REGENERATIVE AGRICULTURAL PRACTICES INCREASE SOIL CARBON CONTENT AND IMPROVE PHOSPHORUS CYCLING

Regenerative agricultural practices have increasingly been advocated as a practical strategy to build soil organic carbon (SOC) and improve nutrient cycling in grain-based production, particularly under no-tillage, where sustaining biological functioning becomes central to long-term productivity. Despite this growing interest, field-based evidence from subtropical environments in southern Brazil is still limited, especially regarding the integration of SOC gains with soil biological processes that regulate phosphorus (P) availability. This study evaluated how regenerative management influences SOC accumulation and key biological processes associated with P dynamics in Imbituba, Paraná, by comparing two long-term no-tillage systems: a traditional system with soybean in summer and wheat or oat in winter, and a regenerative system based on crop diversification and intensification, cover crops, and the use of bio-inputs. Soil samples were collected from the 0–30 cm layer, with five replicates per management. Relative to the traditional system, regenerative practices increased SOC by 11.2%, together with increases of 9.1% in acid phosphatase activity (AP) and 26% in available P, indicating that SOC enrichment was accompanied by improved biological capacity to mobilize P. Moreover, SOC showed positive correlations with AP and P, reinforcing a functional link between SOC accumulation and the strengthening of enzymatic pathways that promote P mineralization and availability. Overall, these findings show that regenerative management not only enhances SOC storage but also stimulates nutrient cycling processes that sustain P supply for crop nutrition, supporting more resilient and sustainable subtropical agroecosystems.