Desertification

By kamal bhusal on Wednesday, March 10, 2010 5:15 AM , 1 Comment

DesertificationDesertification is the process which turns productive into non-productive desert as a result of poor land management. Desertification occurs mainly in semi-arid areas (average annual rainfall less than 600mm) bordering of deserts.

Causes of Desertification

• Overgrazing is the major cause of desertification worldwide. Plants of semi-arid areas are adapted to being eaten by sparsely scattered, large, grazing mammals which move in response to the patchy rainfall common to these regions. Early human pastoralists living in semi-arid areas copied this natural system. They moved their small groups of domestic animals in response to food and water availability. Such regular stock movement prevented overgrazing of the fragile plant cover.

• Cultivation of marginal lands, i.e. lands on which there is a high risk of crop failure and a very low economic return, for example, some parts of South Africa where maize is grown.

• Destruction of vegetation in arid regions, often for fuel wood.
• Poor grazing management after accidental burning of semi-arid vegetation.

• Incorrect irrigation practices in arid areas can cause salinization, (the build up of salts in the soil) which can prevent plant growth.

Increasing human population and poverty contribute to desertification as poor people may be forced to overuse their environment in the short term, without the ability to plan for the long term effects of their actions. Where livestock has a social importance beyond food, people might be reluctant to reduce their stock numbers.

Effects of Desertification:

Desertification reduces the ability of land to support life, affecting wild species, domestic animals, agricultural crops and people. The reduction in plant cover that accompanies desertification leads to accelerated soil erosion by wind and water. South Africa losing approximately 300-400 million tones of topsoil every year. As vegetation cover and layer are reduced, rain drop impact and run-off increases.

Water is lost off the land instead of soaking into the soil to provide moisture for plants. Even long-lived plants that would normally survive drought die. A reduction in plant cover also results in a reduction in the quantity of humus and plant nutrients in the soil, and plant production drops further. As protective plant cover disappears, floods become more frequent and more severe. Desertification is self-reinforcing, i.e. once the process has started, and conditions are set for continual deterioration.

How can desertification be halted?

To halt the desertification the number of animals on the land must be reduced, allowing plants to re-grow. Soil conditions must be made favorable for plant growth by, for example, mulching. Mulch( a layer of straw, leaves or sawdust covering the soil) reduces evaporation, suppress weed growth, enriches soil as it rots, and prevents runoff and hence erosion. Reseeding may be necessary in badly degraded areas. Mulching and reseeding are expensive practices.
However, the only realistic large-scale approach is to prevent desertification through good land management in semi-arid areas.

As a forester, what can we do?

Desertification often occurs over many generations on a very large scale and so it is difficult for individuals to take actions. Some ideas for combating this problem include:
• Participation in the activities of conservation groups is needed.
• Problems of overgrazing and land mismanagement are to be taken care into attention.


1 Response to "Desertification"

  1. Unknown says:
    July 20, 2021 at 8:08 PM

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