The aim of the research was to study the features of the influence of various concentrations of oil on the dynamics of the activity of the microflora of sod-podzolic soil and the residual amount of oil products when using biological products based on oil-oxidizing microorganisms. The article examines the dynamics of the number and composition of such physiological groups of microorganisms as heterotrophs, micromycetes, actinomycetes, cellulolytic. As a result of the studies, the following features were revealed: 1. low oil concentrations stimulate the number of all studied microorganisms; 2. micromycetes are the most resistant to oil pollution; 3. the most sensitive to the pollutant are actinomycetes and cellulite microorganisms. It was found that the biological activity of oil-contaminated soil correlated with the residual amount of oil products. The destruction of oil products is more intensive in the rhizosphere of wheat.

The article provides data on the influence of different levels of oil pollution on the structure of the microbial community and the activity of catalase in sod-podzolic soil during the cultivation of barley and wheat. It also presents data on the effect of biopreparations based on oil-oxidizing bacteria on the total number of microorganisms, microscopic fungi, actinomycetes and catalase activity. Based on the analysis of the microflora of oil-contaminated soddy-podzolic soil, it was found that oil pollution affects the total number of microorganisms, the qualitative and quantitative composition of micromycetes. and actinomycetes. It was also found that small concentrations of oil stimulate the number of microbiota and catalase activity. The introduction of biological products based on oil-oxidizing bacteria has a beneficial effect on the indicators of the general biological activity of the soil. It is noted that the selection of a phytomeliorant is of great importance in the reclamation of non-contaminated soil.

The aim of the research was to study the influence peculiarities of different levels of nitrogen nutrition on the activity of peptide hydrolases and protein content in ontogeny of barley plants.The paper discusses the content of total nitrogen, protein and the dynamics of activity of proteolytic enzymes during ontogenesis of barley plants. The activity of peptide hydrolases, the content of protein and total nitrogen were determined in four developmental phases in the flag leaf and forming caryopses of barley. The aim of the work was to determine the effect of different levels of nitrogen on the quantitative content of protein, the total amount of nitrogen, as well as on the activity of acidic and neutral peptide hydrolases. In the course of the research, the following features were revealed: 1. The content of total nitrogen and protein, as well as the activity of proteases, depended on the developmental phase and on the level of nitrogen nutrition; 2. Increasing doses of nitrogen contribute to a greater nitrogen outflow from flag leaves into the forming grain; 3. High nitrogen norms inhibit the activity of peptide hydrolases. 4. The highest rates of activity of acidic proteases were noted in the phase of full ripeness. 5. The total activity of peptide hydrolases increased in variants with a twoand three-fold nitrogen dose.

The article presents the results of studies of the effect of biological products based on oil-oxidizing bacteria on the enzymatic activity of soddy-podzolic soil contaminated with oil. Barley (Hordeum sativum L) and wheat (Triticum vulgare L.) were used as phytomeliorants. The effect of different concentrations of oil on the activity of enzymes such as invertase, phosphatase, urease is shown. It was found that the activity of the studied enzymes depended on the concentration of the pollutant and the duration of oil exposure to the soil environment. It is noted that the treatment of oil-contaminated soil with biological products contributes to the restoration of its biological activity.