An optimized model for simulating grain-filling of maize and regulating nitrogen application rates under different film mulching and nitrogen fertilizer regimes on the Loess Plateau, China

•Four N rates were applied to summer maize under biodegradable film and plastic film.•The proposed model provided a powerful simulation of the grain-filling process and required relatively few input variables.•The optimal nitrogen application rate of 205 kg ha-1 and 196 kg ha-1 for BM and PM, respectively.