Atividade e diversidade da biota do solo em agroecossistemas regenerativos e convencionais

Abstract

Sustainability of agroecosystems requires changes in agricultural practices that integrate soil biodiversity as a central component, with regenerative (conservationist) practices representing an alternative for coffee production systems. In this context, the present study evaluated biological diversity and its association with coffee production systems under conventional, organic and regenerative management, in areas with contrasting levels of yield: low (LY: 2,148- 3,372 kg ha⁻¹) and high (HY: 2,520-5,360 kg ha⁻¹) in the Cerrado. In this study, indicators of soil microbiota, carbon (C) and nutrients were evaluated, as well as metataxonomic analyses of bacteria and fungi. In addition, soil fauna was assessed using pitfall traps during the dry and rainy seasons. Conventional management showed higher microbial activity and β-glucosidase activity, as well as greater microbial biomass and microbial quotient, whereas regenerative management showed higher urease activity. Bacterial richness in the rhizosphere was higher under conventional management compared with regenerative management and was greater than that observed in Cerrado vegetation and in bulk soil. In contrast, fungal richness and soil macrofauna were higher in natural vegetation, and regenerative management showed greater soil fauna richness than conventional management, which presented the lowest diversity values. With regard to coffee yield under regenerative management, high positive correlation coefficients were found between yield and the microbial quotient, acid phosphatase activity and the rhizosphere C:N ratio, as well as between the Z score of surface soil biological activity and the rhizosphere effect. Conversely, yield showed high negative correlation coefficients with soil carbon and nitrogen contents and with labile carbon. Areas with lower yield showed reduced fungal richness in the rhizosphere and in bulk soil, whereas increased yield was associated with denser and more connected networks, in contrast to the pattern observed for bacterial networks. Differences in yield levels were also reflected in soil fauna, with higher richness and diversity of arthropods and greater abundance of predators (Opiliones and Araneae), and lower abundance of Formicidae, in areas of high coffee yield. Biodiversity (bacteria, fungi and arthropods) was affected by management and was associated with higher and lower levels of coffee yield in the Cerrado.