Evaluation of AquaCrop and WOFOST for Simulation of Sugar Beet Yield and Water Productivity under Different Irrigation Intervals and Fertilizer Stress

Irrigation interval and fertilizer amount have an important effect on sugar beet yield. This study was conducted to evaluate AquaCrop and WOFOST models in terms of simulation of sugar beet yield and water productivity at Qazvin agricultural research station during three years. For this purpose, two treatments were considered; irrigation water management in four levels (6, 9, 12; and 15 days) and Boron fertilizer amount in three levels (21, 30 and 39 kgha-1; as low, medium and proper amounts, respectively). RMSE values for yield simulated by WOFOST and AquaCrop models were 0.29 and 1.07 ton.ha-1, respectively. RMSE values for water productivity simulated by the proposed methods were 0.61 and 0.14 kg.m-3,, respectively. RMSE values for yield simulated by WOFOST and AquaCrop for irrigation treatments were in the range of 2.78-3.50 and 1.91-2.26 ton.ha-1, respectively, and for fertilizer treatments were in the range of 2.34-4.51 and 1.14-2.94 26 ton.ha-1, respectively. The amount of error for water productivity simulated by WOFOST and AquaCrop models for irrigation treatments were in the range of 0.34-0.48 and 0.16-0.38 kg.m-3, respectively, and for fertilizer were in the range of 0.30-0.56 and 0.15-0.41 kg.m-3, respectively. Thus, AquaCrop model had better accuracy compared to WOFOST model for separated treatments. In general, WOFOST accuracy was good. According to the results, it is recommended by caution to use WOFOST model to simulate sugar beet in the simulation of irrigation treatments with fertilizer.