The areal and typological representativeness of chernozem soil diversity throughout Russia and within federal-level specially protected natural areas (SPNAs) was assessed based on geoinformation analysis using a vector soil map of Russia at a scale 1 : 2 500 000 (the combined version of the Soil Map of the RSFSR and Soil Map of Crimea). All chernozem soils cover 123.5 million ha (7.4

The results of implementing a method for assessing the efficiency of the water reclamation and the regime of crop nutrition for 17 districts of the Rostov oblast in various weather conditions are presented. For the first time, the predominant soil type under winter wheat within the district and the corresponding soil characteristics have been determined as input data for the Climate-Soil-Yield system using the digital version of the Soil Map of the Russian Federation (1988). The estimated recourses for providing the wheat production with water and mineral nutrition for 2010-2020 range from 40 to 69% in the Millerovo district and from 73 to 85% in the Zernograd district. In the years with a relatively small yield potential, the level of mineral nutrition resources is high, which is caused by a decrease in the nutrient limitation effect, since radiation and thermal factors limit the maximum biomass and, consequently, the maximum uptake of nutrients by crops. Under adverse weather conditions, an increase in wheat yields is observed when complex melioration is carried out.

The basis of Russia’s natural reserve fund consists of federal state reserves, national parks, and wildlife sanctuaries, the representativeness of which in relation to the diversity of natural complexes, including soils, is the main mechanism for protecting natural diversity. Using the method of geoinformation analysis, the areal and typological representation of the natural diversity of steppe soils in the system of specially protected natural areas (SPNAs) of the country was assessed based on vector maps: Pochvennaya karta Rossii (Soil Map of Russia) on a scale of 1 : 2 500 000 (a combined version of the Pochvennaya karta RSFSR (Soil Map of the RSFSR) and the Pochvennaya karta Kryma (Soil Map of Crimea) and the Karty pochvenno-ekologicheskogo raionirovaniya v Rossiiskoi Federatsii (Map of Soil-Ecological Zoning of the Russian Federation) on a scale of 1 : 8 000 000. The area occupied by steppe soils in Russia is 1 564 000 km2 (9.4

The carbon content of microbial biomass in soil serves as one of the indicators of its biological activity and is often used in assessing the impact of anthropogenic activity and natural changes on the soil microbiome. Significant spatial and temporal variation of the indicator at the level of ecosystems, soil typological units, land use types, etc., makes it difficult to interpret the data obtained during mass monitoring. The aim of the study was to determine the background values of microbial biomass content in the surface sub-litter layer of soils in protected forests of the Moscow region. A reconnaissance survey of various podzolic soils typical for the region and differing in their genesis and texture and formed under mixed southern taiga forests in four protected natural territories was carried out. The soils of autonomous positions and the soils experiencing slight additional moistening were studied. The microbial biomass carbon was estimated by two methods: by the content of phospholipids and by substrate-induced respiration of microbial communities. Significant spatial variability of microbial biomass was noted both at the site level and at the ecosystem level. For the autonomous soils of similar classification positions and textures, it was comparable with the local variability at the experimental sites. The value of microbial biomass depended mainly on the character of soil water regime and soil texture, which largely determined the sorption capacity of the soil and its provision with biophilic elements, and also correlated with the richness of the ground cover providing the soil microbiome with nutrients. In order to obtain correct results of monitoring soil biological activity, unification of the methodology and depth of sampling in soils of background and anthropogenically transformed ecosystems is of great importance.

