Desertification

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Desertification Case Study Sahel
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Desertification
Process via which land turns into desert.
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Where is it?
Label the Sahel on your map.
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What is the Sahel like?

• Semi-arid area.
• Periods of rainfall and drought.
• Supports small bushes and trees.

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Physical Reasons for Desertification in the Sahel

• 1950/60s, there was above average rainfall,
  causing nomadic herders to settle and farmers to
  intensify agriculture.
• 1970s, there was below average rainfall leading
  to extreme drought.

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Human Reasons for Desertification in the Sahel.

• Overgazing. Traditional nomadic tribes settle in
  one place. Vegetation no longer protected the
  soil.
• Cutting down trees. Trees provided protection for
  the soil, from wind and rain.
• Intensive agriculture. The growing of cash crops,
  depleted the soil fertility of the area. The soil
  structure breaks down.

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How does this lead to desert?
Put the following statements into the correct
order as a flow diagram.
Vegetation roots bind the soil.
Leaves are no longer present to intercept rain.
The soil is washed away.
Sun bakes the soil and it cracks.
Wind will blow away the soil.
The soil is degraded, over time losing fertility
and structure.
Vegetation dies.
Soil is left exposed.
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Physical Impact of Desertification in the Sahel.

• Soil erosion.
• Sun baked, cracked soil.
• Loss of plants and animals. (Reduced
  Biodiversity).
• Gullying.
• Dry rivers.
• Growth of desert.
• Increase in sand storms.
• Flash floods

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Human impacts of Desertification in the Sahel.

• Crops and cattle die, resulting in famine.
• Death.
• Migrants move to cities, resulting in the growth
  of informal settlements, shanties, in already
  overpopulated urban areas.

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Tackling Desertification

• Plant Trees.
• Roots bind the soil together. Leaves provided
  shade, and intercept water.
• Cheap, long term.
• Provide fuel wood and building materials.

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Tackling Desertification

• Terracing.
• Prevent rainfall from washing away topsoil and
  nutrients.
• Cheap to build, only man power needed.

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Tackling Desertification

• Magic Stones.
• Similar to terracing, stones are placed along
  contours.
• Topsoil can not be washed past the stones. Water
  infiltrates, instead of running over the surface.
• Cheap to build, only man power needed.
• Effective, shown to increase yields by 50.

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Aidan.