Catenas at the forest-steppe in Western Siberia

To simulate the downward movement of pollutants across landscape catenas, it is essential to gather information regarding the chemical properties of soils along the migration pathways of these substances. Consequently, the classification of catenas becomes challenging due to the necessity of considering numerous factors. In this article, we discuss the primary and most well-known principles for classifying catenas (iee Table 1 and Tables 1-4 in the Supplement 1). To investigate the catenas of the forest-steppe region in Western Siberia, we employed GIS analysis to integrate soils and soil-forming factors, along with a series of thematic maps (see Fig. 1 in the Supplement 2). Utilizing the methodologies developed by Inga S. Uru-sevskaya and Maria D. Bogdanova, as well as GIS analysis and a collection of small-scale maps depicting relief, parent materials, soils, and vegetation, we cataloged the landscape catenas in the forest-steppe of Western Siberia. From these combinations, we compiled a matrix, with its columns and rows containing information about relief and parent materials, which vary in texture, the content of carbonates, gypsum, and easily soluble salts (see Fig. 2 in the Supplement 2). The typification of catenas in the forest-steppe of Western Siberia was validated through field research conducted in seven key areas (see Table 2 and Table 5 in the Supplement 1). The soils and vegetation identified in the field studies corresponded to the dominant landscape catenas of the target territories. Within the region under consideration, 38 variants of landscape catenas have been identified. Among these, catenas featuring Chernozems under herbaceous grass meadows and Phaeozems under herbaceous grass meadows and subtaiga aspen-birch forests predominantly occur in elevated topography on loess plains (see Fig. 1). In the slopes, these soils are replaced by clay-illuvial Chernozems (Haplic Chernozems) or gray gleyic soils (Phaeozems), as well as solonetz (which can also be found in the summit position) and marsh soils (Histic Gleysols). From west to east, the prevalence of catenas with Phaeozems in the summit position diminishes; west of the Irtysh River, they are nearly entirely supplanted by catenas with Chernozems. The northeastern part of the Ob-Irtysh interfluve (located in the southern Vasyugan Plain and northern Baraba Lowland) experiences considerable soil waterlogging, resulting in the formation of Planosols and Gleysols even on watersheds. To the east, Gleysols and Planosols (exhibiting signs of salinity and solonetzity) occupy a predominantly subordinate position in the topography. The least contrasting catenas are characteristic of the extreme eastern and western parts of the Western Siberian forest-steppe. In the flat areas of the Western Siberian forest-steppe, herbaceous grass communities predominantly occur on Phaeozems and Chernozems. The smallest territories, located in the extreme northeast, are occupied by subtaiga pine forests with tall grasses, which are confined to catenas with Phaeozems. The diversity of landscape catenas is greatest on inclined and stepped plains and least in the elevated eastern and western parts of the forest-steppe in Western Siberia. Three pairs of catenas were identified, each exhibiting a similar set and sequence of soils, but differing in the genesis of parent materials or topography (two pairs) and texture (one pair). The composition of vegetation and soils is closely correlated. Only three pairs of catenas with identical soil cover differ in their vegetation composition. This variation is attributed to the absence of birch-aspen associations in catenas located in depressions occupied by Planosols, or it resulted from the presence of subtaiga forests with tall grasses on catenas with Phaeozems situated on elevated topography in the eastern part of the forest-steppe in Western Siberia. The article contains 1 Figure, 2 Tables, 2 Supplements, 45 References. The Authors declare no conflict of interest.