Background soils humus of Vakhsky oil deposit (average taiga of Western Siberia)

In the study results of pilot studies of qualitative structure of a humus of background (uncontaminat-ed) soils of the Vakhsky oil deposit are presented (Khanty-Mansi Autonomous Area). In geomorpho-logical relation the studied territory is located in central lowered part of the West Siberian (mainly erosive and accumulative) plain, according to geobotanical division into districts - to the zone of boreal and taiga woods, a subband of an average taiga. The soil cover of a license site is presented by soils of a postlithogenic trunk (types of podzols of alfahumus, podzolic, peat-podzolic-gley, peaty-podzolic-gley soils), and the trunk of organogenic soils (the type of peat oligotrophic soils). Severe climatic conditions, the increased humidity, weak fitness of the territory, poverty in the specific rela-tion of vegetation lead to accumulation on the sur-face of soils of organic substance in the form of laying and the peaty horizons that in total with pov-erty of soils the bases define their low humus for-mation. The feature of qualitative structure of the humus of studied soils is prevalence in group struc-ture of fulvic acids. The formation of humus acids is expressed poorly. As accumulative feeding horizon of podsolic soils the forest laying in which roots, microorganisms and mesofauna are concentrated serves in the basic. As a part of humus the share of not hydrolyzed rest is considerable. The soils of a postlithogenic trunk have characteristic for taiga, have a humate-fulvate humus type which is charac-ter for taiga soils, synlithogenic trunk ones have a fulvate-humate humus type. Humus acids and fulvic acids connected with mobile one-and-a-half oxides prevail. The most valuable fraction of humus acids connected with calcium makes insignificant part of organic carbon. Integrated characteristics of struc-ture of humus (its low composition, a mostly humate-fulvate type, predominance of aggressive and connected with mobile sesquioxides fractions of fulvic acids) coupled with severe bioclimatic con-ditions show low buffering of background soils and therefore their weak resistance to man-caused loads including oil pollution.