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

Abstract

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.

Modeling Sugar Beet Responses to Irrigation with AquaCrop for Optimizing Water Allocation

“…To overcome these limitations, more complex process-based models have also been adapted to simulate sugar beet production, such as Broom's Barn crop growth model [6,11], CSM-CERES-Beet model, or DSSAT [12], STICS [13,14], Greenlab [14,15], LNAS [14], and PILOTE [14,16]. In addition, the AquaCrop model [17], in an attempt to develop a simple, versatile, and robust water-driven model, has been calibrated and validated for sugar beet [18][19][20][21][22]. This model can simulate the yield response to water more accurately with a relatively small number of parameters than other models, which makes it more attractive for simulations under water-limited conditions or for irrigation scheduling.…”

“…Nevertheless, as for any model application, AquaCrop must be accurately calibrated and validated. In the case of sugar beet, earlier calibration and validation efforts in AquaCrop have yielded uncertain results [18][19][20][21][22]. One reason may be that important modifications in the quantification of soil water stress have been introduced in the new model versions (v6.0 and v6.1), which makes it necessary to carry out a new calibration and validation process.…”

Sugar Beet Agronomic Performance Evolution in NW Spain in Future Scenarios of Climate Change

“…whereĀ = mean observed data. Values of RMSEn smaller than 10% are considered as excellent, between 10 and 20% as good, between 20% and 30% as fair and, if larger than 30%, as poor [51].…”

“…In comparison with experimental data from 2011 and 2012 growing seasons, errors remained below 10% in all cases, except for one plot in 2012 (14.72%) ( Table 2). The yield RMSE value, of 2 t/ha, and the yield RMSEn, below 10% (rated as 'excellent', according to [51]), imply that the model would be adequate with a view to analyzing spatial trends for the crop in future scenarios of Climate Change.…”

“…This increase would be a direct consequence of the temperature rise, given that temperature was the only parameter modified in FAO-56 PM equation. below 10% (rated as 'excellent', according to [51]), imply that the model would be adequate with a view to analyzing spatial trends for the crop in future scenarios of Climate Change.…”