The soil is a special natural body, a multiphase biokosnaya system that performs the most important planetary functions and at the same time is the main means of agricultural production. The methodological basis of this map is the idea of genetic geography of soils, based on the comparative-geographical method developed by V. V. Dokuchaev and firmly established in the Russian soil-cartographic school. The diversity of the soil quality in Russia is extremely high: from the Arctic soils of the islands of the Arctic
Ocean to the brown semi-desert soils of the Caspian Sea and the subtropical yellow soils of the foothills of the Caucasus. Arctic and tundra soils occupy 13% of the total land area of Russia. Taiga-forest soils predominate in the soil cover: podzols (including gley soil) —8.9%, taiga-frozen and gley-frozen soils — 8.1%, brown — 6.0%, taiga-brown — 3%, pale yellow-frozen — 2.8%, gleepepodzol and podzolic – 2.4%, sod-podzolic – 8.2%, podzolic and marsh soils – 8.5%. Smaller areas are occupied by gray forest soils – 3.3%, brown soils – 1.8%, black soils and meadow-black soils – 7.2%, chestnut and brown semi-desert soils and their complexes with saline soils – 1.9%. unparalleled plain, accounting for 2.5%.
In the distribution of soils, global bioclimatic patterns are clearly pronounced: horizontal (latitudinal) and vertical zonality, mainly caused by changes in hydrothermal conditions with latitude on the plains and with altitude in the mountains, as well as facies due to climate change and continental climate as distance from oceanic margins into the interior of the continent. The influence of bioclimatic factors significantly changes depending on the features of the relief, soil-forming rocks and the geological history of the territory. Mutually imposing, bioclimatic, lithological-geomorphological and historical-geological patterns determine a complex picture of the soil quality in Russia. The horizontal (latitudinal) zonality is particularly well pronounced on the inland plains. In the map legend, latitudinal zonality is underlined by soil grouping by geographic zones (polar, boreal, subboreal, subtropical). The latitudinal-zonal spectrum of soils on the East European Plain is represented by soils from tundra to brown semi-arid. In the north of the Russian Plain, in conditions of a cold humid climate and almost ubiquitous permafrost occurrence, tundra gley soils form on loamy rocks, and tundra podburs on better drained sands and fine-grained sediments. Tundra gley soils have a humus or peaty horizon on the surface, under which lies the mineral gley stratum, underlain by icy permafrost. The barbers are not ogleyan, in their profile the peated litter is replaced by an illuvial-alumo-ferruginous-humus mineral horizon.
Various cryogenic processes are associated with permafrost (frost heaving, mixing of the soil mass, the formation of spots and cracks), which determine the main common feature of the tundra soil cover – complexity. Dominant-spotted complexes of tundra gley soils with tundra-bog and soils of spots and large- and flat-hilly bog complexes prevail soil quality in Russia. In the northern taiga subzone, on loamy rocks under dark coniferous moss-shrub forests, gley-podzolic soils are spread in the most drained relief conditions (ridge tops, riverside slopes) in combination with peaty and peaty-podzolic-gley and peaty soils. In gleepepodzol soils under a coarse humus litter lies a clarified podzolic horizon with signs of surface gleying. The profile has eluvial-illuvial differentiation according to the distribution of silt and one-and-a-half oxides. Combinations of podzols of illuvial-ferruginous and illuvial-humus with podzols of gley and peaty bog soils are formed on sandy sediments under pine forests.
In the middle taiga on loamy sediments in drained positions, the gley-podzol soils are replaced by typical podzolic soils, differing from the first ones by the absence of gleying in the eluvial horizon. On the binomial sediments (thin sands and sandy loam underlain by loams), signs of eluvial gleying appear on the contact of the rocks due to stagnation of the water pipe in podzolic soils. Soil combinations on sands are generally similar to northern taiga, but humus leakage decreases in podzols and profile thickness increases.
