ИСТИНА

Fresh plant material (e.g., litter) represents a readily available substrate for both soil microorganisms and soil fauna. Changes in the structure of soils microbial community caused by soil litter replacement (oak leaves and grasses) were investigated in this study. The method of microbial diagnostic based on gas chromatography – mass spectrometry of fatty acids, hydroxy acids and fatty aldehydes – was used for the study of the plants and soil microbial community. The amount of microorganisms in the microbial community under leaves and under grasses did not differ, but relatively to the untreated soil it was increased by 60%. The main increase was due to the bacterial phylum Actinobacteria, which is characterized by high hydrolytic abilities. Biomass of microscopic fungi that also possess hydrolytic capacities, on the contrary, decreased by 8 times. The plant substrate promoted Protozoa reproduction: their number increased by 2 and 3 times in the soil under leaves and under grasses, respectively. Key word: plant litter, soil microorganisms, gas chromatography-mass spectrometry (GC-MS)