Land degradation

Land degradation is a process in which the value of the biophysical environment is affected by one or more combination of human-induced processes acting upon the land.It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable.Natural hazards are excluded as a cause, however human activities can indirectly affect phenomena such as floods and bush fires.

Land degradation caused by agriculture takes many forms and has many causes. Some of the most important types of land degradation include

Degradation related to overgrazing by livestock

Degradation related to soil erosion , here related to inappropriate cultivation practices)

Degradation attributable to soil salinization (a build up of salts in soil that results from irrigation in certain situations)

Degradation attributable to waterlogging (another problem related to irrigation)

It is estimated that up to 40% of the world's agricultural land is seriously degraded and Around 33 percent of the land is going to be wasted at the end of this century

Soil erosion occurs everywhere in the world. It is more common in the Australia, India, Spain, U.S.A and Africa. The air and water erosion affects around 40 thousand hectares of land in a year

Ways of preventing land degradation

The erosion is prevented by the crop rotation, mulching which leads to decrease in the evaporation and increase in the absorption, presence of suitable outlet channels which can carry the water, sowing of certain crops which check the erosion and include the grasses, groundnut, pulses and berseem. The planting of tress also checks the erosion. The control on grazing and the terracing of lands which decrease the speed of water also keeps a check on the erosion. The contour bunding has an ability to hold the rain water and control erosion
The deserts in the world are made by man. The land is degraded by the development activities of humans which include the dams, canals, railways, buses and industries. The land degradation is prevented by the crop rotation, mulching which leads to decrease in the evaporation and increase in the absorption, presence of suitable outlet channels which can carry the water, sowing of certain crops which check the erosion and include the grasses, groundnut, pulses and berseem. The planting of tress also checks the land degradation. The control on grazing and the terracing of lands which decrease the speed of water also keeps a check on the land degradation


http://en.wikipedia.org/wiki/Land_degradation
http://www.thebigger.com/biology/pollution/what-is-land-degradation/
http://people.oregonstate.edu/~muirp/whatdegr.htm