Morphological features of soils in post-pyrogenic forest plantations

The subject of the study is post-pyrogenic pine forest plantations and their effect on the external signs of soils. The influence of the forest fires of 2021 on the morphological features and structure of the soil cover on sandy soils of the Republic of Mari El was studied. The results showed a significant change in the composition and condition of vegetation in the studied areas, as well as the upper organogenic and organomineral horizons, both in composition and thickness. Grass-roots fires caused the burning of the bark of pine plantations to a height of 1-2 m, the destruction of the grass and shrub cover. As a result of forest fires, a peculiar pyrogenic horizon Orig is formed, characterized by ash residues of plant litter with a small variability in power in all the studied areas. The sinterability of the mineral particles of the upper horizons has not been detected. The structure of the soil profile and the changes that occurred in the post-fire period were studied by the method of laying full-profile soil sections with the identification of diagnostic horizons and features. The classification, diagnosis and description of soils were carried out according to the "Classification and diagnosis of soils of Russia" with amendments and additions (2008, 2022) and the "Field soil Determinant of Russia" (2008). The main conclusions of the work explain the formation of pyrogenic forest litter (Orig) in the form of ash residues with a thickness of about 3 cm, the absence of signs pyrogenicity in the upper mineral horizons and unusual color changes. The formation of an underdeveloped protohumus horizon with signs of gilding, manifested in an uneven distribution of silica powder along the horizon, has been revealed. A feature of all the studied soils is a light granulometric composition throughout the profile and poor soil-forming rock, represented by ancient alluvial sands. The author pays special attention to the description of soils using the modern soil classification (2004, 2022), which uses a more up-to-date indication of soil horizons and features. For a more detailed analysis of the impact of fires on the power of various horizons, a statistical analysis of the data was carried out, which clearly shows a decrease in the variability of the power of the upper horizons.

forest fires, morphological features of soils, soils, soil section, soil-forming rock, soil diagnostics, forest ecosystems, post-pyrogenic plantings, Republic of Mari El, forest litter