Biological functioning of Brazilian Cerrado soils under different vegetation types

Abstract

Over a 2 year period, we compared the soil biological functioning (SBF) of Cerrado physiognomies ranging from grassland-savannic to forest formations, sampling in the middle of the dry and rainy seasons. Soil samples were collected at two depths (0 to 5 cm and 5 to 20 cm) under the following physiognomies: Campo Sujo, Cerrado Ralo, Cerrado sensu stricto, Cerradao and Mata de Galeria. The SBF was represented by the simultaneous analyses of microbial biomass carbon, soil basal respiration and the activity of enzymes linked to the C, P and S cycles (β-glucosidase, acid phosphatase and arylsulfatase, respectively). The results demonstrated that Cerrado physiognomies are a major determinant of SBF patterns. The forest-like physiognomies (Mata de Galeria and Cerradao) presented the highest biomass and activity compared to the grassland (Campo Sujo) and savanna physiognomies (Cerrado Ralo and Cerrado sensu stricto). These differences were more evident in the topsoil layer (0 to 5 cm), and the seasonal effect on the SBF of the Mata de Galeria and Cerradao was more pronounced than on the other physiognomies. These results provide a benchmark for evaluating changes in SBF and related processes in Cerrado areas due to shifts toward agriculture and cattle production.