Spatial-Temporal Dynamics of the Ephemeral Gully Belt on the Plowed Slopes of River Basins in Natural and Anthropogenic Landscapes of the East of the Russian Plain

Oleg Yermolayev,Benedict Essuman-Quainoo,Evgeniya Platoncheva

doi:10.3390/geosciences10050167

Oleg Yermolayev, Benedict Essuman-Quainoo + Show 1 more

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https://doi.org/10.3390/geosciences10050167

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Journal: Geosciences	Publication Date: May 6, 2020
Citations: 9	License type: CC BY 4.0

Affiliation: Kazan Federal University

Abstract

Erosion is the leading process of soil degradation on agricultural land. In the spectrum of erosion processes, the most unfavorable for soil degradation are the processes of linear (ephemeral and gully) erosion. An assessment of the dynamics of linear erosion in the intensive farming zone of the European part of Russia (EPR) is relevant due to the lack of generalized data on the development of this type of erosion in the post-Soviet period and also, due to the highest intensity of soil erosion in the ephemeral gully erosion. The development of information technologies and the availability of high-resolution and ultra-high-resolution satellite images make it possible to solve the problems of ephemeral gully erosion belts identification, and also makes it possible to trace the dynamics of development of stream erosion on arable lands over a period characterized by the greatest changes in the climate system and economic conditions in the post-Soviet period (1980s–2010s). The study was conducted on the eastern wing of the boreal ecotone of the Russian Plain within the southern border of these zones of mixed and broad-leaved forests, forest-steppe, and steppe landscapes using the basin approach. For the initial material, satellite images of medium (30 m) and high resolution (0.5–1.5 m) were used in the work. The study used methods of image interpretation such as remote sensing of the earth and geoinformation mapping. For 70 key areas (interfluve spaces of river basins), the study developed a method of geoinformation mapping of the ephemeral gully erosion belt dynamics on arable lands. In the same way, the research developed a system of quantitative indicators characterizing its development on arable slopes. The dynamics of ephemeral gully erosion was evaluated over three-time intervals: the 1980s, 2000s, and 2010s by determining the horizontal dissection (density) and density of ephemeral gully erosion. Over the past 30 years, in the direction from the south of the forest sub-zone to the forest-steppe and steppe landscapes, there was a sharp increase in the horizontal dissection and density of the ephemeral gully network: an average of 4.6 and 10 times, respectively. The ephemeral gully erosion belt advances toward the watershed because of the formation of new erosion in the upper parts of the ephemeral gully networks and its extension, while there is a noticeable reduction in the width of the erosion-weakly active belt-sheet and rill erosion.

Highlights

The formation of water and sediment runoff on slopes follows the patterns driven by the peculiarities of the slope morphology, the erosion resistance of the soil cover, and the specifics of Geosciences 2020, 10, 167; doi:10.3390/geosciences10050167 www.mdpi.com/journal/geosciencesGeosciences 2020, 10, 167 rainfall accumulation or the accumulation and spatial distribution of snow cover in combination with variability in the depth of soils freezing
Its identification is based on the following main points: (1) Surface runoff on flat watershed sections of the processed slopes is practically absent because of slopes with close to zero inclination; (2) in the top to the bottom direction of the plowed slope, the concentration of surface runoff occurs, with the only exception of the scattering type slopes, where runoff is dispersed down the slope; (3) in the same direction, a transformation of water flow is observed; (4) the dominant morphological forms of the fluvial relief, which are formed in the process of erosion-accumulative processes development on arable slopes, reflect all the changes in water flow
The dynamics of changes in the ephemeral plowing in the absence of intensive runoff and flushing, the reverse process can occur—a gradual gully level network is a good indicator of theplowing

Summary

Introduction

The formation of water and sediment runoff on slopes follows the patterns driven by the peculiarities of the slope morphology, the erosion resistance of the soil cover, and the specifics of Geosciences 2020, 10, 167; doi:10.3390/geosciences10050167 www.mdpi.com/journal/geosciencesGeosciences 2020, 10, 167 rainfall accumulation or the accumulation and spatial distribution of snow cover in combination with variability in the depth of soils freezing. Its identification is based on the following main points: (1) Surface runoff on flat watershed sections of the processed slopes is practically absent because of slopes with close to zero inclination; (2) in the top to the bottom direction of the plowed slope, the concentration of surface runoff occurs, with the only exception of the scattering type slopes, where runoff is dispersed down the slope; (3) in the same direction, a transformation of water flow is observed; (4) the dominant morphological forms of the fluvial relief, which are formed in the process of erosion-accumulative processes development on arable slopes, reflect all the changes in water flow The identification of these qualitative changes allows to establish a special type of spatial organization of fluvial forms, represented by the so-called “belts of erosion”. Each erosion belt is created by a well-defined set of slope erosion processes of various intensities and directions [1]

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Conclusion