World Applied Sciences Journal 29 (3): 453-459, 2014 ISSN 1818-4952 © IDOSI Publications, 2014 DOI: 10.5829/idosi.wasj.2014.29.03.13868

Erosion Processes of the Forest and Forest-Steppe Zones in the Eastern Part of the Russian Plain

Oleg Petrovich Yermolaev

Kazan Federal University 18 Kremlevskaya St., 420008, Kazan, Russia

Abstract: This article analyzes a complex of erosion processes at the slopes of river basins in an extensive region of Russia-the eastern part of the Russian Plain (area of about 150 000 km2 ). This region with forest and forest-steppe landscape has large number of arable lands. We are analyzing processes of soil and gully erosion in this region. The river basin is taken as an area unit (more than 3000 m). Indicators were implemented in order to perform integrated estimation of basin erosion. The general method used for spatial analysis is a geoinformational mapping method.

Key words: Soil erosion Gully erosion Basin erosion GIS-technology Demarcation River basins

INTRODUCTION were on a small geographic scale. Lots of materials were outdated and do not reflect the current erosion Today the slope erosion which takes place in the occurrence during the past couple of decades. conditions of arable land in forest, forest-steppe and steppe areas of Earth is the main factor of pedosphere MATERIALS AND METHODS degradation. Erosion that takes place on agricultural and pasturable slopes of river basins is a natural The soil erosion assessment has been conducted anthropogenic process which is quite intensive. Besides, using the medium-scale maps (1:200 000) constructed on the nature of spatial organization of the effect itself is the basis library materials of Giprozems in accordance with changing: its structure in the river basins of natural regional erosion maps (on the scales of: 1:10 000, 1:25 000, landscape changes from a local areas to belt structures 1:50 000). Most reliable sources of information on the (“erosion belts”) in natural-anthropogenic landscapes spatial extent of soil erosion on the crop lands of the [1, 2]. Russian Federation (and former USSR) are the thematic The main goal of the studies was to identify patterns maps. Complete soil erosion mapping of arable lands in spatial development and functioning processes of within the borders of state farms has been performed natural anthropogenic erosion on the slopes of small earlier according to the government program. These rivers in the east of the Russian Plain using geo- investigations were on the basic scales of 1:10 000 and informational technologies. 1:25 000, depending on the investigated area. All soils The eastern region of the Russian Plain was our area are subdivided into three key categories: slightly eroded, of choice due to a wide range of erosion processes. moderately eroded and severely eroded. Main emphasis is placed on the processes of soil and This analysis used the basin approach. During the gully erosion. Basin erosion was evaluated integrally in quantitative erosion assessment we used the total of 3331 accordance with the development of gullies and eroded minor river basins with an average area of 39 km2 . soils in catchment basins of lesser rivers within the Generally these were the basins of the 3rd tier rivers. territories of Tatarstan, Chuvashiya, Mariy-El and Methodology used in the basin approach gives the best Ulyanovskaya region (total area of about 150 000 km).2 picture on spatial organization of slope erosion Analysis of collected materials related to the erosion processes [2, 3, 4, 5, 6, 7 etc.]. This technique allows us to process of soils in the east of the Russian Plain shows reliably identify spatial-temporal relations of the process that the studies performed through the areas of the region on the regional and global generalization levels due to

Corresponding Author: Oleg Petrovich Yermolaev, Kazan Federal University 18 Kremlevskaya St., 420008, Kazan, Russia.

