Abstract

ORTIZ C., Randon  and  CHILE A., Maritza. Métodos de cálculo para estimar la evapotranspiración de referencia para el Valle de Tumbaco. Siembra [online]. 2020, vol.7, n.1, pp.1-10. ISSN 2477-8850.  https://doi.org/10.29166/siembra.v7i1.1450.

The precise determination of the reference evapotranspiration ensures computing real values of the crop water requirements. The objective of the study was to evaluate nine methods to determine the reference evapotranspiration for the environmental conditions of the Tumbaco Valley located in the province of Pichincha (Ecuador). Monthly climatological data from La Tola station was used to estimate ET . The methods used to determine ET were FAO56, Class A pan, modified Thornthwaite, Hargreaves, Jensen-Haise, Makkink, Priestley-Taylor, Turc and FAO Radiation. The following inferential parameters were used in the analysis, considering FAO56 as base: the absolute mean error, the coefficient of determination, the concordance coefficient and the confident coefficient. The results for monthly average climatological data showed that: i) the FAO Radiation method presented good statistical indexes; ii) the methods Jensen and Haise, Makkink and Priestley and Taylor presented poor indexes; iii) the methods Class A pan, modified Thornthwaite, Hargreaves and Turc presented o the lowest inferential values. In conclusion, the method that should be used to estimate monthly ET for the agro ecological environment of the Tumbaco Valley with good accuracy is FAO56.

Keywords : Penman-Monteith; irrigation requirements; water budget; Ecuador.

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