[Geog] 點解soil erosion會導致desertification?

Soil erosion will lead to loss of surface soil underdischarging of water. (Surface run-off). Since the surface soil contains mostof the nutrients, that is the most fertile soil is being washed away.
As a result, the nutrient content of the soil decreases. (Thefertility of the soil decreases). So it will lead to degradation of soil. Sothe vegetation in the region decreases.
Also, less vegetation leads to less interception, less infiltration,more surface run-off, less transpiration. The water level of the region islowered, and the water content in the region decreases.
Therefore, the environment unfavours the growing ofvegetation. As a result, desertification occurs.