Abstract
Intercropping can enhance agroecosystem functioning through complementary resource use and niche differentiation, yet how plant interactions across aboveground and belowground domains translate into multifunctional benefits, and how these effects vary with environmental and management contexts, remains insufficiently resolved. This review develops an integrated framework of “ecological mechanisms–functional consequences–system optimization” to connect interaction processes with system-level performance and identify pathways toward predictable intercropping design. We synthesize how canopy and root complementarity, rhizosphere microbial interactions, and biogeochemical regulation jointly shape resource-use efficiency, productivity, stability, and ecological regulation, while assessing their context dependence across crop traits, spatial configurations, management regimes, and environmental conditions. We further identify critical barriers to scalable implementation, including weak coordination between agronomic design and mechanization, the lack of intercropping-oriented crop ideotypes, incomplete resolution of microbiome-mediated interactions, and limited digital tools for system-level optimization. Building on these gaps, we propose a transition from empirical evaluation toward mechanism-based design, multi-objective optimization, and intelligent management that explicitly accounts for ecological trade-offs and environmental constraints. By linking interaction mechanisms to functional outcomes and optimization strategies, this framework provides a basis for transforming intercropping from a site-specific cultivation practice into a predictable, scalable, and sustainability-oriented agroecosystem design strategy.
