield increases under CA are possible but uncertain given the low average yields that pertain in these regions, and yield gains are more likely to be observed after several years. CA is not widely adopted in Sub-Saharan Africa and South Asia owing to a lack of economic incentive for smallholder farmers—that the process of conversion to CA is not profitable over planning horizons of most farmers. There is no clear trend for greater carbon sequestration under CA, so the potential for subsidizing farmers to adopt CA using payments for ecosystem services/carbon credit schemes seems limited in scope. There is early evidence that farmers perceive a benefit from CA adoption in regions that are prone to erratic rainfall, suggesting a potential risk mitigation role. In addition, throughout this overview paper we offer a commentary on some of the scientific issues that constrain our ability to understand the performance of CA in these systems more comprehensively.