Optimizing nitrogen application for drip-irrigated winter wheat using the DSSAT-CERES-Wheat model

Improper application of nitrogen fertilizer for winter wheat production in the North China Plain (NCP) limits N use efficiency and increases the risk of non-point pollution. Crop simulation models may help with the assessment of N fertilizer management, to improve nitrogen use efficiency and to mitigate environmental pollution. In this study, the DSSAT-CERES-Wheat model was calibrated and validated with two-year field experiment, which coupled with five N rates (0, 120, 180, 240, and 300 kg ha(-1)) and three irrigation levels (40, 30, and 20 mm per irrigation) under drip irrigation. The calibrated DSSAT-CERES-Wheat model performed well in simulating the anthesis date (nRMSE=1.47%, d=0.89), maturity date (nRMSE=0.97%, d=0.92), shoot biomass (nRMSE=10.97%, d=0.92), grain yield (nRMSE=6.19%, d=0.96), and actual evapotranspiration (nRMSE=9.96%, d=0.76) of drip-irrigated winter wheat in two years. The calibrated model was subsequently used to evaluate drip-irrigated winter wheat production in response to six N rates (0, 120, 180, 240, 300, and 360 kg ha(-1)) under 40 meteorological scenarios, and the results showed that grain yields, water use efficiency, irrigation water use efficiency, and net margins increased with increasing N application rates until it reached 180 kg ha(-1). Above 180 kg ha(-1), negligible changes were measured in these values as the N rate increased. The nitrogen physiological efficiency and nitrogen partial factor productivity were greatly improved at a N rate of 180 kg ha(-1), compared with those at a N rate of 240, 300, and 360 kg ha(-1). Consequently, N rate of 180 kg ha(-1) was the optimal nitrogen application rate for drip-irrigated winter wheat production. These results may provide a scientific basis for nitrogen management of drip-irrigated winter wheat in the NCP.

Automated summary

Improper nitrogen fertilizer application in winter wheat production in the North China Plain can lead to reduced nitrogen use efficiency and increased risk of non-point pollution. The study calibrated the DSSAT-CERES-Wheat model and found that 180 kg ha(-1) was the optimal nitrogen application rate for drip-irrigated winter wheat production in the NCP.