Nikolay Andreevich Avetov

The taxonomy of peat soils is not currently given more attention, especially with regard to taxonomic units in the species rank. The procedure of diagnostics of 51 soil profiles in the various oligotrophic mire types in the Numto nature Park (north taiga subzone of West Siberia) allows to make some proposals to improve the existing soil classification. These ones are: 1) to limit the peat horizon thickness in the peat-gleyzem type to 30 cm; 2) to divide the peat-gleyzem type by the trophic status into oligotropic and eutrophic subtypes; 3) to expand the list of taxa, determined by the botanical composition of peat, by means of the division of soil species into subspecies on the basis of classifications of peat and peat deposits; 4) to use current vegetation as one of the main diagnostic (indicative) criteria in determining the soil type in mires; 5) in order to determine the variety of peat soil it is suggested to use the degree of decomposition of the peat layer underlying the peat soil. The article draws attention to the difficulties in determining the classification position of soils of frozen large mounds in palsa bogs and proposes alternative solutions to this problem.

The process of natural remediation of oil-polluted and salt-polluted raised bogs of KhMAO - Yugra reclaimed 14-16 years ago is analyzed. In general, the revegetation is proceeding successfully, although mesophytic grasses sown during reclamation have almost completely fallen out of the grass stand. In salt-contaminated areas, there is a gradual desalination of peat soil, accompanied by a succession of halophytic (hemigalophytic) plant communities dominated by Calamagrostis epigeios, Eriophorum angustifolium and Phragmites australis with the participation of sphagnum and brown mosses, as well as liverworts. A characteristic feature of these habitats is the settlement of a number of rare protected species ( Heterogemma laxa, Thelypteris palustris, Triglochin maritimum ). In oil-polluted bogs, during the re-vegetation, hydrocarbons often flow from the underlying peat soil horizons to form the surface crust. At the same time, grass stands from Eriophorum angustifolium and some other species with powerful root systems are replacing grass-sedge-cotton grass communities. Sphagnum riparium and Warnstorfia fluitans play also a certain role in the overgrowth of crusted surfaces. Unsuccessful recovery is typical for hollows with difficult runoff in the case of salt-contaminated bogs and the most dry locations in the case of oil - contaminated ones.

The laboratory study of the solid phase of salted peat by X-ray fluorescence analysis revealed the presence of some halogen-organic compounds. Cl-organic compounds were formed in one third of peat samples, while their share is small: 14-15% of the total Cl. On the contrary, Br-organic compounds are formed more often and Br_org proportion is higher: from 12 to 23% of total Br. Relatively weak development of halogenisation of the organic matter in salted peat bog is explained by the recovery conditions that prevent the synthesis of halogen-organic compounds. In X-ray diffraction analysis of peat ash, errors are possible, both due to the growth of minerals, and due to incomplete identification of the number of phases in high-ash peat samples. The second type of error can be corrected using data on the content of chlorine in peat by X-ray fluorescence analysis. In the characteristic of peat bog contamination, in addition to salt profiles in the solution, it is necessary to determine the number and composition of halogen-organic compounds, some of which have herbicide properties.

Milestones in the study of oil-contaminated soils at the Faculty of Soil Science for 50 years of its foundation are dis- cussed from the prospects for the development of environmental regulation and new technologies of soil reclamation. The development of a methodological framework for the determination of oil and petroleum hydrocarbons in soils, studies of soil properties, the chemistry of oil and its components in soil and adjacent media are shown. The devel- opment of legislation on the rationing of petroleum hydrocarbons in soils is given, including the important role of the staff of Faculty of Soil Science of Moscow State University in the work out of a number of regional standards for the permissible residual content of petroleum hydrocarbons in soils is noted. The approaches to ecological rationing of oil and petroleum hydrocarbons in soils are proposed, in the aspects of natural climatic zones and the type of landuse. The importance of improving the regulatory and methodological framework and continuing work in this direction is emphasized. The necessity of research at developing technologies for reclamation of oil-contaminated lands and special use of oil-contaminated waste is indicated.

The article provides data on a comparative analysis of the features of vegetation restoration in areas of oligotrophic bogs with a high degree of oil product pollution, located on the territory of an oil field in the Middle Ob region, reclaimed according to standard schemes, widely used in the 2000s, and by cutting off oil-contaminated soil. The total projective vegetation cover (TPVC) of all reclaimed areas mostly reaches standard values (above 30%). The TPVC in areas without cutting is slightly higher than in areas with cutting due to the difference in recovery time in favor of the former. At the same time, the average number of all recorded species in areas with cutting is slightly higher, and they include some oligotrophic vascular plants (heather shrubs, Drosera rotundifolia, Eriophorum vaginatum), which spread much less frequently in areas without cutting. The projective cover of the herb-shrub layer is higher in areas without cutting. The content of oil products in the surface layer of 0‒20 cm in areas with cutting is generally lower compared to areas reclaimed by traditional methods. However, even high concentrations (more than 250 g×kg^-1) do not have a significant negative effect on the total projective cover of the grass/herb-shrub layer, while its minimum values are primarily associated with a lack of moisture on high microrelief elements. Similarly, high concentrations of hydrocarbons do not serve as an obstacle to the development of moss cover dominated by sphagnum mosses in areas of cut-off hollows. At the same time, polytrichous and brown mosses were much more sensitive to oil pollution in the form of bitumen crust, and thus avoided areas without cutting.