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There is growing recognition that forest ecosystems are a key component in the global carbon cycle, and there is a clear demand for their study. This research is a comparative analysis of forest growing stock volume (GSV) and determination of annual growth in Bashkiriya Nature Reserve (Russia) for 1979 and 2015 using 8395 and 8405 observation plots, respectively. Also, we evaluated the spatial distribution and produced digital maps of the species and their GSV for each year. The results showed that pine and birch were the dominant species (60.5 and 24.8% of the area in 2015, respectively) and there were no significant changes in the area of stands during the 36-year period. We found that the GSV in the reserve had increased by an average of 23.2% over the 36-year period. Specifically, the total forest GSV increased from 7,678,960 in 1979 to 10,003,890 m3 in 2015, representing an annual gain of 0–1.5 m3/ha. The increase in GSV was mainly associated with an increase in birch and pine trees. The annual growth of GSV was determined as 1.8–2.1 and 1.4 m3/ha per year for pine and birch forests, respectively. However, these types of trees belong to the age categories of mature and overmature stands, i.e., with reduced intensity of GSV gain. Digital maps produced as part of this study provide a visual representation of the changes in forest spatial patterns and GSV over time, highlighting areas of the reserve where the stock has increased or decreased. This study leveraged a substantial dataset, which provided valuable retrospective insights into the dynamics of pristine forest ecosystems, allowing for the assessment of changes over a 36-year period. Overall, this study highlights the importance of the ongoing monitoring and assessment of GSV levels, especially in the context of rapidly changing environments and climates. [ABSTRACT FROM AUTHOR]

The article provides an assessment of climatic characteristics and changes in floodplain soils after the implementation of a drainage system. The study was conducted in the northern forest-steppe zone of the East European Plain (Republic of Bashkortostan, Russia). Through the analysis of long-term meteorological observations from 1961 to 2020, it was found that there was a steady increase in air temperature in all months and throughout the year, an increase in the period with positive temperatures, a slight increase in annual precipitation, and a reduction in precipitation during certain months of the warm season. Over the past 40 years, the drainage system has transformed the soil cover from Gleysols to Anthrosols, due to a decrease in the level of groundwater, agricultural use, as well as warming of the climate in the region. Thus, the transformation of soil cover can potentially contribute to climate change through the depletion of soil organic carbon stocks and increased greenhouse gas emissions. Nevertheless, currently, the natural and climatic conditions, morphological, water-physical, and agrochemical properties of Anthrosols allow for the production of two harvests of fodder crop (Bromus inermis L.) during the vegetation period. In general, the change in climatic indicators in the study area is consistent with the global trend. Our results underscore the sensitivity of soil systems to climatic variations and human activities, highlighting the need for local studies to understand regional and global environmental changes. [ABSTRACT FROM AUTHOR]

This paper presents the evaluation and digital mapping of forest growing stock volume (GSV) and carbon stocks of the natural park Kandry-Kul (Republic of Bashkortostan, Russia). The field observations were conducted in the process of forest surveys in 1994 and 2018. According to these materials, we identified the predominant tree species in each studied plot. Then, we produced the digital maps of GSV and carbon stocks for each study year and calculated the annual increment. The results showed that birch (Betula pendula) and pine (Pinus sylvestris) were the dominant species in the studied park. The comparison of the two maps showed that the maximum annual GSV between 1994 and 2018 occurred in areas with a fairly small GSV in 1994. These areas were characterized by young trees of different species and pines of different ages, which had not yet reached the age of maturity, when the growth of trees is significantly reduced. We found that young pine crops contributed the greatest potential of carbon sequestration, with an annual GSV of 4.2 m3/ha per year. The birch trees made a minor contribution to the sequestration potential, characterized by relatively average annual growth (1.2 m3/ha per year). The change in carbon stocks for pine stands was on average 2 t/ha per year. For birch stands, the change in carbon stocks was approximately 0.5 t/ha per year, which is 30% of the average values for the forest-steppe region. Our results provide quantitative information on the carbon accumulation rate in secondary forests under conditions of intensive recreational load. [ABSTRACT FROM AUTHOR]

