Sat, November 4, 2017 at 11:39 am GMT
Soil erosion is a process of detachment and transportation of soil by natural agencies of water and wind.
There are many factors which influence the process of soil erosion;
1. Rainfall:
Precipitation is the most forceful factor causing erosion. Erosion is dependent on the amount, duration, intensity and frequency of rainfall. By the action of dashing rain drops on soil, soil granules are loosened, detached and separated into fine particles. Erosion is greater where the rainfall is not only heavy, but concentrated over short periods.
2. Slope of Topography:
The slope accelerates erosion as it increases the velocity of the flowing water.
3. Vegetation:
The vegetative cover protects the soil from the beating and dispersing action of the raindrops by forming a canopy over the soil surface. Vegetation also acts as a mechanical obstruction to flowing water, thus reducing its erosive potential. The plant roots help in building a better structure. They said in opening the soil and thereby accelerating water absorption and reducing surface run-off.
4. Tillage:
The infiltration and permeability of the soil is improved by the
practice of proper tillage and thereby reducing the chances of erosion. But excess tilling exposes the soil to erosion, especially by wind.
5. Nature of the Soil: Erodability of the soil is influenced by the nature of the soil, particularly its texture, structure, organic matter, amounts and kinds of salts present, presence of hard pan in the soil and presence of high water table.
6. Soil Moisture:
The presence of high water table checks the infiltration and permeability, thus allowing more flow of water on the surface, and greater erosion. At the same time, long continuous rain less periods cause loosening of soil and thus expose the soil to erosion by wind.
7. Wind Velocity:
Stronger winds have greater erosive potential, thus wind velocity is directly proportional to intensity of erosion.
The causes of soil erosion are directly related to improper landuse, and are, therefore, entirely man-made.
These include the following:
1. Deforestation:
Removal of vegetation cover has caused widespread erosion in Western Ghats,
2. Faulty Cultivation Methods:
For instance, in the Nilgiris, land has been opened for cultivation of tuber crops like potatoes and ginger without undertaking anti-erosive measures like terracing of slopes. Also forests on slopes have been cleared at places to make way for plantation crops. Such faulty cultivation methods have caused soil erosion—landslides are a common feature in these areas. 3. Shifting Cultivation:
4. Overgrazing:
A surplus of livestock population in our country is a big strain on grasses and fodder. The tread of cattle hardens the soil and prevents new shoots from emerging.
5. Diversion in Natural Drainage Channels by Railway Embankments and Roads:
Railway tracks and roads have had to be constructed in such a manner that they are at a higher level than the surrounding area. But sometimes, road and rail embankments come in the way of natural drainage channels. This causes waterlogging on one side and water loss on the other side of embankments. All these factors contribute to erosion in one way or the other.
6. Lack of Proper Surface Drainage:
Because of proper drainage, waterlogging occurs in low lying areas which loosens the top-soil and makes it prone to erosion.
7. Denuding Forest Fires:
These fires, sometimes natural but often man-made, are very destructive. As a result of these, the forest cover is lost forever and soil is exposed to erosion.
Effects of Soil Erosion:
The main effects of soil erosion are as follows.
1. Loss of Soil:
2. Harmful Effects of Erosion on Organic Matter and Soil Structure:
3. Decline in Soil Capacity:
4. Deposition of Sand and Gravel on Agricultural Lands:
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