Soil changes in a subtropical seasonal forest chronosequences in the south of Brazil

The abandonment of field crops and the vegetation recovery in exhausted soils have been a recently studied subject as a way to assess the forest role on the soil recovering. The aim of this study was assess changes in the chemical (14 variables) and grain size (sand, silt, and clay) soil features in four forests chronosequences grew over abandoned field crops in the edge of the Brazilian Southern plateau, Rio Grande do Sul State. There were selected 25 forests aging from 5 to > 100 years old in areas of slopes and highlands where samples of Leptosols and Regosols were collected at 15cm in depth. The Fisher's Discriminant Analysis showed that some variable groups of soils can distinguish significantly the soils under different forest ages. Six chemical features of soil fertility were the best monitoring indicators of areas impacted by agriculture. Changes in soil did not occur in a linear way towards time.