Soils of Steppe Areas in the Cis-Tundra Open Woodland Subzone on the Right Bank of the Kolyma River in Its Lower Reaches

• Published in: Eurasian soil science Vol. 57; no. 5; pp. 762 - 779
• Main Authors: Fedorov-Davydov, D. G., Davydov, S. P., Gubin, S. V., Davydova, A. I., Zanina, O. G., Shchelchkova, M. V., Boeskorov, G. G.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.05.2024; Springer Nature B.V
• Subjects: Acidic soils; Acidity; Carbonates; Decomposing organic matter; Dithionite; Earth and Environmental Science; Earth Sciences; Genesis and Geography of Soils; Geotechnical Engineering & Applied Earth Sciences; Humus; Organic matter; Organic nitrogen; Organic soils; Rivers; Salts; Silt loam; Soil; Soil formation; Soils; Steppes; Taiga; Thawing; Tundra; Woodlands; Kolyma River; petrophytic steppe; thermophytic steppe; temperature regime of soils; cryoxerozemic pedogenesis; cold steppe; northeastern Eurasia; cryoarid soils
• ISSN: 1064-2293; 1556-195X
• DOI: 10.1134/S1064229324600027

Small areas of steppe-like vegetation (steppoids) occur on southern slopes among open larch woodlands in the lower reaches of the Kolyma River, northeastern Siberia. Depending on the soil parent material, they are divided into petrophytic (on the bedrock colluvium) and thermophytic (on silty loam of the Yedoma (Ice Complex) formation) steppoids. Xeromorphic deeply thawing soils with diverse humus-accumulative horizons, high content of roots, fine subangular blocky structure, and an increased content of water-stable microaggregates are formed in steppoids. These soils from differ from the soils of surrounding taiga landscape by the decreased actual and potential acidity; higher contents of exchangeable bases, soluble salts, carbonates, and organic nitrogen; smaller ratio between concentrations of oxalate- and dithionite-extractable iron. The soils of steppoids, especially thermophytic steppoids, are zooturbated. Dark mull-like forms of humus on the surface of mineral grains are present among the microaccumulations of organic matter in these soils. The features of cryoxerozemic pedogenesis are better manifested in petrophytic steppoids. The soils of thermophytic steppoids have similar features with steppe cryoarid ones, but differ from the latter in the absence of carbonate-accumulative and cryohumus horizons and in a relatively high acidity. Among the soils of petrophytic steppoids, gray-humus lithozems and gray-humus or mucky–dark-humus soils with carbonate incrustation can be distinguished. The soils of thermophytic steppoids can be classified as gray-humus or mucky–dark-humus surface-turbated (zooturbated) soils.