Probabilistic assessment of cereal-rye impacts on regional crop yield and soil carbon

Abstract Field research for exploring the impact of winter cover crops (WCCs) integration into cropping systems is resource intensive, time consuming and offers limited application beyond the study area. To bridge this gap, we used the APSIM model, to simulate corn (Zea mays L.) – rye – corn – rye and corn – rye – soybean (Glycine max L.) – rye rotations in comparison to corn – corn and corn – soybean rotations across the state of Illinois at a spatial resolution of 5 km × 5 km from 2000–2020 to study the impact of WCCs on soil organic carbon (SOC) dynamics and crop production. By propagating the uncertainty in model simulations associated with initial conditions, weather, soil, and management practices, we estimated the probability and the expected value of change in crop yield and SOC following WCC integration. Our results suggest that integrating cereal rye into the crop rotations did not incur any yield penalties, and on the contrary, imparted greater yield stability for corn across the state. It was found that the areas with low probability of increase in SOC (p < 0.75) respond equally well for soil carbon sequestration through long-term adoption of WCCs. Furthermore, the average simulated soil carbon sequestration rate was found to be higher than 0.4% as set by Lima Paris Action Agenda to meet sustainable development goals. This study presents the most complete uncertainty accounting of WCC benefits across broad region and provides greater insight into the spatiotemporal variability of WCCs benefits for increasing WCC adoption rate.