What causes soil erosion in different environments?
Written by
Kiana Okafor
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Soil erosion occurs through various mechanisms in different environments, depending on specific combinations of natural forces and human activities. In rainy climates, water is the dominant eroding force. At the same time, wind domination occurs in areas characterized by a lack of moisture. Human actions (particularly construction) accelerate the processes of erosion greatly compared to normal rates of erosion.
Agricultural Areas
- Water runoff on unprotected slopes during planting seasons
- Wind action across over-tilled fields with loose topsoil
- Removal of ground cover during harvest periods
- Heavy machinery compaction reducing water absorption
Coastal Regions
- Wave action removing shoreline sediments daily
- Storm surges during hurricanes eroding dunes rapidly
- Saltwater intrusion weakening soil structure
- Reduced vegetation from higher salinity levels
Urban Developments
- Construction activities stripping protective vegetation
- Stormwater runoff from impervious surfaces like roads
- Excavation for utilities destabilizing soil layers
- Compaction from heavy equipment reducing drainage
The rain regime has a marked effect on the erosion process. Tropical regions experience torrential rains, which wash the soil away quickly. In arid areas, the rains are usually irregular but very heavy, sufficient to transport large quantities of material. In Mediterranean countries, the intensity of erosion becomes marked during the winter rains that follow the dry summer and autumn periods.
Soil composition determines vulnerability. Sandy soils lose soil easily to the wind but drain well. Clay soils resist wind erosion but crust over, causing water runoff. Loamy soils, with a well-balanced texture, will hold their structure best. Organic matter below 2% in any soil type will make it very susceptible to erosion.
Slope gradients exponentially increase erosion potential. Flat lands lose soil slowly through sheet erosion. Moderate slopes experience rill erosion, forming small channels. Steep slopes can develop gully erosion, causing tons of soil to be moved quickly. I've measured 10 times faster erosion on 30-degree slopes compared to flat terrain.
The common cause of vegetation destruction remains intact. Forests lose their underground root network, which holds soil in place, when they are clear-cut. Grasslands lose their vegetative cover and become subject to erosion if they are grazed to less than 50% cover. Urban development removes plant cover. Universal prevention involves maintaining a constant vegetation cover.
Read the full article: 10 Soil Erosion Prevention Methods That Work
