The practice of cover crops has gained popularity as a strategy to improve agricultural sustainability, but its full potential is often limited by environmental trade-offs. Using meta-analytic and data-driven quantifications of 2302 observations, we optimized cover crop practices and evaluated their benefits for global agroecosystems. Cover crops have historically boosted crop yields, soil carbon storage, and stability, but also stimulated greenhouse gas emissions. However, combining them with long-term implementation (five years or more) and climate-smart practices (such as no-tillage) can enhance these services synergistically. A biculture of legume and non-legume cover crops, terminated 25 days before planting the next crop and followed by residue mulching, is the optimal portfolio. Such optimized practices are projected to increase agroecosystem multiservices by 1.25%, equivalent to annual gains of 97.7 million metric tons in crop production, 21.7 billion metric tons in carbon dioxide sequestration, and 2.41 billion metric tons in soil erosion reduction. By 2100, the continued implementation of optimized practices could mitigate climate-related yield losses and contribute to climate neutrality and soil stabilization, especially in harsh and underdeveloped areas. These findings underscore the promising potential of optimized cover crop practices to achieve the synergy in food security and environmental protection.

Soil pollution from potentially toxic elements (PTEs) is a serious environmental issue worldwide that affects agricultural safety and human health. Arbuscular mycorrhizal fungi (AMF), as ecosystem engineers, can alleviate PTE toxicity in crop plants. However, the comprehensive effects of AMF on crop performance in PTE-contaminated soils have not yet been recognized globally. Here, a meta-analysis of 153 studies with 3213 individual observations was conducted to evaluate the effects of AMF on the growth and PTE accumulation of five staple crops (wheat, rice, maize, soybean, and sorghum) in contaminated soils. Our results demonstrated that AMF had strong positive effects on the shoot and root biomass. This is because AMF can effectively alleviate oxidative damage induced by PTEs by stimulating photosynthesis, promoting nutrition, and activating non-enzymatic and enzymatic defense systems in crop plants. AMF also decreased shoot PTE accumulation by 23.6% and increased root PTE accumulation by 0.8%, demonstrating that AMF effectively inhibited the PTE transfer and uptake by crop shoot. Meanwhile, AMF-mediated effects on shoot PTE accumulation were weaker in soils with pH > 7.5. Overall, this global survey has essential implications on the ability of AMF to enhance crop performance in PTE-contaminated soils and provides insights into the guidelines for safe agricultural production worldwide. Graphical abstract