The understanding of the main factors influencing microbial diversity in soils is necessary to predict the effects of current land use trends on diversity. In this study the effects of soil management (high and low input systems and pasture) on microbial biomass and diversity was investigated. Respiration responses to the specific substrate were used to measure soil microbial diversity. Catabolic evenness and richness of microorganisms as a measure of soil microbial diversity was measured. In this case, richness is the number of substrate used by the heterotrophic community, whereas heterotrophic evenness is the variability of substrate use, across the substrate tested. In comparison with agricultural systems, native pasture resulted in an increase in organic matter and microbial biomass. However, in this three soil managements, in high input systems basal respiration was higher than under other soil managements, suggesting the presence of a small but highly metabolically active micro floral community. Analysis of catabolic response profiles demonstrated that there were large differences in the catabolic capability of the soil microbial communities under different soil management type. Values for Shanon’s and simpson’s diversity indices indicated that greatest catabolic existed under native grassland and least diversity under high input systems. This was attributed to broad range of organic pool in pasture. It was concluded that soil management has a substantial effects on the size, activity and diversity of the soil microbial community and that these changes could be broadly related to changes in soil organic matter content. Although the implications of losses of microbial diversity are unknown, but diversity may results more resilient to stresses or disturbances.