Water Balance in a Tropical Eucalyptus plantations in the Doce River Basin, Eastern Brazil

The rapid expansion of Eucalyptus plantations in Doce river basin, eastern Brazil, by changing the grassland and the natural surface cover in the savanna ecosystem, can potentially cause significant changes to water resources of the region. Especially for the higher amount of water transpired by the trees. The objective of this work was to model the water balance in an area cultivated with clonal E. grandis × urophylla in the Doce river basin, state of Minas Gerais, Brazil. Between October 2007 and September 2010, the water balance model estimated the daily variation of available soil water as a function of the water loss via evapotranspiration. Components of the evapotranspiration process were estimated by modifying the stomatal resistance of the Penman-Monteith equation. Evapotranspiration (ET) and precipitation (P), during the three years, were 3,467 mm and 3,439 mm, respectively. The evapotranspiration/precipitation ratio (ET/P) was of 1.01. Precipitation input was approximately balanced by water losses to evapotranspiration, without significant changes to water stored in soil and groundwater.