Removal of soil material naturally or by human action is called soil erosion. The soil erosion of three types: 

(i) Wind erosion.

(ii) Sheet erosion and 

(iii) Gully erosion.

1. Wind Erosion: Wind carries away vast quantities of fine soil particles and sand from desert and spread over the adjoining cultivated land and thus destroy their fertility. This type of erosion is called wind erosion.

2. Sheet Erosion: Water when moved as a sheet takes away these layers of soil. This type of erosion is called sheet erosion.

3. Gully Erosion: When water moves as a channel down the slope it seeps out of the soil and forms gullies which gradually multiply and in the long run spread over a wide area. This type of erosion is called gully erosion.

Methods to conserve soil: There are various methods to conserve soil:

1. Protection of forests: The trees hold the soil material together. It is desirable to protect them from falling. This has led the government to declare the forest as reserved and cutting of trees has been banned.

2. Afforestation: Planting of trees along rivers conserves waste lands, reducing the excessive erosion taking place in this region. Afforestation is also effective in controlling wind erosion along the desert regions.

3. Flood control: During the rainy season floods are frequent which causes erosion of soil. Dams are built to control the floods and consequently the soil erosion.

4. Planned grazing: Over grazing on hill slopes helped wash away the soil. Grazing of animals will be carried out in the planned way which will check the soil erosion.

5. Bunding: Construction of bunds are applied in lands affected by gully erosion. This method is not only helpful in controlling soil erosion but maintaining soil fertility also.

6. Terracing: Terracing refers to the construction of terraces across the slope in a mountainous region. This will help in controlling soil erosion.

7. Adaptation of strip farming: This method is most suited on raising plains and regions suited in arid and semi-arid regions. Fields are divided into strips for farming and alternative strips are used for farming.

8. Contour ploughing: This method is most suited for soil conservation. Ploughing along the contour level in order to cause furrows to run across the landscape reduces the rate of soil erosion.

9. Crop rotation: It is also an important method to check the soil erosion. In this method crops are cultivated in rotation. This method is applied in most of the countries.

10. Reclamation of Lands: Soil erosion is also being controlled by levelling lands gullied down by water. This method of soil conservation is most suited in river basins and hilly terrains.