Sensitivity Analysis of Basil Crop Growth Parameters in the Aquacrop Model under Different Nitrogen Fertilizer Stresses

Crop model parameters are influenced by different management and environmental conditions. Sensitivity analysis is recognized as an effective approach for identifying the most influential parameters in the modelling process and output uncertainty assessment. In present study, the sensitivity of AquaCrop model parameters for basil was evaluated under different nitrogen fertilizer stresses. For this purpose, an experiment was conducted in the research greenhouse of the College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran. Crop growth parameters used for sensitivity analysis include normalized water productivity (Wp < sup>*), initial canopy cover (CC0), maximum transpiration coefficient (), canopy growth coefficient (CGC) and canopy decline coefficient (CDC) which analyzed by Beven (1979) approach. The results showed that the highest sensitivity of the AquaCrop model was due to the change in the Wp < sup>* parameter. Therefore, it is necessary to calibrate this parameter under different environmental conditions and for diverse crop species to increase the accuracy and performance of the model. Also, comparison of the sensitivity coefficients obtained for each of the growth parameters showed that by increasing nitrogen fertilizer stress, the model sensitivity also increased. But the growth rate was not the same among the selected parameters. In other words, the impressibility of parameters was different from nitrogen deficiency.