From Cooperation to Centralization: Tillage Systems Differentially Structure Soil Physical Properties, Microbial Communities and Enzymatic Activity in Organic Farming

This study evaluated the effectsof tillage systems on soil biological and physical attributes in a certified organic farming system in Brazil. The experiment was conducted using a randomized block design with four replications under two management systems: no-tillage and conventional tillage. Each plot received a cover crop consortium sown at 50% of the recommended seeding rate, consisting of millet (Pennisetum glaucum), sunn hemp (Crotalaria juncea), and jack bean (Canavalia ensiformis). Soil samples were collected after corn harvest, five years after the establishment of the tillage systems and cover crop consortia. No-tillage promoted greaterfungal richness than conventional tillage. Differential abundance analysis showed that conventional tillage significantly affected the relative abundance of bacterial and fungal phyla, particularly Chloroflexota and Ascomycota. Network analysis revealed distinct microbial co-occurrence patterns, with fungal networks showing higher connectivity under no-tillage, while bacterial networks exhibit contrasting structures under conventional tillage. No significant differences were observed in β-glucosidase or arylsulfatase activities between management systems. However, arylsulfatase accounted for most enzymatic activity in both no-tillage (72%) and conventional tillage (73%), highlighting the importance of sulfur cycling in this organic farming system. Principal component analysis associated no-tillage with Proteobacteria, soil bulk density, and mean weight diameter, whereas conventional tillage was associated with β-glucosidase, arylsulfatase, Actinobacteriota, Firmicutes, Acidobacteriota, and Ascomycota. The results demonstrate that tillage systems influence soil physical, microbiological, and enzymatic attributes under organic management, reducing soil disturbance combined with cover crops represents an effective strategy for maintaining soil biological and structural quality. Conventional tillage promoted more centralization of bacterial networks. No-tillage increased fungal richness and improved soil structural stability. Arylsulfatase activity predominated under both tillage systems in organic farming.