The sorption characteristics of sand, peat, the arable layer of Moscow urbanozem and a mixture of these substrates were studied in conjunction with the surface topography of their solid phase, studied by scanning electron microscopy (SEM). The arable layer has the greatest ability to absorb nitrogen, and the peat substrate showed very low values of the sorbed gas. A different picture of the mutual arrangement of substrate sorption isotherms is observed when water vapour is used as a sorbing gas. Peat is distinguished by high values of sorbed moisture in the entire studied range of relative humidity. This leads to differences in the ranking of substrates by specific surface area in descending order of its values. So, the specific surface area by water sorption in the series: peat / arable layer / mixture / sand was: 420 / 72 / 45 / 4 m2/g, respectively. The given surface was ranked according to nitrogen sorption in a different sequence: 8.31 / 2.41 / 1.45 / 0.55 for the series: arable layer, mixture, peat and sand, respectively. The analysis of microstructural characteristics by the SEM method at various magnifications revealed the most developed, rough surface in the arable layer. It turned out to be geometrically the most diverse, even at magnification of ×20 000. The variety and heterogeneity of the relief of the interface of the phases leads to the appearance of hysteresis of the sorption/desorption curves. Its severity in the range of nitrogen vapor concentration in which hysteresis is detected, and in the maximum width of the hysteresis loop, also turned out to be the most significant in the arable layer. The very low nitrogen specific surface of peat, which is close to a sandy substrate, is associated with the presence of organic films draping and leveling the surface of peat particles, which was revealed by analyzing images obtained by scanning electron microscopy. The sorption of water showed their high hydrophilicity, which led to high values of substrate humidity in the entire studied range of relative humidity.

Changes in the physical properties of podzolic soils were analysed three years after a cutting of coniferous-deciduous plantings in the territory of the middle taiga of the Komi Republic with three- and ten-fold forwarder passes, as well as after leveling deep ruts formed after ten passes. The influence of different number of passes on soil density, filtration coefficient, penetration resistance is shown. An assumption about various mechanisms of soil change has been made: three forwarder passes lead to compression, ten - to compression and turbation, which was confirmed by indications of soil density and hardness. It was revealed that compression leads to an increase in density by 0.15 g·cm-3 and penetration resistance by 25%. Meanwhile, filtration rate did not change. Ten passes lead to turbation, which levels the possible compaction due to an introduction of forest litter into the upper mineral soil horizons. Moreover, hardness values decreased by 2-3 times and water permeability decreased from 70 to 1 cm·day-1. It was revealed that leveling deep ruts causes a noticeable decrease in soil density after three years, including in comparison with the undisturbed soil. Furthermore, filtration rate increases several times. Penetration resistance is also increased. An estimation of the water retention curve approximation parameters by the van Genuchten equation made it possible to identify changes in soil of ruts compared to the a mechanically undisturbed site. A decrease in the range of mobile moisture was noted as a result of compaction after heavy equipment usage, leading to moisture stagnation in ruts.

There are various methods for experimental determination of the thermal conductivity dependence on soil moisture and substrates. The influence of the sample structure (monolith, bulk sample), sample temperature, the method of installing the probe into the sample on the obtained readings of the TEMPOS device was studied and methodological recommendations were proposed. The dependence of thermal conductivity of soils bulk samples and substrates on moisture is shown. The spread of thermal conductivity values in the moisture range from hygroscopic to full moisture capacity for soddy-podzolic soil is 0.229–1.430 W/(m*K), for peat – 0.250–0.521 W/(m*K), for sand – 0.280–2.605 W/(m*K), for a mixture – 0.234–1.568 W/(m*K). ). The influence of properties such as density, particle size distribution, specific surface area, organic matter content, salinity affected thermal properties to a lesser extent. The established patterns can be used to calculate the temperature regime of soils in solving a number of applied problems related to the construction of special soil objects, for example, when creating urban soil structures. For this, it is necessary either to determine the thermal conductivity experimentally, or to calculate it, using the physical parameters of soils and substrates. The first method is labor-consuming, the second is less accurate. As an example, the equations available for work in the HYDRUS-1D (Chang–Horton and Campbell) model are used. These equations either overestimate the thermal conductivity in the area of high substrate humidity, or underestimate the thermal conductivity in the area of low substrate humidity (sand, loam, peat and a mixture based on them).

