The Effect of Irrigation Water Management and Fertilizer Amount on AquaCrop Accuracy and Efficiency for Tomato Yield and Water Use Efficiency Simulation

Irrigation water and nitrogen fertilizer management have an effective effect on tomato yield and water use efficiency. So, it is important to know the best amount of irrigation and nitrogen fertilizer for tomato cultivation. Since doing farm researches need time and funds, it is necessary to use crop growth models like AquaCrop. Regarding that, data collected from Ismaeel Abad research station was used. The study was conducted there, irrigation was considered as four levels (E1: 50, E2: 75, E3: 100, and E4: 125 mm evaporation from pan class A) and fertility uses was considered as three levels (F1: 70, F2:100, and F3: 40 percent as fertility needed). At first, AquaCrop was calibrated without considering any fertility stresses using first year data. Then, F3 treatment in the first and second year was used to calibrate AquaCrop for fertility stress (40 percent as fertility needed). Results showed high correlation between observation and simulation values for yield (R2=0.915) and water use efficiency (R2=0.893). MBE, RMSE and NRMSE values showed a good precision for the model. The mentioned values were -0.02 (ton.ha-1), 0.42 (ton.ha-1) and 0.07 for yield, respectively, and -0.01 (ton.ha-1), 0.02 (ton.ha-1) and 0.03 for water use efficiency, respectively. Due to AquaCrop efficiency for simulating tomato yield (EF=0.41) and water use efficiency (EF=0.19), it is recommended to use AquaCop for simulating tomato yield and water use efficiency.