ИСТИНА

South Siberia is the most extensive mountainous regions of Russia, it is located in the very heart of the largest continent. Extreme ultracontinental climate combined with mountainous environment account for a geographical uniqueness of the area which has obviously imprinted both in landscapes and soils. There are a number of exotic and even endemic landscapes, soils and soil covers. Unusually sharp, short-distance variability of environments within the region result in contrast short-distance variability of soils. Hardly wherever else in the world one can find tundra landscapes with Mollic, Cambic and even Histic Cryosols bordering with Kastanozems and Cambisols (Protocalcic) under cryo-xerophitic steppe; or feather grass steppes where Chernozems transit within a short distance to Chernic Cryosols, and further to Entic Podzols or Cambisols under larch taiga. Soils of this highly specific vast region are not enough studied up to now. A bulk of factual material concerning soils and soil covers of the region was obtained in the first half of the last century. Latest studies were mainly devoted to individual, applied questions of soil science; both the soil genesis, nor their evolution, ecology and palaeoecology was paid due consideration. We consider a variety of cold steppe and semi-desert soils of the South Siberia to be a regional soil identity. Uniqueness of these soils is explained by a combination of certain water deficit (at least some part of the warm season), and long term influence of negative, sometimes very low temperatures. This combination is often accompanied by presence of permafrost which strongly influences downward and lateral geochemical flows in soils and also often serves as an additional source of water during warm seasons. Mountainous environment very often results in lithic discontinuity, high proportion of coarse fragments and shorten profiles. These preconditions stipulate a considerable difference of steppe and semi-desert soils of South Siberia and soils of other semiarid and arid regions of the world. Very specific closely related group of soils include marginal varieties of Chernic and Natric Cryosols with close to 200 cm permafrost layer, Chernozems and Mollic Solonetzes (Tonguichernic, Turbic) where permafrost table is a little deeper than 200 cm. Chernic Cryosols and Chernozems, Natric Cryosols and Solonetzes are very close to each other from genetic point of view being shared only due to formal criterion of the cryic horizon’s depth. Extreme for steppe communities cold, ultracontinental, and water deficit conditions restrict the depth of soil formation in their own, so that permafrost table in fact does not act in this case as depth restricting factor for pedogenesis. It allows full-profile development of Chernozems and Solonetzes quite typical for the region even over a shallow cryic horizon. Soils of ultracontinental cryo-xerophitic short-grass steppes of the South Siberia were discriminated as a specific genetic group in 70-s of the XX c. and recently were included as a separate soil type in Russian Soil Classification. A variety of cryoarid soils get into three groups according WRB: these are Kastanozems Cambic, Cambisols Protocalcic and Cambic Calcisols. These soils combine features typical for soils of cold, permafrost-affected areas, such as patterned ground, frost sorting, cracks, tongues of humus horizon (manifestations of “wet” cryogenic features such as turbation, involutions, formation of schlieren structures are very modest due to water deficit and coarse texture of soils), and features typical for morphology and geochemistry of steppe soils with well expressed water deficit (calcareous and siliceous accumulations, alkaline environment etc.). The most arid varieties have evidences of aeolian activity, varnished pavement on the surface associated with a vesicular layer. Soils with limited depth of soil forming processes: Cryosols, Leptosols and Leptic soils in cold, ultracontinental climate with restricted water-supply results in formation of well differentiated though shorten soil profiles. The physical restriction of pedogenesis over-permafrost sediments or over continuous bedrock often still allow a development of full-profile well differentiated soil. At the same time very modest intensity of cryoturbations in well-drained soils with only atmospheric water supply, and low rates of erosion under natural vegetation in semiarid climate often allow to preserve general pedogenic differentiation of a soil profile. Furthermore, pedogenesis is able to produce here physiognomic, easily recognizable environmentally-dependant features in highly specific extreme cryoarid ultracontinental environment, on tough weatherable bedrocks, even if the formation of well-differentiated soil profile is impossible. Basing on the analysis of earlier published data as well as on 7 years own regional research experience, we will observe in the presentation a number of reference soil profiles we regard the most distinctive, spectacular and regionally specific. Also we will mention possible analogues of the discussed soils beyond the region (if any).