| In order to evaluate the suitability of the AquaCrop model in the Guanzhong area and explore the best irrigation scheme, the model was used to simulate and validate the growth of summer maize under different irrigation and nitrogen levels. Then,we used the calibrated model to study the changes of summer maize yield and water use efficiency under 11 kinds of irrigation scenarios under three precipitation types. The results showed that the AquaCrop model well predicted the summer maize grain yield and biomass under different irrigation and nitrogen levels in Guanzhong. The coefficient of determination(R2), root mean square error(RMSE), normalized root mean square error(NRMSE), consistency(d) and model efficiency(ENS) between the simulated and observed values of yield were 0.919,0.249 t·hm-2,4.112,0.977 and 0.915 for all treatments, respectively; As for biomass, R2, RMSE,NRMSE,d and ENS between the simulated and observed values were 0.860,0.977 t·hm-2,6.407,0.933 and 0.694 for all treatments,respectively. Then using the calibrated model to study the changes of summer maize yield and water use efficiency in 11 kinds of irrigation scenarios under three precipitation types. Based on the simulation results and combined with the physiological water requirement of summer maize, the water requirements during the jointing and tasseling stages should be emphasized. Optimized irrigation scheme for different precipitation year are: if we can guarantee good seedling emergence, irrigation is not needed during the wet year; in the normal year, 60 mm can be irrigated during the jointing period; in the dry year, 60 mm of irrigation water should be applied during jointing and tasseling. These schemes will guarantee the stable production and high yield. |