Chemical and microbial attributes as indicators of erosion stabilization in gullies in the Atlantic Forest biome

Water erosion is a natural phenomenon that is sometimes intensified by anthropogenic actions. The objective of this study was to analyze the soil attributes of the soil in gullies with different formation times. Soil samples were collected at 0–10 cm depth on the external and internal faces of gullies in the initial (IN), intermediate (INT), mature (MA) and senile (SE) stages. There were higher levels of total organic carbon (TOC), mineral-associated OC (MAOC), β-glucosidase, total glomalin-related soil protein (T-GRSP) and arbuscular mycorrhizal fungi spore abundance (SPA) on the external faces of the IN, INT and MA stages when compared to the internal ones. For the SE stage gully, there was no difference between the faces for most of the attributes evaluated, showing the benefits of regeneration of natural vegetation and, consequently, less potential for soil erosion. Considering the internal face of the gullies, the highest values of TOC, particulate OC, MAOC, Labile organic C, β-glucosidase, T-GRSP, SPA and AMF species richness were found in the gully in the SE stage. The effect of erosion on soil chemical and microbiological attributes is more intense in gullies at the initial formation stages (IN, INT, MA). It is concluded that the attributes related to organic matter (fractions) and microbiota (β-glucosidase activity, T-GRSP, SPA, total species richness) of the soil are good indicators to evaluate erosion stabilization in gullies.