Microclimate, forage production and carbon storage in a eucalypt-based silvopastoral system

Abstract

This study aimed to assess microclimate regulation, forage production, and carbon storage as Environmental Services (ES) of a Silvopastoral System (SPS). The evaluations were conducted from June 2019 to June 2021 in a ranch establishment in Uruguay. The SPS was implanted in 2012 with trees of Eucalyptus grandis in triple rows and alleys of Campo Natural (CN), the grazed native grassland. The area of assessment presented a density of 425 trees ha−1, and the treatments were: i) Full Sun (FS), representing the CN without trees, the standard condition at the zone of study; ii) SPS alley; iii) SPS under trees. The microclimatic variables evaluated were air temperature and relative humidity, wind speed, black globe temperature, flux density of photosynthetic active radiation, and solar global radiation, which were used to calculate indexes of animal thermal stress. Events of heat waves were identified and used for data analysis. The forage biomass production was seasonally evaluated, and the carbon storage estimation considered 60 cm of soil depth, aerial forage carbon, and the stem of trees. The results indicated higher thermal comfort in the SPS during heat waves, especially under trees. The inclusion of convection and radiation processes in thermal exchange allowed obtaining differences between positions. The forage biomass was reduced in the SPS with respect to the FS condition, presenting the highest difference during winter and the lowest in spring. Carbon storage was promoted in the SPS due to the biomass accumulation in trees. The results obtained suggest that the SPS is an integrated agricultural production scheme in which multifunctionality can be achieved, and specific ES can be promoted.