In this study, we examined the influence of long-term conventional tillage on the water-physical, chemical properties, and composition of the organic matter of chernozems. The study has been conducted on an arable plot subjected to water and wind erosion in the Pre-Ural steppe zone (Republic of Bashkortostan, Russia). Soil samples were collected from non-eroded and eroded arable plots as well as from an adjacent pristine forest windbreak. Key structural fragments of soil organic matter under different land use types were identified and quantified using 13C-NMR spectroscopy. The results showed that the water-physical properties deteriorated in agrochernozems: the number of valuable soil aggregates decreased and the soil bulk density increased, which may limit the growth of crops. The soil organic matter content for the different samples varied in the following direction: arable non-eroded > forest windbreak > arable eroded. It has been found that long-term plowing by conventional methods decreases aliphatic and increases aromatic structures in soils. As a result of the reduced inputs of plant residues, the processes of humification slowed down compared to unplowed soils. To increase soil fertility and carbon sequestration potential, it is necessary to stop degradation processes and implement conservation tillage practices. [ABSTRACT FROM AUTHOR]

The morphological, water-physical and chemical properties, basal respiration of the southern chernozem (Chernozem Haplic Endosalic) and erosional sediment in the Trans-Ural steppe zone (Republic of Bashkortostan, Russia) were studied. The surface soil horizon significantly differs from the sediment by the better structure and water aggregate stability. The particle size distribution of the sediments, due to erosion, contains more silt and clay fractions compared to the slope soil. It indicates a great potential for the carbon saturation of the soil which is limited by degradation. The slope soil is slightly saline, the type of the salinisation is sulfate with the participation of hydrocarbonates. The СО2 emissions, the organic carbon and alkaline-hydrolysable nitrogen content is low; and significantly lower than in the erosional sediment, but the content of exchangeable cations and water-soluble salts is higher. The structural composition of the humic acid (HA) extracted from the soil and erosional sediments was determined by 13C NMR spectroscopy. Aliphatic structural fragments predominate (65%) with a maximum signal level in the area of C, H-alkyls in the HA of the surface horizon. In the HA of the erosional sediment, the proportion of aromatic structural fragments is higher (up to 59%), which is associated with the processes of hydrolysis and condensation. In the HA of the slope soil, the formation of predominantly C, H-alkyls, oxygen-containing groups, including carboxyl ones, takes place. Differences in the composition of the structural fragments and functional groups of the soil and sediment HA are due to the different stability of the organic matter under conditions of the development of the soil erosion processes. [ABSTRACT FROM AUTHOR]

Agricultural development in northern polar areas has potential as a result of global warming. Such expansion requires modern soil surveys and large-scale maps. In this study, the abandoned arable experimental field founded by I.G. Eichfeld one century ago in Salekhard city (Russian Arctic), located in the polar circle, was investigated. Our aims were to assess the nutritional soil properties and their spatial variability. For spatial assessment and mapping, ordinary kriging (OK) and inverse distance-weighted (IDW) methods were employed. We found that due to long-term agriculture use, the soil cover was represented by a unique Plaggic Podzol (Turbic) that is not typical of the region. The soil was characterized by relatively low soil organic carbon (SOC) content, high acidity and a high content of plant-available forms of phosphorus in the humus-accumulative horizon. The results showed that some properties (pH H2O, pH CaCl2) were characterized by large-scale heterogeneity and showed clear spatial dependence. However, some properties (ammonium and nitrate nitrogen, basal respiration) showed a pure-nugget effect, presumably due to experimentation with fertilizer over a long period of time. [ABSTRACT FROM AUTHOR]

