Résumé
Conservation agriculture (CA) involves the simultaneous adoption of three agroecological practices: no-tillage or reduced tillage, maintenance of soil organic cover, and crop diversification. This paper develops a conceptual and methodological framework for assessing the economic benefits of CA. More than 150 studies were reviewed to create a conceptual diagram that identifies and links the key economic and environmental effects of adopting CA. The review reveals contradictory impacts of CA on production costs. Labor and machinery costs are significantly reduced, but these savings may be offset by increased pesticide costs due to greater weed pressure. Evidence is also mixed regarding whether CA adoption increases or decreases crop yields and water pollution. However, implementing CA is likely to promote biodiversity, reduce soil erosion, mitigate global warming, and improve soil quality in the long term. These effects vary depending on the CA practices adopted, experiment duration, climatic conditions, soil textures, and crop types. Adopting no-tillage alone may be ineffective at controlling soil erosion and is likely to result in yield losses or insignificant yield gains. CA impacts extend from individual farms to national and global levels and involve various risks and uncertainties. In light of these findings, a methodological approach is proposed to assess the probability distributions of the private and public benefits that CA generates. Assessing these benefits will help farmers and policymakers make informed decisions, thereby ensuring successful transitions to CA practices.