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4AGRICULTURAL SCIENCES
ASSESSMENT OF FACTORS AFFECTING THE POTENTIAL RISK OF EROSION OF MOUNTAINBLACK AND MOUNTAIN-BROWN SOILS SPREAD IN THE TERRITORY OF GADABAY
DISTRICT
Aliyev B.
doctor of technical sciences, professor
Hajiyev T. dissertant
National Aerospace Agency (NASA) Institute of Ecology DOI: 10.5281/zenodo.6532491
Abstract
It is necessary to identify and assess erosion-prone soils in order to properly prepare measures to protect soils from erosion. This issue is of particular importance in connection with the intensification of agricultural production and more efficient use of land in other areas of production. In mountainous and foothill areas, the most eroded lands are used for agricultural purposes. Therefore, in connection with the further intensification of agricultural production, these areas require special consideration.
Keywords: Soil erosion, relief, natural factor, digital map, spatial analysis, surface flow.
Introduction. The protection of the soil surface from the effects of erosion is one of the most important issues in the conditions of surface runoff of mountain slopes.
The complexity of the country's relief, as well as the diversity of soil-forming factors, lead to erosion and the spread of large areas. It has been determined that at present 43.3% of the country's lands are subject to erosion [1]. As in all mountainous areas, erosion is widespread in the northern part of the Lesser Caucasus.
In modern times, the pace of development of any economic region is directly proportional to the intensity of natural changes in this territory. One of the main problems facing the geographers is to quickly apply the map to the rapidly evolving process. It is no longer possible to ensure such efficiency by classical methods. The best way to do this is to use remote sensing data and GIS technology [2]. Modern geographic information technologies (GIS) are used to determine the risk of all types of erosion, protect soils and predict future complications.
Over time, when studying and analyzing spatial (spatial) data, it becomes necessary to apply new methods for obtaining results (collecting and storing information) that meet modern standards and their effective use. It is the approach to the ecological state of emerging soils from the point of view of erosion hazard that plays a key role in identifying natural and anthropogenic impacts, accompanied by significant changes not only in quantity, but also in quality. In this
regard, the small detail of each soil sample obtained should be considered an important quantitative indicator for future forecasting. According to the famous American theorist Turner, the importance of such an approach in preventing the erosion process is undeniable [3]. The high elevation of the existing relief and the steepness of the slopes are the main factors that create favorable conditions for the occurrence of erosion processes. One of the main morphometric indicators of slopes is the exposure. It characterizes the degree of solar energy supply of the slopes and affects almost all areas of agriculture in the local area.
Research object and methodology. Mountain-brown and mountain-black soils, formed in different expositions of the northern slope of the northern part of the Lesser Caucasus, were taken as the object of study. The degree of soil erosion at the object of study was determined on the basis of a comparative geographical method proposed by K.A. Alekbarov, and the determination of morphogenetic features by Sh.G. Gasanov [4,5].
Analysis of results. The terrain model DEM (Digital Elevation Model) was created using GIS technologies. The created digital height model combines the following procedures. The first stage includes scanning of topographic maps and geographic closure in the coordinate system, digitization of the map, creation of vertical and isotopic vector layers, electronic design of topographic maps at a scale of 1:100,000. (Picture 1).
Picture 1. Digital altitude model of Gadabay district
At the next stage, it is very quick and easy to create a map of exposure and slope rates based on GIS technology with the help of the DEM model. Different characteristics of the slope of the relief of the area where the soil layer is formed are widely used in geographical research. Spatial analysis of slope slopes directly confirms their connection with the geolithological and morphostructural structure of the area [6]. The relief conditions of the area have a great influence on the occurrence and development of erosion. One of the relief factors that affect the occurrence of erosion in the mountain-steppe zone is the shape of the slopes. Depending on the shape of the slopes, the direction of erosion and the impact force change rapidly. Depending on the relief forms on complex slopes, the erosion process also proceeds in different directions. As the length of the slopes increases, the mass of water increases, resulting in the destructive energy of the water flow. Erosion is stronger on flat and convex slopes. In the lower parts of such slopes, the risk of soil erosion is greater. However, on gentle slopes, most of the topsoil accumulates at the
bottom of the slope as the slope decreases downstream of the watershed. As sloping areas are replaced by steep slopes on steep slopes, the effect of erosion is drastically reduced, i.e. terraces reduce or stop surface water runoff and erosion.