The article discusses the valuation of ecosystem services in connection with the economic activity of the Russian Federation in the Arctic zone. It also considers the categories of ecosystem services in general and the assessment of ecosystem services in the Arctic in particular. The article also considers types of negative impacts on the Arctic ecosystems, their assessment, and investment risks existing in ecosystem services. It is shown that the application of the methodology and ecosystem services contributes to the adequate assessment and creation of a hierarchical classification of "usefulness" and "benefits" for society derived from the existence, use, and non-use of ecosystems. The concept of Arctic ecosystem services consists of three components: identification, monetisation, and ecological risk assessment. Identification, classification, and initial assessment, mainly at the qualitative level, allow us to determine and classify services for further improvement of life quality and regulation of socio-economic effects of environmental changes. Quantitative assessment is related to the identification of the degree of ecosystem service amenability. The example of the Arctic ecosystems shows that the possibility to assess and the accuracy of the assessment can be quite different and largely depends on the type of service. The analysis of possible ecosystem services and their relationship with the quality of life in the Russian Arctic indicates significant investment risks. [ABSTRACT FROM AUTHOR]

The intensive urbanisation of terrestrial environments and industrial activity have an effect on the accumulation of risky metals in the soil and increase the toxicological risk to the terrestrial ecosystems and human health. Ninety-six topsoil samples from of St. Petersburg Russia as the source of the content of seven key risky metals (As, Cd, Pb, Zn, Ni, Cu, Hg) and polycyclic aromatic hydrocarbons (PAHs) have been investigated. To identify the spatial distribution of the risky metals and PAHs, GIS technologies have been used. Based on the data obtained, interactive maps of urban soil pollution were made. The spatial distribution of seven metals and their metalloids greatly varied from the local anthropic inputs. The results indicate that the highest concentrations of copper, mercury and lead were found in the urban environment. The most polluted areas were located in the city centre and the areas adjacent to industrial zones. The topsoil in this area represents an environmental pollution risk with regards to the elements Cu > Pb > As > Zn > Ni > Hg > Cd. The contents of the risk-type elements in the industrial area were higher than those in other land-use types in the north of city, indicating a considerable risk of metal migration and accumulation to the Neva River, the Gulf of Finland and the groundwater. [ABSTRACT FROM AUTHOR]

Soil salinization is an up-to-date worldwide issue. This problem is especially urgent in the territories of arid and semi-arid regions. The aim of this work was to analyze the relationships between the level of soil salinity and the key spectral indices obtained on the base on Sentinel-2A satellite data. The study has been conducted on an area of 5127 ha in the Trans-Ural steppe zone (Republic of Bashkortostan, Russia). Vegetation index NDVI and 15 salinity indices have been used to analyze the relationships. The salinity index III (G×R)/B using quadratic statistical relation showed the best correlation values with salinity level (R=0.89, R²=0.79). In general, it was found that the highest correlation values are observed with indices based on the three channels of visible range: salinity index 2 √(G×R) (R=0.82, R²=0.67), salinity index 4 √(G²+R²) (R=0.82, R²=0.67), salinity index VII (G+R)/2 (R=0.82, R²=0.67). The vegetation index NDVI showed the absence of a correlation with the values (R=-0.10, R²=0.01), due to weak development or dry state of vegetation. The areas of saline soils using salinity index III were calculated. The methods elaborated could be useful for mapping and accounting of saline soils based on satellite data under environmental conditions similar to this study. [ABSTRACT FROM AUTHOR]

