Soil aggregation recovery under regenerative agriculture: effects of management duration and soil texture along the profile

The conversion of natural ecosystems into agricultural land often degrades soil structure and limits soil organic matter stabilization. Regenerative agriculture practices, such as no-tillage and crop diversification, have been proposed to restore soil aggregation and carbon dynamics, although their effectiveness depends on management duration and soil texture. This study evaluated soil structural recovery and carbon and nitrogen fractions under contrasting regenerative systems in clayey and sandy soils, compared with native forest references. We assessed soybean–cotton systems under no-tillage with 1, 6, and 10 years of adoption in clay soils, soybean–cotton and soybean–brachiaria–pasture systems under no-tillage in sandy soils, and their respective native forests. Indicators of soil aggregation, total carbon and nitrogen, particulate and mineral-associated organic carbon, and carbon stocks were evaluated down to 40 cm depth. Results showed that soil structural recovery was progressive and strongly dependent on management time, with the most pronounced improvements in the upper soil layers. Longer no-tillage adoption increased macroaggregation and structural stability, approaching native forest conditions. Early recovery stages were associated with particulate organic carbon accumulation, whereas longer management favored mineral-associated carbon and higher carbon stocks, indicating enhanced stabilization. In sandy soils, brachiaria accelerated aggregation recovery and carbon retention, reinforcing the effectiveness of long-term, soil-specific regenerative practices.