Researches conducted in the Gadabay district showed that along with surface erosion, linear erosion also developed intensively. This is due to the relief of the area, especially the presence of mountain plateaus (Slavyanka, Duzyurd, Bashkend and others). Thus, on the territory of 1 km2 around the village of Gadabay there are small ravines and pits 10 km long. Active landslides are more pronounced on slopes at altitudes of 1000-2000 m. This is due to the diversity of lithological composition of the rocks that make up these slopes and the large amount of atmospheric sediment. The exposition of the slopes determines the flow of sunlight (radiation) to the earth's surface, determines the microclimate of the slopes, the development of vegetation, productivity, erosion and washout (Picture 2).
Picture 2. Exposition map of Gadabay region
The southern and western slopes erode faster than the northern and eastern slopes. Temperature and humidity fluctuate more on the southern exposition slopes than on other slopes. In summer, the southern exposition slopes become hotter and drier, the process of humus formation is disrupted due to the rapid destruction of vegetation on these slopes, and the amount of humus in the soil gradually decreases [7]. From this point of view, the humus and soil layer is less on the southern exposition slopes, and the sparseness of the vegetation in the fields increases. All this increases erosion on these slopes, causing soil erosion and a sharp decrease in fertility. The exposure map of the slopes, compiled in electronic form, allows you to analyze the spatial patterns of illumination of the area. This makes it easier for us to assess the conditions of landscape formation in terms of heat supply. The first approach reflected the proportional duration of direct exposure to sunlight. The processing of the obtained data makes it possible to compare and compare areas, to find patterns of spatial expansion on them.
In the obtained digital maps, each selected area is assigned a serial number. The parts are then grouped by major types. According to the exposition, the slope is divided into two types - cold and hot. Transitions are considered moderately cold and moderately warm. Cold and moderately cold slopes prevail. On the northern slopes, landslide and denudation processes predominate; on the southern slopes, the processes of
surface and linear erosion are accelerated. Due to the sparse vegetation of the southern slopes, well warmed by the sun's rays, the soil layer can partially retain its structural composition without being completely washed out by atmospheric sediments. The strongest erosion is observed on the southern and very gentle eastern and western slopes, since the vegetation on these slopes is so sparse that it cannot prevent the destructive effects of precipitation and surface runoff. Therefore, the soils on these slopes are very skeletal, and rocks often come to the surface.
It should be noted that in the eroded areas of the study object, the arable soil layer was erased, the profile was shortened and degraded. The structure of the soil on arable land was sharply disturbed, and the subsoil was strongly compacted. In such areas, the roots of crops, especially potatoes, are poorly supplied (gas exchange), making it difficult for them to breathe, resulting in low quality products [8]. Erosion has intensified due to the lack of improvement of hayfields, as well as unsystematic and excessive grazing of these areas after hay harvesting, as a result of which the grass cover of hayfields has significantly thinned out and productivity has decreased. Pastures in the surveyed area have fallen into disrepair. There are practically no non-eroded soils on pastures. Erosion in the mountainsteppe zone is widespread in all areas of natural economy and covers a very large area. All types of erosion occur here. (Picture 3).
Picture 3. Soil erosion map of Gadabay district
Water erosion is more common on sloped crops. This is due to the fact that plowing, sowing, sowing and tillage are often carried out along the slope. This makes it possible to form a surface runoff of water and easily wash out fertile soil particles along the slope [9]. With prolonged planting of plants in the same area, especially tilled crops, the topsoil loses its structure more, and in such crops erosion becomes more frightening, and in some areas the parent rock comes to the surface. In mountainous areas, hayfields and pastures have also become badly damaged as a result of erosion. It should also be noted that erosion is caused by natural and anthropogenic factors. Natural factors include relief, climate, soil and vegetation of the area, anthropogenic - types of human economic activity.
Result. Based on the maps of exposure and slopes, it was found that most of the area is at risk of moderate to severe erosion. Taking into account the characteristic features of the terrain where the object of research is located, it can be seen that the areas where the erosion process proceeds intensively are located mainly on the northern and western slopes. Especially on the northern slopes, low temperatures throughout the year lead to an increase in relative humidity, and the latter leads to rotting of the grass cover. It is concluded that sufficient soil moisture in the spring-autumn period causes its aggravation and increased plasticity, and the latter leads to large-scale landslides.
References
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