Abstract Soil health has been used worldwide for soil monitoring in different soil use and management. The objective of the study was to evaluate, in a Subtropical Oxisol of the Campos Gerais region in Paraná state, if the Visual Evaluation of Soil structure (VESS) and Soil Management Assessment Framework (SMAF) approaches allow evaluate soil response to various land uses or soil tillage used in the region. The land use and tillage practices consist of conventional tillage, minimum tillage, no-tillage, and secondary forest. The SMAF was used as a tool to evaluate the soil health using five indicators: pH, phosphorus, potassium, bulk density, and soil organic carbon. The VESS was used to determine the soil structural quality. The secondary forest showed the best soil structure and tillage practices declined soil structure quality. Similarly, the soil health index was higher in secondary forest compared to tillage practices, and the tillage had little effect on soil health. The SMAF showed differences between land use and tillage practices. The VESS method could be used as a complementary tool for monitoring the soil health. management state (VESS (SMAF notillage, notillage no no-tillage indicators pH phosphorus potassium density carbon quality Similarly

ABSTRACT To meet the growing demand for bioenergy such as ethanol, the area cultivated with sugarcane has expanded, especially in areas currently occupied by extensive pastures with low productivity. However, land-use change (LUC) from pasture to sugarcane implies changes in soil structure and variations in organic matter (SOM) stored in the soil. This study aimed to quantify the impact of LUC on organic matter fractions – particulate organic matter (POM) and mineral-associated organic matter (MAOM) – in soils with contrasting textures, and to explore the correlations between possible alterations in soil aggregation and the effects on carbon (C) stocks and SOM fractions. The study was conducted in two areas in Central-Southern Brazil, one with clayey soil and the other with sandy soil. In each area, a LUC chronosequence was evaluated: native vegetation (NV), pasture (PA), short-term sugarcane (SC1), the area analyzed during the sugarcane plant cycle; long-term sugarcane (SC2), area analyzed during the ratoon sugarcane cycle. In each use, undisturbed and disturbed samples were collected and macroaggregates and microaggregates were obtained by wet sieving and soil samples. In these samples, the physical fractionation of the SOM and the calculation of the C contained in each fraction of the SOM and C total stock of each use were performed. The conversion of NV to PA increased C stocks by more than 50 %, mainly in the MAOM fraction, and maintenance of macroaggregates (more than 80 %) in sandy site; and reduction of C stocks by more than 30 %, mainly MAOM in the clayey area. These benefits acquired from grazing on sandy area were lost with the expansion of sugarcane, a reduction of more than 20 % in macroagregation and C stocks. The sugarcane expansion into pasture with clayey site resulted in C accumulation (more than 2 Mg C ha-1 yr-1) and recovery of stocks on a SC2 basis. Expanding sugarcane areas into low-productivity pasture areas can be considered a sustainable strategy, especially in clayey soils, in which multiple gains occur through C sequestration and improved soil quality, as well as the reduction of CO2 emissions through the diversification of the energy matrix with the production of ethanol. ethanol expanded productivity However landuse land (LUC (SOM POM (POM mineralassociated mineral associated (MAOM textures (C CentralSouthern Central Southern Brazil evaluated NV, , (NV) PA, (PA) shortterm short term SC1, SC1 SC (SC1) cycle longterm long SC2, (SC2) performed 5 8 3 ha1 ha 1 ha- yr1 yr yr-1 basis lowproductivity strategy quality CO (NV (PA (SC1 (SC2 yr- (SC