Evaluation of CropSyst model in simulation of Alvand variety of wheat

The purpose of this study was to investigate CropSyst model accuracy in simulating winter Alvand variety of wheat grain yields under different irrigation regimes. In this study, the CropSyst model was calibrated and evaluated for winter Alvand variety of wheat in the Eghlid region, Fars Province, under different irrigation treatments of 50, 75, and 100% of the field capacity. The agreement coefficient and normalized mean square error of calibrated model using Presley-Taylor evapotranspiration (ET) equation were 0.97, 11.4. The performance of the CropSyst was acceptable. Different irrigation regimes resulted in the difference in product performance and the min performance was obtained from the 50 percent regime. The productivity was different every year and the maximum yield was gained from 100% irrigation regime. Simulation error was minimum at 100% regime. Time of maturity was increased from 100 to 75 and 50% regime. Maximum of dry biomass and performance (ton/hectare) was obtained in 100% irrigation regime, and the minimum was obtained from 75% irrigation regime in the third year, so the performance of 50% regime was more than 75% in the third culture year. It could be from the complicated interaction of water, climate, soil, and plant in different years. The CropSyst can be used for winter Alvand wheat production simulation under different irrigation regimes (with no fertilizer deficit and no salinity).