Cover crop performance under a changing climate in continuous corn system over nebraska.

Fall-planted cover crop (CC) within a continuous corn (Zea mays L.) system offers potential agroecosystem benefits including mitigating the impacts of increased temperature and variability in precipitation patterns. A long-term simulation using the Decision Support System for Agrotechnology Transfer (DSSAT) model was made to assess the effects of cereal rye (Secale cereale L.) on no-till continuous corn yield and soil properties under historical (1991-2020) and projected climate (2041-2070) in eastern Nebraska. Local weather data during the historical period was used, while climate change projections were based on the Canadian Earth System Model 2 (CanESM2) dynamically downscaled using the Canadian Centre for Climate Modelling and Analysis Regional Climate Model 4 (CanRCM4) under two Representative Concentration Pathways (RCP) namely, RCP4.5 and RCP8.5. Simulations results indicated that CC impacts on corn yield were non-significant under historical and climate change conditions. Climate change created favorable conditions for CC growth, resulting in an increase in biomass. Cover crop reduced N leaching under climate change scenarios compared to an average reduction of 60% (7 kg ha-1) during the historical period. Cover crop resulted in a 6% (27 mm) reduction in total water in soil profile (140 cm) (SW) and 22% (27mm) reduction in plant available water (PAW) compared to no cover crop (NCC) during historical period. Cover crop reduced cumulative seasonal surface runoff/soil evaporation and increased rate of SOC buildup. This research provides valuable information on how changes in climate can impact performance of cereal rye CC in continuous corn production and should be scaled to wider locations and CC species.