Evapotranspiration of a mango orchard in a semiarid site of Northeast Brazil

Data of a field experiment carried out in Petrolina, PE, Brazil were used to evaluate the evapotranspiration of the 1999 fruits productive cycle of a mango orchard. Sensors of net radiation, two levels dry and wet bulb air temperature and wind speed were installed above a mango tree in a micrometeorological tower. Soil heat flux sensors were installed at 5 and 15 cm bellow soil surface and soil humidity was measured by batteries of tensiometers installed each 15 cm from the surface to 200 cm soil depth. The individual mango tree evapotranspiration was obtained by two methods: Bowen ratio energy balance and soil water balance. Daily evapotranspiration increased slowly from 3.1 mm/day at the beginning of the observational period (June, 6) to 5.5 mm/day at the fruits growth period. Then, decreased to reach approximately 4.3 mm/day at full fruits maturity. The accumulative trees water consumption for the whole fruits productive cycle was 612 mm and 643 mm by the soil water and energy balance, respectively. For the experiment conditions, the water balance showed to be more efficient in the determination of the mango orchard daily evapotranspiration as compared to the energy balance method.