The soil cover of the forest-steppe and steppe zones of the East European Plain is characterized by diverse soil combinations revealed during large-scale and detailed soil mapping against the background of a traditional zonal sequence of dominant automorphic soils alternating from the north to the south and clearly displayed on small-scale soil maps. The composition, configuration and functioning of particular soil cover patterns are determined by the soil forming factors acting within a given area. The elementary soil areas (detailed scale) and elementary soil cover patterns maps (large scale) of the Central Russian, Kalach, and Volga Uplands are created by both traditional and digital soil mapping methods. Low-contrasting soil combinations with the background Haplic Chernozems (Loamic or Clayic, Pachic) alternating with zooturbated Haplic Chernozems (Loamic or Clayic, Pachic) on convex elements of the microtopography and Luvic Chernozems (Loamic or Clayic, Pachic) on concave elements of the microtopography prevails under conditions of thick clay loamy parent materials and free drainage. Under conditions of shallow embedding by low-permeable clayey sediments, the soil cover includes Chernozems or Chernic Phaeozems with stagnic features in some part of the soil profile or even Mollic Stagnosols. The presence of shrink-swell clays of different ages leads to the formation of Bathyvertic Chernozems, Vertic Chernozems, Vertic Chernic Phaeozems and/or Pellic Vertisols. The presence of soluble salts in the parent material leads to the development of solonetzic soil complexes consisting of Protosodic or Sodic Chernozems and different types of Solonetzes.

Laboratory analytical methods suitable for the determination of the hydrocarbon status of soils (a specific soil characteristic involving information on the total content and qualitative features of soluble (bitumoid) carbonaceous substances and individual hydrocarbons (polycyclic aromatic hydrocarbons, alkanes, etc.) in bitumoid, as well as the composition and content of hydrocarbon gases) have been considered. Among different physicochemical methods of study, attention is focused on the methods suitable for the wide use. Luminescence-bituminological analysis, low-temperature spectrofluorimetry (Shpolskii spectroscopy), infrared (IR) spectroscopy, gas chromatography, chromatography–mass spectrometry, and some other methods have been characterized, as well as sample preparation features. Advantages and limitations of each of these methods are described; their efficiency, instrumental complexity, analysis duration, and accuracy are assessed.

Water movement in soils contributes to the formation of a number of specific soil properties; their interpretation makes it possible to characterize the features of particular hydrological processes and the soil water regime in general, which is important because of the limited possibilities to conduct direct monitoring of soil water movement. In this review, we consider the diagnostic indicators of mineral soils determined in the field and under laboratory conditions and characterized by different formation times and tolerance toward changes in the environmental factors. Field methods for diagnosing soil water regime make it possible to formulate hypotheses about the features of water behavior within the soil profile, which can later be confirmed or refuted as a result of laboratory diagnostic methods, regime observations, and physical and mathematical modeling. In particular, on the basis of a standard field description of soils, it is possible to identify the zone of maximum water turnover, parts of the soil profile with constant or periodic water stagnation, and the capillary fringe level. Clay coatings, root channels, and burrows of soil animals mark the preferential flows. Laboratory diagnostic methods are aimed at assessing the quantitative ratio of hydrological processes in the soil; basically, they allow to characterize the source, duration, and intensity of the period of soil overmoistening. The Schwertmann coefficient is the most commonly used and efficient analytical indicator for diagnosing soil overmoistening, which has been shown for a wide range of soils. Verification of the results of hydrological modeling on the basis of data on soil properties is potentially possible for the processes of downward and lateral runoff, physical evaporation, transpiration, evapotranspiration, and capillary rise of soil water.

To characterize the native component of the hydrocarbon status of soils in different bioclimatic zones, representative soils were studied in the East European Plain within the middle and...