The results of experiments to study changes in the hydrological properties of soil substrates composing profiles of artificial soils (constructozems) 1–4 years after their creation are presented. Constructozems are represented by two variants, layered soil including Ap horizons, lowland peat and quarry sand of equal thickness, and a mixture of these substrates in an identical amount by weight, as for layered constructozems. Water retention curves obtained by the capillarimetric method on samples with undisturbed structure are compared. A decrease in the water-holding capacity of the peat layer and an increase in the mixture samples are found a year after constructozems had been placed. The laboratory and field experiments have shown a statistically significant difference in moisture filtration rates of the layered constructozem and the mixture. The sharp boundaries between soil horizons contrasting in their properties reduce moisture migration rates to zero values. The obtained breakthrough curves of potassium ions suggest that the continuous pathways of rapid movement of moisture and dissolved substances have formed after 4 years of functioning of artificial soils and are most pronounced in the structures with the homogeneous soil profile.

Changes in physical properties of podzolic soils (Albic Retisols) were analyzed three years after the cutting of the coniferous–deciduous forest in the middle boreal forest of the Komi Republic with three- and ten-times forwarder passes, as well as after leveling out the deep ruts left after ten passes. The study gained insight into an influence of the different numbers of passes on soil density, filtration coefficient, as well as resistance to wedging and compression. A hypothesis was made with respect to various mechanisms of soil changes—specifically, three forwarder passes lead to compression, while ten passes result in compression and turbation, which was confirmed by measurements of soil density and penetration resistance. After three passes, compression was found to lead to an increase in density by 0.15 g cm‒3 and penetration resistance by 25

We have studied mechanical characteristics of soils of Syktyvkar of the same genesis and different land use: agrosoddy–podzolic urban-stratified soil within the city, park postagrozem, and suburban podzolic soil. Their relationship with the organic-matter content and particle-size composition is analyzed. Strength properties are mainly related to the content of coarse fractions (>0.25 mm) in agrosoddy–podzolic urban-stratified soil and to the organic matter content in podzolic soil. Soils are arranged in sequences according to rheological parameters. The strength of structural bonds estimated by the parameter of initial elasticity modulus is the greatest in podzolic soil, and horizons of agrosoddy–podzolic urban-stratified soil are characterized by a wide range of linear viscoelastic status. The starting point of the viscous flow region is the same for postagrozem and podzolic soil.

The effect of cationic polyelectrolyte poly(diallyldimethylammonium chloride), anionic polyelectrolyte potassium lignohumate, and their interpolyelectrolyte complex on the aggregate composition and phytotoxicity of constructozem, an artificially constructed soil, is investigated. The original constructozem is characterized by a wide range of structural aggregates with a high proportion of large particles. Addition of the polycation to the constructozem completely destroys large aggregates, while addition of the polyanion has almost no effect on particle size distribution. The polycomplex sharply reduces the proportion of large particles and blocks the appearance of small particles, thereby significantly increasing the content of agronomically valuable aggregates in the constructozem and, at the same time, stimulating the growth and development of plants.

