ABSTRACT

Conservation Agriculture (CA) is a Sustainable Agricultural Intensification strategy based on minimum soil disturbance, permanent soil coverage by living or dead biomass, and diversification of crop rotations. We reviewed the literature on benefits, trade-offs, adoption and adaptation of CA in sub-Saharan Africa (SSA). While CA can improve soils and sustain crop yields, benefits are inconsistent and there are trade-offs with crop residue use, weeds and insect pests, labour demands and short-term yield penalties. Adoption rates by smallholders in sub-Saharan Africa are generally low. We hypothesize that underlying adoption constraints are 1) the magnitude of transformation of management practices required from farmers moving to CA, 2) the multiple inherent trade-offs associated with CA practices and 3) the incompatibility of CA practices to local conditions. We suggest CA adoption in SSA could be improved by focusing the promotion of CA to environments where it best fits, or by facilitating smallholders’ adaptation of the practices of CA to respond to their conditions and constraints. We, therefore, propose to move from Conservation Agriculture to Conservation Practices by: (A) identifying and overcoming locally important CA trade-offs through adaptations and complementary practices, and (B) finding farm-specific optimal combinations of practices in terms of feasibility and benefits.

摘要

保护性农业 (CA) 是一种可持续农业集约化战略，其基础是最小的土壤干扰、活或死生物量的永久土壤覆盖以及作物轮作的多样化。我们回顾了关于 CA 在撒哈拉以南非洲 (SSA) 的收益、权衡、采用和适应的文献。虽然 CA 可以改善土壤并维持作物产量，但收益并不一致，而且在作物残留物使用、杂草和害虫、劳动力需求和短期产量损失方面存在权衡。撒哈拉以南非洲小农的采用率普遍较低。我们假设潜在的采用限制是 1) 农民迁移到 CA 所需的管理实践转变的程度，2) 与 CA 实践相关的多种内在权衡以及 3) CA 实践与当地条件的不兼容。我们建议通过将 CA 的推广重点放在最适合的环境中，或通过促进小农适应 CA 实践以应对他们的条件和限制，来改进 CA 在 SSA 中的采用。因此，我们建议通过以下方式从保护性农业转向保护性实践：(A) 通过适应和补充实践识别和克服当地重要的 CA 权衡，以及 (B) 在可行性和好处。或通过促进小农适应 CA 的做法来应对他们的条件和限制。因此，我们建议通过以下方式从保护性农业转向保护性实践：(A) 通过适应和补充实践识别和克服当地重要的 CA 权衡，以及 (B) 在可行性和好处。或通过促进小农适应 CA 的做法来应对他们的条件和限制。因此，我们建议通过以下方式从保护性农业转向保护性实践：(A) 通过适应和补充实践识别和克服当地重要的 CA 权衡，以及 (B) 在可行性和好处。