Evaluation of AquaCrop model performance under mulched drip irrigation for maize in Northeast China

Abstract

Establishing scientific management and grain production strategies through crop models is an important means to ensure stable and increased food production. To explore the performance of the AquaCrop model for simulating maize growth under mulched drip irrigation in Northeast China, the model was calibrated and verified locally based on three years of measured field data. The simulation effects of canopy cover (CC), total soil-water (TSW), aboveground biomass, crop evapotranspiration (ETC) and grain yield under mulched or nonmulched drip irrigation treatments with different water stress conditions were evaluated and compared. The study found the model had a good simulation effect on CC excluding the rainfed treatment, the root mean square error (RMSE) was <15.2%. The simulated values of TSW and ETc were quite different from those observed in the field. The TSW content was generally underestimated in the middle and late stages of maize growth, with RMSE values ranging from 12.8 to 60.7 mm. The simulated ETC values were generally high, and the prediction error of some treatments exceeded 20%. The model simulated the aboveground biomass and yield well in the calibration year (2016) and the RMSE values were 0.9–2 t/ha and 0.8 t/ha, respectively, but the simulation performance of predicting yield declined in the verification year, and the prediction error exceeded 20%. Compared with the mulched treatments, the model had a better simulation effect on the nonmulched treatments. In general, the simulation of soil moisture under drip irrigation needs to be improved, and the larger overestimation of transpiration and the lower underestimation of evaporation caused to overestimate the maize ETc. It is recommended to improve the simulation of mulched drip irrigation to ensure model applicability in the region of interest.