Agropedogenesis and related changes in morphology, fertility and microbiome diversity of soils in cryogenic ecosystems on the example of the central part of Yamal region (West Siberia)

Agro-development of northern territories results in radical transformation of soils of these ecosystems. On the example of Nadym district (N 65.5; E 72.6) of Yamal-Nenets Autonomous Okrug (Russia) it is shown that the process of agrogenic transformation of reference podzols is similar to the process of formation of Plaggen soils, which were repeatedly found in Northern Europe and other regions (Plaggen Anthrosols – result of Plaggen Management). As a result of the application of large amounts of organic substrate (Plaggen Material), the thickness of the surface horizons increases considerably (from 3 cm to more than 30 cm in some cases). These soils occupy an intermediate position from reference soils to highly transformed − Hortic/Plaggic Podzols. Hortic and Plaggic horizons are characterized by reduced acidity (pH H₂O 5–6, pH CaCl₂ 4–5), increased content and stock of organic carbon (5.4–14.5 %). Soils of agrogenic and postagrogenic ecosystems are characterized by relatively high content of basic nutrients (P-P₂O₅ up to 386 mg kg⁻¹, K-K₂O up to 239.0 mg kg⁻¹) and clay (up to 20.9 %), also the degree of their microstructure increases in comparison with reference Podzols of Nadym district. The taxonomic composition of soil microbiome also changes greatly in the process of agricultural development of soils. In reference Podzols Proteobacteria, Actinobacteria and Bacteroidetes dominate. In general the microbiological profile in the of agrogenic and postagrogenic soils shifts towards the increase of the phyla Proteobacteria, Acidobacteria, Planctomycetes, Nitrospirae, Verrucomicrobia (for abandoned lands) and Actinobacteria, Bacteroides, Firmicutes, Euryarchaeota (for soil in use).