Soil Erosion
Soil Erosion refers to the removal of the topsoil by running water and wind. It causes
the maximum loss to soil fertility. This is so because all the mineral nutrients are
present in the top soil. Soil can be eroded in many ways. Two most common ways are
Sheet erosion and Gully erosion.
Sheet Erosion:
Sometimes during heavy rain fall the volume of run-off is very high. If the topsoil is
not protected by sufficient plant cover, it is washed away by the force of surface
run-off. This is known as sheet erosion.
Gully Erosion:
When there is heavy rainfall over an uneven terrain, the run-off scoops out narrow
and deep grooves. With time, these grooves or gullies grow in size and spread over a
large area. This is known as gully erosion.
Soil Erosion is caused by both physical and human factors. The Physical factors
include slope of the land, intensity of rainfall and velocity of the wind. The human
factors that contribute to soil erosion are deforestation, over grazing, over use of
chemical fertilizers and over-irrigation.
Soil Conservation:
Soil is the greatest gift of nature to humans. We take almost everything that we
need from soil.
Primary products like grains, fruits and vegetables are obtained directly from the
soil.
Milk, eggs, meat, honey etc are the secondary food products which we indirectly from
soil. Soil also provides us with fibers, construction materials and a host of other
products. The protection of soil from harmful effects of erosion is called Soil
Conservation.
Soil Exhaustion:
Unscientific agriculture practices can reduce the fertility of soil. If the same crop is
grown every year on the same plot of land, the soil becomes deficient in some specific
nutrients. This is called Soil Exhaustion.
Farm lands should be left Fallow for 3-4 years to regain their fertility. There are
certain plants like the leguminous plants such as pea and beans which return nitrogen
to the soil. They help to maintain then fertility. Manures and fertilizers can be
added to the soil to bring back its fertility.
Chemical fertilizers should be used in moderation, as their overuse is harmful for the
soil.
Soil conservation methods:
Contour plowing
Strip cropping
Terrace farming
Crop rotation
Multiple cropping