Environmental Hazard: Soil Erosion

Subject: Basic Science

Class: JSS 3

Term: First Term

Week: 4

Age: 12 – 14 years

Topic: Environmental Hazard: Soil Erosion

Sub-Topic: Definition, Causes, and Control of Soil Erosion

Duration: 40 minutes

Behavioural Objectives

By the end of the lesson, students should be able to:

1. Define soil erosion.
2. List and explain the causes of soil erosion.
3. Describe ways to control soil erosion.
4. Understand the importance of controlling soil erosion for environmental sustainability.

Keywords

• Soil Erosion: The removal of the topsoil by natural forces like wind or water.
• Topsoil: The uppermost fertile layer of soil.
• Deforestation: The clearing of trees that leads to soil erosion.
• Terracing: A method of farming on sloped land to reduce erosion.
• Mulching: Covering soil with organic material to prevent erosion.

Set Induction

The teacher introduces the topic by asking:

• “Have you ever seen gullies on roads after heavy rain? Do you know why some farmlands lose their topsoil?”
  This will get students thinking about the impact of soil erosion in their environment.

Entry Behaviour

Students are aware of natural disasters such as floods and may have observed soil washed away after rainfall.

Learning Resources and Materials

• Picture charts showing examples of soil erosion.
• Videos demonstrating soil erosion and its effects.
• Samples of mulching materials and terracing diagrams.

Building Background/Connection to Prior Knowledge

The teacher links the lesson to students’ prior knowledge about natural hazards such as flooding, explaining how water and wind contribute to soil erosion.

Embedded Core Skills

• Observation Skills: Identifying the signs of soil erosion.
• Environmental Awareness: Understanding the impact of human activities on the environment.
• Problem-Solving Skills: Suggesting solutions to control soil erosion.

Instructional Materials

• Basic Science Textbooks
• Lagos State Scheme of Work
• Whiteboard and markers

Content

1. Definition of Soil Erosion

• Soil erosion is the process by which the top layer of soil is removed by agents like wind, water, or human activity.
• It is a major environmental hazard that affects the fertility of land and leads to the degradation of ecosystems.

2. Causes of Soil Erosion

1. Deforestation: Cutting down trees exposes soil to wind and rain, increasing erosion.
2. Overgrazing: Excessive grazing by animals leaves the soil bare and vulnerable to erosion.
3. Poor Farming Practices: Ploughing on slopes and not using protective farming methods lead to soil loss.
4. Heavy Rainfall: Intense rainfall can wash away the topsoil.
5. Wind: In arid areas, strong winds blow away loose soil.
6. Construction Activities: Land cleared for building roads and houses becomes prone to erosion.

3. Control of Soil Erosion

1. Planting Trees (Afforestation): Trees prevent soil erosion by acting as windbreakers and stabilizing soil with their roots.
2. Terracing: Creating steps on sloped land to slow water flow and reduce erosion.
3. Mulching: Covering the soil with organic matter like leaves or straw to protect it from wind and rain.
4. Cover Cropping: Growing plants like legumes to protect soil during off-seasons.
5. Contour Ploughing: Ploughing along the natural contours of the land to prevent water runoff.
6. Constructing Drainage Channels: Proper drainage helps redirect water and reduces soil erosion.

Board Summary

• Soil Erosion: The removal of topsoil by wind, water, or human activities.
• Causes of Soil Erosion: Deforestation, overgrazing, poor farming, heavy rainfall, wind, construction.
• Control Measures: Afforestation, terracing, mulching, cover cropping, contour ploughing, drainage channels.

Class Activity Discussion (FAQs)

1. What is soil erosion?
   • It is the process of topsoil being washed or blown away.
2. How does deforestation lead to soil erosion?
   • Trees prevent erosion by holding the soil in place with their roots.
3. Why is overgrazing harmful to soil?
   • It leaves the ground bare and exposed to erosion.
4. What are the effects of heavy rainfall on soil?
   • It can wash away the fertile topsoil.
5. How can farmers prevent erosion on sloped land?
   • By using terracing and contour ploughing.
6. What is mulching?
   • Covering soil with organic matter to protect it from erosion.
7. Why are drainage channels important?
   • They help redirect water to prevent erosion.
8. What role do trees play in controlling erosion?
   • Trees act as windbreakers and prevent soil from being washed away.
9. What is cover cropping?
   • Planting crops to cover the soil during off-seasons.
10. What are some human activities that cause erosion?

• Construction, deforestation, and poor farming practices.

Teacher’s Activities

1. Introduce the topic with real-life examples of soil erosion.
2. Use picture charts and videos to demonstrate how erosion occurs.
3. Engage students in a class discussion on the causes and control measures for soil erosion.
4. Guide students in group activities to explore solutions for controlling erosion.

Learners’ Activities

1. Participate in class discussions by sharing personal experiences of soil erosion.
2. Work in groups to identify local examples of erosion and suggest control measures.
3. Complete worksheets on soil erosion causes and control methods.

Evaluation: 15 Fill-in-the-Blank Questions

1. __________ is the removal of the topsoil by wind, water, or human activities.
   a) Soil erosion
   b) Flooding
   c) Deforestation
   d) Earthquake
2. Cutting down trees is called __________.
   a) deforestation
   b) mulching
   c) afforestation
   d) terracing
3. __________ helps to protect soil by covering it with organic material.
   a) Mulching
   b) Erosion
   c) Overgrazing
   d) Construction
4. The uppermost layer of soil is called __________.
   a) topsoil
   b) bedrock
   c) humus
   d) subsoil
5. __________ is a farming method used on sloped land to prevent erosion.
   a) Terracing
   b) Overgrazing
   c) Construction
   d) Deforestation
6. __________ is caused when animals graze excessively, leaving the soil bare.
   a) Overgrazing
   b) Terracing
   c) Flooding
   d) Construction
7. __________ is a method of ploughing along the natural shape of the land.
   a) Contour ploughing
   b) Irrigation
   c) Mulching
   d) Reforestation
8. Heavy __________ can wash away the topsoil.
   a) rainfall
   b) wind
   c) sunlight
   d) snow
9. __________ crops are planted to protect the soil during off-seasons.
   a) Cover
   b) Cash
   c) Seasonal
   d) Forest
10. __________ channels help reduce soil erosion by directing water flow.
    a) Drainage
    b) Flooding
    c) Erosion
    d) Construction

Conclusion

The teacher summarizes the lesson, emphasizing the importance of controlling soil erosion to protect the environment. Students’ responses to the evaluation questions are reviewed and feedback provided.

More Useful Links

• Understanding Basic Science: FAQs on Soil Erosion, Family Traits, Deforestation, Desertification, and Bush Burning
• Understanding Erosion, Types, Causes, and Effects Basic Science Primary 5 First Term Lesson Notes Week 3