AquaCrop Model Performance Under Various Reference Evapotranspiration Equations for Simulating the Growth and Yield of Wheat

ABSTRACT This study evaluated the performance of the AquaCrop model in simulating wheat yield, dry matter and evapotranspiration under various irrigation levels (50%, 75% and 100% water requirements) and seed densities (120–280 kg ha −1 ) over 2 years. The model's accuracy was tested via nine ET₀ equations, including Penman–Monteith (PM), Penman–FAO (PFAO), Hargreaves–Samani (HS), Blaney–Criddle (BC), Turc, Evaporation Pan (PAN), Jensen–Haise (JH), Priestley–Taylor (PT) and FAO–radiation (RAD). The results revealed that AquaCrop effectively simulated evapotranspiration, dry matter and yield during calibration and validation. Importantly, the model demonstrated acceptable accuracy in simulating wheat yield across all evaluated ET o calculation equations. The normalized root mean squared error (NRMSE) values were 0.08 for HS, 0.09 for Turc, 0.10 for both BC and PM, 0.11 for PT, 0.14 for both PAN and PFAO and 0.17 for JH. This study highlights the potential of using simplified ET o equations such as HS, Turc, BC, PAN and JH instead of more complex equations such as PM, PFAO and PT as a practical approach for modelling crop growth and yield in regions with limited meteorological data. This provides a useful framework for researchers and practitioners working in water‐scarce environments to simulate crop performance effectively via the AquaCrop model with reduced data requirements.