Biomass and microbial activity have been suggested as appropriate indicators of changes caused by different land use and management systems. The objective of this study was to evaluate alterations in biomass and microbial activity of a typic acric Red-Yellow Latosol (Oxisol), under native Cerrado and different management systems, in the physiographic region Campos das Vertentes, state of Minas Gerais. The evaluated systems were: conventional tillage with potato (CCB); potato followed by oat in rotation with corn (CBAM); conventional tillage with corn (CCM); no-till with corn (PDM); conventional tillage with eucalyptus (CCE); and native Cerrado (CN) as reference. Soil samples were collected in the layers 0-10, 10-20 and 20-30 cm. The microbial carbon (Cmic) and basal respiration were analyzed, and the metabolic quotient (qCO2) and Cmic/organic carbon ratio were calculated. The biomass and microbial activity were influenced by the different soil management systems and the conditions for soil microbiota were most adequate under NC. The most intensive soil managements with frequent pesticide use, as in the CCB and CBAM systems, resulted in lower amounts of Cmic, lower Cmic/TOC ratio and higher qCO2 values, indicating a probable stress condition for microbial biomass.
microbial carbon; soil quality; organic matter
