Soil Erosion

Soil erosion is one of the most important process that leads to soil degradation.

Simply Erosion is a process that transforms soil into sediment.Soil erosion can take place wither by naturally or due to the influence of human activities. 

Geologic erosion occurs naturally where there is no influence of human. It is a natural process. We see canyons, buttes, river valleys, deltas. These are the result of geological erosion and deposition. 

The rate of geological soil erosion varies greatly with both rainfall and type of material comprising the regolith.

Accelerated erosion occurs when human disturb the soil or the natural vegetation by grazing livestock, cutting forest, plowing hillsides or tearing up land for construction purposes. Around 4 billion Mg of soil moved annually by soil erosion only in USA.

Soil erosion is mainly caused by two natural forces. Water and Wind.

Generally in arid and semi arid regions, erosion occurs due to the force of wind whereas in tropical and subtropical regions, erosion occurs due to the force of water.

Erosion by wind

When the momentum of velocity of wind is more than the stability momentum of soil particles, the particles start moving and saltation occurs. In this way wind can carry particles to one place to another. The blowing sands may bury roads and fill the drainage ditches. The sandblasting effect of wind borne soil particles may damage the fruits and foliage of crops in fields.

Erosion by water

Soil erosion by water is generally a three step process:

• Detachment of soil particles from the soil mass.
• Transportation of the detached particles downhill by floating, rolling, dragging and splashing.
• Deposition of the transported particles at some place lower in elevation.

The kinetic energy of raindrop causes most of the detachment. Where water is concentrated into channels, the cutting action of turbulent flowing water detaches soil particles.

 

Do you know why sediment-laden water has more cutting capacity than sediment free water?

Sediment-laden water has more frictional force than sediment free water. Due to having more frictional force, sediment-laden water creates more friction which is responsible for further detachment.