Evaluation of AquaCrop Model in Simulating Yield and Water Use Efficiency of Three Corn Hybrids under Hot-Dry Climatic Conditions

Nowadays, crop simulation models have a key role in crop growth and yield estimation, production planning, production economy and identifying strategies for crops supply. In this research, AquaCrop model was calibrated and evaluated for three corn hybrids; (DC 370, ZP 677, and SC 704) under different levels of water supply (non stress, mid stress, and severe stress) and nitrogen rates (0, 120, 180, and 240 kg N/ha). For model validation, normalized root mean square error (nRMSE) and determination of coefficient (R2) were used. Result showed that the model simulated grain yield of corn hybrids with high precision. Simulation precision decreased with increasing drought stress. The lowest nRMSE (7.5%) and highest R2 (0.93) were obtained from ZP 677 hybrid. The model simulated corn biological yield with more deviation percentage than grain yield. However, it´s variation trend due to variation in drought stress level or nitrogen fertilizer predicted well according to field experiment. nRMSE ranged from 6.8 and 10.9, while R2 varied from 0.82 to 0.92. AquaCrop model simulated the variation of water use efficiency of corn hybrids with reasonable accuracy, so that it´s value increased with increasing drought stress and nitrogen fertilizer application, while, model outputs in most situations were lower than measured values. The best model validation result (nRMSE=6.4% and R2= 0.93) obtained from ZP 677 hybrid. According to the results were obtained, AquaCrop model can be applied with high reliability for simulating corn yield under similar climatic regions of this experiment