Evaluation of AquaCrop Model in Simulating Safflower Yield, Biomass and Water Productivity under Different Irrigation Amounts

Safflower is one of the most important oily plants whose yield decreases under water stress. Therefore, determining its response to different amounts of irrigation is very important. Hence,  the AquaCrop model for simulating safflower under different amounts of irrigation water was evaluated in this research. For this purpose, surface drip irrigation at three levels (T1, T2, and T3 represent 100, 66, and 33% of water requirement, respectively), furrow irrigation at three levels (T4: 100% water supply, T5: application of 50 mm of water at one time during flowering and T6: rainfed), and subsurface drip irrigation (T7) were considered. The results showed that the accuracy of this model for simulating yield (NRMSE <0.2), biomass (NRMSE <0.2) and water productivity (NRMSE <0.3) were in the categories of good, good and medium, respectively. In addition, the error of this model for simulating yield, biomass and water productivity was 22, 12, and 23%, respectively. AquaCrop efficiency was optimal for the three parameters so that the EF values ​​for these three parameters were more than 0.5. According to these results, the use of the AquaCrop model to simulate safflower is recommended.