Soil erosion is a common process in which soil and soil are destroyed by streams and streams of melt, rain, rain and irrigation water or by winds. The harm from such an impact is huge. Soil erosion has already removed 2 billion hectares of agricultural land, including arable land (50 million hectares).
The soil is a self-healing system, however, it will take 300-1000 years to repair a damaged layer 2.5 cm thick.
Types of soil erosion are water and air (deflation).
Erosion forms holes that make soil cultivation difficult; creates ravines, while reducing the area of land for crops; destroys roads, poured agricultural land. On the upper surface of short slopes, the chernozem layer is significantly reduced or completely washed off, which affects yield.
Causes of erosion
The intensity of the occurrence of erosion processes is greatly influenced by climate, terrain, soil erosion resistance, vegetation in these areas, human activities and other factors.
Soil erosion depends on the climate, because erosion processes are amplified as a result of sharp fluctuations in temperature, amount and intensity of precipitation, wind speed and strength. From low temperatures, the soil deeply freezes, and the intensity of its thawing and melting of snow affects the rate of absorption of water into the soil, which affects the flow of water, washout and erosion.
Water erosion of soils is ravine (streaky, linear), flat and irrigation (irrigation).
If in winter the snow is drifted from the slopes by strong winds, the soil is exposed, freezes and prevents melt water from absorbing. This causes an intense flow of water.
The wind also affects the process of water erosion, because it redistributes the snow over the terrain, blows it from the slopes to ravines, beams, etc.
Deflation depends on the erosive force of the wind, starting to appear at a speed of about 12 m / s at an altitude of about 10 m above the surface of the soil.
Wind speed also depends on the vegetation cover. On treeless expanses, in the steppe, the wind speed sometimes reaches 30 m / s, and in the forest zone and forest-steppe it is less.
Precipitation can significantly weaken wind erosion, but their abundance contributes to the development of water.
The intensity of destruction is affected by the relief, steepness and length of the slopes, and the width of the watershed. The longer and steeper the slope, the greater the area damaged by erosion and the more serious its consequences.
The condition and characteristics of soils are reflected in the degree of destruction. So, qualitatively structured, chernozemic ones are characterized by friability, water permeability, and therefore the erosion and rinsing on them is much less.
Soil erosion depends on the mechanical composition of the soil. Under natural conditions of air erosion, light soil is more susceptible - sandy and sandy loam. Clay soils undergo deflation only in a loose, dusty state. Carbonate soils — chestnut and chernozem soils — are easily destroyed by wind. Solonetz soil and solonetz are wind-resistant.
Thanks to the vegetation cover, the development of soil erosion is significantly reduced or completely eliminated. The impact of raindrops is softened by dense vegetation, part of the liquid is retained on the leaves of the plants, and the grass drastically slows down the flow of water.
Soil erosion is reduced if the land is covered with perennial grasses that protect the soil from the effects of raindrops and winds, increasing water permeability.
The erosive processes are greatly influenced by the economic activities of people. With an increase in the specific weight of areas sown with row crops, the intensity of soil erosion increases.
With excessive mechanical processing of the soil, it is sprayed, which enhances both wind and water erosion. The compaction of the soil causes the passage of heavy agricultural machinery through the field, which reduces its water permeability, increases the flow of water, erodes and rinses.