Developement of a Model for Estimating Evapotranspiration from an Open Row Crop Field

Abstract

An investigation was made to estimate soil surface evaporation separately from evapotranspiration. Monteith's equation was used in this study.
A two-reservoir soil moisture model was adopted. Transpiration was set equal to the potential rate until soil water potential reached-0.063 MPa (pF 2.8): beyond which the ratio of actual tanspiration to potential transpiration decreases with decreasing soil moisture potential. The model for soil evaporation was also divided into a potential rate stage limited by the available energy, and a non potential rate stage regulated by soil resistance.
The results were in good agreement with the evapotranspiration estimated by the Bowen ratio method.