The effects of land use on biomass and catabolic diversity of soil microbial communities

Abstract

An understanding of the factors influencing microbial diversity in soils is essential 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 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 comparison with agricultural systems, pasture resulted in an increase in organic matter and microbial biomass. However, in the soil managements, in high input systems, basal respiration was higher than 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 Shannon’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. Key words: Microbial diversity, land use, microbial biomass, catabolic response profiles methodology.