The structure and functions of the “Soil-Geographical Database of Russia Information System” (ISSGDBR) implemented on the platform of the Soil Science Faculty of the Lomonosov Moscow State University are considered. The current state of national soil databases and developing on that base international soil information systems are described. The created information system consists of three sections. The first section includes soil maps of different scales and maps of the natural conditions of the territory of the Russian Federation. The second section is represented by a natural-attribute database, which is based on a soil profile with associated analytical characteristics. In the third section, with the help of software tools, the collected varied information about the soil cover becomes the basis for modeling the spatial distribution of various indicators, performing calculations in applied projects for a wide range of users. The ISSGDBR is considered as an expert and analytical center, which acts as a coordinator and supports the functioning of a distributed network, as well as the development and distributing of internationally relevant standards for description, storage, presentation of soil information and data exchange through the use of specialized programs adapted to regional features. In addition, the purpose of the center is the implementation of communication between primary digital resources of natural and soil information localized in various organizations, agrochemical-service regional centers, and federal agencies accumulating information necessary for making managerial decisions.

This paper provides an overview of scientific publications in Russia and other countries devoted to the soil organic carbon (SOC) content and stocks mapping at regional and local levels. The analysis showed that the cartographic assessment of the SOC content and stocks was conducted using various approaches that the choice depends on the multiple factors: the size of the territory (continental, national, regional, local levels); the cartographic basis availability (maps of soil types, of landscapes, of vegetation formations, remote sensing data, etc.) and laboratory and field surveys data. Two main approaches were generally used for SOC content and stocks mapping: (1) based on available thematic maps; (2) digital soil mapping. The review also provides the analysis of all spatial predictors that were used in collected papers in concordance with the SCORPAN model widely used in digital soil mapping. Spatial terrain data was one of the most commonly used predictors, followed by the vegetation and climate variables. The accuracy of predictive maps significantly increased by using soil maps. The reviewed studies showed that climate variables had a significant impact on the spatial variation of the SOC content and stocks at the regional level, while at the local level the influence of climatic variables was less significant. The analysis showed that the most common methods used in digital mapping were machine learning algorithms. Random Forest method often showed the best results. Results were cross-validated almost in all studies. Tests of the map’s accuracy using an external independent validation dataset were rare, although this was the most important stage of digital soil mapping. R was the most popular software, that was used for modeling the SOC content and stocks. SAGA GIS, QGIS, ArcGIS, and cloud platform Google Earth Engine (GEE) were most commonly used to prepare predictors.

An approach was developed and tested to spatial assessment of soil organic carbon stock in uniform groups of mineral and organic (litters, peat deposits, and peaty horizons of semihydromorphic soils) soil horizons. Estimation algorithm allowed us to utilize various datasets with different scales, both spatially and attributive sparse data of different veracities, which complemented each other. A series of maps of different accuracies and scales, including coarse-scale maps covering the entire country and more detailed maps for regions well covered with field measurements. Using these maps, the total organic carbon amount and its distribution over different pools in the 30-cm topsoil layer for the entire Russia and for three administrative regions of European Russia (more detailed) were estimated. The soil organic carbon pool of mineral soil horizons was estimated at 101 Gt C, which corresponded to 62% of the total organic carbon stock within the layer of 0–30 cm; 38% is allocated in organic horizons, including 9% in litter horizons (in rapidly decomposing organic pool) and 29% in peat deposit and peaty horizons of semihydromorphic soils. The organic carbon stocks in the 30-cm soil layer gradually increase from the north to the south: from 87 t/ha in Vologda oblast to 91 t/ha in Moscow oblast and 109 t/ha in Rostov oblast. The share of organic horizons in the total carbon stock decreases from the north to the south. Information on the size and structure of organic carbon pools may facilitate more reliable assessments of soil tolerance toward natural and anthropogenic changes and the development of regionally specific land use strategies.

