Marie Ruillé, D. Beillouin, Rémi Prudhomme
Intercropping, a cornerstone of ecological intensification for sustainable agriculture and biodiversity conservation, has not fulfilled its potential to support global food-security promises under growing land and climate constraints. A major barrier lies in the context-dependent and often unpredictable nature of yield benefits, which emerge from complex interspecific interactions that remain poorly characterized across agroecosystems. Through a novel global meta-analysis (4,195 partial Land Equivalent Ratio observations from 334 studies across 60 countries) coupled with machine learning to disentangle the roles of plant functional traits and species-specific interactions, we demonstrate a substantial untapped potential to increase the production of major cereals—maize ( + 51%), barley ( + 6%), and wheat ( + 1%)—solely through optimized deployment of intercropping on existing agricultural land. Crucially, despite reduced planting density in intercropping, the mean partial Land Equivalent Ratio (pLER) of 0.79 (95% CI: 0.76-0.82) indicates that yield reductions for component species are proportionally smaller than the decrease in density, revealing consistent beneficial interactions. Our quantitative framework identifies relative planting density (RD), temporal niche differentiation (TND), and relative height difference as key levers for optimizing intercropping performance. We further unveil a predictable trade-off governed by asymmetric competition: targeted manipulation of RD and TND can selectively benefit either taller or shorter species, providing mechanistic insights into how interspecific dynamics shape intercropping success. This finding offers a scalable and ecologically grounded pathway to increase global crop production without cropland expansion, advancing sustainable agricultural intensification.