Land Use Impact on Microbial and Biochemical Indicators in Agroecosystems of the Brazilian Cerrado

Abstract

Microbial and biochemical properties are of great importance in soil quality evaluation. In Brazil, and especially in the cerrado (Brazilian savanna), benchmarking studies are needed to assess the impacts of land use on microbial and biochemical indicators. This study aimed to compare the impacts of land use on the microbial, chemical, and biochemical properties of the soil under Cerrado (CE), 32‐yr‐old pine forest (PF) and 11‐yr‐old no‐till (NT). Soil samples were collected at a depth of 0 to 10 cm in January, June, and December of 2008 and were evaluated based on chemical properties, basal respiration, soil organic carbon (SOC), microbial biomass carbon (MBC) and enzymes (β‐glucosidase, dehydrogenase and acid, neutral, and alkaline phosphatases). Comparative analysis of respiratory activity and MBC showed that the NT system had a positive effect and PF a negative one relative to the reference CE. NT soil management practices improve quality mainly by benefiting chemical characteristics (C and N), increasing MBC, and increasing microbial activity relative to CE and PF. Soil enzymatic activity (dehydrogenase, β‐glucosidase and phosphatase) was lower in PF and higher in NT than in CE. Principal component analysis showed that indicator variability, regarding soil sampling period, was higher in NT than in either PF or CE. In conclusion, we recommend β‐glucosidase and MBC as indicators of the impacts of land use practices.