عنوان مقاله [English]
In order to determine the amount of irrigation water, it is required to calculate the amount of plant water requirement or evapotranspiration. The equations used to calculate evapotranspiration do not use the same climatic parameters and are not suitable for all climatic conditions due to their experimental nature. Potential evapotranspiration and reference evapotranspiration are different in concepts, equations, and contexts; however, many researchers have considered the use of the two terms to be the same. This study provides a comprehensive review of the ETp and ETo equations. In this regard, using meteorological data of synoptic station and lysimetric information of the region, reference evapotranspiration and potential were compared and studied based on four experimental groups during 4 years. The equations were calibrated using statistical indicators to select the most ideal model. The results showed that the evapotranspiration potential and the reference are completely different from each other, so that the temperature method in the equations of evapotranspiration, the reference and potential with RMSE 1.17 and 1.1, mm/day, respectively. which shows the difference between the two methods. Also, according to the studies from the potential evapotranspiration group and from the reference evapotranspiration group, the temperature group equations had the best performance, which has shown the superiority of this group of equations in areas with arid and semi-arid climate.