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Abstract
Simulation models can be useful for providing predictions of surface residue decomposition and nitrogen (N) release, which is dependent on residue temperature and water potential (WP). We developed a mechanistic model of residue WP based on water transfer according to differences in WP between residue and atmosphere. The calibrated model simulated diurnal patterns in residue WP well, with R2=0.81 under no canopy and R2=0.91 under a maize canopy. The WP model was integrated into a web-based model of N mineralization and was calibrated and validated with a two-year field study. Model performance was acceptable when simulating loss of residue biomass and N, particularly for clover, as indicated by higher NSE and R2 values. The model simulated a steadily increasing amount of N mineralized and did not predict observed peaks nor N losses. We conclude the integrated model could be useful for producers when making management decisions in surface residue systems.