Calibration of the Aquacrop Model to Simulate Sugar Beet Production and Water Productivity under Different Treatments

Abstract. The AquaCrop model, calibrated for 2002 and validated for 2003, is used to simulate sugar beet root dry yield, dry biomass, water productivity based on irrigation (WPi), and water productivity based on total water input (WPi+p) in an experimental field of the Karaj Sugar Beet Seed Institute (Karaj, Iran). Three irrigation treatments including full irrigation, 75% deficit irrigation, and 50% deficit irrigation were carried out in the main plots. The results of statistical comparison between the model output and observed data in the calibration (2002) and validation (2003) years showed that the AquaCrop model reliably simulated sugar beet yield and the biomass under different genotypes and irrigation levels. AquaCrop did a better job of simulating dry biomass than root dry yield. The findings show that by decreasing water input, including irrigation and precipitation, WPi, and WPi+p will increase. In total, statistical indicators and scatter plots indicated that the AquaCrop model had enough fitness to predict yield, biomass, and water productivity for the future. Keywords: AquaCrop, Yield; Biomass, WPi, WPi+p.