Digital mapping was applied for a key site located at the Southern Cis-Ural region near Ufa city (the Republic of Bashkortostan, Russia). The digital soil map (DSM) was created using the open-source GIS software packages and compared to a conventional (CSM) one. As input parameters, we used standard morphometric values of the topography and field descriptions of soils, including the authors’ data. The DSM was created at the same scale (1:25,000) as the CSM, and soils of different classes were grouped according to the principle of genetic homogeneity and regional agroecological value. Comparing DSM and CSM showed several significant differences in the position, areas, and boundaries of hydromorphic soils and chernozems. The DSM has advantages over CSM at estimating smaller soil areas (areals) and their boundaries, in particular, on elevated topography elements (hills and steep slopes) and upper links of the erosion network (small dry valleys, hollows, and gullies). On the other hand, fluvial soils are mapped rather poorly by the digital approach, and CSM is more appropriate for such soils’ areals. The highest discrepancy is confined to the areas of eroded soils and fluvisols (15% and 12% of total area, respectively) due to significant differences in DSM and CSM approaches for such soil groups. We suppose that the digital method is effective and suitable for the Cis-Ural region, despite 57% soil taxa (types) prediction accuracy and the complexity of the territory by its ruggedness, erosion, and suffusion processes. The implementation and further use of digital mapping methods increase the quality of work, reduce its cost and terms in the region.

The conventional measuring methods (runoff plots and soil morphological comparison) and models (WaTEM/SEDEM and regional model of Russian State Hydrological Institute (SHI)) were tested with regard to the Southern Cis-Ural region of Russia, along with data from rainfall simulation for assessing soil erosion. Compared with conventional methods, which require long-running field observations, using erosion models and rainfall simulation is less time-consuming and is found to be fairly accurate for assessing long-term average rates of soil erosion and deposition. In this context, ¹³⁷Cs can also be used as a marker of soil redistribution on the slope. The data of soil loss and sedimentation rates obtained by using conventional measuring methods were in agreement with the data based on the used contemporary modeling approaches. According to the erosion model calculations and data on the fallout of radionuclides in the Southern Cis-Ural (54°50–25′ N and 55°44–50′ E), the average long-term annual soil losses were ~1.3 t·ha⁻¹ yr⁻¹ in moderate (5°) arable slopes and ~0.2 t·ha⁻¹ yr⁻¹ in meadows. In forests, surface erosion is negligible, or its rates are similar to the rate of soil formation of clay–illuvial chernozems. The rates of soil erosion and sediment deposition on the arable land obtained using different methods were found to be very close. All the methods, including the WaTEM/SEDEM, allowed us to measure both soil erosion and intra-slope sedimentation. The regional SHI model fairly accurately assesses soil erosion in the years when erosion events occurred; however, soil erosion as a result of snowmelt did not occur every year, which should be taken into account when modeling. The concentrations of ¹³⁷Cs in the topsoil layer (0–20 cm) varied from 0.9 to 9.8 Bq·kg⁻¹, and the ¹³⁷Cs inventories were 1.6–5.1 kBq·m⁻², with the highest values found under the forest. The air dose rate in the forest was higher than in open areas and above the average of 0.12 μSv·h⁻¹ on the slope (0.1 μSv·h⁻¹ in the meadow and 0.08 μSv·h⁻¹ on the arable land), with the value increasing from the watershed to the lower part of the slope in all the areas. The γ-background level in the studied ecosystems did not exceed the maximum permissible levels.

Based on data from old and modern maps and satellite images we reconstructed the arable land borders within a key plot (100 km2) in the Moscow region for 8 time periods, from the General Land Survey (1767) to the present day. Brief descriptions for the special geometric plans of the Bogorodsk, Dmitrov and Moscow districts (“uyezd”) of the Moscow province (“guberniya”) were analyzed for accurately describing the land use displayed on the General Land Survey plans. The contours of arable lands on the general land survey plans (1767) of the studied area refer to those under constant cultivation, while periodically abandoned land were described and measured separately. The dynamics of arable land borders for the studied period was analyzed using the scheme of landscape zoning, and data on the lithological and geomorphologic structure of the territory and morphometric characteristics of its relief. The prevailing slope gradients and the area of arable lands are identified for each time period. The maximum percentage of arable land under constant cultivation (42%) is characteristic for the end of the 18th century; the minimum (8%) is in evidence at the present time. It was found that the proximity to settlements and the degree of soil drainage were the principal factors determining the spatial structure of arable lands.

Based on data from old and modern maps and satellite images, we have reconstructed the arable land borders of a key plot (100 km2) in Moscow oblast from th

The popularity of soil erosion modeling is growing rapidly. However, less attention is given to the erosion model verification, which is mainly based on sediment yield estimates. Spatial model verifications are very few.In this study soil losses over the 250 years (calculated by WATEM/SEDEM) have been verified by the soil truncation method on the site in the Moscow region, Russia. Just over 1,500 soil sampling points were analyzed on the area 100 km2.Methods for spatiotemporal reconstruction of input parameters and calculations of soil erosion losses are presented in [1]. The degree of soil erosion, assessed at the sampling points, was compared with the soil losses calculated by the model. A clear tendency was revealed in the change in the proportion of non-eroded soils with an increase in the volume of modeled erosion losses: with losses <50 mm non-eroded soils was 87%; 50-100 mm 86%; 100-150 mm 81%; 150-200 mm 78%; 200-250 mm 70%;  250-300 mm 63%. 13% of points with losses <50 mm were diagnosed as weakly and moderately eroded soils. All such points are located nearby the multi-temporal borders of the arable land. This discrepancy is probably related to the inaccurate calculation of erosion due to the inaccuracy of restoring the cropland boundaries.It is important to note that the relief and significant changes in the configuration of the cropland led to significant redeposition of sediments and the formation of a large area of warp and washed-warp soils.It remains unclear why non-eroded soils predominate even in areas with erosion losses >250 mm calculated by the model. There are two possible explanations: i) model calculations are universally overestimated; ii) plowing changed the soil-forming process and contributed to a change in the depth of the subsurface horizons of Umbric Albeluvisols. Overestimation of erosion losses is unlikely since soil erosion rates have been verified on several slopes by independent magnetic tracer method [1]. The role of the soil-forming process needs further research.In general, the spatial verification of the WATEM/SEDEM can be considered successful given the complexity of the historical reconstruction of input parameters over the past 250 years.This work was supported by the Russian Science Foundation No. 22-27-00170 and state research program No. 0439-2022-0015. [1] Zhidkin A., Fomicheva D., Ivanova N., Dostál T., Yurova A., Komissarov M., Krása J., 2022. A detailed reconstruction of changes in the factors and parameters of soil erosion over the past 250 years in the forest zone of European Russia (Moscow region). International Soil and Water Conservation Research, 10 (1), 149-160, https://doi.org/10.1016/j.iswcr.2021.06.003