Wearing down of topsoil is known as soil erosion.
Topsoil is the most fertile since it contains the most organic materials.
Winds transport a large number of small soil particles and sand from deserts, scattering them over surrounding cultivated fields, reducing fertility.
This type of erosion is known as wind erosion.
It takes place in and around all desert regions of the world.
In India, over one lakh kilometers of land is under the Thar Desert, spread over parts of Gujarat, Haryana, Punjab and Rajasthan states.
These areas are subject to intense wind erosion.
Water when moves as a sheet take away thin layers of soil.
This type of erosion is called sheet erosion.
Such type of erosion is most common along the river beds and areas affected by floods.
In the long run, the soil is completely exhausted due to the removal of topsoil and becomes infertile.
Running water removes surface material of soil.
Running water creates many tiny channels (rills) a few centimeters wide, most of which only carry water during storms.
When water flows down the slope as a channel, it scoops out the soil and forms slowly growing gullies, spreading across a large area in the long run.
This type of erosion is called gully erosion.
The land thus dissected is called Bad Lands or ravines.
In India, the two rivers Chambal and Yamuna are famous for their ravines in U.P. and M.P. states.