In the soil cover of the southern taiga zone on the loamy plains dominate sod-podzolic soils in combination with peat-and sod-podzolic-gley and humus-peat-gley soils of transitional and lowland marshes. Sod-podzolic soils, unlike podzolic soils, have a humus-accumulative horizon under the litter. On the sands, sod-podzols are formed, silt-fermented and ferruginous in combination with gley and marsh podzols. To the south, gray forest soils dominate in the soil cover of the zone of deciduous forests on clayey and loamy sediments. They differ from sod-podzolic less pronounced eluvial-illuvial differentiation of the profile and increased process of humus accumulation. Bog massifs are rare and are represented mainly by humus-peaty-gley soil quality in Russia of lowland marshes. In the sandy languages, the alluviums of the south-western plains penetrate the zone with sod-podzols, illuvial-ferruginous.
In the forest-steppe, the soil cover is represented by podzolized, leached, and typical chernozems, forming combinations of mainly negative terrain elements with meadow-chernozem and meadow soil quality in Russia. Only on poorly drained Oka-Don lowland, meadow-chernozem soils occupy flat watershed areas, they are often solonetsous and form complexes with solods along depressions. Typical chernozems have a humus horizon with a capacity of up to 80-100 cm, directly under which lies the accumulative-carbonate horizon with mycelial carbonate forms. The mineral mass is stable, there is no redistribution along the profile of the sludge and sesquioxides. Black podzolized and leached chernozems to the northern forest-steppe and are characterized by weak eluvial-illuvial differentiation of the profile and lowering of the carbonate horizon. On the loamy and clayey plains of the steppe zone, common and southern chernozems, with a humus horizon 40–80 cm thick, dominate; carbonate new formations are white-eyed. In Ciscaucasia, on the Azov-Kuban Plain, common black and southern myatocente-carbonate chernozems are common. They are distinguished by a large thickness of the humus horizon (up to 120 cm and more), carbonates appear from the surface. In the dry steppe zone, the soil cover is represented by dark chestnut and chestnut soil quality in Russia, including solonets in complexes with solonets.
In the semi-desert of the Caspian lowland, the soil cover is complex. The complexes are extremely diverse in terms of the composition of the components and their ratio, and are formed by light chestnut, brown desert-steppe solonets soils, salt marshes with the participation of meadow-chestnut soil quality in Russia. In the West Siberian Plain, as well as in the East European Plain, the latitudinal zonality of the soils is clearly pronounced. The latitudinal range of soils begins with arctic-tundra and tundra gley soils, forming deep-humpy and fissure-polygonal complexes with tundra-bog and marsh and soil soils and ends with chestnut soils. However, the large continental climate, low heat supply, and mainly flat topography, multiple stratification of soil-forming rocks, which impedes drainage, and the predominance of tectonic subsidence for a long time determined the specific features of the soil geography of the West Siberian lowland plain: abundant marshes, sharp soil contrast. the cover of narrow riverine drained territories and marshy extensive interfluvial areas, increased soil hydromorphism, the presence of relict signs in them.
In the subzones of the northern and middle taiga, vast areas of flat watersheds are occupied by peat soils of upland and transitional bogs, which form flat-hilly and ridge-urine complexes. In the best conditions of drainage on loamy sediments, gleezems are widespread here, in the profile of which there is a mineral gley stratum under the litter, and deep-gley podzolic soils and gley soils. In the soil cover of southern taiga, besides marsh soils, sod-podzolic soils, often with a second humus horizon, sod-podzolic-gley and peculiar sod-gley soils are widespread. Podzols are confined to the sands in the northern and middle taiga, sod-podzols are illuvial-ferruginous in the southern taiga. The soil cover of the forest-steppe and steppe zones is distinguished by a large diversity. Along with poor drainage, the presence of saline soil-forming rocks becomes an important factor in the heterogeneity of the soil quality in Russia. On flat interfluves with closely-lying, often mineralized groundwater, meadow-chernozem and meadow solonetsous soils, salt licks and solodies dominate over depressions. Gray forest, often gleyey and solodized soils and leached chernozems are common in forest-steppe on drained riverine strips and more elevated parts of the plain, and chernozems ordinary and southerly in the steppe, which differ from European ones in lower humus horizon and linguality of its lower boundary.
