Soil Transformation along the Coast of Baikal Due to Lake Level Fluctuations (Irkutsk Oblast)

Abstract

As a result of soil-geochemical studies, we have determined the degree of hydrogenic transformation of soils on the most developed and periodically flooded territories of the western and southern coast of Lake Baikal. Indicators are selected and a scale is proposed for a point assessment of hydrogenic transformation of soils and soil cover. The following indicators are used as indicators of the hydrogenic transformation of soils and soil cover: morphological signs of hydromorphism, soil pollution, reduction of physical clay content, increased area of exposed soil-forming and underlying rock, reduction of humus reserves, the area of natural forage land and arable land removed from land use, and others. An assessment is made of the environmental damage caused to the soil cover of the coastal area as a result of the influence of fluctuations in the lake level. It is revealed that most of the key areas of the western coast of Lake Baikal are characterized by an average degree of soil transformation. A high degree of soil transformation is noted at the mouths of the Goloustnaya and Anga rivers and on the coast of the Gulf of Shida and Lake Ulan-Khan. On most of the studied territory of the southern coast of Baikal (the mouth of the Snezhnaya, Utulik, Pokhabikha, and Kultuk rivers), a high degree of transformation of soil cover has been established, where an anthropogenic impact is also observed. In all periodically flooded soils of the lake coast, geomorphological signs of hydromorphism are observed, and in some areas there are processes of increasing the fraction of physical sand, sediment from organic remains of dead vegetation, a decrease and increase in humus reserves, and a decrease in the area of forage land. Increased concentrations of petroleum products and some heavy metals have been detected in the soils of the estuaries of the southern coast of Lake Baikal. The soils of most of the key areas are characterized by low levels of plant nutrients.