Short-term effects of agroforestry systems on soil health in Southeastern Brazil

The Soil Management Assessment Framework (SMAF) has successfully been tested as an objective tool to quantify land use and management effects on soil health, including under some Brazilian soil conditions. Thus, the objective of this study was to evaluate soil quality under five land uses, including: three types of agroforestry systems, a degraded pasture, and a secondary forest in Southeastern Brazil. The study was conducted at an experimental farm in Sapucaia, state of Rio de Janeiro, where diverse management practices had been implemented on plots with similar soil properties and management history prior to the establishment of three distinct agroforestry systems. We collected soil samples in the dry and rainy seasons, and assessed biological (soil organic carbon, β-glucosidase, microbial biomass carbon), chemical (pH, phosphorus, and potassium), and physical (bulk density, macroaggregation) soil properties. Using the SMAF scoring curves, the measured values were transformed (0–1 range) and an overall soil health index was calculated. We found overall SMAF scores values of 0.87, 0.88 and 0.87 for AS1, AS2, AS3, respectively, 0.83 for pasture, and 0.82 for forest, and the values differed significantly between land uses. The establishment of agroforestry systems over areas previously occupied with extensive pasturelands enhances soil fertility (12.79%) and soil physical indicators (6.5%). Our results show that AS not only enhance the provision of key soil ecological functions, but also restore soil quality of unmanaged pastureland.