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On the territory of the Republic of Buryatia due to global climate change, significant transformations of the natural environment have been observed. Statistically significant trends of increase in temperature and decrease in precipitation with identification of wet and dry periods have been established. In the last 20 years due to the abnormally high air temperatures and the increasing aridity of the territory, the frequency and area of fires have increased, the rate of permafrost degradation on the southern boundary of the permafrost zone in the soils of meadow-steppe landscapes has increased twice.

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The content of microelements (Mn, Zn, Cu, Co, Ni, Cr, Pb, and Cd) and Fe is determined in the soils and plants of the Lake Kotokel' basin. Their content in the soils is proved not to exceed the regional background and the existing MPC and APC. The content of Cd is revealed to exceed its clarke value for the world soils, which is related to the natural origin of this element. The concentrations of Mn, Co, and Pb are close to their clarke values, and those of Zn, Cu, Ni, and Cr are lower than their clarkes. The studied soils are specified by the maximal amount of the mobile forms of microelements. The profile distribution of the microelements differs depending on the genetic soil type. For Mn, Zn, and Cu, a significant biogenic accu mulation is pronounced in the organic soil horizons. The content of microelements in the aboveground phy tomass exceeds the maximal permissible levels for Mn, Co, Cr, and Fe. The intensity of the microelements absorption by the plants varies widely, being specified by the high coefficient of the biological adsorption (except for Fe). Mn, Zn, and Cu are accumulated in the plant phytomass the most intensely.

To clarify the probable role of the stage of the post-lake soil in the evolution of clay-illuvial frozen chernozem the studies were carried out in the southern Vitim plateau of Transbaikalia. The research covers soils in the area of ancient currently dried lakes and the lakeside plain of the Yeravninskaya depression. The obtained data evidence the dissimilarity of parent rocks, as well as radical differences in the soils’ characteristics and properties.

The soil cover patterns in the subtaiga landscapes on the northern spurs of the Tsagan Daban Ridge in the Selenga Mountains have been studied. Gray humus lithozems and bedrock outcrops are typical of the steep south facing slopes under herbaceous pine forests. Soddy iron illuvial podburs are formed under forest vegetation on gentle slopes of northern and western aspects with a thick mantle of loose colluvial depos its. Dark humus metamorphic soils occur on the slopes of western and northwestern aspects below 700 m a.s.l. under secondary forb-grassy communities that replaced the initial herbaceous pine forests. Windblown hollows (yardangs) are occupied by humus psammozems under steppe pine forests. The morphological and physicochemical characteristics of these soils are discussed in the paper.

The basis for assessing the stability of geosystems to changes in external heat cycle conditions is the calculation method. It is shown that permafrost soils are characterized by increased values of annual heat cycle QY ≥ 300 MJ/m2, i.e., half-sum of heat arrival and flow rate per year. This is due to the high heat consumption for melting soils (QPh = 0.7–0.8 QY) and warming them in the negative temperature range (QF). The heat cycle in frozen soil (QF) always has more heat cycle than in the thawed soil (QH). The condition QF > QH means the dominance of processes occurring at negative temperature, and the difference QF − QH is a quantitative assessment of the energy stability of soils to changes in heat exchange conditions on the surface.