BALANCE OF WATER AND ENERGY FOR EUCALYPTUS PLANTATIONS WITH PARTIAL SOIL COVER

http://dx.doi.org/10.5902/1980509813329Eucalyptus plots with initial development ages presented discontinuity in soil cover, resulting in greaterexposure of the leaves to wind and solar radiation, which alters soil-plant-atmosphere interactions. Theobjective of this study was to study the components of the water and energy balances along the first yearof eucalyptus development in the Brazilian coastal plain region. The experimental site is located in anarea belonging to the company Fibria in the municipality of Aracruz, Espírito Santo state, Brazil. Thespace between the planted eucalyptus trees in the area studied was 3 x 3 m and the data of planting wason August 15th , 2004. The period of study lasted from the planting date until the plot reached an ageof 19 months. It was verified that there was a greater availability of energy during the summer and theprecipitation directly influenced the energy balance where during the period of study the energy available necessary for evapotranspiration was always greater than the fraction necessary for heating the soil-plantatmospheresystem, presenting a λE/Rn ratio of 59.57%. It was also observed that the water balance with themodeled evapotranspiration showed a good correspondence with the observed moisture content, presentinga determination coefficient of 0,94. In the majority of trees, greater indices of leaf and root system areasfavored evapotranspiration, indicating that most energy available was utilized for changing the phase ofwater