Modern aeolian morpholithogenesis of cold period in the South-East part of the Sub-Taiga Zone of the West Siberian Plain

The natural conditions in the subtaiga zone of the southeast of the West Siberian plain are favorable for the development of aeolian processes such as deflation, migration and accumulation of aeolian material. The vegetation prevents the spread of aeolian processes in natural landscapes. Deforestation and plowing of the land which were particularly intense in the mid-twentieth century, led to the advent of natural-anthropogenic aeolian processes on arable land. These processes develop mainly on loamy soils in the studied area, while in other regions deflationary processes are common on lighter soils. Both meso- and microrelief of arable land are complex. There is an alternation of the upper reaches of the gullies, hollows, and watersheds. The gullies have a depth of 15 m; the depth of the hollows is up to 5 m and their diameter up to 150 m. The steepness of slopes on arable land varies from 0-1 to 7°. The topography of the arable land creates an additional roughness of surface, which increases wind turbulence. South winds prevail over the territory. Windward slopes are subjected to deflation. Transportation and accumulation occur on the leveled surface of arable land and the near natural barriers such as forest belts, forest edges, and road embankments. The studied area is characterized by strong winds, with the speed of > 15 mps, and wind gusting to 20-25 mps. There are storms with wind speeds up to 34 mps. Thus, the wind speeds exceed the critical value for loamy soils (not more than 9-10 mps). Parent material is loess loam, characterized by high dust content. Aeolian processes develop in the fields all over the year, but they have different intensity. The paper contains the results of monitoring of aeolian processes in cold-season (October-April). Two stages of the development of aeolian processes are distinguished. The first stage starts since the formation of steady snow cover until the time of maximum accumulation (from October to the third decade of March). The second stage. The second stage occurs during snowmelt (from end of March to April). For both the first and the second phases irregularity of the accumulation of aeolian deposits in the profiles is marked. At the first stage from 0.8 to 879 grams per cubic meter aeolian sediments are accumulated in the snow on the arable land; and from 0.1 to 320 grams per cubic meter sediments are accumulated at the second stage. During the period from 2007 to 2016 in the neighbouring pine woods there were not more than 12 grams per cubic meter deposits, this sedimentation level is much lower than on arable land. Aeolian sediments have mainly silty composition and a close genetic relationship with soils of the region, they contain humus, N, P, Ca, Mg. Aeolian process is characterized by from 1 to 6 year cycles of activity.

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