Simulation of annual productivity and water dynamics of winter wheat-summer maize production system

Abstract This study focuses on the winter wheat–summer maize double-cropping system and aims to develop an annual process model that can accurately simulate crop growth and development along with soil moisture dynamics. Based on the field split-plot experimental data that combined different varieties with sowing date treatments, a wheat-maize double-cropping production system model was built, incorporating modules for crop development stages, leaf area dynamics, biomass accumulation and partitioning, yield formation, and soil moisture balance. The model parameters were calibrated using 2008–2009 data, and validated with independent 2009–2010 data, and model performance in key physiological and ecological processes and in yield formation is systematically evaluated by using root mean square error (RMSE) and normalized root mean square error (NRMSE). Validation results show: 1) excellent simulation of crop phenology, with NRMSE for development stages at 1.87% for winter wheat and 5.36% for summer maize; 2) the model capture of leaf area index dynamics, with NRMSE of 27.52% for winter wheat and 11.96% for summer maize; 3) aboveground biomass accumulation was simulated with NRMSE of 16.02% for winter wheat and 15.50% for summer maize; 4) yield simulation achieved NRMSE of 5.78% for winter wheat and 17.80% for summer maize; 5) soil water storage in the 0–60 cm soil layer was simulated with good accuracy (NRMSE = 15.13%). Under the specific site conditions and the tested genotype-by-sowing-date combinations, the model demonstrated reasonable capability in simulating key processes of the winter wheat–summer maize production system.