Diagnostic value of some indicators of soil nitrogen regime for assessing the ecological state of oil-pollutant soils

The results of studies of the nitrogen regime of oil-contaminated soils in recent years are considered. Insufficient knowledge of this issue for man-made soils is emphasized, despite the fact that soil pollution with oil and petroleum products can cause significant changes in the nitrogen cycle and lead to irreversible violations of the ecological functions of soils. The generalization of the research results made it possible to identify the most informative indicators for assessing the processes of the nitrogen regime and the ecological state of oil-contaminated soils. Under conditions of oil pollution, the ratio of carbon and nitrogen contents in the soil increases, the nitrifying activity of soils decreases, and the proportion of ammonium forms of nitrogen increases relatively. It is shown that violations of the processes of the nitrogen cycle, the content and the ratio of the contents of different forms of nitrogen characterizing certain stages of its transformation in the soil can be restored to varying degrees during reclamation, depending on the properties of the soil. At the moment, the most promising areas of research into the processes of the nitrogen cycle in oil-contaminated soils are: the study of the vital activity of soil microorganisms carrying out various stages of the nitrogen cycle processes, the relationship of the structure and diversity of the microbiota with the rate of biodegradation of oil and transformation of nitrogen compounds in contaminated soils. The study of the nitrogen cycle processes is important for assessing the effects of soil pollution with petroleum products and choosing the most effective strategies for their restoration.