The aim of this study was to verify the effects of different soil tillage systems on microbial biomass and the total organic C and N stocks in an Oxisol. The soil tillage systems evaluated were: no-tillage (PD) and conventional tillage (PC). A deforested area (ARD) and another with native vegetation (AVN) were used as references. The soil samples were collected in the 0-5, 5-10 and 10-20 cm depths, and in these soil samples were quantified the contents and total stocks of C and N, basal respiration, microbial biomass C (Cmic), and microbial (Cmic/COT) and metabolic (qCO2) quotients. The values of microbial biomass C (Cmic) in the soil under PD were higher than those observed in PC and ARD in all depths. The area under no-tillage (PD) showed larger contents of C and N, and stocks of C on the surface of the soil. For the stocks of N, there were no differences among the evaluated areas, in all depths. No-tillage adoption provides an increase in the soil microbial biomass and total C and N stocks, indicating improvement in soil quality.
no-tillage; microbial biomass; basal respiration
