ESTIMATE OF THE REFERENCE EVAPOTRANSPIRATION OF THE POÇO VERDE REGION - DOI: 10.7127/rbai.v11n500764

The Poco Verde region is the largest bean producer in the State of Sergipe and the twelfth in Brazil, being the second largest producer of irrigated corn in the State. Most of the cultivated area is without irrigation, which provides low productivity compared to regions that use irrigated agriculture, such as the municipality of Simao Dias that grows irrigated beans and corn, reaching almost twice as much productivity (IBGE, 2015). Irrigation is an alternative to increase productivity, but without proper management it results in wasted water and low productivity. The use of reference evapotranspiration (ETo) represents a very widespread management in the world. However, there are several methods for estimating it. In this context, the objective of this work was to estimate the ETo by the empirical methods of Camargo, Hargreaves-Samani, Blaney-Criddle and Linacre, and to compare them with the Penman-Monteith method, standard of the United Nations, for the climate conditions of the city of Poco Verde at the Sergipe State, using climatological data from the automatic meteorological station of the National Meteorological Institute (INMET). The correlation between the Camargo, Hargreaves-Samani, Blaney-Criddle, Linacre and standard Penman-Monteith methods was performed based on statistical indicators, in order to observe the precision given by the correlation coefficient (r) that is associated to the deviation between estimated and measured values indicating the degree of dispersion of the data obtained in relation to the mean. The Hargreaves-Samani method had a good correlation in the estimation of ETo with the Penman-Monteith method.