Morphological description of the soil profile must provide further hierarchical morphogenetic analysis and adequate diagnostic and classification of soil in any substantive-genetic taxonomic system. In a brief taxonomy-oriented description, priority should be given to soil properties having diagnostic significance; they may be different for different horizons, and those discriminating similar horizons should receive special attention. It is proposed to compile an updated field handbook for soil morphological description, supporting the recent classification system of soils of Russia.

The analysis of publications has shown that the period of intensive development of several spheres in micromorphology in the second half of the XX century was followed by a period when micromorphology became more required in applied research. Addressing micromorphology for solving pedogenetic and taxonomic questions became reduced both in Russia and in the world. Further progress of traditional micromorphology in Russia is expected owing to application of sophisticated equipment, participation in hierarchical morphogenetic studies, as well as to the possibility for students and professionals to work with a “database” - collection of thin sections representing a broad array of soils. This work is initiated at V.V. Dokuchaev Soil Science Institute, where many thin sections are already accumulated, and most specialists worked and are now working there.

The main advantages of applying computed tomography to studying soil samples include non-invasiveness, independence of the moisture content in the samples and the possibility for mathematical modelling. The methodological problems of this imaging technique include restrictions of the sample size, resolution limitations and segmentation difficulties.

The history of applying soil micromorphology in archaeology in Russia and abroad is overviewed. The main objectives of soil micromorphological analysis of archaeological objects are specified. The possibilities offered by this method are illustrated by the example of a micromorphological study of a cultural layer of an Early Medieval settlement. The prospects of archaeological soil micromorphology development are outlined.

The color is one of the main morphological properties of soils, as it integrally reflects their material composition. Most of the macro-, micro- and nano-morphological methods in pedology are based on the analysis of soil reflectance characteristics within the visible spectrum (i.e., soils color). The evolution of soil color study methods and the features of modern instruments are described in the report. The main directions in the development of this field of soil science as well as the achievements and problems to be addressed in the study of soil color are demonstrated by specific examples.

Cryogenic processes that occur in permafrost-affected and perennially frozen soils are analyzed and systematized. Their influences are observed at the three levels of soil organization. Thin sections are prepared from thawed and frozen soil samples.

Each of four hierarchical levels in the morphogenetic research is characterized in terms of technical and information facilities. A detailed hierarchical study was performed for the first time for chernozems and may be qualified for a basic one. Its results comprise confirmation of occurrence and details in manifestations of pedogenetic processes well-known in chernozems, as well as additional information on the pedofauna contribution to chernozem formation, variability and dynamics of carbonate pedofeatures, stability of the mineral soil ingredients.

A comparative micromorphological analysis of soil fabrics within two- and three-component semidesert solonetz complexes formed within closed-drainage plains with different types of microtopography in the northern of the Caspian Lowland has been conducted. Micromorphological features of soils of most extensively studied three-component solonetz complexes having soil cover with a high degree of contrast are indicative of divergent evolutionary trends during the past half century. On the basis of these features, different directions of degradation of solonetzic and saline horizons are revealed. Although degradation of solonetz horizons is practically undetectable at a macro-scale, its micromorphological features are clearly manifested in parameters of aggregates, characteristics of coatings and types of salt pedofeatures. Common factors of solonetz evolution in nearby regions allow extrapolation of the micromorphological indicators of solonetz degradation to a wide range of objects including two-component solonetz complexes.

Pedofeatures of salts and gypsum in arid and semi-arid soils indicate the salinization process and its dynamics. Mineralogical and morphological features of these pedofeatures, their distribution in the soil profile as well as confinement to individual components of microstructure are indicators of soil processes, both modern and relict. The paper presents the results of a comprehensive morpho-mineralogical analysis of the newly formed salt and gypsum pedofeatures in saline soils in the south of European Russia and Cis-Baikal region as well as Transcaucasia, Central Asia, Kazakhstan and Mongolia.

The paper presents a detailed study on structure and composition of endolithic and hypolithic systems. The following issues are discussed: morphology at macro to submicro levels, biochemical weathering, formation of carbonates and oxalates in situ, migration of Fe compounds, and spatial patterns of endolithic systems. Endolithic and hypolithic systems have major features attributed to soils: (a) rock layer exposed to external abiogenic factors, (b) lithomatrix inhabited by living organisms which are synthesizing and decomposing organic matter, (c) as a result initial parent rock (lithomatrix) is transformed in situ by biogenic and abiogenic factors, the products of transformation are retained and/or removed, the vertical heterogenity is established in a form of microhorizons composing microprofile. Examined profiles of endolithic systems in granitoids of East Antarctica with high quartz content had clear eluvial-illuvial differentiation patterns. Similar patterns have been discovered in different landscapes from the Plateau Ozark in Missouri to the Table Mountain in South Africa.