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the specific source materials presentation. The GIS- where -is the soil erosion indicator; 1, 2, 3-slightly, technology method has been used as the main method for moderately, severely eroded soils respectively, km2 ;-areas spatial analysis and creation of thematic maps: erosion of farming lands, km2 . and demarcation. Additionally a specialized erosion geo- informative system was created which contains vector Basin Erosion Indicator (BE): Was created using the soil “layers” of river basins borders, drainage system, eroded erosion data and density of gully breakdown. The final soil contours, gully density, forest density, arable land formula of the indicator is: zones, as well as hydro-climatic, geo-morphological and other types of indicators [8, 9]. Overall geo-informational (2) database for spatial analysis contains more than 50 parameters. where Áî - basin erosion indicator; Ã -density of gully Several indicators that characterize soil and basin erosion (km/km2 ); 0,3-weight factor, units of measurement: erosion are given in order to perform quantitative analysis km. and acquire spatial erosion data [1, 2]. In our opinion it is better to use this indicator during the quantitative assessment of basin erosion Soil Erosion Indicator (SE): Area (in km2 ) has been as it reflects nearly a full range of erosion processes determined for each category of eroded soil. SE data was that take place on the slopes of river valleys. In fact input into the program database. The ratio of arable zones SE prevails on the fields located beyond the borders has been calculated for each basin and it matches a of gully systems. Here soil coverage gets destroyed certain category of eroded soils. The sum of slightly by sheet erosion and rill erosion. Here the slightly eroded, moderately eroded and significantly eroded soils eroded soils are created due to the impact of sheet provided integral indicator of SE area development for the erosion, moderately eroded soils are formed due to specific basin. Meanwhile, conducted analysis shows that the sheet erosion and the rill erosion and severely it is not reasonable to directly use fractions of total eroded soils are created only due to rill erosion [2]. erosion during demarcation and especially during The gully density is a reliable intensity parameter of quantitative assessment of soil erosion factors. This is gully erosion in a basin. Though, weight factor has to be due to the fact that this approach does not allow us to explained. It was chosen on the assumption that gully sufficiently reflect the intensity of soil washout when we erosion intensity is an ecological disaster of a local area have the same values of total erosion. and using average-scale data on width of gullies and In connection with the abovementioned, in order percentage of gully erosion based on the total basin to estimate SE in basins we suggest using other erosion. indicator that shows not only the areas of eroded soils, It is common knowledge that intensity of gully track but the intensity of the process as well. The value erosion is very high (all subsoil and undersoil layers get coefficients for soils of different erosion categories were eroded) and the intensity of soil erosion is even higher. picked on the basis of detailed analysis of humus This is why at the first stage the weight factor was equal decrease (in t/ha) and percentage content of humus in to 30. subsoil of most common soils (sod-podzol, light-gray, However, this high intensity compared to the soil gray, dark-grey forest and chernozemic) in the studied erosion has been noticed only in the limited areas-along areas, considering their granulometric content. The the lines of gully erosion. This is why initial factor of 30 analysis of this information allows us to suggest that has been multiplied by the average gully width, in the the intensity of soil erosion from slightly washed out studied region this figure for all gully types is 0.01 km. soils to moderately and severely washed out soils The average width of gullies has been determined in changes in the ratio of: 1: 3: 5. Acquired ratio is used accordance with the data on the average area and length further on as weight factor during the assessment of SE for 7000 gullies of different types in the east of Russian intensity in the basin. Plain, this data has been collected by I.I. Rysin [10]. The The resulting index that is further used for materials regarding gully width presented by E.F. quantitative evaluation of soil erosion in river basins now Zorina are very similar to these results. The weight factor has the following formula: in the formula reflects existing relation of transferred material volumes between soil and gully erosion. This is easily shown by calculations for the mid layer gully

