The aim of this work was to verify if the presence of trees and its height in formed silvipastoral systems with eucalyptus planted in rank can modify the microclimate and improve the environment for bovine raising during the day in summer. It was evaluated the microclimate of the environment in formed silvipastoral systems in rank of eucalyptus with 8 m, 18 m and 28 meters of height, compared to a system no shade in the summer. The experimental design was a split plot with six hour time in sub parcels. The systems are made up of parcels and the months as block in four replications and the interaction hour × system. The air temperature, black globe temperature, relative humidity and wind speed were observed to create the following indexes for thermal comfort: temperature-humidity index; black globe-humidity index; heat load index and the radiant thermal load. Excepted for the relative humidity, there was interaction for time × system for all variables and indexes. Interaction occurred for: air temperature at 10 a.m. and 6 p.m.; wind speed from 8 a.m. to 4 p.m.; temperature humidity index at 10 a.m. and 12 p.m.; black globe temperature, black globe humidity index, heat load index, and radiant thermal load at all the hours. During the summer, the system with shade of 28 m trees had the lowest average of black globe temperature; wind speed; black globe humidity index; radiant thermal load index; and heat load index. There was a reduction of wind speed average in systems 8 m, 18 m and 28 m trees in, respectively, 20.7; 50.0 and 48.0% in relation to no shade system; however it was not proportional to the height, with influence of the rank porosity and pantries height. Nevertheless, for radiant thermal load index the reduction was proportional to the height of the trees with 10.24; 12.49 and 20.76%, respectively, for 8 m, 18 m and 28 meters of height. There was a reduction of the thermal stress in the environment due to the presence of trees, being the heat load index thermal the index that better demonstrated the effect, despite of not being proportional to the rank height.

The expansion of silvipastoral system could be achieved through reform of forage grass monoculture system in soil with a sandy surface layer, but ranchers are concerned that there may be competition for soil water between the pasture and eucalyptus.The objective of this study was to evaluate the moisture and water available in silvipastoral system and forage grass monoculture in different seasons, distance of eucalyptus trunks or terracesat 1 m depth ina Hapludox soil.Reclamation forage grass monoculture was held with cassava (2008-2010), being the eucalyptus seedlings planted simultaneously to the planting of cassava in August 2008. Two systems of terraces spaced 20 m were evaluated: a) forage grass monoculture stargrass (Cynodon nlemfuensis) system and b) silvipastoral system (2x3) +20 with stargrass forage and eucalypttree(Eucalyptus grandis).The soil water content(θ) was determined in four seasons for eucalyptus tree had 2-3-year-old, from July/2010 to March/2011. Use the following sampling positions: 2.5, 5 and 10 m away from the rowsof eucalyptus trees downstream of the terraces. Disturbed soil samples were collected at 0-0.2 m (A horizon –sandy texture), 0.2-0.4 (Bw1–sandy loam texture), and 0.4-0.6, 0.6-0.8 and 0.8-1.0 m (Bw2 –sandy clay cloam). Field capacity and permanent wilting pointwaters contents was determined.The silvipastoral system compared to forage grass monoculture system decreases θ on the horizon Bw2.The θ was within the limits of the water available in the horizons A and Bw1 for the stargrass forage between the double rows of eucalyptus trees in silvipastoral system during the seasons. Thesilvipastoral system implemented does not compromise θ to stargrass forage at 0-0.4 m depth.