Nomenclature and taxonomic diversity of soils and their horizon-profile diagnostics/descriptions define morphogenetic soil indicators used in the Unified State Register of Soil Resources of Russia (with Russian abbreviation of EGRPR). Most of these soil indicators are of non-metric origin, i.e., established conventionally by agreement. Subject area of soil science includes a hierarchy of 5 types of soil objects (pit, profile, horizon, morphological element and sample), 380 indicators, 607 methods and 3019 values of the indicators.

The structure of gilgai soil complexes is a combination of 3-D units complimenting, entering and/or crossing each other and having different morphological features: colour, slickensides, dispersed calcium carbonate, calcareous and gypsum pedofeatures, eluvial (leaching) and solonetzic features. The 3-D units with these morphological features are described. Nine variations in the vertical-lateral morphological structure of gilgai soil complexes are identified on the basis of reviewing literature on Vertisols of tropics and subtropics. Thirteen variations of gilgai soil complexes are identified on the basis of observations on Vertisols within the East European Plain.

This paper discuss the changes in understanding of the central image of Vertisols and leading processes of their formation. The early concept described Vertisols as black or dark clayey soils with homogenous undifferentiated profile resulted basically of pedoturbation. The further studies discovered vertical differentiation of Vertisol attributes. The application of trench method discovered spatial heterogeneity of Vertisols with alternation of bowl and diapiric structures. Such spatial complex subsurface pattern seems to be rather common and can be found even in the absence of gilgai microrelief. A new central image of a mature Vertisol is a combination of two structural types, one being homogenous and monotonous, generally corresponding to the initial central image, and the other - heterogeneous profile with fragmented horizons. A leading process forming the new central image of Vertisols was defined as lateral shearing or plastic deformations, i.e., plastic movements and gradual upward pushing of moist material (analogy of defluction process). Pedoturbation or more exactly the vertical falling of surface material into the cracks results in the vertical mixing rather than in deformations. Micromorphological features typical of Vertisols and associated with shrink-swell phenomena, cracking, mixing and lateral shearing that are reflected in the central image of Vertisols are summarized in the paper and illustrated by microphotographs.

The morphological record of pedogenesis (mostly at a micromorphological scale) and the features of paleosols developed at the northern geographical extremity of the MIS3 paleopedoshpere (including the Bryansk fossil soils) are described. The profiles of the MIS3 paleosols (dark humic gley and peaty gley with the¹⁴С-age around 29-50 cal kyr BP) are located within the periglacial zone in the centre of the Russian Plain (56.7°-58.5° N) within the Upper Volga drainage basin. An assemblage of stable micromorphological features of paleosols studied includes the following: 1) ferruginous nodules and other pedofeatures, occasionally fragmented; 2) concentration (separation) of sand grains within certain microzones; 3) inclusions of raw organic matter, often deformed and oriented to different degrees within the matrix. Despite being buried for a long time period and superimposed by the Holocene pedogenetic processes (clay illuviation), the paleosols preserve some features of short-term (10¹-10² yr) and medium-term (10²-10^3-4 yr) elementary pedogenetic processes (EPP). The short-term EPP include gleying, structure forming and cryogenic processes. The medium-term EPP include humus formation, peat formation and organic matter accumulation. A hypothesis of cryogenic formation of the paleosols studied is substantiated. Only an almost impermeable layer of permafrost could cause water-logging and gleying in these geological and geomorphological conditions.

Microbiomorphic analysis is a detailed study of microscopic particles of biogenic nature (plant detritus, phytoliths, shells of diatoms, spicules of sponges, pollen, etc.). Each of such particles characterizes environmental conditions at the time of its formation and, therefore, provides useful information for palaeoenvironmental reconstructions. The Early Pleistocene deposits were studied in Armenia at the sites, where tools of ancient hominids (Early Acheulian) were found. The genesis of these deposits was identified. It was shown that these ancient alluvial-lacustrine sediments were transformed by soil-forming processes. The environmental conditions at the time of the ancient hominids’ migration were reconstructed.