Impact of Shading of a Silvopastoral System on Microclimate and Botanical Composition of Polyphytic Pasture: A Preliminary Study in the Subtropics

The silvopasture system is an integrated system which has been widespread in tropical and sub-tropical climates. However, there is a lack of detailed studies regarding agroecological silvopasture systems. This study assessed whether the different levels of shading in an agroecological silvopastoral system influences the microclimate and botanical composition of polyphytic pasture. We used eight paddocks composed of a silvopastoral system in a subtropical climate, with different tree species arranged in simple lines with polyphytic pasture. In each paddock, we established three levels of visual shading (under the canopy, intermediate and full sun). The following microclimatic variables were recorded monthly during the daytime: illuminance, air temperature, air relative humidity, wind speed, and surface soil temperature. The samples of forages were separated into grasses, legumes and spontaneous, then fractionated into leaves, stems, and senescent material. We observed lower values of illuminance and surface soil temperature under the canopy, with differences between full sun and under the canopy at noon. Regarding the forage, the percentage of legumes was higher in full sun, and spontaneous species and leaves had high proportions under the canopy. Based on the results, the agroecological silvopastoral system changed the microclimatic characteristics and altered the plant composition of polyphytic pasture