Response of cereals to intercropping with non‐food crops in tropical and subtropical regions: A meta‐analysis

Abstract

Abstract Intercropping cereals with non‐food intercrops (NFICs) provides a means to enhance cereal productivity while providing additional benefits such as improved soil health or forage production. We conducted a meta‐analysis to investigate the effect of NFICs on cereal yields, cereal nitrogen uptake, and striga ( Striga spp.) infestation, using 874 observations from 97 peer‐reviewed studies across tropical and subtropical regions. Results showed that maize ( Zea mays L.) grain yield increased by 7% and decreased by 10% when intercropped with Fabaceae and Poaceae, respectively, compared to sole cropping. Sorghum ( Sorghum bicolor (L.) Moench.) grain yield was significantly reduced by an average of 47% under intercropping with Fabaceae NFICs (mostly perennial woody species) compared with sole cropping, likely due to competition for nutrients, light, and particularly water, as most sorghum trials included in this review were conducted under semi‐arid climatic conditions. In general, higher rainfall and higher soil organic matter content increased the performance of intercropping relative to sole cropping. Performing intercropping for multiple consecutive years favored positive yield responses. NFICs had limited effect on nitrogen content in cereal biomass. Striga density in maize fields was significantly reduced (−130%) under intercropping with Desmodium spp. compared to sole cropping. Overall, intercropping maize with Fabaceae NFICs emerges as a promising strategy for enhancing maize yields in tropical and subtropical regions, though its effectiveness depends on factors such as NFIC category and climate. While caution is warranted when intercropping sorghum with perennial Fabaceae NFICs in semi‐arid climates, the limited number of published studies on sorghum intercropping with annual Fabaceae NFICs suggests that further investigation is warranted.