454 World Appl. Sci. J., 29 (3): 453-459, 2014 erosion in the Udmurtiya territory conducted by I.I. Rysin RESULTS [11]. The analysis of acquired data indicates that the mid layer of gully erosion for the whole period of gully Soil Erosion: Along the selection with farmlands (3269 development on the arable lands of the Republic is only basins) we can see the category with the majority of 0.2 mm. According to our materials on yearly soil loss at slightly washed out soil. On average this percentage is erosion belts, for a complete agricultural period, the level about 27%, where the percentages of moderately washed of soil erosion from the basin slopes is significantly out soil and severely washed out soil are 6.6% and 0.7% higher than the level of gully erosion [2]. Similar figures respectively. At the same time it has to be noted that there were acquired by other researchers [11-15 etc.]. The is an uneven distribution of spatial and intrabasin soil search for spatial patterns of erosion process erosion. For example, slightly eroded margins in the basin development as well as solution of practical tasks on can be from 0% to up to 100% of the areas, moderately development of territorial models on anti-erosion eroded margins can take up to 99% and severely margins measures is impossible without cartographic picture of can be up to 80.5%. studied natural phenomenon. Spatial development of In accordance with values of calculated soil erosion different slope erosion types is shown on the intensity indicators the studied territory has been divided corresponding thematic maps. The network of basins has into the following typological regions: 1) without been vectorised in order to construct this information farmlands; 2) very slight erosion (0,0); 3) slight erosion layer. We have to mention that despite the well-studied (0.0-0.5); 4) moderate erosion (0.5-1.0); 5) severe erosion erosion area there was yet no published maps of erosion (1.0-1.5) and 6) extremely severe erosion (>1.5) breakdown that would match the regional generalization (picture 1). level. The existing maps of separate republics and The largest group (1196 basins) contains basins that regions were constructed in accordance with legends have average and moderate soil erosion. Most of the using non-matching breakdown intervals and that areas with this level of erosion are located in the north- significantly hinders material generalization. east of Mariy-El, in the basins of rivers Bulla, Meshi,

Picture 1: Territorial demarcation in accordance with the soil erosion intensity Fig: 1.-no arable lands; 2 -very little erosion; 3-slight erosion; 4-moderate erosion; 5-severe erosion; 6-very severe erosion;

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Kazanka and interfluves of Stepenniy Zay-Sheshma and Bet’ki and lower courses of Barysh. In this region soil is Menzeli- Lesnoy Zay. Moderate erosion can be found in eroded nearly everywhere. Maximum erosion values the conditions of elevated terrain (mostly in the intervals (up to 2.01) can be found in the basins on the right bank between 180-240 m). Slopes of river valleys have an of Volga. These regions have typical horizontal average length of 1500 m and breakdown depth of 80-120 (> 2.4 km/km2 ) and vertical (>160 m) breakdown, almost m. Erosion is developing on various levels of soil solid slope plowing (> 80%), significant spring grain-size subtypes: from lixiviated and typical runoff from plowed fields with 5% probability argillaceous soils and rich argillaceous black soils to (>130 mm) breakdowns, average basin slopes (>3 light argillaceous light-grey forest and sod-podzol soils degrees), light-gray and gray forest soils of argillaceous (average humus content is 4.6%). All these basins have and rich argillaceous composition with humus content forest density percentage of 5% to 25% with slight slopes of 3.5%. of about 1.5 degrees to 2 degrees, water reserve in the snow cover is <95 mm and they have significant Gully Breakdown (Picture 