SOIL EROSION

Soil erosion is the removal of top layer of soil by human activities or other factors.Soil erosion is a naturally occurring process that affects all land forms. In agriculture, soil erosion refers to the wearing away of a field's topsoil by the natural physical forces of water and wind or through natural forces usually by human activities.

Erosion occurs by many activities like water, wind etc. But it mainly involves three distinct actions – soil detachment, movement and deposition. Topsoil, which is high in organic matter, fertility and soil life, is relocated elsewhere "on-site" where it builds up over time or is carried "off-site" where it fills in drainage channels. Soil erosion reduces cropland productivity as well as fertility and contributes to the pollution of nearby rivers, lakes etc.

Soil erosion can be a slow process that continues relatively unnoticed or can occur at an alarming rate, causing serious loss of topsoil. Soil compaction, low organic matter, loss of soil structure, poor internal drainage, salinisation and soil acidity problems are other serious soil degradation conditions that can accelerate the soil erosion process.

There are various types of erosion but the common ones are listed below.

•  Water induced soil erosion

1.Sheet erosion: 

Uniform removal of a thin layer of soil

from a large surface area due to run-off water

2.Rill erosion: 

Rapidly running water due to heavy

rainfall produces finger-shaped grooves or rills over

the area.

3.Gully erosion:

 Due to very heavy rainfall, deeper

cavities or gullies are formed in the shape of U or V.

It’s more prominent type of soil erosion

4.Slip erosion: 

Mainly found on slopes of hills and

mountains due to heavy rainfall

5.Stream bank erosion: 

In heavy raining session the

fast running stream take a turn in another direction,

cut the soil and make a cave in the banks.

• Water induces soil erosion

1. Saltation: 

Light soil particles (>1 mm and < 2 mm in diameter) move up

in vertical direction due to power of stormy wind.

2.Suspension:

Fine soil particles (<1 mm diameter) which are suspended in

the air are kicked up and taken away to distant places.

3.Surface creep:

 Larger particles (5-10 mm diameter) creep over the soil

surface along with wind.

• Factors responsible for soil erosion are:

 The top soil is disturbed or rendered devoid of vegetation cover.

 The land is directly exposed to the action of various physical

forces.

 Deforestation is the permanent destruction or removal of

forests in order to make the land available for other uses

 Uncovering of land from forest the top soil available for erosion

• Effects of soil erosion:

•Decrease in productivity of land 

•Desertification of land

•Reduction in the agricultural land at the banks of rivers

•Deposition of soil in river beds and canals causing diversion of 

their natural flow and hence leading to disasters