RZWQM2 simulated N 2 O flux: Nitrogen inhibitor and variable rainfall impact on spring wheat

Additions of urease and nitrification inhibitors to nitrogen (N) fertilizers can reduce N losses and improve crops’ N use efficiency (NUE). However, the benefits of inhibitors depend on interactions among crops, soils, and weather variables. Root Zone Water Quality (RZWQM2) models can simulate such complex interactions to predict N dynamics but need evaluation for systems with additions of inhibitors. For this study, RZWQM2 model was used to simulate the dual applications of nitrification and urease inhibitors (Inhibitor) on the spring wheat grain yield and denitrification loss of N in the form of nitrous oxide (N 2 O) in western Minnesota during 2014 and 2015 growing seasons. The RZWQM2 model was calibrated for the urea only application at 146 kg N ha −1 . Model reliably reproduced spring wheat yield across years and treatments, with simulated values closely matching observation ( R 2 = 0.64, Nash–Sutcliffe model efficiency [NSE] = 0.49, relative root means square error [RRMSE] = 0.14, mean absolute percent error [MAPE] = 11.5). Model overestimated yield by 29% and flux by 326% under urea only treatment during dry season (2014) but consistently captured the relative reduction in denitrification N loss from inhibitor additions. Long‐term scenario simulations (2000–2024) indicated that inhibitors clearly reduced N losses and that wetter springs (+10%) decreased the probability of higher N 2 O emissions, while drier springs (−10%) increased the flux which is consistent with other related studies. This study highlights the long‐term potential of inhibitors to mitigate fertilizer‐N losses. It also demonstrates the utility of the RZWQM2 model in evaluating inhibitor efficacy under spring wheat production in the Northern Great Plains.