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The notions of saline and solonetzic soils are compared in two Russian (1977 and 2004), American (Soil Taxonomy 1999), and the International (WRB 2014/2015) classification systems. The diagnostics and lists of soils referred to as solonchaks, solonetzes, and other soils containing soluble salts and exchangeable Na are presented. Some features of similarity and differences were revealed in the approaches to identifying salt-affected soils and their taxonomic position. In the Russian systems, data on soil water extracts (1 : 5) are used for the assessment of soil salinization; in addition, the contents of toxic salts are calculated. In western classifications, soil salinity is assessed on the basis of the analysis of extracts from water-saturated pastes. Solonetzes are estimated according to their morphological features and data on the content of exchangeable Na. In three classifications (except for Soil Taxonomy), solonchaks and solonetzes are distinguished at the high taxonomic level. In addition, in all classification systems, soils (both saline and containing exchangeable Na), whose saline and solonetzic horizons do not completely fit their definitions, are considered at a lower taxonomic level. While improving the classification of soils of Russia, some changes and corrections to the definitions of saline soils are recommended.

The principles of typological soil-genetic zoning based on the substantive-genetic classification of Russian soils (2004) and realized for the State Soil Map of Russia on a scale of 1 : 1 M are considered. Three categories of characteristics are applied to the system of zoning units: taxonomic, process-based, and landscape- indicative characteristics. The relationship between them changes in dependence on the taxonomic level of the zoning unit; at the lower level, the spatial (landscape-indicative) criterion plays the major role. This criterion is also important in the delimitation of soil groups (soil communities) serving as the central taxonomic unit of the zoning. At this level, all the three groups of characteristics are equally important. The definitions of the taxonomic units of the soil-genetic zoning are given, and their characteristic features are described. An algorithm of the zoning procedure is illustrated by the example of the maps developed for the Privolzhskii federal okrug. It is suggested that the soil-genetic zoning can be used as one of the ways to update the State Soil Map.

Relationships between the salinization of agrochernozems, agrochestnut soils, and textural carbonate agrozems on the plains and factors of soil formation in the Central and Western Ciscaucasia are considered. Among the studied factors are the following: parent rock, climate, relief, depth of groundwater table, and human activity (irrigation in particular, which is considered as one of the strongest anthropogenic impacts). In the territory of the objects studied, saline parent rocks predominate. They determine the potential (in autonomic landscapes) or actual (in subordinate landscapes) salinity of the main soils and their instability under intense use. The influence of climatic conditions can be registered only in the soil salinity over vast loess plains, where the agrochernozems are replaced by the agrochestnut soils. The influence of the meso- and microrelief on soil salinization is manifested in the regular transformation of soil cover structures in catenas. In the northeast of the loess plains, this phenomenon was expressed in the appearance of agrosolonetzic complexes on slopes and, then, in their predominance in subordinate positions. The response of the soil cover pattern to changes in the salt regime of the soils in catenas and its reconstruction under irrigation may serve as an indicator of trends in the dynamics of the soil cover related to human activities and climate fluctuations.

Observations over the dynamics of the freezing-thawing processes and the migration and accumulation of salts in the soils of the Ivolginsk Depression in Buryatia showed the existence of two stages in the annual cycle of salt migration: the short-term desalinization stage alternates with the long-term salinization stage. The latter stage actually combines two phases: the fall and winter phase of the migration of solutions towards the freezing front and the spring phase of the ascending migration of melt water towards the drying soil surface with further concentration of the solutions owing to evapotranspiration. The desalinization stage in the summer is only typical of the upper soil horizons because of the insufficient amount of summer precipitation; moreover, this stage is not observed every year. Thus, the salt regime of the soils of the depression is greatly affected by the seasonal soil freezing; the long-term salinization in the fall, winter, and spring seasons alternates with a short period of the leaching of salts at the end of summer.

The soil-genetic zoning proposed, unlike the known scheme of soil-genetic zoning, is based on the analysis of soil properties and soil-forming processes. Its objective is to interpret the soil cover in the format of the substantive-genetic soil classification of Russia (2004). The units of the soil-genetic zoning are distinguished according to the manifestations of horizon-forming processes: the main processes determining the principal trend of pedogenesis and the soil profile composition at the first level and the additional processes (forming the associated soils) serving as criteria for distinguishing the units at the second level. The results obtained allow considering this investigation as an experience of a new interpretation of a small-scale soil map and its analysis from two positions: the geography of the soil-forming processes and the complexity of the soil cover. The soil-genetic zoning has been carried out on the basis of the State Soil Map sheets; it can be an instrument for the conversion of the map’s contents into the substantive-genetic soil classification of Russia (2004).

The ways of further development of the State Soil Map (SSM) of the Russian Federation are discussed. This map represents the most valuable product of soil mapping projects in Russia. It has been developed since the 1930s. A long duration of the map compilation has resulted in certain differences in the methods of mapping, topographic base, and classification decisions applied on separate pages of the map. Another specific feature of the SSM is related to different amounts of soil information available for different parts of the country. At present, two major challenges face researchers working on this map. First, it is necessary to preserve rich information collected by several generations of Russian pedologists and reflected on the map. Second, this information has to be renewed on the basis of new information sources (satellite images, modern topographic base, and new data on soils and their geography), common ideology of the map, and new digital technologies of the map compilation. The analysis of several pages of the map on the territory of the North Caucasus is discussed. An algorithm of introducing corrections to the map and its renewal is suggested. In the course of our work, a digitized version of two pages of the map, the digital elevation model, and Landsat imagery were used. The cartographic work was performed using GeoDraw software. Our experience in the correction and renewal of the SSM attests to the high potential of the methods of digital soil mapping for these purposes. The analysis of the map in the GIS environment makes it possible to reveal possible drawbacks in the initial map pages and to suggest feasible methods of their correction and further development of the SSM.

A method for compiling soil maps from the results of digital processing of remotely-senseddata is presented. The method is based on graphic analysis of mean digital values of clusters in the green-red and (green-red)–(NIR-red) projections in conjunction with visual analysis of the cluster map and spectral curves and their interpretation on the basis of thematic maps and ground data. The proposed technique allows interpretation of the soil types of arable lands with 50 per cent vegetation density and differentiation of the soils with regard to their water regime. The accuracy of the resulting soil map was evaluated as 0·82.

A paper addressing general issues of concern in organizing a system of soil monitoring based on remote sensing imagery covers such topics as general principles which must be observed, the selection of indices optimizing the acquisition of useful information, and the adoption of suitable methodologies. A subsequent section of the paper focuses on the types of information to be derived from soil monitoring in arid regions and areas susceptible to heightened soil erosion. Translated by Edward Torrey, Alexandria, VA 22308 from: G. V. Dobrovol'skiy and V L. Andronikov, eds., Aerokosmicheskiye metody v pochvovedenii i ikh ispol'zovaniye v sel'skom khozyaystve: sbornik nauchnykh trudov [Remote Sensing Methods in Soil Science and Their Utilization in Agriculture: A Collection of Scientific Works]. Moscow: Nauka, 1990, pp. 154–161.