The article considers the role of hydromorphism in the soil formation processes on ancient alluvial sandy deposits at the primary succession period. Soil organic matter was given special attention. The studies were carried out in the European north-east of Russia (the Komi Republic) in the middle taiga subzone in the territory of a building-sand quarry (61°57′35″ N, 50°36′22″ E) and background sites near the quarry. The authors analyzed the morphological structure of soil profiles, and the principal physical-chemical properties of mature and young soils forming under pine forests. Formation of forest litter and humus-accumulative horizons, as well as soil organic matter accumulation were thoroughly studied. Already in the fourth–fifth succession decades, the soils in a series of increasing hydromorphism actively demonstrated regularities that are normally characteristic of background soils, for example, increase in acidity, silt fraction, carbon and nitrogen reserves. Against moisture deficiency, the accumulation rate of organic carbon became slow and amounted to 0.07–0.11 t ha⁻¹ year⁻¹. The excessive soil moisture content increased the rate up to 0.38–0.58 t ha⁻¹ year⁻¹ due to the conservation of plant material in the form of peat. The upper 50-cm profile layer of young soil contains Corg stock 3–5 times less than that of background soils. The major soil-forming processes are litter formation and podzolization in drained conditions, litter formation in conditions of high moisture, and peat formation and gleization against excessive moisture.

This paper provides the results of a study on fungal species diversity in the active and permafrost layers of peatlands within frozen peatbogs in the flatland areas of the cryolitozone, European Northeast of Russia (forest-tundra zone, southern and northern tundra subzones). Fungal taxonomic list includes eighty-three species from seventeen genera and two forms of Mycelia sterilia. The phylum Mucoromycota is represented by fifteen species (18% of total isolate number), and these species exhibit the following distribution by genus: Mucor (four), Mortierella (seven), Umbelopsis (three), Podila (one). Ascomycota is represented by sixty-eight species from thirteen genera. The genus Penicillium dominates the species saturation (thirty-seven species, 44%). Soil microfungal complex is represented by rare species (51%), random species (32%), frequent species (15%), and dominant species (2%). In peat soils, dominant species are Penicillium canescens (72%) and non-pigmented (albino) Mycelia sterilia (61%); abundant species are Talaromyces funiculosus (41%), Pseudogymnoascus pannorum (36%), albino Mycelia sterilia (29%), Umbelopsis vinacea (25%), Mortierella alpina (17%), Penicillium decumbens (21%), P. spinulosum (20%), and P. canescens (17%). In active layers of peat soils, abundant species are Penicillium thomii (14%), Mycelia sterilia (13%), Penicillium spinulosum (13%), Penicillium simplicissimum (13%) in forest-tundra; Talaromyces funiculosus (21%), albino Mycelia sterilia (15%), Umbelopsis vinacea (14%) in southern tundra; Penicillium decumbens (23%), P. canescens (17%), P. thomii (13%) in northern tundra. In permafrost peat layers, abundant species are Penicillium spinulosum (17%), Talaromyces funiculosus (34%), and Umbelopsis vinacea (15%) in forest-tundra; Pseudogymnoascus pannorum (30%) and Mortierella alpina (28%) in southern tundra; Pseudogymnoascus pannorum (80%) in northern tundra.

Physicochemical properties and parameters of biological activity of forest litter horizons of illuvial-ferruginous podzols, formed the main part of soil cover of the largest recreational zone of Ukhta city, the G. A. Karchevsky Central Park, have been determined for the first time ever. In the park soils, a change in the basic agrochemical parameters (alkalinization and an increase in the content of available forms of the most important biogens with the exception of organic compounds carbon), the accumulation of heavy metals (up to moderately toxic level according to value of total pollution index) and petroleum hydrocarbons were indicated in comparison with background soils. An increase in soil enzymes (catalase, invertase) activity and a metabolic activity of soil microbial community was established. Based on the spectra of organic substrate consumption (multisubstrate testing method), a higher activity of all microbial functional (trophic) groups, with the exception of bacteria that consume alcohols, hexoses, and amino acids as an energy source, was revealed.

Background: Forest recultivation can accelerate the formation of tree stand and increase carbon dioxide absorption. This study investigated the growth rates, biomass accumulation and carbon stock in stands of native Scots pine (Pinus sylvestris L.) (SP) and introduced lodgepole pine (Pinus contorta Dougl.) (LP) planted on remediated land quarries. A comparative analysis of the parameters is performed 1) in cultures using same planting material (bare-root SP seedlings) but developing on different parent materials (ancient alluvial sands, fluvioglacial sandy loams, and moraine loams) and 2) in pine cultures on the same deposits (fluvioglacial sandy loams), but using different planting materials: bare-root SP seedlings, container SP seedlings and container LP seedlings. Allometric equations were used to calculate stand biomass. The ground cover biomass was determined by the mowing method. Results: Biometric parameters, biomass and carbon reserves, and the share of wood in the total biomass reserves increase along with the soil texture transformation from sands to silty loams. The aboveground biomass is dominated by mosses and lichens on sands to sandy loams and by herbaceous plants on loams. The LP cultures have better growth, survival, biomass and carbon stock values compared with those of the SP. In the quarries of the middle taiga subzone of Russia, 20-year-old experimental LP cultures accumulated 38% more carbon in the aboveground phytomass than SP cultures. Conclusion: The soil conditions of quarries affect the growth and survival, biomass and carbon stock of pine crops. LP cultures outperformed SP cultures related to carbon storage on sandy loam substrates, highlighting its potential for recultivation in Northwest Russia.

The morphology and properties of soils of the Yugorsky Peninsula at the junction of plain (Bolshezemelskaya Tundra) and low-mountain landscapes (Pay-Khoy Ridge) have been studied. The specific features of these soils reflect subzonal, regional, and landscape characteristics of pedogenesis. On the plain, gleyzems and cryometamorphic gleyzems, including permafrost-affected, cryoturbated, and stagnic soils with thin (<10 cm) organic horizons dominate. On well-drained sites with silt loamy parent materials, cryometamorphic soils with a CRM horizon are formed. In the low-mountain landscape, cryometamorphic gleyzems and cryometamorphic soils predominate on the slopes and at the foothills of the ridges, whereas cryometamorphic podburs and abrazems developed on the eluvium of bedrock are found on the tops. Soils of the low mountains are characterized by stoniness, weak gleyzation throughout the profile, and deep occurrence of the permafrost table. Compared to their plain analogues, mountain soils have a more acidic reaction, higher hydrolytic and exchangeable acidity, lower base saturation, and a high content of sesquioxides. The results reveal the regional specificity of pedogenesis in the northern permafrost zone at the boundary between subarctic plain and low-mountain geosystems and serve as a basis for monitoring ongoing climate and permafrost changes.