This is the washing away of top soil by agents like water or wind.

 

The lowlying valleys where the eroded soil is deposited becomes fertile at the expense of an expanse of farmland along hillsides.

Causes of soil erosion:

Deforestation: This involves cutting down trees which would have otherwise reduced the impact of wind or rain drops that would make soil loose enough to be carried away by rain. The roots of trees would also hold soil particles into crumbs and the dead leaves that drop allow penetration of water and thus preventing run off erosion.

Poor farming methods like ploughing down the slope which creates channels through which water can easily run off; burning which not only loosens soil particles but also removes ground cover which continuously and so could lead to erosion; monocropping where only one crop is grown continuously and so could lead to erosion since there is no interplanted cover crop.

Overgrazing which removes vegetation cover and the animals' hooves which trample soil to dust that is easily blown off by wind.

Types of soil erosion:

- Sheet erosion where only thin layers of top soil are removed.

- Rill erosion where channels are cut into soil.

- Gulley erosion where large channels arise due to careless ploughing and tracks by vehicles and animals.

- Raindrop (splash) erosion caused by the force of rain drops.