Sensitivity Analysis of Potato Growth Parameters using AquaCrop Model Under Different Irrigation Managements (Case Study: Shahrekord)

Sensitivity analysis is one of the steps in preparing a crop model before calibration, which helps researchers to find more information about the effects of each parameter on the results to increase the accuracy of the model in the calibration stage. Because of the capabilities of AquaCrop, researchers use it to simulate crop growth in different irrigation managements. The present study was conducted to analyze the sensitivity of AquaCrop in simulation of potato biomass to changes in crop growth parameters includes normalized water productivity (WP*), maximum transpiration coefficient (KCTrx), initial canopy cover (CC0), canopy growth coefficient. (CGC) and canopy reduction coefficient (CDC) using Baven (1979) method. Data were collected from a research farm in the Chahartakhteh area of Shahrekord, Iran, during two years. These data included the effect of two factor includes: irrigation method (surface and subsurface drip irrigation) and different irrigation levels (FI: 100% water supply, RDI80: 80% water supply and RDI65: 65% water supply). The results showed that the model AquaCrop had the highest sensitivity to WP* and the lowest sensitivity to CCo and CDC. The trend of potato biomass changes was inverse for CDC and direct to other parameters. Increased water stress in WP* and KCTrx parameters decreased the sensitivity of AquaCrop model. Therefore, in order to calibrate the AquaCrop in the conditions of a large difference between the simulated and observed values, it is better to change WP*. Otherwise, it is suggested to change the other parameters.