Soil water availability in a full sun pasture and in a silvopastoral system with eucalyptus

Abstract

Silvopastoral system is becoming an important strategy to reduce the impacts of climate variability and change on animal production. However, such system interferes in the soil water availability for the pasture, which is not already very well understood. Based on that, the aim of this study was to assess two pastoral systems: a full sun pasture system of Piata palisadegrass and a silvopastoral system with the same pasture associated with Eucalyptus rows, and their influence on soil water availability (SWA). The tree rows were oriented near East–West, with 15 m spacing. The treatments comprised SWA measurements at 0.00, 3.75, 7.50 and 11.25 m from the trees of the North row, and under full sun. A capacitance probe was used to measure soil moisture. During dry periods, SWA until 1-m depth was higher at the inter-row than under the trees, which indicates a faster water uptake by the trees; however when the inter-row was shaded, SWA was lower at the open pasture than at the inter-row. It occurred as a consequence of the shading and windbreak effects on evapotranspiration. Soil water recharge, during rainy days, was higher close to the trees, as a result of large water interception by trees and its subsequent deposition into the soil, increasing the amount of SWA at this position.