What are the causes of increased soil erosion?
1 Answer
Mostly deforestation that exposes the soil to heavy rainfall.
Explanation:
Deforestation is the main cause of increased soil erosion, especially in tropical countries. Trees and understory vegetation provide a "soaking" capacity that allows rainfall to slowly seep into groundwater. Vegetation also provides an anchor to soil that inhibits erosion.
In the image below, we can see that the roots of the tree extend into the topsoil and the subsoil, helping to secure the tree in place but also keeping that topsoil layer in place.
So, when you deforest an area you lose the soaking aspect and the soil becomes more prone to erosion.
Drought conditions often bring intense winds that can make soil erosion worse - this seems to be happening more often in the south west dry areas of the U.S.
Other contributing factors to soil erosion include: extensive livestock grazing that kills stabilizing grasses, human recreational activities, extensive farming (especially in hilly terrain, without contour plowing).
Increased rainfall or severe rainfall events are also another factor. See pic of soil erosion in the U.K after a heavy rain. Heavy rainfall events seem to be happening more frequently around the world and scientists believe this is due to global warming. So, as the Earth warms, soil erosion could become an increasing problem - especially if deforestation continues. A double whammy!
