Nonlinear and Divergent Responses of Crop Yield and Soil Nitrous Oxide Emissions to Precipitation Change

Global food demand is projected to increase by 50-60% between 2019 and 2050, making it critical to understand how crop yield and soil health respond to increasing climate variability, particularly drought. In this study, we coupled a 40-year climate dataset (1981-2020) with the biogeochemical model DNDC (DeNitrification-DeComposition) to simulate corn yield and soil nitrous oxide (N₂O) emissions under 20 precipitation treatments ranging from severe drought (-90% precipitation reduction) to extreme wet conditions (+100% precipitatino increase). We quantified interannual variability (IAV) and precipitation sensitivity of both responses. Corn yield and soil N₂O emissions each exhibited substantial IAV but with contrasting patterns: yield variability peaked under moderate drought (-30% to -50%), whereas N₂O variability intensified with increasing precipitation. Yield increased linearly from severe drought to ambient precipitation but plateaued when precipitation exceeded ambient levels, while N₂O emissions rose steadily across nearly all precipitation treatments. Under most precipitation scenarios, corn yield responded linearly to precipitation, whereas N₂O emissions were significantly sensitive to precipitation only under drought conditions (-30% to -70%). We also identified a precipitation threshold for maximum yield and an optimal precipitation range in which yield gains exceeded increases in N₂O emissions. Overall, our results demonstrate nonlinear and asymmetric responses of crop productivity and soil N₂O emissions to precipitation changes, highlighting the importance of adaptive agricultural management strategies under growing climate variability.