Soil erosion is simply the carrying away of the soil by various agents, like rain water or wind. It could also be defined as the wearing away of soil/the topmost, fertile layer of soil which makes the soil unfertile.
Soil pollution is the pollution of the soil. It is mainly because of human interference.
Soil erosion could be prevented by planting more trees, planting trees on embankment, etc, . Where as soil pollution can be checked by the less use of plastic substance which spoil the fertility of the soil.