What Can Erode Soil?

Wind Erosion

• Wind erosion encompasses moving air that detaches and transports particles of soil. Particles in motion can additionally dislodge other particles. Very fine particles can become suspended in the wind and transported great distances while larger particles are blown along the ground and suffer abrasion that breaks them into smaller particles. Nutrients are most closely associated with fine soil particles, so wind erosion that blows small particles off-site can greatly affect soil nutrition.

Factors That Affect Wind Erosion

• Several factors affect the rate and quantity of soil eroded by wind. Smooth, ridge-free soil surfaces offer less resistance to wind than rough, ridged land. The climate, wind speed and other wind qualities directly impact soil erosion. This also includes moisture levels as drier soils can release more particles into the wind. A lack of shelters, or windbreaks, in the landscape will increase particle abrasion and erosion. Finally, vegetation, or lack thereof, influences soil erosion by wind.

Water Erosion

• Water can erode soil in multiple ways. Erosion begins with raindrops falling on the soil surface that cause soil particles to become dislodged and splash upward before returning to the soil surface where the particles clog soil pores and reduce the soil's permeability. When more water is applied than the soil can absorb, the water will puddle and run off. The running water detaches and transports soil particles. There are three primary types of water-induced soil erosion. Sheet erosion describes the removal of a thin, fairly uniform layer of soil. Water eventually begins to concentrate in small channels, known as rill erosion. Gully erosion describes a large quantity of water that becomes concentrated and generates a large channel.

Factors That Influence Water Erosion

• The intensity of soil erosion caused by water is influenced by several factors. The intensity of rainfall and amount of runoff influence the type and quantity of soil particles removed. Soil erosion is influenced by a handful soil characteristics. Soils that contain ample organic matter and have good structure or a high infiltration rate suffer less erosion. Finally, the steepness and length of the slope and the presence or absence of vegetative cover affect the rate and magnitude of erosion.

Gravitical and Frozen-Melt Erosion

• Although soil erosion caused by wind and water are most prevalent in many landscapes and are affected greatly by human activities, gravity and the freeze-thaw process also cause the movement of soil particles. Gravity is the principle force behind mass movements of soil, such as seen in landslides, slips, slumps and flows. This type of erosion can occur quickly, as with landslides, or may be a slow-acting type of gravitical erosion known as creep. Frozen-melt, or freeze-thaw erosion, occurs where the ground and water freeze and thaw repeatedly. Water collects within and below a layer of soil before freezing and heaving the ground upward irregularly.