Suchergebnisse

International audience ; AbstractConservation agriculture (CA)—the simultaneous application of minimum soil disturbance, crop residue retention, and crop diversification—is a key approach to address declining soil fertility and the adverse effects of climate change in southern Africa. Applying the three defining principles of CA alone, however, is often not enough, and complementary practices and enablers are required to make CA systems more functional for smallholder farmers in the short and longer term. Here, we review 11 complementary practices and enablers grouped under six topical areas to highlight their critical need for functional CA systems, namely: (1) appropriate nutrient management to increase productivity and biomass; (2) improved stress-tolerant varieties to overcome biotic and abiotic stresses; (3) judicious use of crop chemicals to surmount pest, diseases, and weed pressure; (4) enhanced groundcover with alternative organic resources or diversification with green manures and agroforestry; (5) increased efficiency of planting and mechanization to reduce labor, facilitate timely planting, and to provide farm power for seeding; and (6) an enabling political environment and more harmonized and innovative extension approaches to streamline and foster CA promotional efforts. We found that (1) all 11 complementary practices and enablers substantially enhance the functioning of CA systems and some (e.g., appropriate nutrient management) are critically needed to close yield gaps; (2) practices and enablers must be tailored to the local farmer contexts; and (3) CA systems should either be implemented in a sequential approach, or initially at a small scale and grow from there, in order to increase feasibility for smallholder farmers. This review provides a comprehensive overview of practices and enablers that are required to improve the productivity, profitability, and feasibility of CA systems. Addressing these in southern Africa is expected to stimulate the adoption of CA by smallholders, with positive ...

International audience ; AbstractConservation agriculture (CA)—the simultaneous application of minimum soil disturbance, crop residue retention, and crop diversification—is a key approach to address declining soil fertility and the adverse effects of climate change in southern Africa. Applying the three defining principles of CA alone, however, is often not enough, and complementary practices and enablers are required to make CA systems more functional for smallholder farmers in the short and longer term. Here, we review 11 complementary practices and enablers grouped under six topical areas to highlight their critical need for functional CA systems, namely: (1) appropriate nutrient management to increase productivity and biomass; (2) improved stress-tolerant varieties to overcome biotic and abiotic stresses; (3) judicious use of crop chemicals to surmount pest, diseases, and weed pressure; (4) enhanced groundcover with alternative organic resources or diversification with green manures and agroforestry; (5) increased efficiency of planting and mechanization to reduce labor, facilitate timely planting, and to provide farm power for seeding; and (6) an enabling political environment and more harmonized and innovative extension approaches to streamline and foster CA promotional efforts. We found that (1) all 11 complementary practices and enablers substantially enhance the functioning of CA systems and some (e.g., appropriate nutrient management) are critically needed to close yield gaps; (2) practices and enablers must be tailored to the local farmer contexts; and (3) CA systems should either be implemented in a sequential approach, or initially at a small scale and grow from there, in order to increase feasibility for smallholder farmers. This review provides a comprehensive overview of practices and enablers that are required to improve the productivity, profitability, and feasibility of CA systems. Addressing these in southern Africa is expected to stimulate the adoption of CA by smallholders, with positive ...

In a continent facing a fast increasing population, smallholder farming in Africa is exposed to double challenge: 1) to increase food production and, 2) to preserve natural resources. While conventional tillage-based agriculture has been held accountable for soil degradation, Conservation Agriculture (CA) based on minimal or no-tillage is increasingly seen as a promising alternative for highly productive and sustainable farming. Despite its potential, CA adoption rates in Africa, compared with other continents, have remained extremely low. While literature on adoption contraints is abundant, comprehensive, holistic frameworks and tools for explaining or predicting adoption are still lacking. In particular, such frameworks and tools could help in assessing systematically under which ecological, socio-economic and institutional conditions CA is best suited for smallholder farming in Africa and for its scaling up. The objective of this contribution therefore is to demonstrate how a newly developed Qualitative expert-based Assessment Tool (QAToCA) was applied in case studies across Malawi, Burkina Faso, and Zimbabwe; 1) to determine the Relative Adoption Potential (RAP) of CA, 2) to assess the institutional, agro-ecological, socio-economic and cultural influences on the RAP of CA, and 3) to determine the site-specific hindering and supporting factors to the RAP of CA for the different case studies. Results show that for the two south African case studies, Malawi has a high RAP for CA while Zimbabwe has a much lower potential. On the other hand the two case studies in south western and northern Burkina Faso both showed a relatively high adoption potential of CA. Major differences in adoption potential are explained by economic market incentives, prevailing institutional arrangements as well as some biophysical incentives.