By George Munene
Diversified legume cropping systems have been shown to enhance main crop yield (e.g., rice, wheat, maize) in Africa by 43 per cent on average with reduced inputs and environmental impacts.
Legumes increase yields, especially in low-input regions such as Africa and in low-input conditions like in organic farming. By comparison, the average gain observed in fertiliser intensive farming such as in Europe was only 15 per cent.
A legume refers to any plant from the Fabaceae family.
Common examples include; peanuts, beans, soybeans, peas, chickpeas, lentils, lupins, alfalfa, desmodium, lucerne, glycine, Sesbania, and clover.
According to the study, greater yield advantages (32% vs 7%) were observed in low yielding versus high-yielding environments.
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These yield advantages decline with increasing chemical nitrogen fertiliser rates: “Legumes fix atmospheric nitrogen in the soil”, says researcher Damien Beillouin, “so where high levels of nitrogen inputs are already used, this advantage has less impact”.
This shows that legumes are key in increasing crop production in regions/ farming systems applying low inputs (e.g., in Africa or organic agriculture).
The study was conducted in 53 countries from 1959 to 2020 with 60 major legume-based cropping systems.
Crop yield after legumes is often enhanced due to the combined and interrelated effects of nitrogen (N) provision and non-N effects (e.g., suppressed pest and disease, improved soil properties).
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Enhancing crop biodiversity (e.g., intercropping) or crop rotation promotes pest and disease control, carbon sequestration, and soil fertility.
These services reduce the dependence on external inputs while maintaining high crop yields and production stability.
Diversification through the inclusion of legumes in cereal, root, or tuber-based cropping systems represents a key strategy for sustainable agriculture.