Sensitivity Analysis of Crop Growth Parameters for Evaluation of AquaCrop in Potato Simulation under Different Irrigation Water Management in Kermanshah

Potato is one of the most important crops, which is very sensitive to the amount of irrigation water. This leads to a lot of research to determine its yield and water productivity in different irrigation conditions. Doing the researches waste time and cost. For this reason, researchers have suggested that crop growth models such as AquaCrop be sensitively analyzed and evaluated to simulate the crop under different conditions. Due to this issue, the present study was conducted using three irrigation treatments including T1: 100% supply; T2: 75% supply and T3: 50% supply of potato water requirement. To analyze the sensitivity step, Beven method was used. To evaluate AquaCrop, statistics criteria root mean square error (RMSE), normalized root mean square error (NRMSE), mean bias error (MBE), efficiency factor (EF) and agreement index (d) were used. The results showed that AquaCrop model was very sensitive to changes in water productivity parameters. The sensitivity of this model to changes in evapotranspiration coefficient and crop growth coefficient was moderate and to changes in initial crop canopy and crop decay coefficient was low. According to MBE values, AquaCrop model suffered a low estimation error in determining yield and water productivity. The error of this crop model was acceptable for determining yield (RMSE=1.5) and water productivity (RMSE=0.23). Its accuracy was also excellent for simulating yield (NRMSE=0.06) and water productivity (NRMSE=0.06). Based on the values of EF and d, AquaCrop was more efficient than water productivity in determining yield. Therefore, it is suggested that this crop model be used to simulate potatoes under similar conditions.