Biochemical activity in Brazilian Cerrado soils is differentially affected by perennial and annual crops

Organic matter mineralization depends on how microbiota access nutrients, substrates and soil fertilization. This study shows influence of perennial (sugarcane) and annual (soybean and corn) crops on the activity of enzymes participating in the carbon, nitrogen and phosphorus cycles and proposes using hydrolases as bioindicators of soil quality. Samples were collected, during dry season and rainfall, in six different plots where sugarcane, soybean, corn and native Cerrado soils could be found at the same location. We evaluated chemical properties and activity of α- and β-glucosidase, acid phosphatase, protease and glycine aminopeptidase from 48 samples collected at 0-10 cm depth. Sample of monoculture soils showed low organic matter content, total organic carbon, total nitrogen and microbial biomass carbon. Native Cerrado soils had major activities of alpha- and beta-glucosidase, acid phosphatase and glycine aminopeptidase while sugarcane areas showed minor values. Despite native vegetation replacement decreasing biodiversity and reducing soil biochemical activity, annual crops stimulate microbial activity in this environment and maintain nutrient cycling. Soil hydrolase activities can be used as bioindicators of these ecosystems.