Аннотация:Hydrophilic-hydrophobic properties of organic matter and the content and distribution of watersoluble organic matter (WSOM) in soils of the Subpolar Urals are discussed. It is shown that the type of predominant vegetation in the system of altitudinal zones controls the amount and nature of soil organic matter (SOM). The litter of moss–lichen vegetation of the alpine tundra is enriched in hydrophobic compounds (up to 24.0%). In the grass communities of the subalpine zone, hydrophilic fractions of the SOM predominate (first fraction, 42.4–77.0%; second fraction, 0.3–12.6%). Woody vegetation of the mountainous forest zone is specified by an increased content of hydrophobic lignin-containing fractions (16.4–34.8%). Permafrost-affected soils of the alpine tundra are characterized by an increased hydromorphism leading to the accumulation of compounds associated with Fe and Al (up to 75.4%) in mineral horizons. The calculation of the WSOM carbon stock indicates that it reaches 0.3 to 9% of the total carbon stock in the soil profiles.
