Soil Erosion and
Conservation
Page 41 - Geoecology
Soil Erosion and Conservation
Exam Brief: Typical Exam Questions
Discuss how human activities can accelerate soil
erosion...
Soil Erosion
Soil is a fragile resource. Most
soil erosion is caused by
natural processes such as
water flowing downhill a...
Soil Erosion is caused by:
Natural Processes
• Water flowing downhill
• Wind
Human Activities
• Overcropping
• Overgrazing...
Problems caused by soil erosion:
1. Loss of valuable topsoil.
2. Burying valuable topsoil.
3. Damage to fields.
4. Plant p...
Case Study:
SoilErosionand Desertificationin the Sahel
The Sahel stretches for
5,400km across Africa from the
Atlantic Oce...
Case Study:
SoilErosionand Desertificationin the Sahel
• Soil erosion (caused by overgrazing, overcropping
and deforestati...
Video Clip
• 2009 – BBC News Report about the famine affecting Ethiopia.
Overgrazing
• When farmers allow too many animals to graze
an area of land.
• This damages the soil structure and removes
...
Overcropping
• When land is continuously farmed, the nutrients
are drained from the soil which destroys soil
structure and...
Deforestation
• Large areas of forest are cut down leaving bare
landscape. Tree and plant roots prevent soil
erosion. When...
Climate Change
• Global warming has
caused a rise in the
temperature of the
atmosphere in the
Sahel region.
• As a result ...
Methods of Conservation:
Windbreaks / Shelter Belts
Barriers formed by
trees and plants
with many leaves.
Methods of Conservation:
Contour / Strip Ploughing
The tractor operator follows
the contours of the hillside.
The furrows ...
Methods of Conservation:
Stubble Planting
• The old stubble of harvested
crops is not ploughed back into
the soil (as usua...
Methods of Conservation:
Terraces
• Large steps cut into a hillside.
• This reduces slope length and steepness to
limit th...
Methods of Conservation:
Stone Walls / Bunds
• Low walls placed along the contour of a hill.
• These walls capture water a...
Methods of Conservation:
Reduce ploughing in dry/windy weather
•Ploughing in dry and windy weather
increases the risk of w...
Homework:
Exam Question: 2009 Q 17
‘Discuss how human activities can
accelerate soil erosion’ (80 marks).
Marking Scheme:
...
Upcoming SlideShare
Loading in …5
×

Soil Erosion and Conservation

22,114 views

Published on

Soil Erosion and Conservation
Studied as part of the Geoecology option at Leaving Certificate Higher Level Geography in Ireland.

Published in: Education
0 Comments
23 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
22,114
On SlideShare
0
From Embeds
0
Number of Embeds
105
Actions
Shares
0
Downloads
1,646
Comments
0
Likes
23
Embeds 0
No embeds

No notes for slide

Soil Erosion and Conservation

  1. 1. Soil Erosion and Conservation Page 41 - Geoecology
  2. 2. Soil Erosion and Conservation Exam Brief: Typical Exam Questions Discuss how human activities can accelerate soil erosion.(2009) Examine how overcropping/overgrazing and desertification can affect soils. (2007) Examine two ways in which human activities have impacted on soils. (2010) Examine the causes of soil erosion and outline methods used to prevent it. (Sample paper) See above – the causes of soil erosion are more important than the solutions – going by past exam papers.
  3. 3. Soil Erosion Soil is a fragile resource. Most soil erosion is caused by natural processes such as water flowing downhill and by the wind.
  4. 4. Soil Erosion is caused by: Natural Processes • Water flowing downhill • Wind Human Activities • Overcropping • Overgrazing • Deforestation
  5. 5. Problems caused by soil erosion: 1. Loss of valuable topsoil. 2. Burying valuable topsoil. 3. Damage to fields. 4. Plant productivity decline. 5. Desertification.
  6. 6. Case Study: SoilErosionand Desertificationin the Sahel The Sahel stretches for 5,400km across Africa from the Atlantic Ocean in the West to the Red Sea in the East. It includes countries such as Mali, Nigeria and Ethiopia.
  7. 7. Case Study: SoilErosionand Desertificationin the Sahel • Soil erosion (caused by overgrazing, overcropping and deforestation) is leading to desertification in the Sahel region of Africa. • Increased drought in the Sahel region as a result of climate change is also causing soil erosion and desertification.
  8. 8. Video Clip • 2009 – BBC News Report about the famine affecting Ethiopia.
  9. 9. Overgrazing • When farmers allow too many animals to graze an area of land. • This damages the soil structure and removes plant cover, allowing the soil to blow away.
  10. 10. Overcropping • When land is continuously farmed, the nutrients are drained from the soil which destroys soil structure and makes it less fertile.
  11. 11. Deforestation • Large areas of forest are cut down leaving bare landscape. Tree and plant roots prevent soil erosion. When they are removed the soil dries out due to constant exposure to the sun and is easily blown or washed away.
  12. 12. Climate Change • Global warming has caused a rise in the temperature of the atmosphere in the Sahel region. • As a result the air can hold more water vapour and rain is less likely to occur. “The rain doesn’t come on time anymore. After we plant, the rain stops just as our crops start to grow. And it begins to rain after the crops have already been ruined.” - Quote from an Ethiopian farmer.
  13. 13. Methods of Conservation: Windbreaks / Shelter Belts Barriers formed by trees and plants with many leaves.
  14. 14. Methods of Conservation: Contour / Strip Ploughing The tractor operator follows the contours of the hillside. The furrows thrown up by the plough (going in different directions) stop the flow of water and encourage percolation in the soil.
  15. 15. Methods of Conservation: Stubble Planting • The old stubble of harvested crops is not ploughed back into the soil (as usually is done). • Instead the stubble is left in place in order to reduce wind and water erosion while the new crop is growing.
  16. 16. Methods of Conservation: Terraces • Large steps cut into a hillside. • This reduces slope length and steepness to limit the energy of running water and its ability to carry soil away.
  17. 17. Methods of Conservation: Stone Walls / Bunds • Low walls placed along the contour of a hill. • These walls capture water allowing it to filter into the soil rather than run off downhill.
  18. 18. Methods of Conservation: Reduce ploughing in dry/windy weather •Ploughing in dry and windy weather increases the risk of wind erosion.
  19. 19. Homework: Exam Question: 2009 Q 17 ‘Discuss how human activities can accelerate soil erosion’ (80 marks). Marking Scheme: And answer Question 8 on pg 50 __________________________________________________________________

×