Study on the In-Field Water Balance of Direct-Seeded Rice with Various Irrigation Regimes under Arid Climatic Conditions in Egypt Using the AquaCrop Model

Crop growth models are cost-effective and user-friendly tools for decision-makers to develop efficient in-field management strategies. These particularly important in countries such as Egypt, where the risk of water scarcity is inevitable. The present study aimed examine balance direct-seeded rice (Giza 178) under various irrigation regimes arid conditions during two growing seasons (2019 2020). Four regimes, namely, continuous flood with a fixed depth 5 cm, 3-, 6-, 10-day frequencies (FI, 3IF, 6IF, 10IF, respectively), were arranged randomized complete block design three replicates. Then, feasibility using AquaCrop simulating development was assessed. Five statistical indicators, including normalized root-mean-squared error (NRMSE), index agreement (d), coefficient determination (R2), Nash–Sutcliffe efficiency (EF), percent deviation (Pd), used evaluate performance AquaCrop. field trial results demonstrated that both 3IF 6IF best achieving highest biomass (21.0 t·ha−1, 3IF), yield (9.8 saving (18.3–22.4%, 6IF), making them apply Egypt. Moreover, simulation showed good correlation between observed simulated (Y) (R2 = 0.99 0.98 2019 2020, respectively). excellent canopy cover (CC) (B) (5.0 ≤ NRMSE 15.0, 0.97 d 0.99, 0.92 R2 EF 0.99). In addition, model acceptable components. Reasonably recorded crop actual evapotranspiration (ETact). Meanwhile, average Pd percolation (P) −15.3% 5.4% seasons. Overall, adequate accuracy CC, B, Y, ETact, P but relatively low ETact severe scarcity. Therefore, may serve valuable tool prediction even regions,