Nikita R. Kriuchkov

Spatial information on soil clay content addresses critical needs in precision agriculture and soil health assessment worldwide. This study utilizes a mapping workflow for topsoil clay (0–20 cm) across croplands in southern Russia using Sentinel-2 bare soil mosaics and regional covariates representing soil-forming factors. We generated 26 multi-temporal mosaics via per-pixel and per-date approaches and then tested five scenarios with regional covariates in combination with three variable selection techniques: variance inflation factor (VIF), recursive feature elimination (RFE), and modified greedy feature selection (MGFS). We found that among 26 temporal mosaics, the best single mosaic (scenario 1) explained 25% of the clay variation (RMSE = 10.03%, R² = 0.25, RPD = 1.16). Using only regional covariates selected after VIF and RFE approaches (scenario 2) yielded comparable results (RMSE = 9.77%, R² = 0.27, RPD = 1.18). Combination of the best bare soil mosaic and all regional covariates without the variable selection method (scenario 3) improved the predictions (RMSE = 9.45%, R² = 0.33, RPD = 1.24), and with the VIF/RFE application (scenario 4), the model showed slightly worse accuracy (RMSE = 9.65%, R² = 0.31, RPD = 1.21). MGFS implementation (scenario № 5) boosted the model performance and resulted in the best predictions (RMSE = 8.73%, R² = 0.42, RPD = 1.34). NIR bands from the bare soil mosaic, and terrain attributes with Landsat and MODIS variables from the regional covariate set were the key variables. We demonstrate that combining multi-temporal Sentinel-2 mosaics with regional covariates, when paired with an appropriate selection strategy, yields superior clay predictions.

The long-term patterns of the erosional potential of precipitation (R-factor) in the monsoon climate of Primorsky Krai are investigated using modern time series analysis methods. This study presents an analysis of the rainfall erosivity potential (R-factor) under a humid continental climate with hot summers (Dwa in the Köppen climate classification) using Detrended Fluctuation Analysis (DFA) and Power Spectral Density (PSD) methods. The original data, covering the period from 1960 to 2022, were pre-processed by removing trends and seasonal components, which allowed for identifying the dominant role of seasonal and random fluctuations in shaping temporal variations of the R-factor. The DFA results demonstrated a high degree of linear conformity in logarithmic scale (R ² = 0.983) with a scaling parameter α ≈ 0.534, indicating weak persistence and moderate correlations typical for processes dominated by short-term episodic precipitation events. The analysis of local DFA slopes revealed a stable region at a scale of approximately 15.8 months, reflecting the influence of annual seasonal cycles and potential interannual climate oscillations, such as the Pacific Decadal Oscillation (PDO) or the Atlantic Multidecadal Oscillation (AMO). Meanwhile, PSD analysis confirmed the absence of pronounced long-term memory and fractal structure in the spectrum, consistent with DFA findings. These results emphasize the importance of a comprehensive approach to studying rainfall erosivity potential and highlight the promising application of fractal analysis methods for identifying climatic and hydrological patterns in regions with pronounced seasonality and high rainfall variability.

This study presents the first comprehensive examination of ¹³⁷Cs behavior in northern taiga ecosystems of the Kola Peninsula, a previously understudied region regarding radionuclide mobility. The background radioactive contamination of these ecosystems stems from global fallout and differs from more extensively studied contaminated areas. Twelve monitoring sites at varying distances from the Kola nuclear power plant were established to assess ¹³⁷Cs accumulation in dominant plant species across three forest tiers. Gamma-spectrometric measurements revealed high mobility of ¹³⁷Cs with specific activity ranging within 4.7–34.5 Bq/kg in trees, 8.4–164.8 Bq/kg in shrubs, and 15.0–94.5 Bq/kg in mosses. Notably, Ericaceae family plants demonstrated the highest accumulation capacity. ¹³⁷Cs concentrations were significantly higher at the background site (30 km from the power plant) than in the sanitary protection zone, indicating no detectable influence from the nuclear facility. Strong correlations (up to |rs| = 0.93) between bioaccumulation indicators and soil properties were found—particularly with potassium content, exchangeable cation concentration, and organic matter content—suggesting that soil characteristics primarily determine ¹³⁷Cs mobility. These findings highlight the potential risk of ¹³⁷Cs movement through food chains in northern taiga ecosystems, with bioaccumulation coefficients exceeding those of central Russian landscapes and being comparable to those of Scandinavian taiga ecosystems.