Aggregates and capillary-saturated pastes from loamy soddy-podzolic soils (Albic Glossic Retisol (Lomic, Cutanic)), typical and vertic chernozems (Haplic Chernozems (Loamic, Aric, Pachic) and Vertisols), and yellow soils (Alisols) were studied by scanning electron microscopy (SEM) and on a Reotest-2 rotary viscometer with a coaxial cylindrical system. Aggregates of plow horizons of Retisols and Chernozems have less pronounced porosity and denser packing of their microaggregates in comparison with native soils. Microaggregation of the plow layer of Vertisols is observed at high magnifications, while in the humus horizon of the fallowed Vertisol, the section of the aggregate has a massive structure. The study of the rheological behavior of the soils revealed the predominance of condensation-crystallization structural bonds in the plow layers, whereas coagulation structures prevailed in the deeper horizons. However, in the upper horizons of Vertisols, coagulation structure is well developed and thixotropy occurs. The limit of a plastic-viscous breakdown of the structure is higher in soils that are not involved in agricultural use, and the Shvedov limit corresponding to the beginning of deformation processes, on the contrary, is lower. All studied soil samples had several strength limits, which indicates the hierarchical organization of the structure of soil aggregates.

Yeasts number and diversity in urban soils of Krasnodar, Maykop, Simferopol, and Sochi was investigated. The soils of botanical gardens and suburbans were studied as a control. Maximum number was found in the topsoil 0-20 cm in the urban soils of Sochi and Simferopol, where it was 5.7 ± 0.2 and 5.4 ± 0.01 lg(CFU/g), respectively. The minimum number, 2.0 ± 0.1 lg(CFU/g), was characteristic of a 60-80-cm layer in the suburban soils in all cities. The number of yeasts was shown to depend primarily on the depth and type of soil and to a lesser extent on location. A total of 20 yeast species were isolated. In the soils of the major tourist cities of Sochi and Simferopol, a high relative abundance of Candida sake and Meyerozyma guilliermondii was found, which fundamentally distinguished the studied soils from the ones of Krasnodar and Maykop. The cities of Sochi and Simferopol are characterized by a higher anthropogenic load compared to Krasnodar and Maykop, which is associated not only with their high population, but also with a significant tourist load. Detection in urban soils of C. sake and M. guilliermondii which are clinically significant species, was therefore consequential.

When creating “Zaryadye Park” in the center of Moscow, the tasks of creating soil constructions and artificial plantations were solved. The task was to form landscape-analogs of all natural zones of the European territory of Russia from tundra to subtropics in one small park in the center of Moscow. Based on the climatic conditions of the city, the selected range of plants, recreational load and the regime of visiting the park, a certain structure of soil cover was suggested, which is formed on the roof of underground constructions. The creation of fertile substrate and vegetation cover lasted from October 2016 till June 2017. 2 months after the planting had been completed, the first determination of soil properties in various types of forest stands was carried out.

The topsoil bulk density of two abandoned small rural settlements situated at Tver and Yaroslavl regions of Russia was studied. The key sites had light grain soil texture. They had a long history of rural land use, and they were abandoned simultaneously. There were no stone buildings. The values of the abandoned rural settlements' topsoil bulk density are correlated with the land use type and the time of reforestation. The topsoil bulk density of the former buildings and the dirt roads was significantly higher than the one of the plough horizons of the former gardens, orchards and arable lands (1.7 and 1.4 g/cm(3), respectively). Soil horizons of former buildings' territory are characterized by coarser granulometric composition of fine-grained fraction; however, they do not differ from plough horizons in bulk density that may be related to 2-3 times higher organic carbon content.

Three variants of model soil constructions were created. Variant 1 (control) is made from Aarable horizon (0-18cm); variant 2 (layered construction) is represented by Aarable horizon (0-6cm), lowland peat (6-12cm), sand (12-18cm); variant 3 is a mixture of Aarable horizon, peat and sand in the same mass proportion as in the layered variant (0-18cm). Water retention capacity of Aarable horizon increased in all variants regardless of the location in the profile. Number of macropores increased and number of mezopores decreased in Aarable horizon of control and layered variants. The greatest number of moisture-saiving pores is observed in the peat-containing layers of variants 2 and 3 as a result of 4-year functioning. The lowest content is in the control in all layers.

