Simulation of sugar beet growth under water stress using AquaCrop model

Simulation models that illustrate the effects of water on crop yield are useful tools to optimize water productivity and improve farm level water management. In this study, the performance of AquaCrop model to simulate canopy cover, biomass and yield of the sugar beet and soil water content under six irrigation treatments was evaluated. The irrigation treatments were consisted of full irrigation (T1) as control, removing last irrigation (T2), applying irrigation water at 10% greater than control (T3), applying irrigation water at 10 (T4), 20 (T5) and 30% (T6) less than control. The experiment was conducted at Aleshtar in Lorestan province during growing seasons of 2014 and 2015, using a randomized complete block design. The first and second year’s data were used for calibrating and validating of the model, respectively. Evaluation of the model was performed using the coefficient of residual mass, root mean square error, normalized root mean square error, index of agreement and coefficient of determination. According to the results, the normalized root mean square error in the canopy cover and soil water content simulations for calibration was 5.18 to 9.41 percent and 9.91 to 17.23 percent, respectively and for validation was 6.64 to 9.2 percent and 12.36 to 25.77 percent, respectively. Also, the normalized root mean square error in the yield and biomass simulations for calibration was 7.3 and 8.67 percent and for validation was 7.69 and 9.82 percent, respectively. The results indicated a good performance of the AquaCrop Model in simulating the canopy cover development, biomass and yield of sugar beet and soil water content under different irrigation managements. Therefore, the AquaCrop model can be used to explore management scenarios to improve the sugar beet water management over the study region.