Surface energy fluxes and evapotranspiration of a mango orchard grown in a semiarid environment

Data from field experiments conducted in the semiarid climatic conditions of northeast Brazil were used to investigate the energy flux relations and evapotranspiration (ET) of a mango (Mangifera indica L.) orchard. The Bowen ratio-energy balance method was applied during the 1998-1999 fruiting cycles to estimate the energy balance components of the mango orchard, while the FAO Penman-Monteith approach was used for determining the reference evapotranspiration (ETo). Results indicated that latent heat flux density (lambda E) could be obtained, with reasonable precision, as a function of measured net radiation flux density (R-n). The percentage of R-n used as lambda E was higher for the fruit growth and fruit maturation phenological stages, and lower for the flowering and fruit fall stages. For both field campaigns, lambda E was found to be the major component of energy balance, comprising >70% of the available energy. Soil heat flux was always the smaller component, comprising <8%. Daily mean value of ET was higher during the 1998 fruiting cycle than that observed in 1999. Inversely, the ET increased approximately 6% from the 1998 to 1999 fruiting cycle. These results may be used for planning and management of irrigation for mangos grown in similar environmental conditions.