Heavy metals and other trace elements that are not subject to degradation are among the priority pollutants. Significant amounts of heavy metals and related elements with variable valence are deposited on the soil surface as part of aerosols. Accumulating in the soil, they are very slowly removed from it, only changing the level of content or the state during migration, turning the soil over time into a source of secondary pollution. In this regard, an extremely urgent task is to assess the territory, especially such a highly developed and densely populated area as the Moscow Region, in terms of its protective potential to heavy metal pollution. The paper proposes and tested an algorithm for the cartographic assessment of the protective potential of the soil and vegetation cover of the region using GIS analysis methods based on the database “Digital medium-scale soil map of the Moscow region” and a vector map of forest cover. The formula used for calculations includes data on the soil texture, the content of organic matter in soil, the position of the soil in the landscape and the degree of forest cover of the territory. According to the proposed approach, in the Moscow region, the soil cover, taking into account the forest cover, forms 4 groups according to the level of protective potential for contamination with heavy metals and metalloids. The maximum estimate was obtained for noneroded sod-podzolic soils of medium or fine texture, gray forest soils, chernozems and peat bog soils under forest vegetation (17 % of the area). Unerroded soddy-podzolic soils of varying degrees of podzolization and gleying (45 %) received an average rating. Even lower is the protective potential of 22 % of the territory represented by eroded gray forest soils, various sod-podzolic, alluvial and peat bog soils. This group is the most heterogeneous in terms of soil texture, organic matter content and degree of forest cover. The group with a minimum protective potential included eroded soils, soils of gully-girder complexes, sod-podzolic soils of coarst texture, as well as alluvial peat and peaty soils (about 16 %).

Results of the comparison of organic carbon stocks in the automorphic and semihydromorphic forest soils are discussed. The database includes information on 289 soil profiles in the forest zone of European Russia. On the average, the total organic carbon pool (including forest litter) in semihydromorphic soils is three times higher than that in automorphic soils. The difference decreases with an increase in the thickness of the considered soil layer from 3.2 times for the layer of 0–30 cm to 2.6 times for the layer of 0–100 cm. The greatest difference in carbon stocks is noted for the organic horizons; in semihydromorphic soils, the carbon storage in them averages 73 ± 8.2 t C/ha; in automorphic soils, it is seven times smaller. The neglect of the contribution of semihydromorphic soils results in underestimation of the total soil organic carbon stock of the region. The degree of underestimation depends on the soil cover pattern of particular areas and on the thickness of the considered soil layer. Calculations made for Karelia show that the underestimation of organic carbon stocks in various landscapes ranges from 10 to 40%. For the total area of this republic, it is estimated at 22, 19, and 13% for the soil layers of 0–30, 0–50, and 0–100 cm, respectively. A comparative analysis of known pedotransfer functions for calculating soil bulk density shows that the best results (RMSE = 0.15; R 2 = 0.36) for mineral horizons of forest soils in European Russia are provided by the pedotransfer function suggested by O.V. Chestnykh and D.G. Zamolodchikov.

Aim . To estimate the humus content and stocks of arable chernozems of two soil-ecological zones (Predcaucasia and Yuzhno-Russkaya) within the Rostov region, as well as the possibility of the optimization of the state of their humus under current conditions. Material and Methods . The following data sources were used: soil and general geographic information accumulated in the Soil-geographic Database of the Russian Federation information system, the Red Book of the Rostov Region Soils database, digitised archived soil survey data of 1977-1995 and agrochemical monitoring data of 2012-2017. Results . The stabilisation of the humus content of the arable chernozems of the Predcaucasian zone in recent decades has been demonstrated and can be explained by a decrease in the dehumification rate under minimal tillage. The average humus content in the soils of the Yuzhno-Russkaya zone decreased by approximately 0.5% during the same period, which may be caused by the high proportion of row-crops cultivated in an erosion-prone area. The current average humus content in arable chernozems is very low, it is close to the critical level, below which crop yield is decreased despite of sufficient mineral fertilizers using. Conclusion . The main causes of soil dehumification in the region are agrogenic humus mineralization due to a constant deficit of compensating amounts of fresh organic matter, deflation of fine soil material from ploughed surfaces and water erosion. The optimisation of land use structure and crop structure, which takes into account the characteristics of these territories, is required to reduce the intensity of these processes under current conditions.

