Soil and crop improvement technologies for cowpea production in Zimbabwe

About the project

UK-registered partner: Durham University – Steven Chivasa
Africa-registered partner: Verager Ltd – Maureen Vere

Agriculture is an important sector of the Zimbabwean economy and supports the livelihoods of millions of smallholder farmers. The strong market demand for maize products attracts farmers into maize production. However, the requirement for high fertiliser inputs and vulnerability of maize to drought and heat is a persistent problem that curbs yields for the resource-poor smallholder farmers.

Verager Ltd is a spinout company addressing this problem by developing an alternative strong value chain using cowpeas, a crop indigenous to Africa and so adapted to thrive under conditions where maize fails. The company manufactures vegetarian cowpea burgers and sausages and subcontracts cowpea production to rural women farmers.

Nevertheless, cowpea yields are still suppressed by poor soil fertility since degraded soils have low nutrient- and water-holding capacity. In this project, biochar addition to degraded agricultural soil from a field in Zimbabwe improved cowpea growth. Under limited water in unamended soil, plants quickly withered and died, while in a control fertile soil the plants survived for longer by shedding older leaves and keeping the meristems alive.

An unexpected key finding of the research was that root interactions with soil microbes underpinned the leaf-shedding plant behaviour, as this could be recapitulated with fertile soil bereft of microbes. The significance of these results is the possibility of developing agritechnology to seed infertile degraded soils with microbes to improve its biological functions in crop yield performance.

Our results show that both soil rehabilitation and microbial seeding of degraded soils constitute feasible strategies to improve cowpea production.