Simulation of Canopy Cover, Soil Water Content and Yield Using FAO-AquaCrop Model under Deficit Irrigation Strategies

The model was used to simulate tomato green canopy (CC), soil water (SWC) and final yield under deficit irrigation regimes as 1.25, 1.00, 0.75 and 0.50 percentages of crop evapotranspiration (ETc). The model was calibrated by used an experimental data and fine-tune to some conservative crop parameters. The NRMSEs in simulated CC and SWC in different treatments were 4.1–19.6 and 6.3–14.1%, respectively, that corresponds to overall averages of 0.92 and 0.84 for R2 in CC and SWC. In exception to severe water stress treatments, the model showed overestimation trend on biomass and yield, and proved satisfactory performance. The maximum simulated biomass and yield was 12.88 and 6.04 t/ha, respectively. The lower values in yield and biomass belong to less water applied treatments, that shows the model accuracy declines in high water deficiency. Simulated biomass WUEs varied from 2.26 to 3.73 kg/m3, likewise the yield WUEs varied from 1.06 to 1.71 kg/m3. The higher WUEs obtained in less water applied treatments, obviously, the WUE increases when applications of water decreased. The findings of water saving potential (WSP), recommended 0.75 of ETc to saved 25.09% of water with only 12.00 and 15.52% reduction in measured and simulated yield.