THE EFFECT OF GRAZING ON SOIL MICROBIAL BIOMASS AND COMMUNITY ON ALPINE PASTURES

Within in a multidisciplinary project the effect of termination of cat tle grazing on grassland and forest on soil microbial properties was i nvestigated. The changes of microbial biomass (C-mic), basal respirati on and the ecophysiological parameters (metabolic quotient and the C-m ic:C-org ratio) were small. Mainly in the dry summer of 1993 an increa se of basal respiration, microbial biomass and the C-mic:C-org ratio w as observed for the fenced in sites. The effects were not observed in the moist summer gf 1995. For the pasture site, a substrate utilizatio n assay employing 95 different C sources (Biolog(R)) indicated some ch anges in the functional abilities of the bacterial communities after 9 years of protecting the site from grazing. The changes were attribute d to a change of litter quality.