Harnessing cover crop-rock weathering synergies for climate-smart agriculture.

The use of cover crops (CCs) is increasingly promoted to diversify cropping systems and advance agricultural sustainability. Yet, CC adoption can involve context-dependent trade-offs, including resource competition and elevated greenhouse gas (GHG) emissions. In this opinion article, we propose enhanced rock weathering (ERW) as a complementary strategy to improve biogeochemical synchrony within CC systems. By synthesizing emerging evidence, we show how CC-ERW interactions can synergistically enhance carbon sequestration, nutrient cycling, GHG mitigation, and soil food-web functioning, mainly via root-driven weathering processes and soil feedbacks. We further outline opportunities for application across diverse agroecosystems and highlight key challenges for scaling, including weathering thresholds, potential metal risks, and governance constraints. Overall, harnessing the CC-ERW nexus offers a promising pathway toward climate-resilient and multifunctional agriculture.