2); This map has been agricultural and pasture areas (>12 %). Soil generally constructed using the database created during the contains argillaceous-loamy and argillaceous-limestone analysis of gully breakdown in the east of the Russian deposits of Tartarian and Ufa layers in upper Perm. Plain [13]. This region has developed all categories of washed out According to the map we can see that gullies are soils. Basins with severe soil erosion (552 basins) are unevenly distributed in the area. Most of the gullied located as a compact group in the basins of rivers: basins are located within the Privolzhskaya highland Tsivilya, Kubni, Ulem, Kazanka, Mesh as well as in (except for Lesnoe Zasur’e Chuvashiya) and Predkam’ya Bolzhsko-Cviazhskoe interfluves, on the right bank of Tatarstana. Here you can also find catch basins with Sura’s undercurrent, in the minor basins on the right bank maximum gully breakdown indicators: 3.87 km/km2 -4.51 Kama within the borders of Western Predkamye of the km/km2 . Most of the basins with high breakdown values Tatarstan Republic. Separate large group with severe SE (> 0.5 km/km2 ) are located in the catch basins of river contains basins that are located in the northern part of Tsivilya, Barish, Tereshka and headwaters of river Privolozhskaya highland within the borders of Cviyaga and Syzranka, in the interfluves of river Volga Chuvashkoe Predvolozhye. Highly ploughed area (61.7%), and river Silitsa and on the right bank of Toyma. Mostly low forest density (<10%), high percentage of rural the territory has very little gully breakdown (r. settlements (8.5%), which shows high agricultural impact Yushut-0.03 km/km22 , Bolshaya Kokshaga-0.012 km/km ) or on soil, here it is mostly of argillaceous and rich none at all (r. Rutka, Vetluga). There are 627 such basins. argillaceous light-grey forest subtypes with average Gullies are less developed in highly forested regions of humus content in the topsoil of 4.0%. Large areas contain Mariy El, right bank of Sura within Chuvashiya and in not only slightly washed out soils (43.8%), but moderately valley Zavolzh’e (until r. Sheshma). Also little gully washed out soils (26.5%) as well. Gully erosion here is development is typical for basins on the left bank of r. Ik significantly higher-it is about 1.5 times more than average (0.091 km/km22 ), r. Zay (0.087 km/km ), r. Mellya (0.116 breakdown density indicators (0.499 km/km2 ). Erosion km/km2 ) etc. Average density figures of gully breakdown processes take place mostly because of the terrain and were estimated using major river basins is 0.231 km/km2 . climatic conditions. Here we can find high basin slopes The map with basins erosion demarcation (Picture 3) with relatively short average length of river slopes (1150 has been constructed using on the calculated indicators m). Generally absolute heights are in the interval between and materials on the intensity of soil and gully erosion. 140-200 m (72.2%). Following things are characteristic for Minimum value of basin erosion equals to zero, maximum this region: one of the strongest spring flows in Srednee value is 2.03. The following area groups are divided in Provolzhye with 5% occurrence (122 mm), erosion accordance with basin erosion: 1) sporadic (0.0); 2) very potential of 10-minute maximum intensity precipitation is little erosion (0); 3) slight erosion (0.3-0.6); 4) moderate 11-12 units, water reserve in the snow is 95 mm, flow erosion (0.6-0.9); 5) severe erosion (0.9-1.2); 6) extremely factor is 0.23 and there are also some other factor which severe erosion (1.2-2.05). we have not included here. Severe soil and gully erosion is typical for regions Very severe erosion is common for more than 1% of with severe and extremely severe basin erosion. basins. It occurs locally mostly on the right banks of More specifically, the total erosion of soil cover is about Volga, in the basins of river Kazanka, river Bersuta, river 70%-76%. The structure of washed out soils contains

