Soil Erosion
Overview
Topsoil is the thin, dark, fertile skin of the land, and it takes nature hundreds of years to build a few centimetres of it. Yet a single storm on a bare hillside, or a season of drought on overworked ground, can strip it away in days. When the topsoil goes, so does the fertility, and once-productive farmland can turn to dust or desert.
In this lesson you will learn what causes soil erosion, the chain of damage it sets off from silted rivers to famine and the movement of whole communities, and the practical methods farmers use to hold soil in place. By the end you should be able to link a cause to its impact and recommend a suitable conservation method for a given piece of land, which is exactly what the exam asks.
Objectives
- 2.3.1 Describe the causes of soil erosion, limited to: (a) unsustainable agricultural practices (b) deforestation (c) farming on steep slopes (d) bare soil (e) wind and water erosion.
- 2.3.2 Describe the impacts of soil erosion, limited to: (a) silting of rivers (b) desertification (c) mass movement: landslides, rockslides and mudslides (d) loss of habitats and biodiversity (e) reduction in crop yield (f) malnutrition and famine (g) displacement of people.
- 2.3.3 Describe and explain strategies to reduce soil erosion, limited to: (a) terracing: reduces movement of soil and surface run-off (b) contour ploughing: reduces surface run-off (c) bunds: reduces surface run-off, reduces wind speed and wind erosion (d) wind breaks: protects crops, reduces wind speed and wind erosion (e) maintaining vegetation cover: roots bind the soil, vegetation reduces surface run-off and absorbs water (f) addition of organic matter: improves soil structure.
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Soil Erosion. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which of these is a major cause of soil erosion? A. Planting windbreaks B. Adding organic matter C. Removing natural vegetation D. Contour ploughing Answer: C
- A deep channel cut into the soil by fast-flowing rainwater run-off is called a: A. Terrace B. Bund C. Gully D. Windbreak Answer: C
- Terracing reduces soil erosion mainly by: A. Increasing wind speed B. Reducing surface run-off on slopes C. Removing all vegetation D. Drying out the soil Answer: B
- The process by which fertile land turns into desert is called: A. Salinisation B. Eutrophication C. Desertification D. Silting Answer: C
- Which method is most suitable for reducing WIND erosion on a flat, dry field? A. Terracing B. Contour ploughing C. A windbreak D. Deeper ploughing Answer: C
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Recommended Books
Practice Mock Questions
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