Determination of Normalized Water Productivity and Sensitivity Analysis of AquaCrop Model for Radish Product

AquaCrop model simulates biomass yield under deficit irrigation management. This model developed by FAO and requires less input data than other similar models. One of the input data of this model is the normalized water productivity (wp*) that should be known for each plant. This parameter for the radish plant, which is part of the C3 plant, has not yet been determined. Therefore, the first objective of this study is to determine it for Pakdasht area and its second objective is to analyze the sensitivity of the Aquacrop model to the input data of reference evapotranspiration (ETo), Wp*, initial canopy cover (CCo) and maximum canopy cover(ccx). This research was carried out in the research center of Abourayhan Campus, University of Tehran in Pakdasht District during 2018 crop year. According to the results of this study, normalized water productivity of radish was determined to be 11.3 g / m2. The results of sensitivity analysis showed that the AquaCrop model has the most sensitivity to the normalized water productivity parameter for full irrigation conditions, in which the sensitivity coefficient was estimated to be 0.88. Under deficit condition, the model is most sensitive to the ETo parameter, and the less irrigation is more severe, the sensitivity coefficient increases. The sensitivity coefficient for 60% deficit irrigation was -10.99.