Progressive destruction or degradation of arid or semiarid lands to desert. Desertification leads to the conversion of range lands or irrigated croplands to desert.
Desertification is characterized by devegetation, depletion of ground water, salination and soil erosion.
Harmful effect of desertification
Around 80% of the productive land in the arid and semi-regions are converted into desert. Around 600 million people are threatened by desertification.
Causes of Desertification (a)Deforestation
The process of denuding and degrading a forest land initiates a desert.
If there is no vegetation to hold back the rain water, soil cannot soak and groundwater level do not increases.
This also increases, soil erosion, loss of fertility.
The increase in cattle population heavily grazes the grass land or forests and as a result denudes the land area.
The denuded land becomes dry, loose and more prone to soil erosion and leads to desert.
Over utilization of ground water, particularly in the coastal regions, is resulting in saline water intrusion into aquifers which is unfit for irrigation.
(d)Mining and quarrying
These activities are also responsible for loss of vegetal cover and denudation of extensive land area leading to desertification.
Formation of deserts may also take place due to climate change, ie., failure of monsoon, frequent droughts.
Excessive use of fertilizers and pesticides and disposal of toxic water into the land also leads to desertification.
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