Abstract

TORO-TRUJILLO, A. María; ARTEAGA-RAMIREZ, Ramón; VAZQUEZ-PENA, M. Alberto  and  IBANEZ-CASTILLO, L. Alicia. Estimation models for the reference evapotranspiration value in the northern banana zone of Antioquian Uraba (Colombia). Agrociencia [online]. 2015, vol.49, n.8, pp.821-836. ISSN 2521-9766.

The standard method for estimating evapotranspiration (ET) to calculate the water requirement of crops is the function used by FAO Penman - Monteith (PM), but uses variables not available in the study area. Therefore, a methodology to calculate the reference evapotranspiration (Eto) in the northern banana-growing region of Antioquian Urabá, Colombia is required. The aim of this study was to evaluate the reliability of methods Hargreaves and radiation (Eto-PM-Samani) regarding the PM method to calculate Eto. To estimate the solar radiation we generated the Angstrom-Prescott coefficients (coefficients of stations), along with the coefficients a=0.25, b=0.50, a=0.2, b=0.52 and a=0.29, b=0.42, plus two methods. The estimation of solar radiation with the coefficients of the ap and bp stations presented the lowest values of the root square mean error (RSME) and the relative error (RE), followed by the Frere 1978 method. The best estimate of evapotranspiration was obtained with EtoHS1985 because it had the lowest values of RSME and RE and the highest values of R², whereas EtoHargreaves and Eto-PM-Samani methods showed similar RSME and RE and are better for the first; with the linear model between Eto PM and EtoHS1985 we reduced the error and had R²>0.8.

Keywords : Angstrom-Prescott; evapotranspiration; Hargreaves; Penman-Monteith.

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