Soil erosion is the removal of soil by forces of nature,particularly wind and water,more rapidly than the various soil forming processes can replace it.
What are the types of soil erosion?
On the basis of natural agents water and wind,which are constantly indulged in soil erosion,there are two types of soil erosion.
1- Water Erosion– During heavy rains,a lot of soil is removed by water.Run off water is responsible for much soil erosion.
If erosion continues unchecked for a long period of time,numerous finger shaped grooves develop all over the area due to silt laden runoff. The whole pattern resembles that of the twigs,branches and trunk of a tree.This is called Rill Erosion.
With further erosion of soil,the rolls may deepen and become enlarged and are ultimately turned into Gullies.The cutting of soil goes to immense size and volume and the entire area may get turned into badland topography.
When a gully bed cuts into soil with a immediate drop of 3 to 4 metres and gradually flattens out,a Ravine is formed.
When the entire top sheet of soil is carried away by water or by wind,leaving behind bare rocks,it is called Sheet Erosion.Sheet erosion is particularly harmful because it attacks the top soil and renders the land almost unfit for cultivation.
The slope of the land is an important factor in determining the velocity of water and the consequent soil erosion.Other things being equal,the steeper the slope,the more rapidly does the water run down resulting in more soil erosion.
In coastal areas,tidal waves dash along the coast and cause heavy damage to soil.This is called Sea Erosion.
In the higher reaches of the Himalayan region,soil erosion on a large scale is caused by glaciers.This is called glacial erosion.
2-Wind Erosion–Winds blowing at considerable speed,remove the fertile,loose soil leaving behind a depression devoid of top soil.Wind erosion is aggravated when the soil is dry,weekly aggregated,devoid of vegetation cover along with over grazing.
What are the Human factors responsible for soil erosion?
Man’s ill judged activities such as deforestation,overgrazing and faulty methods of agriculture such as wrong ploughing,lack of crop rotation and practice of shifting cultivate, have made soil erosion a serious national problem.Besides, diversion of natural drainage courses, wrong orientation of roads and railway lines,embankments and bridges have also led to soil erosion.
What are the effects of Soil Erosion?
Few adverse effects of soil erosion include:
1- Top Soil gets eroded which leads to loss of soil fertility and fall in agricultural productivity.
2- Natural Vegetation Cover dries up and arid lands expand.
3- Ground water level gets lowered,and soil moisture decreases.
4- Frequency and Intensity of floods and drought increases.
5- The incidence and damaging power of landslides increases.
How it can be contained?
Few mitigation steps which can be taken to curb Soil erosion are as follows:
1- Afforestation– Planting more and more trees would lead to lesser Soil Erosion.
2-Changing agricultural practices would help in containing soil Erosion.These include crop rotation,strip cropping, contour ploughing, terracing, checking shifting cultivation, ploughing the land in right direction.
3-Checking Overgrazing– Grazing should be controlled and new pastures should be developed.