A. A. Dymov, E. V. Abakumov, I. N. Bezkorovaynaya, A. S. Prokushkin, Ya. V. Kuzyakov, E. Yu. Milanovsky
Section: Theoretical problems of ecology
We examined changes in the morphological, physicochemical properties and features of the organic matter of forest
soils impacted by wildfires on the territory of Russia. Morphological signs of pyrogenesis (pyrogenic horizon formation,
partial charring of litter and illuviation of organic compounds) are most evident detected in the first decade after a fire.
Ground fires in lichen pine forests, formed on Albic Podzols lead to complete burning of litter. Low intensity ground fires
in sphagnum pine forests, developing on Histic Podzols, contribute to partial burning of litter (charring). Fires change
the hydrothermal regime of soils, which is most clearly demonstrated for soils formed on permafrost soils / cryosols. Fires
lead to hydrophobization of the upper mineral horizons, estimated from the contact angle of wetting. Resistant products
of pyrogenesis (charcoals, soot) are retained in soils for several centuries. The most common changes in the physical
and chemical properties of soils after fires are a decrease in acidity by 1–2 units of pH, an increase of saturation with
base saturation. Fires increase aromaticity of soil organic matter. After fires, the content of polyaromatic hydrocarbons
in soils increases, and the concentrations of water-soluble organic compounds decrease. Restoration of soil properties to
the prefire state takes a decade to several centuries. The introduction of a universal subtype “pyrogenic” is proposed in
describing the morphological characteristics of forest soils.
ISSN 1995-4301
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