Analysis of water demand for winter wheat production in Cangzhou Area using CERES-Wheat model

Crop growth simulation model provides a new method for water resources analysis of farmland and optimization of management measures for water use efficiency improvement in crop production. The characteristics of annual variation of simulated yield, evapotranspiration (ET), plant transpiration (EP), soil evaporation (ES), and water productivity (WP) of winter wheat in Cangzhou area in the North China Plain during 19812014 were analyzed using a calibrated CERES-Wheat model. The calibration of CERES-Wheat model was done using a two-years’ field experiment with 4 irrigation treatments conducted in Wuqiao County of Cangzhou City, Hebei Province. The irrigation treatments included T0 (no irrigation during wheat growth period), T1 (75 mm irrigation at jointing stage), T2 (75 mm irrigation at jointing stage and anthesis stage, respectively), T3 (75 mm irrigation at regrowing stage, booting stage and anthesis stage, respectively), with a preplanting irrigation of 75 mm for all treatments. The winter wheat cultivar ‘Shijiazhuang 8’ was taken and the cultivar coefficients of the model was obtained by a program of genotype coefficient calculator (GENCALC) combined the method of ‘trial and error’. The calibrated model was proved that it adapted for predicting yield and ET of winter wheat and could be used in this district. Based on the calibrated CERES-Wheat model, the annual yield, ET, EP, ES, and WP of winter wheat were simulated using the meteorological data during 19812014 by the method of scene simulation. The quantitative relationship model between ET and WP was built according to the simulated data, and the calculated economic ET was 435 mm when WP got the maximum value. Subtracting the average rainfall from the average ET during 19812014, the average water demand mainly including irrigation water and soil water during winter wheat growth period was 189 mm (T0), 264 mm (T1), 298 mm (T2) or 319 mm (T3), and the corresponding average yield for the 4 irrigation treatments was 4 144 kghm^-2, 7 293 kghm^-2, 7 301 kghm^-2 and 8 245 kghm^-2, respectively. Deducting the ES by taking proper cultivation management measures like plastic film mulching, 80 mm (T0), 71 mm (T1), 71 mm (T2) or 70 mm (T3) of water could be saved during winter wheat growth period, and if the average rainfall was deducted from the average EP under this condition, the average water demand for the 4 irrigation treatments was 109 mm (T0), 193 mm (T1), 227 mm (T2) and 249 mm (T3), respectively. These conclusions can be used to develop quantitative water management measures for winter wheat planting in Cangzhou area in the North China Plain.