CARBON STORAGE AND PHYSICAL AND CHEMICAL PROPERTIES OF A MEDIUM-TEXTURED SOIL IN AGRICULTURAL SYSTEMS IN BRAZIL

The objective of this study was to evaluate the physical and chemical properties and carbon storage in different agricultural production systems in medium-texture soils in the subtropical region of Brazil. Soil samples were collected in three management systems: Pasture (PP), no-till (NT), and no-till + Urochloa (NT+U), in addition to a native forest area (NF), in four soil layers up to 0.40 m. Chemical and physical soil analyses were performed. Bulk density and penetration resistance results did not indicate soil compaction in the areas managed after 24 years. The PP area had higher total porosity and microporosity values than the NT and NT+U areas. The PP area had the highest values of the sum of bases and CEC. NT+U and PP areas had the highest TOC contents and carbon storage potential up to the 0-0.40 m layer. The PP area in the 0-0.40 m profile had 52.89%, 72.21%, 79.79%, and 97.08% Mg ha-1 more stocks than the NF area in the four soil layers evaluated. In the 0.20-0.40 m stratum, the NT+U area had StockC values of 11.21 Mg ha-1, which was 17.62% more than the NT area. These results show the potential of grasslands for carbon storage in medium-texture soils under subtropical climates, mainly due to the characteristics of grasslands that can produce significant amounts of biomass constantly deposited in the soil.