Processes of primary soil formation in technogenic ecosystems at the dumps of the Borodino Brown Coal Deposit (eastern part of the Kansk-Achinsk Fuel-Energy Complex)

The properties of the soils and functional responses of microbial complexes of soils to the environment settings in the technogenic soils at the dumps of the Borodino Brown Coal Deposit have been investigated. It has been revealed that the lithostrata of the dumps are originally fertile. Fertility levels are partly inherited from the parent rock and built up as a result of the microbiological processes of decomposition of the organic matter which provides plants with nitrogen and mineral elements and indicates the primary soil-forming processes. Intensity of the biological transformation and accumulation of the organic matter depends on the smoothed surface, which, in turn, determines the level of dump fertility. The level of basic nutrients in lithostrata dumps is significantly lower than in background soils. The 28-year-old lithostratum of woodland formed on the smoothed surface is characterized by the greatest balance of microbiological processes, whereas the 20-year-old lithostratum of dumps with constant planar erosion is marked by the lowest levels of activity and instability of the microbial complex functioning. Application of topsoil on the smoothed surface of dumps does not lead to the restoration of the basic physical and chemical properties even after 28 years and does not feed plants on the level of background soils. In turn, the development of microbial complexes is faster due to the initial fertility level of the soil applied, as well as to the more rapid accumulation of the biomass resulting in the accumulation of the soil organic matter and intensification of the processes of mineralization and humification. 20-year-old replantozems are characterized by balanced immobilization and mineralization processes of the organic matter, expressed intraseasonal dynamics of the microbiological processes, as well as integrity and differentiation of the microbiological profile, which is characteristic of mature microbial communities. The young 4-year-old replantozem is being developed (active exploration of the substrate). The instability of young replantozem microbial complexes functioning may be associated with active soil-forming processes (formation of soil structure) and competition for the available organic matter and nitrogen with the rapidly growing vegetation.

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