IRECTION AND STRENGTH OF MICROBIOLOGICAL PROCESSES IN LAYERS OF GRAY FOREST SOIL UNDER DIFFERENT REGIMES OF MANAGEMENT

The aim of the work was to study the direction and intensity of mineralization and immobilization processes in different layers of gray forest soil at fallow fields, extensively and intensively used agrosoils. The research included laboratory analysis, microbiological studies, and statistical processing. For the fallow plots, the layers chosen for study were Hd – turf (010 cm), He – humus-eluvial (11–40 cm), Hi – humus-illuvial (4174 cm), Ih – illuvial-humus (75115 cm), Ip – transitional from the illuvial layer to bedrock (116156 cm), Pi – bedrock with occasional insertions of illuvial soil (157191 cm); for the agrosoils of the stationary experiments: He – humus-eluvial (0-10 and 11–40 cm), Hi – humus-illuvial (4174 cm), Ih – illuvial-humus (75115 cm), Ip – transitional from the illuvial layer to bedrock (11656 cm). We found that humus mineralization differed in some layers of the gray forest soil under these management regimes. At fallows, the intensity of humus mineralization tended to decrease with depth, and it was interrupted in the Ih and Ip layers. In the intensively used agrosoil, humus mineralization was more active in Hi- and Ih- layers. Comparatively, the activity of humus mineralization smoothly decreased in the profile of the extensively used agrosoil from the uppermost layer to the lower by 97.2%. The mineralization coefficient of Nitrogen compounds gradually decreased in the fallow ground and extensively used agrosoil, unlike the intensively managed agrosoil, in which the intensity of mineralization-immobilization of nitrogen compounds increased in the He and Hi layers. It was shown that the fallow ground had the more efficient system to transfer substrates and mineral ions down the profile to the lower layers. The difference in biologic activity between the upper and lower layers was maximum in the fallow ground, intermediate in the intensively used agrosoil and minimum in the extensive agrosoil.