BIOLOGICAL ACTIVITY OF GREY FOREST SOILS OF THE STARODUB AND BRYANSK OPOLIE AGROECOSYSTEMS

Abstract

The main indicators of biological activity of grey forest soils of the Starodub and Bryansk Opolie in natural ecosystems, regular and intensive agroecosystems, including radioactively contaminated ones, were determined year by year. It is established that the radioactivity of the soils in the natural ecosystem catena of the Starodub Opolie is practically identical. In agroecosystems the radionuclides in soil catenas are redistributed. They are accumulated in the agrohorizons of soil cavities. In the natural ecosystem the total number of invertebrates and the absolute number of earthworms are higher in grey forest soils, having the second humus horizon cavities, than in the grey forest soils of the neighboring low ridge. In both soils of opolie the earthworms predominate among invertebrates, accounting for about 81 % of their total number. Radioactive contamination reduces the number of earthworms less than the intensification of crop cultivation technologies. In the grey forest soil of the regular agroecosystem, this figure is reduced by 56%, and in the grey forest soil with the second humus horizon by 76 %. In intensive agroecosystems the number of earthworms is reduced less, by 39 and 23 %, respectively. The biomass of the microbiota is significantly greater in the grey forest soils with the second humus horizon of the soil cavities than in the grey forest soils of the neighboring low ridge. Radioactive contamination of these soils reduces microbiota biomass less than intensification of crop cultivation technologies. In the grey forest soils of the agroecosystem, this figure is reduced by 50%, and in the grey forest soil with the second humus horizon by 61 %. In the intensive agroecosystem the biomass of microbiota decreases less intensively, by 30 and 46 %, respectively. In the incubation experiment on the grey forest soils of the Bryansk Opolje it is marked that soil enrichment with organic matter activates the soil microbiota more than 2 times. To a lesser extent, soil respiration increases with NPK application. This figure rises more than 5 times with the combined use of straw and NPK. In the field experiment, the cultivation of winter wheat in the crop rotation after annual grasses and mineral fertilization at the rate of NeoPeoKm+Neo activated the soil microbiota by 75-76 %. The biological cultivation technology on the background of the aftereffect of dung, straw and green manure without mineral fertilization causes a decrease in soil respiration and cellulolytic activity, as compared with the intensive technology.