Evaluation of models to estimate the actual evapotranspiration of soybean crop subjected to different water deficit conditions

Abstract Optimization of water use for irrigation will only be possible with the adjustment management, which is directly related to correct estimate actual evapotranspiration crop. The present study aimed evaluate different mathematical approaches used in estimating a new soybean cultivar (BRS 7581RR) subjected deficit conditions. For this, ETa estimated by FAO56 Dual, Jensen and Hermann, AquaCrop Ritchie models was evaluated. experimental design randomized five treatments four replicates. Irrigation management conducted so as maintain levels available soil (AW). T1 treatment performed applying 80 100% AW; T2 treatment, allowed variation 60 80% T3 it 40 60% T4, from 20 40% T5, 0 20% AW. results showed that Dual model better performance estimation winter conditions most treatments, NSE ranging 0.42 0.83. In summer, Hermann best results, 0.70 0.94.