The aim to solve the methodological problem of assessing variability of soil organic carbon content (C_org) in layer 0–20 cm based on 10-fold independent mixed sampling from the same field during one day. The soil sampling was carried out on 4 fields ranging from 6 to 16 hectares (Tver region). The soil cover pattern is represented by patches of agrosod-podzolic gleyic sandy loam and loam soils (Albic Retisols (Aric, Loamic)) developed from binary deposits and agrosod-podzols (Albic Podzols (Aric, Arenic)) developed from sands underlying loamy moraine from the depth 80–150 cm. It has been established that the variation in C_org content in mixed samples reflects the spatial component that is sometimes comparable to, but more often significantly higher than analytical reproducibility of laboratory methods for determination C_org (Turin method and dry combustion method). To compare single measurements of C_org in mixed samples obtained at different time periods or from different fields, the use of even the full confidence range based on the interlaboratory reproducibility of the determination method turns out to be an unreasonably low estimate. To conduct monitoring of C_org content, it is necessary to assess the spatial variation of the indicator, even when selecting mixed samples.

Morphological studies of soil solid phase within a narrow range of magnifications (approximately 10–20×) using optical devices and known as mesomorphology, are not widely used by soil scientists in their research activities. However, it is not expensive and provides useful pedogenetic information. The mesomorphological level is a part of a hierarchical investigation of the arrangement of the soil mass, which was most completely performed by soils scientists of the Institute of geography, RAS in 1974 headed by Victor Targulian. It is hardly possible to repeat such pedogenetic investigation now, although its ingredients are applied, whereas the mesomorphological one received much less attention. In order to extend the sphere of mesomorphology application, some proposals to improve the method concerning sampling, photographic technique, computer processing of photographs are proposed, as well as indicating objects and purposes for most efficient application of mesomorphology. It is concentrating on the solid phase, namely, shape and fabric of aggregates in three-dimensional image, pedofeatures like iron-manganic and carbonate segregations and nodules, traces of soil fauna activities, organic residues transformations, coprolites, and diverse coatings – their location in the soil mass and abundance.

Decomposition of needle litter was studied in a series of three successive two-year experiments in a pine forest. The effect of the weather conditions proved to be significant only in the first two months of needle decomposition. Analysis of the dynamics of needle degradation in our experiments shows the early needle destruction process falls into three phases: fast (the first warm period, up to ~30% needle mass loss); moderate (from the onset of the first cold period to the onset of the second cold period, ~30% to ~55% total needle mass loss); slow (from the onset of the second cold period, from ~55% total needle mass loss onward). A comparison of empirical data on degradation dynamics with the asymptotic model revealed a 10–13% misfit in annual needle loss. The reason is the specific features of decomposition of certain chemical components of needles, especially lignin/AUR. An attempt was made to simulate the destruction of needles based on the decomposition patterns of their various chemical components. The resultant model and its simplified version quite accurately reflect the destruction characteristics but have some substantial limitations.

Soil surface subsidence is a natural hazard that has been reported in arid and semi-arid lands of the world. From the last few decades to the present, soil surface subsidence has been a major phenomenon of most plains in Iran. The core reason of this phenomena is water extraction from ground water by pumping wells. The study area located on the clayey plain covered by the complex of Aridisols and Vertisols in the east of Yazd city in central Iran with cracks of longitudinal and polygonal shapes. This experiment had been planned to find micro-relief dynamics in a time series after rainfall and drought periods followed by soil surface subsidence and soil cracking. For modeling of soil vertical dynamics and cracking processes, a sampling area was selected with 100 points for surveying with Box Jenkins model. The topography measurements of surveying data showed soil surface height variations from a few millimeters to some centimeters (-14 to +14 mm in a year) with sinusoidal rhythms. Auto Regressive (AR) model could predict the land height variations up to 5 years ahead with high accuracy (3 mm). Based on field surveying, drone imagery data confirmed the temporal forecasting model. In the study area land depressing resulted from minerals degradation into amorphous silicas after soil alkalization. Thereupon the monthly changes of soil surface wetting and drying were major factors for land altitude dynamics, whereas the very deep level of groundwater had no effect on soil surface subsidence. It is suggested that for monitoring of soil surface subsidence and soil cracks over time, the surveying with complementary and drone imagery could be much more appropriate method, which allows predicting temporal soil surface subsidence in local scale.

