What is Soil Erosion ? Describe two types of soil erosion? (4 marks)
Answers
Explanation:The loss of soil cover due to natural agents like wind and running water is called soil erosion.
Types of Soil Erosion :
(a) Water Erosion : Water is a powerful agent of soil erosion. Following are the major types of erosion caused by water.
(i) Sheet Erosion : When the top layer of the soil is removed over a large area by the running water, it is called as sheet erosion.
(ii) Rill Erosion : This is the second stage of sheet erosion. If erosion continues unchecked for a sufficient time, (rills) or small finger-shaped grooves which are a few centimetres in depth, may develop on the landscape. Over a period of time, the fine rills increase in number and also become deeper and wider, and resemble the twigs, branches and trunk of a tree. This is called as rill erosion.
(iii) Gully Erosion : This is the third stage of sheet erosion. With further erosion of the soil, the rills may deepen and become enlarged, and are ultimately turned into gullies. The main cause of gully erosion is the removal of vegetation, particularly of trees with their widespread binding roots. Gullies cut up agricultural land and the entire area may be turned into a bad land topography. Gully erosion is also responsible for the formation of ravines.
(b) Wind erosion : Wind is a powerful agent of erosion in arid and semi-arid lands with little rainfall. Wind can lift the valuable top soil from one area and deposits in another area. The wind erosion is very dangerous type of erosion because due to wind most of the deserts of the world are expanding.