Features of pedogenesis and spatial distribution of the South-Eastern Altai highland soils

The aim of this work was to determine the genesis peculiarities and automorphic properties of mountain-tundra and alpine mountain-meadow soils of the Kurai ridge alpine spur zone of the South-Eastern Altai formed on the slopes of varying steepness and exposure (50°6'4'' N and 88°51'48'' E, 2484 m above sea level), as well as their classification category. We examined the territory by comparative-geographical and morphological method of studying to assess the soil properties at the level of the soil profile and genetic horizons. We defined chemical and physical and chemical properties and granulometric composition with the help of conventional methods in soil science. We carried out soil diagnostics using "Classification and diagnostics of soils in the USSR" and "Classification and diagnostics of soils in Russia" (2004). We obtained information which characterizes patterns of distribution, structure and properties of soils. On the slopes and tops of the South-Eastern Altai ridges there is a gradual reduction in the deficit of moisture as it rises into the mountains and an increase in scarcity of heat in the same direction. Phenomena of winter temperature inversions in the Southeast Altai cause inversion in the distribution of soil types and vegetation formations. We established that in the alpine zone of the considered territory, under original climatic conditions under various formations of the alpine tundra vegetation, mountain-tundra sod and mountain-tundra peat soils are widespread. Along with that, alpine mountain-meadow soils are formed over a large area covered with mixed grass alpine meadows. An important factor in the development of mountain soils is solar radiation, especially large at high altitudes, so on the southern slopes mountain-tundra soils are gradually reduced and replaced by alpine mountain-meadow soil. On the northern and north-eastern slopes the alpine mountain-meadow soils are replaced by automorphic mountain-tundra sod and mountain-tundra peat soils. The studied soils belong to Litozems and soil types are raw humus Litozems, peat Litozems and dark-humus Litozems. Granulometric composition of the studied soils ranged from medium to light loam. They are characterized by a decrease in silt particles down the profile and an increase in the amount of sand fractions and coarse dust with depth. A feature of these soils is a significant accumulation of organic matter, but raw humus or mor is observed. A large amount of humus is detected in BC horizon (0,5-2%). The above discussed soils are characterized by a rather high content of exchangeable forms of calcium and magnesium. Thus, the main elementary processes of soil formation are primary, sod-forming, humification and peat accumulation. We noted the absence of morphologically overt signs of processes of podzolization, gleying and frost deformations for all variants of the soil because these soils are formed under conditions of good drainage.

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