Impact of land use intensification on key drivers of soil organic carbon pools in Brazil's Central-West

There are studies showing the potential of integrated production systems, such as Crop-Livestock-Forestry (CLF), for soil carbon sequestration, enhancing nutrient cycling, and reducing farmers' dependence on mineral fertilizers. However, more focused research is needed to identify the main biophysical and chemical processes governing SOC accumulation. This study investigated the main drivers of soil organic carbon sequestration and soil quality in a very clayey Rhodic Ferralsol under an 11-year-old CLF system in the Central West region of Brazil. CLF was implemented in 2009 in a conventional Pasture area and soils samples were collected in 2012 and 2020 under two land uses, CLF and conventional Pasture as time-zero reference. The soil in CLF was evaluated within the tree lines (CLF-WL) and in the alley pasture between the tree lines (CLF-BL) having palisade grass. Our results showed that SOC stocks was higher (both in 2012 and 2020) for the CLF-WL (86.70 and 83.74 Mg ha(-1)) than in pasture reference (71.81 and 74.96 Mg ha(-1)) within the 0.3-1.0 m soil layer. Most of the soil's carbon content was in the mineral associated fraction (96-97 %) for all sites. Soil available water for plants (at -8 and -6 kPa) within 0.0-0.1 m soil depth increased in CLF system. Soil nutrient availability increased from 2012 to 2020 in CLF system. While in the Pasture the main drivers of SOC pools were the soil physical properties, in the CLF these were chemical soil properties. These key parameters underscore the role of CLF systems in promoting carbon storage and supporting low-carbon agriculture, particularly in the Brazilian Savanna and similar tropical regions. This knowledge allows farmers to optimize CLF management, balancing soil health with productivity.