Ecosystem service provision of grain legume and cereal intercropping in Africa

Abstract

Achieving food security is challenging in Africa, a continent beset by low crop yield and soil quality, climate adversities, pests, weed infestations, and crop disease outbreaks. In this context, it is important to re-visit the resource-use efficiency and ecosystem service values of intercropping of grain legumes and cereals, a practice that has long been used by small-scale producers to mitigate the risk of crop failure and to safeguard household food availability. Despite its historical use, there are significant knowledge gaps regarding multiple aspects of intercropping, including examination of the different crop combinations on ecosystem services from agriculture. Using meta-analysis approach of land equivalent ratio (LER), a widely-accepted index to assess the efficiency of intercropping production systems, we found that intercropping of cereals with legumes resulted in an elevated LER (i.e., 1.31), regardless of species combination. A significantly greater LER than the overall LER (P < .05) was observed with the combination of maize-pigeon pea (LER = 1.57) and maize-groundnut (LER = 1.52). Increasing LER with intercropping was constant across rainfall variability, as well as in the absence of nitrogen fertilizer, which are the hallmark properties of intercropping in resource-deprived Africa. Intercropping could also reduce soil erosion, pest/weed incidence, and increase carbon sequestration by about ~46%, ~20–30%, and ~15%, respectively, compared to its sole crop control. In this comprehensive quantitative assessment of intercropping benefits across the African continent, we highlighted the provision of different ecosystem services from agroecosystems, a crucial foundation to achieving sustainable agricultural production.