Soil erosion: causes, impacts and prevention
Explain how exposed soil is moved by wind or water, assess consequences and select controls that match the process.
Section 2 · Land
This original StudyForA sequence supports Cambridge IGCSE Environmental Management 0680 Topics 1–4 for exams in 2027, 2028 and 2029. Named local examples are chosen by the learner and centre; verify current conditions and local context with reliable sources. It is not a Cambridge paper, official grade or complete course.
Before you begin
- Use the 2027–2029 syllabus and check your exam year and centre's entry arrangements. Topics 1–4 are taught on this page; Topics 5–7 are still being built.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
How can vegetation cover reduce erosion?
What you will learn
- Explain how exposed soil is moved by wind or water, assess consequences and select controls that match the process.
- Use evidence from an unfamiliar case to compare options and justify a context-sensitive judgement.
Identify why soil becomes vulnerable
Causes include unsustainable agriculture, deforestation, farming on steep slopes, bare soil, and wind or water erosion. These factors can interact: removing vegetation from a slope exposes loose soil to rainfall and runoff.
Erosion removes fertile topsoil and nutrients. Explain the process that moves soil rather than treating erosion as a land-use label.
Follow impacts from field to community
Eroded soil can silt up rivers, contribute to desertification and increase mass movement such as landslides, rockslides and mudslides. It can remove habitat and biodiversity and reduce crop yield.
Lower production can contribute to malnutrition or famine and displacement of people. These are possible linked impacts, not an inevitable result of every eroded field; use context and evidence.
Match prevention to the mechanism
Terracing reduces soil movement and surface runoff on slopes. Contour ploughing follows land contours and slows runoff. Bunds reduce runoff and wind speed; windbreaks protect crops and lower wind speed.
Maintaining vegetation cover lets roots bind soil while vegetation reduces runoff and absorbs water. Adding organic matter can improve soil structure. Choose methods for the slope, rainfall, wind, crop and maintenance capacity.
Sources for this lesson
Pause and explain
Which method is designed to reduce wind speed and protect crops?
Worked example
A steep, bare field loses topsoil during heavy rain. Explain the cause, one downstream impact and two measures suited to the slope.
Show the worked solution
- Bare soil on a steep slope is exposed to water erosion and runoff.
- Sediment can enter and silt up a river, while loss of topsoil can lower crop yield.
- Terracing can reduce soil movement; maintaining vegetation cover can bind soil and slow runoff.
Answer The bare steep slope is vulnerable to water erosion. Sediment may silt up a river and loss of topsoil may reduce yields. Terracing and vegetation cover target slope movement and runoff, but require suitable design and maintenance.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A farmer cultivates a steep slope in straight lines down the hill and leaves soil bare after harvest. Explain two erosion risks and choose a suitable alternative.
Give me a hint
Consider runoff direction, soil cover and the slope.
Compare my reasoning
- Down-slope ploughing can channel runoff and move soil downhill.
- Bare soil after harvest is exposed to both rainfall and wind.
- Contour ploughing, terracing or maintaining vegetation cover can reduce movement, depending on slope and farm conditions.
The slope, bare soil and down-hill furrows increase exposure to runoff and soil movement. Contour ploughing or terracing can reduce runoff; vegetation cover can bind soil between crops.
Look for these in your work
- Two risk factors identified
- Runoff mechanism explained
- Control matched to the site
A dry, windy field and a steep, wet field both lose topsoil. Select two different erosion controls and explain why the controls suit the different settings.
Give me a hint
Match wind controls to wind erosion and runoff controls to water moving down a slope.
Compare my reasoning
- Windbreaks can reduce wind speed and protect crops in the dry, exposed field.
- Terracing or contour ploughing can slow runoff and soil movement on the steep wet field.
- Vegetation cover may support both sites, but species, water needs and maintenance should fit local conditions.
Windbreaks target wind speed on the dry field; terracing or contour ploughing targets water runoff on the steep field. Vegetation can add protection when it is suitable and maintained.
Look for these in your work
- Controls differ by setting
- Mechanisms accurately explained
- Local suitability considered
An erosion-control project is evaluated after one rainy season. Propose what to measure and explain why one season may be insufficient to judge success.
Give me a hint
Track soil movement and crop or water outcomes, and account for rainfall variability.
Compare my reasoning
- Measure runoff or sediment leaving plots, soil cover and topsoil condition.
- Record slope, rainfall and crop yield, and compare treated and untreated areas if safe and practical.
- One season may be unusually wet or dry; repeat observations across conditions to judge durable change and maintenance needs.
Measure soil loss, cover, runoff, rainfall and yield with a suitable comparison. A single season may not represent normal conditions or show whether the method continues working, so monitor over time.
Look for these in your work
- Direct erosion measure included
- Weather and comparison considered
- Time limitation explained
Common mistakes
- Confusing erosion with weathering
- Assuming all soil loss causes famine
- Recommending a windbreak without considering water runoff
- Ignoring maintenance and slope conditions
What can you explain now?
Which method is specifically described as reducing surface runoff on slopes?
Compare with the explanation
Terracing
The correct answer is “Terracing”. The alternatives “Pesticide spraying” and “Deep mining” do not match the syllabus concept. Explain how exposed soil is moved by wind or water, assess consequences and select controls that match the process.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Explain one cause and two impacts of soil erosion, then match a prevention method to wind or water movement.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.