The paper presents assessment of the current state and risk of soil degradation of arable land (area ~800 sq. km.) from erosion. The rates of soil erosion were calculated by the WATEM/SEDEM. The ...obtained rates of soil erosion were converted into erosion losses of the soil profile and compared with the current thickness of the humus horizons (according to field survey data). The calculated and actual (according to the field survey) soil losses correspond to each other. The rate of soil erosion in the southern section is almost twice higher than in the northern section, however, the difference in the area of eroded soils is 4.4 times higher. The forecast was calculated for each pixel with respect to the current thickness of the humus horizons. With the stable rate of erosion in the next 50 years, the area of eroded soils will almost double on the studied territory, and in 200 years will grow almost 3 times relative to the current state. After 200 years of plowing without soil protection measures, the share of eroded soils in the northern section will only reach the current level of soil degradation in the southern section, while the share of eroded soils on south section will reach almost 35%. These results clearly demonstrate that the areas of priority application of soil conservation measures should be determined not by the rate of erosion, but by the rate of degradation of the soil cover from erosion.
This literature review analyzed more than 100 publications on soil erosion in the Central Russian Upland, one of the most erosion-prone regions of Russia. The selection of scientific papers was ...carried out from open web resources, domestic and international citation databases. The following parameters have been analyzed: time; geographical position; scale and methods of research; soil and geomorphological features; anti-erosion measures; type of erosion and rates of soil washout/accumulation; bibliographic information about the publication. There is a shortage of studies at the small-scale and medium-scale levels. The relationship of large-scale studies to the main watershed of the Central Russian Upland was revealed. There are discrepancies in the estimates of soil erosion by different authors, especially at different scale levels. An analysis of changes in soil erosion over time indicates a decrease in the rate of soil erosion in general on the Central Russian Upland, mainly due to climate change and a reduction in the area of arable lands. A lack of studies of rainfall, tillage and wind erosion of soils in this area has been revealed.
The study of soil erodibility, i.e., its ability to resist the destructing action of water flow and raindrops, is one of the important challenges in erosion science. The values of soil erodibility ...are used in erosion models and make it possible to calculate the rate of soil matter loss/accumulation. The purpose of this study is to assess soil erodibility and its variation on plots of different areas in the northern forest-steppe of the Central Russian Upland. It has been established that the calculated parameter of soil erodibility (
K
-factor) is mainly determined by the soil organic matter content. The mean
K
-factor for gray forest soils is more than 1.5 times higher than that for noneroded chernozems. The
K
-factor increases with an increase in the degree of soil erosion. For example, in a series of noneroded and slightly, moderately, and strongly eroded chernozems, it reaches 38, 42, 44, and 57 kg h/(MJ mm), respectively. Gray forest soils are much more susceptible to the risk of degradation from erosion than chernozems because of their higher erodibility and lower thickness of the humus layer, other factors being equal. The use of different methods of
K
-factor interpolation exerts little effect on changes in the mean soil erosion rates calculated by the WaTEM/SEDEM model, even under conditions of the highly contrasting soil cover. With a change in the scale of soil erosion estimates (the transition from a medium to a large scale, or from a large to a medium scale), the deviation of calculated mean soil erosion rates is less than 15%.
Current medium- and small-scale estimates of soil erosion in Russia are very few. At the same time, a favorable situation has now developed for assessing the rates and volumes of soil erosion losses. ...Erosion models adapted to available digital elevation models, various farmland maps, and climate databases are now available to researchers. We have estimated the rates and volumes of soil erosion with the use of different maps of cropland: world cover from the European Space Agency (ESA WC), global land cover and land use from the University of Maryland (GLCLU), the official unified federal information system of agricultural land (UFIS AL) from the Ministry of Agriculture of the Russian Federation, and the original conventionally reference land cover map of Alekseevskii district of Belgorod oblast. It has been found that the UFIS AL map gives cropland areas close to the average from first three maps. Public access maps (ESA WC and GLCLU) give maximum and minimum estimates of cropland, respectively. A comparison with the conventionally reference large-scale map shows that the accuracy of the UFIS AL does not exceed 90%; the accuracy of ESA WC and GLCLU maps is 84 and 83%, respectively. The total area of cropland in Belgorod oblast varies slightly (from 1445 to 1586 thousand hectares), which is favorable for erosion modeling. Deviations from the average rates of soil erosion calculated using different maps of cropland in the region as a whole are up to 7%; for some districts, they reach 27%. Thus, current estimates of soil erosion at the regional level can be carried out with an error of at least 10–15% only as a result of the uncertainty in mapping the boundaries of cropland. For Russia as a whole, data on the area of cropland vary significantly: from 80 to 132 million hectares. Consequently, the use of existing maps of cropland can lead to significant uncertainties in soil erosion estimates averaged at the level of the subjects of the Russian Federation and large regions.