To the east of the Yenisei within Central and Eastern Siberia, a facies of permafrost soils form in an extracontinental, relatively dry and cold climate and the spread of permafrost. In Central Siberia, the latitudinal zonality is obscured, and the soil cover becomes mosaic, and the soils are often gravelly due to the elevated, deeply dissected relief, dominance among the soil-forming rocks of low-power eluvo-deluvia of various dense rocks, many of which are rich in bases. In soil formation, cryogenesis is of great importance. All this determined the formation of a wide range of autonomous soil quality in Russia. The Arctic soils of the islands are replaced in the north of Central Siberia by fissure-polygonal and deep-bumpy complexes of Arctic-tundra, tundra gley, tundra-bog soils, soils of spots and frozen fissures. In the northern and middle taiga, on loamy and clayey rocks with close occurrence of permafrost, taiga, frozen and gley-frozen, soils under which peaty or humus-humus litter are dominated by monotonous wetted mineral strata with signs of cryogenic mixing. On the gravel products of weathering of the main rocks, podburs are formed, and to the south – brown-taiga soils with poorly differentiated brown profile; on poor sandstones, they are replaced by podzols. Humic-carbonate soils in the north (Anabar Plateau) and sod-carbonate soils are confined to carbonate rocks in the south. The latter in the zone of southern taiga are combined with sod-podzolic soils prevailing here, among which there are gray forest soils of island forest-steppes.
Shallowness and graveliness of soils are also characteristic of Eastern Siberia, but mountain ranges dominate here, and the law of vertical zonality gets the most vivid expression. The soil cover of the Central Yakutian Plain stands out, within which pale yellow frosted, including solodized soils, solods are widespread, and in thermokarst depressions – meadow-chernozem soils, sometimes saline and solonchakous. Fawn soils are formed under the grass-lingonberry larch taiga. They have a weakly differentiated profile: under the humus horizon lies a metamorphic horizon of brownish-pale yellow coloration due to the formation of ferruginous films on the surface of mineral grains during the subsurface weathering, turning into an accumulative-carbonate horizon. The reasons for the peculiarity of the soil cover and the development of salinization processes in the taiga-forest zone are the dryness and sharp continental climate, the salinity of some soil-forming rocks, the presence of permafrost and depression in the basin, contributing to the continental salt accumulation. On the plains of the Far East with a continental monsoon climate in the boreal belt, brown-taiga soils are spread on clay and loamy sediments under larch grass-shrub forests. In the subboreal belt under deciduous forests they are replaced by burozems. Under conditions of poorly dissected relief, on the rocks of heavy particle size, contributing to surface waterlogging, gaps are formed – soil quality in Russia with a sharply differentiated profile and abundance of ferro-manganese nodules in the eluvial bleached horizon. Peaty humus-gley soils of transitional swamps are confined to depressions of the relief. Peculiar meadow-chernozem-like soils of the “Amur prairies” are developed under the steppe meadows on the Zeya-Bureya plain. Their characteristic features: a dark humus horizon of considerable thickness, containing ferrous nodules, the absence of carbonates and signs of gleyateness in the profile.
The peculiarity of the soil cover of the Kamchatka Peninsula and the Kuril Islands is determined by the impact of volcanic eruptions. Periodic loss of volcanic ash leads to the burial of previously formed soil quality in Russia. As a result, layered polygenetic ash-volcanic soils are formed, consisting of several elementary profiles superimposed on each other. The properties of soil-forming rocks determine their specific features: high porosity, abundance of allophane, amorphous forms of iron and aluminum oxides, and high hydrophilicity, despite the light particle size distribution. About 1/3 of the territory of the Russian Federation falls on mountain landscapes. A common feature of mountain soils is the low thickness, rubble of profiles and their constant rejuvenation caused by denudation processes. In the soil cover of the mountains, the law of vertical zonality (zonality) is expressed. The structure of vertical zonality, or the successive change of vertical soil zones with height, is extremely complex and diverse and depends on the latitudinal position of a mountainous country and on its proximity or remoteness relative to the ocean (continental, extracontinental or oceanic facies). In addition, the height of the mountains, the exposure of the slopes and their position relative to the prevailing movement of air masses carrying precipitation are important. The figures illustrate the complexity of the composition and structure of the vertical zonality of the soil cover of mountain structures in the southern latitudes compared with the northern ones and their specificity in the continental and oceanic facies, as well as the role of the slope exposure.