Pyrogenic Transformation of Lithozems in the Forest-Steppe of Western Transbaikalia

The article describes grey-humus lithozems widely distributed in the forest-steppe zone of Western Transbaikalia under pine forests and their secondary forests. The impact of medium intensity surface fires led to the formation of pirogenic organogenic horizons enriched with the charcoal residues of varying sizes. It has been established that one year after the fire the soil is characterized by compaction of the upper part of the profile, decrease in the pore volume, low water permeability, and relatively high levels of the silt fraction content in the texture in relation to the soils of old burnt areas. Post fire changes in chemical properties show a decrease in organic carbon in the humus horizon and a short-term increase in nutrient and CO2 which subsequently decreased. These losses associated with the absorption of substances by the roots of lower layers vegetation with their migration down the soil profile, as well as with the denudation processes actively expressed in the post-fire period in the mountain slopes, negatively affect the regeneration of woody vegetation in burnt areas.