Soil Erosion – Removal of topsoil faster than it can be replaced due to natural action (water and wind), animal and human activity

To remember the meaning of the term Soil Erosion, use the following mnemonic:

The soil man didn't stay. He rode off into the sun (soil erosion) with his animals and human help.

Top soil is eroded by animals, humans, wind and water:

The roots of trees and other vegetation in tropical rainforests help to anchor the soil, so that it is not easily washed away. 

If the ground is cleared, there is no longer anything to keep the soil intact and it can be washed away by rain. When soil is washed into rivers, it can cause major problems for creatures in the rivers and for people who depend on the water for drinking and livelihood.