Abstract

HERNANDEZ-DIAZ, Daniel; ARTEAGA-RAMIREZ, Ramón; SANGERMAN-JARQUIN, Dora Ma.  and  FRANCISCO-CATARINA, Magdalena. Comparative study of two equations with respect to FAO56 Penman-Monteith in Guanajuato. Rev. Mex. Cienc. Agríc [online]. 2024, vol.15, n.7, e2838.  Epub May 27, 2025. ISSN 2007-0934.  https://doi.org/10.29312/remexca.v15i7.2838.

The estimation of reference evapotranspiration (ET0) has been widely used in irrigation engineering to calculate crop water requirements. The correct estimation of ET0 represents a key step in planning and managing water resources. Experts recommend the FAO56 Penman-Monteith method as a standard method for estimating ET0, with the disadvantage that it requires a lot of data on meteorological variables for its execution. This study aimed to estimate the daily reference evapotranspiration by the Hargreaves-Samani and Priestley-Taylor methods during the 2001-2006 period for five automatic weather stations in the state of Guanajuato; the results were compared with those of the FAO56 Penman-Monteith (FAO56 P-M) method to select the most accurate alternative method and determine the distance from any station at which the ET0 data estimated with each of the methods were considered valid. The root means square error (RMSE) and the coefficient of determination (R2) were used to evaluate the performance of the methods compared to the FAO56 P-M. As a result, it was found that Hargreaves-Samani is the best alternative method to estimate ET0 in the five stations in the state of Guanajuato. The distances determined from a station where the data of a method are valid are 93.02, 124.65, and 36.44 km for Hargreaves-Samani, Priestley-Taylor, and FAO56 Penman-Monteith, respectively.

Keywords : Hargreaves-Samani; Priestley-Taylor; reference evapotranspiration.

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