Calibration and Use of Evapotranspiration Equations Under Arid Climatic Conditions

Evapotranspiration (ETr) was measured for two years for an alfalfa-grown crop in three drainage-type lysimeters. The ETr was also estimated using ten well-known equations with climatic data obtained from a weather station in the area and were compared with the measured evaporation from a class A pan. The best correlation was obtained with evaporation from the A pan. The Penman method resulted in the best estimation among all methods used for ET estimation. Wind function was also developed for local conditions. The values of the developed wind function could be used to estimate accurately the ETr values under the arid climatic conditions