A new approach for determining the trend of changes in the rate of degradation of arable soils is suggested. It is based on the assessment of volumes of soil material eroded from arable fields and accumulated on the bottoms of first-order valleys during two time intervals: 1954(1963)−1986 and 1986−2015. For dating of this material, ¹³⁷Cs of global fallout and Chernobyl fallout are used. This approach in combination with a detailed morphometric characterization of the valley bottoms, the pathways of sediment transport from the fields, and the morphology and composition of the sediments accumulated on the bottoms makes it possible to give reliable estimates of the volumes of soil loss from tilled slopes. The benchmarks of 1963 and 1986 are related to maximum ¹³⁷Cs fallout during nuclear bomb testing and immediately after the Chernobyl accident. As an example, the rates of formation of stratozems (stratified aggraded soils formed due to accumulation of eroded sediments) within the first-order catchment of the Veduga River basin (Voronezh oblast, Russia) are analyzed. The results of the study indicate that the mean annual rate of soil loss from arable fields of the catchment in 1986–2015 was at least two times lower than that in the preceding period from 1954 (the beginning of the global fallout) to 1986 (the Chernobyl accident).

For the first time, contemporary trends in water discharge, suspended sediment load, and the intensity of overall erosion in the river basins of the North Caucasus region, as one of Russia’s most agriculturally developed geographic areas, were identified. The study was carried out using monitoring data of the Federal Service for Hydrometeorology and Environmental Monitoring of the country for 21 rivers by comparing two periods: 1963–1980 and 2008–2017. According to the study’s results, trends of an increase in the mean annual water discharge (by 2–97%) and the essential reduction in its intra-annual variability have been found in most of the studied rivers. On the contrary, the trends of reduction in annual suspended sediment load and the intensity of erosion in the river basins were identified in most of the study region. Their most essential and statistically significant decreases (by 47–94%) were recorded within the Stavropol Upland, which several decades ago was considered one of the most erosion-dangerous territories of the entire country, as well as in some river basins of the central part of the Greater Caucasus’s northern slope (by 17–94%). The changes in climate (reducing the depth of soil freezing and meltwater runoff on the soil) and land use/cover (reduction of acreage and load (pressure) of agricultural machinery on the soil, reducing livestock on pastures, and the transfer of water from the neighboring, more full-flowing rivers) are considered the leading causes of the aforementioned trends. The findings will contribute to solving some economic and environmental problems of both the region and adjacent territories and water areas.

The contemporary trend in the degradation of arable southern chernozems (Haplic Chernozems Pachic) in the steppe zone of south-eastern European Russia under the impact of water erosion has been...

This article presents results from the long term-monitoring of gully headcut retreat rates (GHRR) between 1959 and 2015 in different parts of the Udmurt Republic and is based on the use of historical aerial photographs and field observations (measuring the distance from the gully head to a fixed reference point) (Vanmaercke et al., 2016). It was determined that GHRR decreased from 2.4 to 0.3 m yr⁻¹ during the 1959–1997 observation period and the 1998–2015 period, respectively. Measurements of GHRR were made once per year for most of the monitoring sites, and twice per year (after snow-melt in May, and after the rainy season, October–November) for gullies located in the eastern part of the study area that contain high proportions of arable land. 80 % of GHRR occurred during the snowmelt period (1978–1997), and decreased to 53 % since 1997. Spatial patterns of GHRR resulting from changing hydro-climatic factors for different regions of the Udmurt Republic, as a whole, were determined based on the analysis of long-term observations at 6 meteorological stations and 4 gauging stations. The main reason for decreasing GHRR appears to be due to reductions in winter frozen soil depth. The influence of stormwater runoff more clearly occurred within the east and north parts of the Vyatka-Kama interfluve, whereas higher correlations between GHRR and frozen soil depth were found for the western parts of the Republic. The most significant increases in GHRR appear to have occurred during the warm part of the year (June–July), after > 40 mm rainstorms.