Accurate forest growing stock (GSV) mapping is crucial for informed land management decisions, climate change mitigation, and sustainable resource utilization. This study aimed to digital mapping and uncertainty assessment of GSV levels in the Bashkiriya Nature Reserve, Russia. A random forest approach was used to predict GSV at a spatial resolution of 10 m (10 ×10 m) using 8395 plots and a set of 36 environmental covariates representing remote sensing data, relief and climate variables. The results revealed that the GSV levels ranged from 1 to 439 m3/ha, with a median of 200 m3/ha. Our model was evaluated using cross-validation and three performance metrics: root mean square error (RMSE=76 m3/ha), coefficient of determination (R2 =0.55) and Nash-Sutcliffe efficiency coefficient (NSE=0.55). In addition, we assessed the uncertainty of our predictions using a 90% prediction interval. According to the assessment of covariate importance, the significance of explanatory variables decreased in the following order: remote sensing > terrain > climate. We found, that Sentinel-2A satellite data, along with spectral indices, played a pivotal role in our spatial prediction model. Among these variables, the SWIR 12 band emerged as a standout contributor, highlighting the importance of this spectral information in GSV mapping. According to the generated map, the highest GSV values were identified primarily in regions characterized by low-lying terrain with mature trees of the reserve, while the lowest levels were distinctly evident on treeless mountain peaks. While it is widely acknowledged that remote sensing constitutes a primary source for modelling forest properties, our research has underscored the significance of the SWIR spectrum and elevation in future forest investigations. An advantage of the produced map of GSV and their associated uncertainties is that the end users can incorporate these uncertainties into decision-making processes involved in forest and environmental planning. • Random forest (RF) was applied to model forest growing volume (GSV). • A set of 36 covariates and 8395 ground-based measurements were incorporated. • We conducted an uncertainty analysis of GSV predictions. • Sentinel-2A SWIR band 12 was identified as a key variable in the RF model. [ABSTRACT FROM AUTHOR]

In the present study, we evaluated the effects of surface application and plowing of phosphogypsum and turkey litter to a depth of 20 cm on the erodibility of clay-illuvial agrochernozem (Luvic Chernozems (Aric, Pachic)) in the Southern Cis-Urals (Republic of Bashkortostan, Russia). Under laboratory conditions, 1°, 3°, and 7° slopes were modeled. Soil loss, runoff onset time, and turbidity were measured with a rainfall simulator. Particle size distribution and total organic carbon were measured. Under simulated heavy rainfall (360-420 mm h-1) for 30 min, the untreated control had the highest soil loss (28.9 t ha-1). Separate and combined introductions of phosphogypsum and turkey litter significantly increased soil resistance to water erosion. Co-introduction of the amendments strengthened this effect especially when the phosphogypsum to turkey litter ratio increased from 1:10 to 1:2 at the higher dose (60 t ha-1). The turbidity of the runoff from a 1° slope reached a small peak within the first 3 min then gradually decreased thereafter. At 3°, the turbidity remained nearly constant over time and was uniformly distributed. At 7°, the turbidity sharply increased then gradually decreased and its distribution was a deformed bell. Washed-out (trapped) sediments from all treatments and slopes had relatively more very fine sand, silt, and clay and a slightly higher total organic carbon content than the original soil. Phosphogypsum and turkey litter wastes may be effective anti-erosion amendments and potential fertilizers because they increase flocculation, improve the structure, and enrich the organic matter and nutrient content of the soil. [ABSTRACT FROM AUTHOR]

Topographic features of territory have a significant impact on the spatial distribution of soil properties. This research is focused on digital soil mapping (DSM) of main agrochemical soil properties—values of soil organic carbon (SOC), nitrogen, potassium, calcium, magnesium, sodium, phosphorus, pH, and thickness of the humus-accumulative (AB) horizon of arable lands in the Trans-Ural steppe zone (Republic of Bashkortostan, Russia). The methods of multiple linear regression (MLR) and support vector machine (SVM) were used for the prediction of soil nutrients spatial distribution and variation. We used 17 topographic indices calculated using the SRTM (Shuttle Radar Topography Mission) digital elevation model. Results showed that SVM is the best method in predicting the spatial variation of all soil agrochemical properties with comparison to MLR. According to the coefficient of determination R2, the best predictive models were obtained for content of nitrogen (R2 = 0.74), SOC (R2 = 0.66), and potassium (R2 = 0.62). In our study, elevation, slope, and MMRTF (multiresolution ridge top flatness) index are the most important variables. The developed methodology can be used to study the spatial distribution of soil nutrients and large-scale mapping in similar landscapes. [ABSTRACT FROM AUTHOR]