The assessment of the leptosols composition and the increased concentrations of heavy metals in them at the Ulyuk-Bar gold deposit was carried out. The mineral components of the soils are represented by quartz, illite, kaolinite, goethite and iron-manganese nodules. The minerals concentrating of As, which represents the greatest potential danger in the deposit and exceeding (maximum allowable concentration) MAC by 159.5 times, are goethite, and rarely kaolinite. The chemical composition of soils is close to that of soil-forming sandstones. In general, in the process of soil formation, accumulation or minor removal occurs for most elements. The contents of As, Co, Pb, K, Zr, Cu, Mn, Zn, Ni exceed сlark for continental soils. The degree of mobility for soil elements decreases in the range Sb (46.25) – Ca (36.84) – S (31.48) – Sr (27.91) – Mn (15.38) – Pb (8.84) – Ba (5.41) – Mg (2.88) – Zn (2.70) – Ni (1.70) – P (1.55) – Cu (0.76) – Cr (0.45) – Si (0.42) – K (0.39) – Na (0.20) – Al (0.07) – Fe (0.05) – Co (0.05); Ti, V, Zr, As are immobile. The mobile forms of Mn are 2.22 times higher, the gross contents of S are 3.71 times higher than the MAC. Concentrations of heavy metals such as Fe, Mn, Sr, Ba and Cr in soil ammonium acetate extracts increase with increasing alkalinity of the salt extract, and Zn, Cu, Pb and Sb − acidity. To prevent the mobility of heavy metals to an environmentally sustainable level, an effective reclamation program should include a set of methods for selecting the optimal ratios of chemicals added to the soil.

The article focuses on studying the influence of the spatial heterogeneity of lithological and geomorphological conditions on the hydrological characteristics of the soils of the Sambian Plain using aerial photography and electromagnetic induction methods. From 2020 to 2022, at the “Pereleski” test site, topographic surveys were conducted using UAV, soil-forming material heterogeneity was diagnosed, and field measurements of particle size distribution, moisture content, and the degree of gleyization were carried out in reference soil profiles (n = 4). Additionally, the morphology of soil horizons and the degree of gleyization in additional sampling points (n = 18) were described. The method of electromagnetic induction profiling using the EM38-MK2 established a reliable strong correlation between silt content and apparent soil electrical conductivity (R² = 0.88). Multidimensional scaling enabled the ranking of all soil descriptions at the test site by the degree of gleyization, providing a quantitative assessment of the depth and duration of waterlogging in soil profile. Morphometric characteristics and electrical conductivity in the layers of 0–0.375 m; 0–0.75 m; and 0–1.5 m were compared with the calculated gleyization intensity index of soils. Linear regression analysis revealed a relationship that explains 81% of the variability in soil gleyization based on two factors: electrical conductivity in the 0–1.5 m layer and the topographical positional index within a 10 m radius. Consequently, soils were ranked according to the combined characteristics in a sequence of increasing gleyization intensity: Endogleyic Cambisols – Gleyic Albeluvisols– Haplic Gleysols, linked to the differences in their long-term average water regimes. The identified heterogeneity of micro- and mesorelief and the high variability of the soil-forming materials resulted in the alternation of these soils in the form of soil micro-mosaics, indicating the intra-field heterogeneity of the agroecological conditions of the test site.

The soil line concept was proposed in 1977. Since then, it has been widely used for satellite monitoring of vegetation, land cover and soils. A critical review of scientific publications on the use of the soil line concept in remote sensing is carried out. The review is based on the analysis of publications indexed in the scientific databases RISC and Scopus. The search was performed using the terms “soil line” and “soil AND line AND spectral AND reflection” in the titles of articles, in keywords and in abstracts of publications for all available years. The following types of publications were included in the sample: articles in scientific journals, review articles, book chapters, and articles in conference proceedings. A total of 104 articles were analyzed. It was found that the soil line concept is most widely used in the creation of vegetation spectral indices for monitoring vegetation cover. It is also used to assess the state of land cover and in soil monitoring. The leader in the number of publications in this field of knowledge are specialists from China. Together with specialists from the USA and Russia, they have published about half of all publications. By affiliation of the first author, publications of the Chinese Academy of Sciences and the V.V. Dokuchaev Soil Science Institute (Russia) prevail. The concept of soil line is promising for mapping and monitoring of separate groups of soil properties, less often - separate soil properties by the character of their open surface image. For its wider use, additional studies of the influence of individual properties of different soils on their spetcral reflectivity in the visible and NIR spectral ranges are needed. The hypothesis about the possibility of satellite mapping and monitoring of soil types (or other classification divisions) based on the soil line concept requires extensive experimental confirmation.