Contemporary (corresponding to the modern state of ecosystems and land use) and prehistoric (for hypothetic intact natural ecosystems similar to modern virgin ecosystems) stocks of organic carbon were assessed for model regions of southern taiga, forest-steppe and steppe in European Russia. The comparison of these stocks enabled an assessment of the integral result of the multidirectional changes in land use that occurred in the studied regions over the historical period. The carbon stocks were determined using a unified cartographic basis, data on taxonomy and texture of soil units, modern land use types and the type and age structure of reconstructed and contemporary vegetation. The results obtained indicate that the modern carbon pool has reduced by 24% compared to the potential prehistoric one in the Kostroma Region and Rostov Region (southern taiga and steppe zones, respectively) and by 37% in the Kursk Region (forest-steppe zone). It was also demonstrated that the contribution of soil to the total organic carbon stock increases southwards, from southern taiga to dry steppe, from 51 to 95% during the prehistoric period and from 62 to 96% currently. The study results show that forestry and agriculture increase the contribution of soil to maintaining the region’s carbon budget.

In the monitoring of soils contaminated with heavy metals, the choice of the target indicators (background or threshold values) is a challenging task. The determination of the background concentrations is of practical importance, because the pollution of clean soils to the levels below the maximum permissible concentration (MPC) or the tentative permissible concentration (TPC) levels is not recorded and, hence, cannot be prosecuted. Background concentrations are rarely applied in pollution assessment, because they remain unknown in most cases. The study of the soils of specially protected natural areas in Rostov oblast has revealed the regional specificity of the soil cover-elevated concentrations of a number of heavy metals and other trace elements-related to their high concentrations in the parent materials. Therefore, it is impossible to apply current public health standards based on the total concentrations of elements, such as MPC and TPC, in the monitoring of soil contamination in Rostov oblast. The use of background values characterizing the soils of specially protected natural areas seems to be more promising for this purpose. For an adequate environmental monitoring, data on the background concentrations of trace elements in the virgin of slightly transformed soils of specially protected natural areas should be obtained with due account for the regional diversity of soils including their classification position, texture, and the character of parent materials.

An algorithm of regional assessment of the size and structure of the actual (corresponding to the modern state of ecosystems and land use patterns) and potential (for hypothetic natural ecosystems analogous to modern native ecosystems) pools of carbon has been developed and tested. A comparison between actual and potential values of carbon pools makes it possible to assess the integral result of land use in the studied region with multiple changes in the types of land use during the historical period. The calculations are made using a unified cartographic base and take into account the taxonomic position and texture of soil units, the types of modern land use, and the type and age structure of the reconstructed and actual vegetation. The results obtained for the southern taiga and forest-steppe zones of European Russian indicate that the modern actual carbon pool is 24% less than the potential carbon pool in Kostroma oblast (southern taiga zone) and 32% less than the potential carbon pool in Kursk oblast (forest-steppe zone). The actual phytomass reserves in these two regions have decreased by 40 and 75%, respectively, relative the potential phytomass reserves, so the portion of the soil carbon pool in the total carbon pool has increased. It is argues that the use of the territory for forestry and agriculture increases the role of the soil cover in sustaining the carbon budget of the region.

Compilation of the Red Data Books of soils for the subjects of the Russian Federation will provide for conservation of natural diversity of soils in regions significantly modified by management activities. When compiling the list of the reference soils it is proposed to focus primarily on soils, which are typical for provinces of soil-ecological zoning and to identify reference soils within protected nature areas. The research of virgin soils included in the Red Data Book of the Rostov oblast showed that their characteristics can be used as reference in the course of soil monitoring. The maintenance of the fallow regime in soils promotes restoration of their humus condition. In virgin and fallow chernozems, the weighted mean humus content (for a 25-cm thick soil layer) is by 0.7–3.0% greater than that in the arable analogs. It is demonstrated that the available normative documents are not applicable for assessing the degree of pollution of regional soils with heavy metals. To fulfil this task it is proposed to use regional background concentrations established for virgin soils with similar typology and textural composition, while taking into account natural variation of characteristics.