Displacement of soil particles (erosion)
Soil erosion is a special type of land degradation as it involves displacement of soil particles. Soil particles are detached by the impact of raindrops or wind, transported, and deposited away from their origin.
- Soil erosion by water
Involves the removal of soil particles by the action of water. Usually seen as sheet erosion (a more or less uniform removal of a thin layer of topsoil), rill erosion (small channels in the field) or gully erosion (large channels, similar to incised rivers). One important feature of soil erosion by water is the selective removal of the finer and more fertile fraction of the soil.
- Soil erosion by wind
Involves the removal of soil particles by wind action. Usually this is sheet erosion, where soil is removed in thin layers, but sometimes the effect of the wind can carve out hollows and other features. Wind erosion most easily occurs with fine to medium size sand particles.