The soil cover of the Vladimir Opole was investigated by the method of long (up to 40–50 meters long and 1.5 m deep) transects. Four Qualifiers of Phaeozem (PH) were morphologically identified: albic, gleyic densic, grayzemic and PH cambic with the 2nd humus horizon. Agrophysical studies of soils in transects included layer-by-layer determination (every 20–40 cm along the trench, and at depths 0, 20, 40, 60 and 100 cm) of soil density, water permeability, and penetration resistance. The soil compaction (up to 1.57 g cm−3) was observed, which was especially pronounced in a layer of 20–25 cm and connected with the agrotechnological impact. Simultaneously, friable (<1 g cm−3) and, therefore, zones with high moisture capacity confined to PH with 2nd humus horizon, showing that the change in agrophysical properties in the soil cover occurs gradually, continuously and regularly and is determined by both pedogenetic and agrotechnological factors.

— Soil substrates used in model constructozems (artificially constructed soils) of different fabrics created on the territory of Lomonosov Moscow State University in 2012 were investigated. A layered soil construction consisting of the Ap–peat–sand–Ap horizons with a total thickness of 30 cm and a construction made of a mixture of these horizons (18 cm in thickness) underlain by a 12-cm-thick Ap horizon were studied. As a control, a variant with homogenized Ap horizon was chosen. The isotherms of water desorption from the initial soil substrates and from the samples taken from the constructions in 2016 were obtained by the method of hygroscopic equilibrium over saturated solutions of salts. We calculated approximation parameters of the isotherms and values of the total specific surface area of soil substrates according to the BET theory. A shift of water desorption isotherms towards lower values of the water content in the Ap horizon depending on the depth of its location in the profile of constructozems and on the properties of the boundary layers was revealed. It caused a decrease in the total specific surface area by 20–50% in comparison with the initial values in 2012. A sharp decrease in water sorption was noted for the peat of the layered variant of constructozems, in which the median value of the total specific surface area decreased from 560 to 162 cm 2 /g, and the maximum hygroscopicity decreased from 57.8 to 20.96%. By means of scanning electron microscopy, a distinct close-space microaggregation was detected in the Ap horizon that acquired a loose consistence by 2016 on the surface of variant 2. The surface of the initial peat substrate was smoothed and represented an amorphous mass of light color attesting to its organic nature. By 2016, peat samples virtually lost their amorphous coatings, so that a porous cellular surface was exposed, and its topography corresponded to the surface of plant residues. A decrease in the sorption capacity against the background of stronger roughness and complicated surface topography in most of the studied substrates attested to the high sorption capacity of surface formations of organic nature that covered the initial microaggregates, elementary mineral soil particles, and peat particles.

The transformation of microstructure of constructozems was studied in a four-year-long (2012–2016) field experiment with the use of rheological and electron microscopy methods. Field studies were performed in the area of Moscow State University on three variants of artificial human-made soils (constructozems) differing in the structure of their profiles: (1) the control variant with the upper part composed of a homogenized Ap horizon, (2) the layered constructozem composed of a sequence of layers (Ap–peat–sand–Ap), and (3) the constructozem consisting of a mixture of the above-mentioned horizons. Electron microscopy attested to an increase in differentiation of the pore space in the upper Ap horizons in variants 1 and 2: new pores and chambers of different sizes appeared. In the loose porous mass of the peat layer in variant 2, more compact cohesive microstructures were formed. Microaggregation was identified in the upper layer of variant 3. Changes in the spatial arrangement of the solid phase of the soils were reflected in their rheological properties. A gradual increase in stability of structural bonds in the Ap horizon (variant 1) was detected. In variant 2, the underlying peat layer affected the shape of rheological curves in the Ap horizon. In variant 3, changes in strength properties of the mixed soil mass resulted in the formation of rheological behavior of fluid bodies typical of the plowed humus horizons.