Wind erosion

• Wind erosion is a process in which soil particles on the land surface are lifted and blown off as dust storms.
• When the velocity of the dust bearing winds is retarded coarser soil particles are deposited in the forms of dunes and thus fertile lands are rendered unfit for cultivation.
• Wind erosion takes place normally in arid and semi-arid areas devoid of vegetation, where wind velocity is high.

Mechanism of wind erosion

• Wind is responsible for three types of soil movement in the process of wind erosion. They are known as i) saltation ii) surface creep and iii) siltation.

i) Saltation:

• The major portion (50-75 % of the total wind erosion) of the soil carried by the wind is moved in a series of short bunches called saltation.
• The soil carried in saltation consists of fine particles ranging from 0.1-0.5 mm in diameter.
• Saltation is caused by the direct pressure of wind on soil particles and their collision with other particles.
• After being pushed along the ground surface by the wind, the particles leap almost vertically in the first stage of saltation. Some grains rise only a short distance; other leap 30 cm or higher, depending directly on the velocity of the rise from the ground.

ii) Surface creep

• Soil particles larger than 0.5 mm in diameter but smaller than 1.0 mm are too heavy to be moved in saltation but are pushed or spread along the surface by the impact of particles in saltation to form a surface creep.

iii) Suspension

• Very fine soil particles, less than 0.1mm in diameter, are carried into suspension, being kicked up into the air by the action of particles in saltation. The movement of fine dust in suspension is completely governed by the characteristic movement of wind.
• Suspension material is carried long distances from its original location and is thus a complete loss to the eroded area, where the soil moved in saltation and surface creep usually remains within the eroded area, especially when erosive winds are from different directions.