It damages soil because when soil erosion moves the soil it can also break it. Sometimes with soil isn't that strong enough and then it breaks and dissolves in water.
The uppermost layer of soil is loose.when wind blows,it can carry away topsoil.when rains fall and water flows on the land,much topsoil is carried away.erosion by wind and water removes much of the topsoil.
One of the major causes of soil erosion is deforestation. In the absence of trees, the rain water washes away the fertile top soil. Further when it rains, the rain water flows away as surface run-off and then is not available as ground water. Wells dry up or have to be dug deeper. The land is thus laid bare and not suitable for cultivation or plantation. The wind is also responsible for the spread of desert. It blows the sand of the desert to the surrounding areas and the desert spread.