Soil erosion is the detachment and movement of soil particles by water, wind, or ice. It is a natural geological process that is accelerated by human land use, particularly agriculture, deforestation, and construction. Erosion removes the nutrient-rich topsoil that sustains plant growth, reduces water-holding capacity, and can lead to sedimentation of waterways. Effective erosion control strategies combine vegetative, structural, and management practices to protect soil from the forces of erosion.
Water erosion occurs in several forms. Sheet erosion removes a thin, uniform layer of soil from the surface. Rill erosion creates small channels that can be smoothed by tillage. Gully erosion forms larger channels that cannot be repaired by normal tillage. Streambank erosion removes soil from the edges of waterways. Wind erosion, most common in arid and semi-arid regions, removes fine particles and can transport soil over long distances. The Dust Bowl of the 1930s remains the most dramatic example of wind erosion in North American agricultural history.
Vegetative methods include planting cover crops, maintaining permanent grass waterways, and establishing windbreaks or shelterbelts of trees and shrubs. Contour farming, where tillage and planting follow the natural contours of the land, reduces runoff velocity and increases water infiltration. Terracing creates level steps on sloping land to trap water and prevent downslope flow. Keyline design uses subsoil ripping along the contour to improve water infiltration and reduce runoff. No-Till Gardening farming leaves crop residues on the surface, protecting soil from rain impact and reducing erosion by up to 90 percent compared to conventional tillage.
Riprap, retaining walls, and check dams are used in areas with concentrated flow. Grassed waterways convey runoff from fields without eroding. Silt fences and sediment basins trap soil on construction sites. Land restoration projects may use bioengineering techniques such as live staking and brush layering. Cover Cropping combined with contour farming provides an effective year-round erosion control system.