The paper presents the results of mapping of the soil cover structure of the key site “Universitetsky” within the city of Volgograd. The southern part of the territory of Sovetsky and northern part of Kirovsky districts of Volgograd was chosen as the objects of research. The key site has an area of 15 km 2 . The main method of research of the key area was mapping with the use of remote sensing data in the QGIS programme and route ground surveys. High resolution colour space images were used as remote sensing information. Mapping of the soil cover structure of the plot was based on the approaches of M.N. Stroganova and E.Y. Sukhacheva. An automated method with manual training was used for mapping of day surface views of the key site territory. The names of soils and anthropogenic surface formations are given according to the Classification and Diagnostics of Soils of Russia 2004 with additions, as well as WRB (2022). Based on the results of mapping, a soil map-scheme of the key area was created, reflecting the features of the soil cover structure, spatial distribution of individual types (subtypes) of soils and technogenic-surface formations (scale 1 : 50 000), containing 19 legend units. The soil cover of the key site reflects the structure and character of land use and represents a variety of soils of both natural and anthropogenic origin. Among anthropogenic soils various agrozems and surface-agrogenically transformed chestnut soils were identified. Urban soils are represented by urban stratozems, compost-humus stratozems and humus urban stratozems. Among natural soils there are chestnut soils of different granulometric composition and degree of solonetisation confined to the ravine and gully network and adjacent watersheds. The eastern part of the site is represented by alluvial light and dark humus marl soils of different degrees of disturbance. Thus, the soil map-scheme can serve as a basis for a large-scale soil map for the entire territory of Volgograd, and will help to effectively solve the future problems of spatial planning in the implementation of landscaping and improvement of the urban area.

The aim of this work is a regional analysis of the areas of saline soils of different hydromorphism distribution in the Irkutsk region based on data from Rosgiprozem maps at a scale of 1 : 25,000 and explanatory notes to them for the period from 1964 to 2003. In the literature, data on saline soils in the region differ, which requires clarification using large-scale maps. For the first time, an analysis of the areas of saline soils of different hydromorphism in the districts of the Irkutsk region was carried out using 241 soil maps of Rosgiprozem on the scale of 1 : 25,000 and 265 explanatory notes to them. The analysis was carried out mainly on agricultural land. According to various sources, agricultural land occupies only 3.1–3.6% of the region’s area, while almost 90% of the region is under forest. According to maps and essays, saline soils are noted on area of 198.44 thousand hectares, which is 2–3 times higher than according to other sources. Saline soils are found in 27 of the 28 analyzed districts of the region, occupying from 1 to 19% of the surveyed farm area in different districts. The most widespread are hydromorphic saline soils, which are noted in 27 districts, semi-hydromorphic soils are less common – in 15 districts, and only in 7 ones automorphic varieties of saline soils are noted.

The soil cover of the Oka-Don Lowland interfluves differs significantly in its component composition from the soil cover of the Central Russian Upland, despite being formed under similar climatic conditions. The soils of the Oka-Don Lowland are complex in terms of their genesis, which causes difficulties in diagnosing and classifying them. The paper presents the results of field testing of non-drained soils of the Oka-Don Lowland area, as well as their diagnostics according to the three most widely used soil classifications in Russia: system of USSR (1977), system of Russia (2004) and international WRB, a regional correlation of classifications is performed. It is shown that the soil cover is represented by contrasting combinations of soils with a thick humus horizon underlain by a non-carbonate / carbonate / very waterlogged horizon, solonetz, solonetzic, solodized, bog soils, and soils with a light eluvial horizon; as a rule, in the middle and lower parts of the profile; all soil profiles contain traces of waterlogging. The absence of clear diagnostic criteria based on soil properties, the absence of natural vegetation and data on the average long-term level of soil and groundwater makes soil diagnostics according to the USSR soil classification highly dependent on the qualifications of the soil scientist-researcher. The high degree of formalization of substantive classifications (soil classification of Russia and WRB) leads to the fact that genetically close soils can belong to different taxonomic groups at a high level (soil types in the classification of Russia, main qualifiers according to WRB). The assessment of pedodiversity can differ greatly depending on the classification system used.