Evaluation of irrigation scheduling and yield response for wheat cultivars using the AquaCrop model in an arid climate

Yield, soil water balance components and evapotranspiration-based water productivity (WPET) of three winter wheat cultivars were investigated using the AquaCrop model under arid conditions in Shiraz, Iran, for two consecutive years. The irrigation treatments were non-stressed (I-1) and post-anthesis water stress (I-2) with three wheat cultivars. Evaluation of the model was performed using the coefficient of root mean squared error (RMSE), normalized RMSE and R-2. The AquaCrop model performed well in simulating grain yield and final biomass production with R-2 > 0.90, and RMSE and normalized RMSE values less than 10. The I-1 treatment resulted in higher grain yield and biomass productivity than the I-2 treatment. The I-2 irrigation resulted in yield reduction of 21 and 24% in the 2006-2007 and 2007-2008 growing seasons, respectively, as compared with I-2. Using the measured grain yield and AquaCrop-simulated water balance, the amount of WPET was found to vary from 0.68 to 0.95 kg m(-3). The AquaCrop model was able to predict winter wheat biomass and yield production with a good accuracy in the arid conditions of this study and its ability to simulate these variables for different wheat cultivars' was especially notable. The AquaCrop model can be used to explore management scenarios to improve wheat water management in the study region.