Verification of soil erosion models (WATEM/SEDEM for rainfall and tillage soil erosion and regional model of the State Hydrological Institute for snowmelt soil erosion) was carried out on the basis ...of estimates of soil erosion and deposition rates in an arable catchment of dry valley in the Vorobzha River basin located in the central part of the Srednerusskaya Upland in the forest-steppe zone. The rates of soil loss/gain for the entire period of agricultural use were obtained using the soil truncation method. The rate of sediment deposition in the dry valley bottom for the period after the 1986 was determined based on interpretation the Chernobyl-derived
137
Cs depth distribution in the sediments. Comparison of the model calculations with field-based method estimates was generally in good agreement. Also, the erosion model calculation satisfactorily reflected the pattern of zones with different intensity of soil erosion. WATEM/SEDEM made it possible to take into account the movement of soil matter by tillage erosion. Some discrepancies between the modeling results and field data were mainly due to the insufficiently detailed input parameters, e.g., the data on crop rotations or local microrelief specifics. WATEM/SEDEM did not accurately estimate the rate and volume of sediment accumulation, especially for areas beyond cropland.
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A new method of digital mapping of the soil cover pattern with calculation of the share of soils of different taxa and degree classes for soil erosion in the soil associations is proposed. A ...comparative analysis of soil maps obtained using different methods of construction (visual expert and digital) and with their different contents (displaying the dominant soil or soil associations) has been performed. In the case of mapping by the visual expert method (with the display of the dominant soil), a significant underestimation of the total area of moderately and strongly eroded soils in comparison with the digital mapping is noted. These differences are due to the underestimation of the area of small polygons with moderately and strongly eroded soils in the composition of soil associations on slopes of low steepness and in shallow hollows in the visual expert method of mapping. When the content of digital maps is generalized from soil associations to dominant soil categories, a significant change in information on the degree of soil degradation by erosion is also noted. Comparison of visual expert and digital methods for mapping soils of different taxa indicates a high degree of compliance between the spatial location and area of soil delineations with similar component content in both cases. The greatest differences between the soil maps created by these methods are noted for the soils with periodic overmoistening, namely, meadow-chernozemic (Luvic Chernic Phaeozem (Oxyaquic)) and chernozemic-meadow (Luvic Stagnic Chernic Phaeozem) soils because of the poor consideration for microtopography in traditional mapping. In general, it can be concluded that the creation of a digital map is more difficult in terms of the need to use specialized computer programs and mathematical models. However, the resulting digital databases contain information of a higher level of detail than traditional soil maps.
The content of polycyclic aromatic hydrocarbons (PAHs) in soil and snow cover near the carbon black plants in Moscow, Omsk, and Samara regions was studied. The differences in the composition, bulk ...atmospheric deposition, and resources of PAHs in soils in key areas controlled by the production technology and the duration of the plant work were revealed. It was established that all key areas are characterized by lower modern delivery of PAHs in comparison with the activities of plants in the past. The highest amounts and the heaviest composition of PAHs were detected near a nonoperating plant, which previously had used an environmentally unfavorable tube technology. In all areas, the soils are characterized by a higher proportion of phenanthrene associations in relation to the snow; without account for phenanthrene in soils, the same PAHs dominate in the snow. The snow and soil PAH associations are the most similar near the operating plant.
