Pulse crops for sustainable farms in Sub-Saharan Africa

Food insecurity in sub-Saharan Africa is a problem affecting 153 million individuals (ca. 25%). This problem could be worsen by the ongoing soil degradation, being cause by the reduction of soil organic matter and insufficient nutrient supply. Over 75% of the agricultural land in Africa could be classified as degraded by 2020. This situation can compromise food production in sub-Saharan Africa, both quantitatively and qualitatively, and the sustainability of existing agricultural production systems. The use of fertilizer could revert this situation; however, Africa has almost no capacity to produce fertilizers (African fertilizers production facilities work mainly in blending fertilizers) and therefore fertilizers are produced elsewhere outside Africa and transported from long distances at great expenses. This situation grants to sub-Saharan Africa farmers only a very limited access to fertilizers, thus increasing the risk of soil degradation. Pulses have a long history in sub-Saharan Africa due to their multiple benefits. Pulses, and legumes in general, can play an important role in agriculture because their ability to biologically fix atmospheric nitrogen and to enhance the biological turnover of phosphorous; thus they could become the cornerstone of sustainable agriculture in Africa. In this sense, there is a body of literature that points to diversification of existing production systems; particularly legumes species, which provides critical environmental services, including soil erosion control and soil nutrient recapitalization. This publication is a review of some of the promising strategies to support pulses cultivation and utilization on smallholder farms in sub-Saharan Africa. The review is part of the legacy of the International Year of Pulses (IYP), which sought to recognize the contribution that pulses make to human well-being and the environment. One challenge faced worldwide is that the diversity of pulses are not captured well in statistics. There is not a clear picture of what is grown and where, and this leads to an under-estimation of their importance for sub-Saharan Africa and consequently reduce research investment in pulses. Existing agricultural production systems are dominated by cereals, and represent opportunities for enhanced crop diversification, through promoting local and novel pulse varieties. Mixed-maize is a system that is rapidly growing and poses one such opportunity, particularly for beans. This is due in part to the large number of bean varieties that have been developed to meet local and regional market requirements, through decades long partnerships foster by Pan-Africa Bean Research Alliance (PABRA). Bean research has included pioneering participatory plant breeding, extension linked to participatory community organizations and value chains, as well as attention to informal seed systems. This example shows how pulse research can make a different on smallholder farms in sub-Saharan Africa, by broadening the range of genetic options and supporting innovation. There are many such farmers approved varieties available that deserve greater promotion, as do technologies such as doubled up legume system innovation recently released by the Malawi government. At the same time, this review has highlighted that variety release has lagged for some pulse crops, and that there is urgent need for more research on adoption, barriers to adoption, and on impact of adoption. Research priorities suggested include greater recognition and attention to expanding properties associated with multipurpose types of pulses, which are popular in sub-Saharan Africa. Different types of pulses are needed for different functions and in general, multipurpose pulses are the best to respond to the diverse needs of farmers, including food, fuel and fodder, and ecosystem services such as pollination. There is a trade-off between the harvest index and other functions, which have too often been overlooked by researchers and decision makers who tend to focus almost exclusively on increasing grain yields. Pest tolerance, as well as extension of educational approaches and agronomic advice to strengthen integrated pest management (IPM) is another area urgently needing attention. Finally, the role of specific legumes and associated biochemical properties in promoting ecosystem health, community health – this is a crucial area for research that will provide urgently needed options for women farmers – and for sustainability of communities.