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Desertification. An ancient issue Alive today. What is Desertification. Land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climate variations and human activities.

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desertification

Desertification

An ancient issue

Alive today

what is desertification
What is Desertification
  • Land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climate variations and human activities.
slide3

The process through which a desert takes over a formerly non-desert area. When a region begins to undergo desertification, the new conditions typically include a significantly lowered water table, a reduced supply of surface water, increased salinity in natural waters and soils, progressive destruction of native vegetation, and an accelerated rate of erosion.

slide4

The process of making or becoming a desert (a dry barren often a sand-covered area of land characteristically desolate, waterless and without vegetation.)

slide5

Erosion

The wearing away of the land by running water, rain, wind, ice or other geological agents.

slide6

The wearing away of land surface by wind or water, intensified by land-clearing practices related to farming, residential or industrial development, road building, or logging.

slide7

Salinisation

The process whereby soluble salts accumulate within the soil.

Dryland salinity

Areas where soil salinity levels are high enough to affect plant growth.

slide8

Chapter 8

Our Growing Deserts

In Herda, D.J. & Madden, Margaret.

Land Use and Abuse

please make notes with particular regard to
Please make notes with particular regard to:
  • The land’s original condition
  • Current descriptions of it’s condition
  • Causation - why did it change?
  • Desertification
  • Salinity - Salinisation
  • Erosion
slide10

To Summarise:

  • To express an idea in terms of the main points only
  • Express, concisely, the relevant details
  • To restate the main points, or ideas, as well as the most important supporting ideas, of a passage or passages, in condensed form
slide12

Because of mankind’s ignorance and indifference toward the land around him, an entire community reverted to wasteland. And Maryut is only one example of how mismanagement can lead to desertification

slide13

As local human populations have increased, their escalating food needs have lengthened the cultivation period. Grain crops are now planted longer into the dry season preventing trees and grasses from reproducing as they did in the past. Much of the land has reverted to desert.

slide14

As the farmers harvest their fields, the land is left barren, it’s surface broken by ploughing. Dry season winds blow away the topsoil, exposing the land to erosion. The result is desertification.

slide15

When silting and salinity eventually reduced the soil’s ability to support grain and pastureland, the sheikhs moved their tribes to newer, more fertile areas, abandoning the old lands to desertification while they began the process all over again.

slide16

As the limited supply of fresh water is pumped from the ground, the salt water is drawn up and spread across the soil. As the water evaporates, salt deposits are left behind, eventually building up to levels that prevent plant growth. Millions of acres of land have been lost to salinisation. These once fertile lands are today little more than great salt deserts.