Soil erosion is for the first time comprehensively studied in a catchment of 41 ha (near the village of Lomovets, Orel oblast) in the zone of gray forest soils (Luvic Phaeozems), which are ...considerably more susceptible to erosion as compared with chernozems. Analysis of archive data and historical cartographic materials shows that the catchment has been plowed for 200 ± 10 years. The rates of soil erosion and deposition over the entire cultivation period with/without taking into account soil self-restoration, last 50 ± 25 years, post-Chernobyl period (1986–2022), and the single erosion event on May 31, 2022 have been determined using field methods (soil- profile truncation, radiocesium technique, and rill methods, as well as a detailed UAV survey) and the model computations using the WaTEM/SeDEM model. The spatial distribution of soil erosion/deposition pattern is assessed. The estimates of soil losses and accumulation demonstrate considerable fluctuations in the rates of erosion and deposition over the past 200 years, which are mainly determined by the conditions of snowmelt runoff formation, repetition and distribution of runoff-forming rainfalls in the warm season, set of cultivated crops, tillage frequency and practices, and changes in field boundaries. The long-term average annual estimates of soil erosion over the agricultural period are higher than the estimates for the post-Chernobyl period, because the rates of soil erosion have decreased over the last 30 years. The WaTEM/SeDEM-based estimates of soil losses are generally comparable to the soil losses assessed according to soil morphology, provided that the redistribution of sediments to the lower boundaries of arable land is taken into account. The spatial structure of a single erosive event is to a considerable degree close to the spatial arrangement of the eroded and aggraded soil areas formed over the entire agricultural period.
Results of a detailed analysis of pedosediments—sediments composed of transported material of soil humus horizons—are discussed. Five main morphological features of pedosediments attesting to the ...origin of the transported soil material are identified; their allocation to certain types of pedosediments is shown. A map of pedosediments for a small catchment in Tula oblast has been developed on the basis of their morphological analysis. Three types of pedosediments are specified by their morphological features and location: (1)
leveling
, filling depressions; (2)
covering
, extending on the slopes of the ravine; and (3)
protruding
above the surface of the slope represented by “napash”—agrogenic earthwork at the edges of fields. The covering pedosediments formed on the slopes are shown to be predominant both by area (60%) and by the volume of accumulated material (45%). The leveling pedosediments at the bottom of the ravine occupy 25% of the area and retain about 35% of all sediments of the small catchment. Only 2% of the total material of pedosediments in the catchment belongs to protruding pedosediments. The formation and localization of these pedosediments are controlled by the formation of napashes. In general, the material of pedosediments redistributed within the small catchment constituted about 12% of the total mass of humus horizons of the soils-donors. Pedosediments play a significant role in the soil cover and occupy about 10% of the total catchment area.
Dissolved organic matter is the most mobile part of soil organic matter; however, its change and transformation occurring during soil erosion are insufficiently studied. We assess the optical ...properties of water-extractable organic matter (WEOM) in arable soils with different degrees of degradation caused by erosion and sedimentation in a small arable catchment in the Kursk oblast, namely, the WEOM of arable Haplic Chernozems (noneroded and moderately eroded) and their analog with soil matter sedimentation, Fluvic Chernic Phaeosem (Loamic, Pachic). WEOM is isolated from the aggregates of 2–1 mm and >10 mm. In water extracts, the contents of organic carbon and nitrogen were measured. Optical properties were assessed according to absorption spectra and three-dimensional fluorescence spectra. The eroded and aggraded soils emerge to be similar to each other but significantly differ from noneroded chernozem in terms of the main quantitative characteristics of soil organic matter—the content of organic carbon and nitrogen, and pH. However, both the quantitative and qualitative WEOM characteristics show a different trend: the WEOM of Fluvic Chernic Phaeosem (Loamic, Pachic) significantly differs from eroded and moderately eroded Haplic Chernozems. In addition, some characteristics of WEOM (nitrogen content, SUVA
254
,
S
350–400
, and
S
R
) depend on the size of the aggregates from which WEOM is isolated (2–1 or >10 mm). The fluorescent properties of WEOM also depend on the size of the aggregates. Our data suggest that the properties of the WEOM in a small arable catchment of the central forest-steppe zone are variable and are largely determined by the destruction of water-unstable aggregates and consolidation of their particles, as well as by the leaching of dissolved organic matter. When aggregates are destroyed by water, their particles migrate with flows along the slope, and organic matter is decomposed. However, particles accumulate in depressions to become consolidated into blocky structural units, while the properties of soil WEOM are significantly altered, both due to degradation of organic matter and as a result of its leaching.
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