A study of bambara groundnuts, an underutilised indigenous African crop, suggests that October planting could maximise yields in Southern Africa. The findings could support efforts to diversify agriculture and improve food security as water stress and climate change complicate production of rain-fed staples such as maize, wheat and rice.
Using 50 years of climate and soil data, researchers simulated 49 growing seasons across 5,838 altitude zones in South Africa, Lesotho and Eswatini. The Food and Agriculture Organization's AquaCrop model analysed seasons between 1950 and 1999, accounting for daily rainfall, temperature, soil water retention, planting dates and plant density.
October, broadly corresponding to the regional onset of seasonal rains, delivered the highest modelled yields. Later sowing could expose plants to frost and reduce productivity. To produce more accurate suitability maps, the team also excluded incompatible land uses, including mining, commercial forestry, urban development, plantations and orchards, thereby limiting overestimation of potential cultivation areas.
Indigenous crops can often tolerate drought and low-fertility soils, while bambara groundnuts supply fibre, protein, zinc, iron and calcium. Researcher Richard Kunz stressed that farmers need practical guidance on planting locations and timing if they are to adopt neglected crops rather than depend on a narrow range of staples.
Kunz said the modelling approach could also be applied to other underused crops, including cowpea, sorghum and taro. The maps could help locate community seed banks. Leonard Manda of Mzuzu University in Malawi, who was not involved in the research, described the study as a valuable planning tool for maximising bambara groundnut production.
