Albic podzols under pine forests are more prone to fires on the planet. The influence of fire extends to all soil components, including chemical properties, microbiological characteristics, and the composition and structure of soil organic matter, which persists for a long time. Here, we present the results of a study of the morphological, physicochemical, and microbiological properties and features of soil organic matter (SOM) in the albic podzols of pine forests (Pinus sylvestris L.) not exposed to fires for a long time (from 45 to 131 years). The study areas are characterized by different numbers of old fires (from four to five) that occurred over the previous several centuries in various territories of the Russian Federation such as Central Siberia (CS) and the European North (EN). In general, the albic podzols developing in CS and EN are characterized by similar morphological and physicochemical properties, with high acidity and poor mineral horizons. In terms of the lower vegetation layer and stand parameters, forest communities at the CS sites have a lower density and species diversity than those in EN. The ground cover is almost completely restored 45 years after the surface fire. The upper mineral horizon of albic podzols in EN contains higher PAHs in comparison with similar horizons of the CS sites. In the soil of EN pine forests, the MB content in the mineral horizons is, on average, three times higher than those in CS. Differences were also found in the qualitative composition of the studied soils’ microbiomes. The EN soil communities are represented by a wide variety of bacteria and fungi. The presented soil parameters can be used as a reference in assessing the increasing impact of fires on pine forests and podzols.

The microbial activity of peat soils was studied in boggy larch forests and in an oligo-mesotrophic bog in the basins of the Kochechum and Nizhnaya Tunguska rivers (central Evenkia). It was found that the organic matter transformation in the peat soils of all the plots is mainly performed by oligotrophic bacteria composing 88–98% of the total bacterial complex. The major contribution to the organic matter destruction belonged to the heterotrophic microorganisms, the activity of which depended on the permafrost depth and the soil temperature, the soil acidity, and the botanical composition of the peat. Peat soils were characterized by different activities as judged from their microbiological and biochemical parameters. The functioning of microbial communities in the studied ecotopes of the permafrost zone was within the range of natural variations, which pointed to their ecological stability.

The structure and functional activity of microbial complexes of a forest oligo-mesotrophic subshrub- grass-moss bog (OMB, Central Evenkiya) and a subshrub-sedge bog in the polygonal tundra (PB, Lena R

Two types of bogs were studied in Tomsk oblast—Maloe Zhukovskoe (an eutrophic peat low-moor bog) and Ozernoe (an oligotrophic peat high-moor bog). The gram-negative forms of Proteobacteria were found to be dominant and amounted to more than 40% of the total population of the microorganisms investigated. In the peat bogs, the population and diversity of the hydrolytic microbial complex, especially of the number of micromycetes, were lower than those in the mineral soils. The changes in the quantitative indices of the total microbiological activity of the bogs were established. The microbial biomass and the intensity of its respiration differed and were also related to the depth of the sampling. In the Zhukovskoe peat low-moor bog, the maximal biomass of heterotrophic microorganisms (154 μg of C/g of peat) was found in the aerobic zone at a depth of 0 to 10 cm. In the Ozernoe bog, the maximal biomass was determined in the zone of anaerobiosis at a depth of 300 cm (1947 μ g of C/g of peat). The molecular-genetic method was used for the determination of the spectrum of the methanogens. Seven unidentified dominant forms were revealed. The species diversity of the methanogens was higher in the oligotrophic high-moor bog than in the eutrophic low-moor bog.

Key plots of hydromorphic and semihydromorphic peat soils of oligotrophic bogs were studied in the area of the Middle Yenisei Station of the Institute of Forest, Siberian Branch of the Russian Academy of Sciences. Hydromorphic soils were classified as Fibric Histosols (FHS1 and FHS2), and semihydromorphic soils were classified as Histic Albic Podzols (PZ1 and PZ2). It was found that fires had a significant impact on the initial waterlogging of the studied territory. The pyrogenic horizons of peat soils were generally enriched in ash elements and differed from one another in the contents of carbon and nitrogen. The functional activity of microbial communities in the studied soils was low, and this affected the content of microbial biomass and respiration rate. The restoration of microbial activity in pyrogenic horizons proceeded slowly because of the deficit of available organic matter. The qualitative and quantitative compositions of bacterial biomes and mycobiomes of peat soils differed in the studied plot and soil horizons. The number and species diversity of prokaryotes in all areas was quite high. Representatives of Proteobacteria and Archaea played the leading role in the development of pyrogenic horizons; the number of their operational taxonomic units (OTUs) in these horizons was significantly higher than that in the nonpyrogenic horizons, where Acidobacteria predominated. The mycobiomes of the FHS1 and FHS2 plots were significantly less abundant and had lower species diversity as compared to the PZ1 and PZ2 plots. The number of fungi was higher in the nonpyrogenic horizons; the number and diversity of fungi decreased in the pyrogenic horizons. The mycobiomes of the upper pyrogenic horizons included groups of carbotrophic fungi that can develop on charcoal.

The agrochemical properties and microbiological activity of the soils on dump rocks of different ages and degrees of cultivation in the area of the Borodinsk coal strip mine were studied. The technogenic soils of the dumps significantly differed from the native soils in their total nitrogen content. In the young soils (less than 5 years old), the total nitrogen was present in trace amounts; in the 20-year-old dumps, its content was lower than in the control soils by 2.5 times. It was found that a humus horizon 2–3 cm thick was formed on the surface of the dumps after 20 years regardless of the reclamation practice and that the intensity of the biological processes was comparable to that in the control soils, because the microbial complexes functioned under conditions typical for automorphic soils. It was shown that the ecophysiological status of the 3- to 10-year-old soils was unstable and their microbocenoses were at the development stage.