Estimating the Global Influence of Cover Crops on Ecosystem Service Indicators in Croplands With the LPJ‐GUESS Model.

Cover crops (CCs) can improve soil nutrient retention and crop production while providing climate change mitigation co‐benefits. However, quantifying these ecosystem services across global agricultural lands remains inadequate. Here, we assess how the use of herbaceous CCs with and without biological nitrogen (N) fixation affects agricultural soil carbon stocks, N leaching, and crop yields, using the dynamic global vegetation model LPJ‐GUESS. The model performance is evaluated with observations from worldwide field trials and modeled output further compared against previously published large‐scale estimates. LPJ‐GUESS broadly captures the enhanced soil carbon, reduced N leaching, and yield changes that are observed in the field. Globally, we found that combining N‐fixing CCs with no‐tillage technique could potentially increase soil carbon levels by 7% (+0.32 Pg C yr−1 in global croplands) while reducing N leaching loss by 41% (−7.3 Tg N yr−1) compared with fallow controls after 36 years of simulation since 2015. This integrated practice is accompanied by a 2% of increase in total crop production (+37 million tonnes yr−1 including wheat, maize, rice, and soybean) in the last decade of the simulation. The identified effects of CCs on crop productivity vary widely among main crop types and N fertilizer applications, with small yield changes found in soybean systems and highly fertilized agricultural soils. Our results demonstrate the possibility of conservation agriculture when targeting long‐term environmental sustainability without compromising crop production in global croplands. Plain Language Summary: Increasing crop productivity while maintaining a healthy environment is a major challenge for global agriculture. Cover crops (CCs), mostly grown during the fallow period and plowed into in soils, are expected to improve soil fertility and crop yields while reducing chemical fertilizer use, but their overall impacts on global croplands remain unknown. This study investigates the long‐term influence of cover cropping on three ecosystem service indicators across four dominant farming systems (wheat, maize, rice, and soybean) using an ecological model. We find that adoption of CCs can enhance soil carbon stocks, which would contribute to slowing climate change, and benefit environments through reducing nitrogen pollution to water bodies. Among the modeled cover crop species, legumes show higher potential in increasing cash crop yields than non‐legumes, but the effect is highly dependent on the crop rotation, chemical fertilizer rate, and management duration. Our results highlight that proper implementation of legume CCs can support food security and environmental sustainability in global agricultural ecosystems. Key Points: Cover crops (CCs) can increase soil carbon sequestration by 0.11–0.15 Pg C per year while reducing N leaching by 34%–41% in global croplands compared with fallow managementThe influence of CCs on cash crop yields varies widely among crop rotations, climates, management duration, and N fertilizer applicationsLegume CCs in no‐tillage system is overall identified as a promising practice to achieve environmental sustainability without compromising crop production in agricultural ecosystems [ABSTRACT FROM AUTHOR]