Cowpea postharvest losses under smallholder farmer management in Benin: Extent, causes and opportunities

Cowpea is a vital source of dietary protein for millions of people across sub-Saharan Africa. The crop is typically grown by smallholder farmers for household consumption and to generate income through sales. However, postharvest losses are perceived to be high affecting both the quantity and quality of cowpea available. To design targeted loss reduction activities, understanding is needed of the extent, causes and activity stages during which losses occur. The cowpea postharvest systems of 120 farming households across four agro-ecological zones of Benin were explored across two years through interviews. Additionally, directly measured loss assessments at each activity stage from harvest to store loading and during a 6-month storage period were done with a subset of these households. Postharvest activities were mainly done manually. Storage practices included storing untreated grains in woven polypropylene (PP) bags or plastic or metal drums, or treatment of cowpea grains with synthetic chemical pesticide dust, a fumigant or dried chilli and storage in PP bags. Measurement found the cumulative mean quantity losses from harvesting through six months of storage were 19.03-21.96% with the highest proportion of these losses occurring during harvesting (3.34-3.89%), drying of pods (1.96-2.05%), threshing (3.22-3.71%), and storage (10.14-12.01%). Loss levels were similar between years. Loss causes included rainfall during harvesting and/or drying, poor threshing methods, labour shortages, storage insect pest attack and rotting. An opportunity clearly exists for targeted multi-stakeholder participatory action research to co-develop affordable and acceptable ways of reducing these significant losses of such nutritionally and economically important grain legumes.