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Picture 2: Territorial demarcation in accordance with the gully erosion intensity Fig. 1-sporadic erosion; 2-very little erosion; 3-slight erosion; 4-moderate erosion; 5-severe erosion; 6-extremely severe erosion.

Picture 3: This map shows gully breakdown density in the area

457 World Appl. Sci. J., 29 (3): 453-459, 2014 washed out difference from 11% to 35%. Gully density is 13-05-41126-a. The reported study was partially supported increased from 0.396 km/km22 to 0.664 km/km . Erosion by Russian Foundation for Basic Research-RFBR- develops in the conditions of elevated terrain (from 72% research project # 14-05-00503. to up to 80% of the territory lies within the interval of 140- 240 m) with an average breakdown depth figures of 112 REFERENCES m, slope figures are relatively high (>2.3 degrees) and high anthropogenic pressure (arable lands > 60%; 1. Yermolaev, O.P., A.O. Avvakumova, 2012. settlements: 6.5%-8.4%; forest density: 19%-21%). The Cartographic-geoinformational estimation of the magnitude of soil water flow is significantly greater than spatio-temporal erosion dynamics of arable in other regions, the flow from fall-plowed land is 5% soils in forest-steppe landscapes of the and content of humus in plough-layer decreases from Russian Plain. IAHS Proceedings and Reports, 5.5% to 3.9%. 356: 332-337. 2. Yermolaev, O.P., 2004. Erosion in basin geosystems CONCLUSION of the Middle Volga (from a landscape analysis perspective). IAHS Proceedings and Reports, As a part of studies a number of quantitative 288: 60-66. indicators were implemented which can adequately 3. Walling, D.E., 1988. Measuring sediment yield from characterize the intensity of complex erosion processes river basins. In Lal, R. (ed.), Soil Erosion Research on the slopes of river basins. These figures are based on Methods. Soil Wat. Conserv. Soc., Ankeny, Iowa, various flow values, humus content and reserves that are pp: 39-73. typical for each category of eroded soils, in addition there 4. Walling, D.E., 1999. Linking land use, erosion and is a an intensity percentage for soil and gully erosion. sediment yields in river basins. Man and River It has been found out that the most convenient unit Systems Developments in Hydrobiology, for spatial analysis of soil and gully erosion process 146: 223-240. development on the regional generalization level is one 5. Joris de Vente, Jean Poesen, 2005. Predicting soil basin. This approach and application of GIS-technologies erosion and sediment yield at the basin scale: Scale made it possible to construct electronic vector erosion issues and semi-quantitative models. Original maps and new plans of erosion demarcation of the Research Article Earth-Science Reviews, Russian Plain for the first time. 71(1-2): 95-125. Quantitative analysis of basin erosion development 6. Golosov, V., 2006. Erosion and deposition processes on the territory in the east of Russian Plain indicates that in the river basins of cultivated plains. GEOS, its maximum intensity is common for highland regions of Moscow, pp: 296. broadleaved forest area and southern highland regions of 7. Collins, A., I. Foster, Y. Zang, R. Gooday, D. Lee, snow-melting zone. The intensity of basin erosion is D. Sear, P. Naden and I. Jones, 2012. Assessing reduced in the western and eastern parts. To the north “modern background sediment delivery to rivers” and south of broadleaved forest highland regions across England and Wales and its use for catchment intensity decrease is also observed. In the northern parts management. IAHS Proceedings and Reports, it is happening due to reduction of agricultural activity 356: 125-131. and in the south it is defined by development of black 8. Yermolaev, O.P., 2013. Assessment of the Suspended soils that are more resistible to washouts. This nature of Sediment Yield in the Rivers' Basin of the Russian spatial distribution is mostly due to specifics of Plain. World Applied Sciences Journal, 27 (5): 626- agricultural development in the region and soil erosion 631, 2013, Date Views 27.05.2013, www.idosi.org/ occurrence. Gully development is an azonal process as it wasj/wasj. pdf. is mostly determined by the impact of geo and 9. Yermolaev, O.P., K.A. Maltsev, V.V. Mozzherin and geomorphologic factors. V.I. Mozzherin, 2012. Global geoinformation system "Suspended sediment yield in the river basins of the ACKNOWLEDGEMENTS Earth". Geomorphology. Russian Academy of Science, 2: 50-58. The reported study was partially supported by 10. Rysin, I.I., 1998. Gully Erosion in Udmurtiya. Izhevsk: "Russian Geographical Society"-RGO,-research project # Published by Udmurt University, pp: 274.

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11. Zorina E.F., B.P. Lubimov, I.I. Nikolskaya and 14. Makkaveev, N.I. and R.S. Chalov, 1987. Features of S.D. Prokhorova, 1999. Mapping of Gullies on Erosion-accumulative Processes in Various Hydrographic Network of European Territory in Landscape Zones // Activity of Water Flows. Russia // 14th plenary interuniversity meeting on Moscow: Published by MGU, pp: 7-13. the problems of erosion, river mouth and channel 15. Maltsev, K.A., O.P. Yermolaev and V.V. Mozzherin, processes. Ufa, pp: 129-130. 2012. Mapping and spatial analysis of suspended 12. Litvin, L.F., 1998. The Factors and Intensity of the sediment yields from the Russian Plain. IAHS Soil Washout // Book: Minor rivers of Volzhskiy Proceedings and Reports, 356: 251-258. basin.-Moscow: Published by MGU, pp: 64-68. 13. Gully Erosion in the East of the Russian Plain // under the editorship of A.P. Dedkov. Kazan: Published by Kazan University, 1990, pp: 145.

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