Optimizing cover cropping application for sustainable crop production

Cover cropping is a key strategy in sustainable agriculture but faces adoption barriers due to perceived yield risks and uncertain environmental benefits. Through a global meta-analysis of 3160 observations from 271 studies, we assessed the impacts of cover crops on soil organic carbon (SOC), crop yield, and nitrous oxide (N2O) emissions. Results showed that legume and non-legume cover crops increased SOC by 5.9 and 4.0%, respectively. Legume cover crops enhanced yield by 16.0% but raised N2O emissions by 36.2%, which can be mitigated by integrating practices like no-tillage, deficit irrigation, and diversified crop rotations. The greatest benefits in SOC and yield from legume cover crops were observed in farming systems with low nitrogen fertilizer, low crop diversity (especially cereal-dominated systems), and low initial SOC, under humid and warm climates. Incorporating legume cover crops brings co-benefits for both SOC and yield but the trade-offs in N2O emissions should be deliberated.