ABSTRACT
A study was carried out to evaluate different methods used for estimation of reference evapotranspiration (ETo) and its effect on supplemental irrigation depth for corn, in the municipal districts of Seropédica and Campos, Rio de Janeiro, Brazil. Equations of linear regression were fitted having as dependent variable the Eto values obtained by the Penman-Monteith (PM) method, considered standard, and as the independent variable the ETo values obtained by the other studied methods. The results showed a good fitting to FAO-Penman, FAO-Radiation and Hargreaves (HG) methods, when compared to the Penman-Monteith (PM) method. Also, the fitting of the PM equation from HG data gave a good estimation of the demand of supplemental irrigation for different growing seasons in the two studied places.
Key words:
evapotranspiration; Penman-Monteith; supplemental irrigation