Water erosion is one of the most extensive processes of soil and land degradation. This process significantly deteriorates the quality of ecosystem service

The purpose of this study was to compare two methods for assessing damage from the degradation of soils and agricultural lands located in the Kalachevsky district of the Volgograd Region. The amount of damage from soil and land degradation was calculated by the “Methodology for determining the amount of damage from soil and land degradation” (1994) and the cost of restoration (reclamation) of degraded soils was determined using the SmetaWizard estimate program (version 4.1.3). It was established that the most significant contribution to the total amount of damage from soil and land degradation (175 573 000 rubles or 64 955 rubles/ha) was made by the increase in the share of exchangeable sodium in soils (147 424 528 rubles or 54 541 rubles/ha), which is due to the development of the process of alkalinization in the soils of the studied agricultural sector in the region. This degradation process, which is harmful to the agricultural use of soils and lands, was found in areas that comprise 52% of the total farm area. This indicator’s significant damage is also associated with extended periods of restoration (reclamation) work, 4 years. The cost of reclamation work amounted to 11 647 353 rubles or 4309 rub./ha. The maximum contribution (78%) to this was made by damage from soil organic matter losses (the amount of damage was 9 131 525 rubles or 3378 rubles/ha). The significant difference in the total values of the environmental and economic assessment of soil degradation and the land of the Donskoye agricultural enterprise in the Kalachevsky district, calculated in various ways, is associated with the methodological features of this assessment: the assessment of damage from degradation by the “Methodology …” (1994) is a stricter approach than estimating the cost of reclamation (restoration) measures. Thus, soils may be degraded compared with a standard (considered when assessing damage), but this degradation is “insufficient” to justify reclamation.

Testate amoebae are unicellular eukaryotic organisms covered with an external skeleton called a shell. They are an important component of many terrestrial ecosystems, especially peatlands, where they can be preserved in peat deposits and used as a proxy of surface wetness in paleoecological reconstructions. Here, we represent a database from a vast but poorly studied region of the Western Siberia Lowland containing information on TA occurrences in relation to substrate moisture and WTD. The dataset includes 88 species from 32 genera, with 2181 incidences and 21,562 counted individuals. All samples were collected in oligotrophic peatlands and prepared using the method of wet sieving with a subsequent sedimentation of aqueous suspensions. This database contributes to the understanding of the distribution of testate amoebae and can be further used in large-scale investigations.

This research aims to evaluate the dynamics of soil loss through soil erosion by water in agricultural lands in steppe areas using a modification of the RUSLE2 model from the 1980s to the 2010s. The calculation was performed using a raster model of data that included a model of the slope angle, slope length, soil erodibility, rainfall and snowmelt erosivity factors, types of land use, and cover management factor. All data were taken from open sources. The average soil erosion in the territory studied amounted to 1.48 t ha⁻¹ year⁻¹ in the 1980s and 1.72 t ha⁻¹ year⁻¹ in the 2010s. The discrepancy with other studies was 12% for the level of the 1980s and 2–7% for the level of the 2010s. The main factor leading to an increase in soil loss was soil erodibility due to the loss of soil organic matter, which affected about 52% of the studied lands. The increase in the amount of soil loss occurred against a background of compensating processes: reduction in precipitation and climate change (getting drier), as well as the overgrowth of agricultural lands with natural steppe vegetation. Modified model RUSLE2 has shown good results correlated with other studies for the research area.

The damage from soil and land degradation was assessed at three hierarchical levels (the oblast as a whole, municipality, and agricultural sector) of the s

The damage caused by soil and land degradation was assessed at three hierarchical levels (the region as a whole, the municipality, the agricultural sector) of the spatial organization of six test regions of the Russian Federation (Volgograd, Belgorod, Kaliningrad, Vladimir, Samara and Penza regions). The indicators of soil and land degradation for all test objects were a decrease in the content of exchangeable potassium, a decrease in the content of mobile phosphorus, a decrease in the content of humus, a change in the acidity index of soils. In addition, for the test objects of the Volgograd region, the indicator of land salinization was used, the Belgorod region - soil erosion, the Kaliningrad region - the indicator of the metabolic coef cient (qCO2) of soils. It was found that the minimum and maximum values of the specif c total damage from degradation can be detected for regions with a similar composition of soil cover (Saratov and Belgorod regions, respectively, where chernozem soils predominate). When the values of specif c total damage from soil and land degradation are close to each other at various hierarchical levels of spatial organization of regions (Vladimir, Saratov, Belgorod and partly Penza regions), in terms of intensity and scale of manifestation of the studied degradation processes, the agricultural farm is «typical» for the entire municipal district, and the municipal district is «typical» for the entire region.