Desertification is a process where the productive potential of arid and semi-arid land is reduced by the activities of humans. It is a serious and growing problem in many regions of the world including: sub-Saharan Africa, the Middle East, western Asia, northern Mexico and south-eastern South America, western United States, prairies of Canada, and eastern Australia. Scientists estimate that 60,000 square kilometers of new desert are now annually created worldwide.
Desertification occurs when the natural vegetation cover is reduced in its cover and the topsoil becomes susceptible to erosion. The removal of the vegetation and topsoil then initiates a number of other problems including:
= Increase surface runoff and stream discharge;
= Reduction of water infiltration and groundwater recharge;
= Development of erosional gullies and sand dunes;
= Change in the surface microclimate that enhances aridity;
= Drying up of wells and springs; and
= Reduction in seed germination of native plants.
The effects of desertification can be reversed in many cases. Reversal begins by halting the activities that created the desertification. In many parts of the world, overgrazing and deforestation are the primary factors causing this form of soil degradation. Two other remedies for repairing the effects of desertification are the re-vegetation of the soil surface and the planting of windbreaks.
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