Climate-induced shocks and the resilience of legume value chains in the Southern Africa Development Community (SADC) region: a systematic review

Climate change poses significant risks to agriculture in the Southern African Development Community (SADC), where farming systems are predominantly rain-fed and adaptive capacity remains limited. The region increasingly experiences recurrent droughts, erratic rainfall, rising temperatures, and water scarcity, all of which threaten crop productivity, soil health, and the stability of smallholder farming systems. Grain legumes, such as soybeans, groundnuts, common beans, pigeon peas, and cowpeas, are central to regional food security, nutrition, rural income, and soil fertility due to their nitrogen-fixing capacity. Despite their agronomic and nutritional importance, evidence on their performance under climate-induced shocks remains scarce and insufficiently synthesized. This systematic review examines how climate shocks affect legume productivity and resilience across SADC. The findings show that climate-related shocks reduce yields by approximately 15–78%, while simultaneously disrupting biological nitrogen fixation, accelerating soil degradation, and intensifying pest and disease pressures. Though legumes are widely promoted within climate-smart agriculture frameworks, policy and institutional responses remain fragmented. Soil degradation, water scarcity, limited irrigation access, climate-sensitive pest dynamics, weak seed systems, and volatile markets remain insufficiently addressed in agricultural and climate policies. Policy efforts must therefore shift from simple crop promotion toward the development of integrated climate-resilient legume systems that combine climate-responsive breeding, pest and disease surveillance, sustainable soil and water management, and inclusive market development. The review also identifies major research gaps, particularly the limited disaggregation of climate impacts across agroecological zones, management practices, legume species, and the absence of modeling approaches capable of capturing compound climate and market risks.