Climbing Legumes: An Underutilized Resource With Significant Potential to Intensify Farming on Terrace Walls (FTW) for Smallholder Farmers

Millions of subsistence farmers cultivate crops on terraces. These farmers face unique challenges including severe shortages of arable land and remoteness leading to poor access to inputs including nitrogen fertilizer. These challenges contribute to human and livestock malnutrition. Terrace walls (risers) as a vertical surface to grow climbing or trailing legumes represents an opportunity to help overcome these challenges. These crops are rich in minerals and protein, and their associated microbes produce nitrogen fertilizer. Rice bean is already grown on terrace risers in South Asia. This paper reviews the literature concerning crops that are currently farmed on terrace walls (FTW), then surveys climbing legume species that have potential for FTW, focusing on crops that are nutritious and tolerate shade (caused by the terrace wall) and resist drought (many terrace farms experience an extended dry season). A total of 29 legume species are discussed including climbing varieties of jack bean, common bean, cowpea, winged bean, horse gram and velvet bean. The review concludes by discussing the practical challenges of farmer adoption of FTW and makes concrete recommendations. Terrace wall cultivation of legumes represents an opportunity to intensify agriculture and increase resiliency in remote mountainous areas.