Soil Physical quality and Carbon Stocks under Regenerative Agriculture in coarse texture soil in the Brazilian Cerrado

This study investigated the impact of occasional tillage and regenerative management (cropland and pasture) on organic carbon stocks (OCS) and soil physical quality in the Cerrado biome. In Sapezal-MT, Brazil, an on-farm study was conducted in Oxisols. Treatments consisted of 1 (MS1) and 3.5 (MS3-B) years since subsoiling, cultivated with soybean/cotton and soybean/pasture in medium-textured soils and native forest. The following soil properties were analyzed: bulk density (BD), total porosity (TP), macroporosity (Macro), bulk air capacity (ACb), and OCS. Results indicated high physical vulnerability in medium-textured soils, characterized by a 20% increase in bulk density (BD > 1.3 g cm⁻³) in the 0-40 cm depth compared to the native area. A significant 28% reduction in ACb was observed at depths of 30-40 cm, indicating early subsurface aeration restrictions. Both MS1 and MS3-B showed a 20% increase in BD up to 40 cm depth, indicating a trend or possible re-compaction process occurring more quickly (still within the 1^st year), resulting in structural risk. Although the OCS doesn´t show a statistical difference between soil management and native area (15 to 25 Mg ha^-1), MS1 and MS3-B show higher DS (>1.5 gcm^-3) and the lowest values ​​of Macro (<15%) and ACb (<20%), this accumulation alone did not prevent physical degradation. Therefore, physical fragility is the primary limiting factor in these soils, making subsurface Macro and ACb the most critical indicators for monitoring soil health and ensuring the long-term functionality of these regenerative systems, therefore avoiding unnecessary mechanical intervention.