The Role of Mucuna pruriens in Smallholder Farming Systems of Eastern and Southern Africa: A Review

Abstract

Smallholder farmers in eastern and southern Africa face various food production constraints that have resulted in high food insecurity problems. The smallholder cropping systems are affected by poor rainfall distribution, high drought frequencies, poor soil fertility status, limited access to adequate inputs and lack of knowledge among others. The situation has been further worsened by increasing variability in climate. To improve food security, enhance soil conservation and fertility and boost livestock feed in different cropping systems, use of legumes such as velvet bean has been recommended. A literature study has been carried out aiming to review research findings on the roles of velvet bean (Mucuna pruriens L.) in African smallholder farming systems with emphasis on food and feed provision, soil fertility improvement and soil erosion control. The review found that velvet bean adapt very well within the tropical climate, but its uptake in smallholder farming systems in the region remains low. Velvet bean provides food in the form of seed grain after careful processing using different methods including soaking the seeds in running water for 72 h or soaking in water for 48 h with 12 h water replacements, among other methods. It can be integrated into smallholder farming systems through intercropping with other crops, crop rotations, relay cropping and as a sole crop. Velvet bean has high protein concentration (23–35%), which can help reduce the protein deficiency gaps for resource-poor farmers. It has also been used as a medicinal plant. The crop can be used as green manure cover crop to improve soil fertility and as source of soil cover which helps reduce the impact of raindrops which reduces runoff and soil erosion. Velvet bean fixes more nitrogen when compared to other legumes, 34–108 kg atmospheric nitrogen, which helps improve soil fertility. The crop may also be utilised as livestock feed through use of grain seed and the crop residues which both increase the protein availability to the animals. Velvet bean also smooths weeds due to high growth rate and biomass production, which may reduce weed density up to 92% when rotated with maize. In summary, velvet bean has multiple functions which have potential to improve smallholder farmer’s livelihoods through increased livestock and crop production.