Desertification

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Desertification

• An ancient issue
• Alive today

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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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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.
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The process of making or becoming a desert (a dry
barren often a sand-covered area of land
characteristically desolate, waterless and
without vegetation.)
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Erosion The wearing away of the land by running
water, rain, wind, ice or other geological
agents.
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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.
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Salinisation The process whereby soluble salts
accumulate within the soil.
Dryland salinity Areas where soil salinity levels
are high enough to affect plant growth.
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Chapter 8 Our Growing Deserts In Herda, D.J.
Madden, Margaret. Land Use and Abuse
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Please make notes with particular regard to

• The lands original condition
• Current descriptions of its condition
• Causation - why did it change?
• Desertification
• Salinity - Salinisation
• Erosion

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• 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

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Thriving Alexandria
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Because of mankinds 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
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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.
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As the farmers harvest their fields, the land is
left barren, its surface broken by ploughing.
Dry season winds blow away the topsoil, exposing
the land to erosion. The result is
desertification.
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When silting and salinity eventually reduced the
soils 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.
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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.
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