Actual Evapotranspiration for Sugarcane Based on Bowen Ratio-Energy Balance and Soil Water Balance Models with Optimized Crop Coefficients

Evapotranspiration is an important parameter to evaluate soil water deficit and use efficiency, especially in locations with irregularly distributed precipitation. The aim of this study was assess the daily actual evapotranspiration (ETa) estimated by Thornthwaite Mather balance adapted for crops (ThM) dual Kc method crop coefficients optimized from inverse modeling adjustment suggested FAO-56 bulletin. models were evaluated determined Bowen ratio – energy (ET?) sugarcane at full canopy closure grown Alagoas state, northeastern Brazil. objective function problem defined terms ET? ETa ThM or optimizing single coefficient (Kc) basal Kcb, respectively. Optimized (1.05) Kcb (1.03) lower than those adjusted FAO56 (Kc = 1.25 1.20), slightly higher obtained experimentally (1.01 ± 0.08). had similar high precision (r2 > 0.79) accuracy (dm 0.93 RMSE < 0.30 mm d?1). However, using overestimated both models.