Lesson Plan: Definition and Characteristics of Weeds

Lesson Details

• Subject: Agricultural Science
• Class: Basic 8 / JSS 1
• Term: Third Term
• Week: Week 3
• Age: 10–13 years
• Topic: Definition and Characteristics of Weeds
• Sub-topic: Uses of Weeds and Methods of Weed Control
• Duration: 40 minutes

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Behavioral Objectives

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

1. Define weeds and explain their characteristics.
2. List at least five uses of weeds.
3. Describe different methods of weed control.
4. Differentiate between weeds and crops.
5. Explain the economic importance of weeds.

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Keywords

• Weeds – Unwanted plants that grow where they are not needed.
• Herbicides – Chemicals used to kill weeds.
• Mechanical control – Physical removal of weeds.
• Cultural control – Farming practices that prevent weed growth.
• Biological control – Using natural enemies to control weeds.

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Set Induction

The teacher displays pictures or real samples of common weeds such as elephant grass, spear grass, and water leaf. The teacher asks:

• “Have you ever seen these plants before?”
• “Are these plants useful or harmful?”
• “Why do farmers remove weeds from their farms?”

This will stimulate curiosity and introduce the topic.

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Entry Behavior

Pupils already have basic knowledge of weeds from previous lessons. They understand that weeds grow on farms and compete with crops for nutrients, sunlight, and space.

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Learning Resources and Materials

• Pictures of weeds
• Samples of real weeds (e.g., spear grass, elephant grass)
• Flashcards with weed control methods
• Charts showing different types of herbicides

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Building Background/Connection to Prior Knowledge

The teacher reminds pupils about the topic “Introduction to Weeds”, previously taught. Pupils recall that weeds grow on farmlands, affect crops negatively, and need to be controlled.

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Embedded Core Skills

• Communication skills (discussing and explaining weed control methods)
• Critical thinking skills (analyzing the best weed control method for different situations)
• Scientific inquiry skills (understanding herbicides and biological control)

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Reference Books

• Lagos State Scheme of Work
• 9-Year Basic Education Curriculum
• Agricultural Science Textbooks and Workbooks

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Instructional Materials

• Real samples of weeds
• Pictures of weeds and weed control methods
• Charts showing herbicides and their effects
• A hoe, cutlass, and sprayer for demonstration

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Content Development

Definition of Weeds

Weeds are unwanted plants that grow where they are not needed. They compete with crops for space, nutrients, and water.

Characteristics of Weeds

1. Rapid Growth – Weeds grow quickly and spread fast.
2. High Reproduction – They produce many seeds.
3. Survival Ability – Weeds can survive in harsh conditions.
4. Resistance to Control – Some weeds can resist herbicides and regrow after cutting.
5. Compete with Crops – They take nutrients meant for crops.

Uses of Weeds

Some weeds are useful in many ways, including:

1. As cover crops – Some weeds protect soil from erosion.
2. As animal feed – Weeds like elephant grass are used to feed livestock.
3. For making compost – Weeds improve soil fertility.
4. For medicinal purposes – Lemon grass is used for treating colds.
5. As fuel (firewood) – Some weeds are used for cooking.
6. For beautification – Some weeds, like morning glory, are planted as flowers.
7. For environmental purification – Weeds absorb carbon dioxide.
8. As edible plants – Some weeds like water leaf are eaten.

Methods of Weed Control

Weeds can be controlled using different methods:

1. Physical/Mechanical Weed Control

• Hand pulling – Removing weeds with hands.
• Hoeing – Using hoes to remove weeds.
• Mowing – Using machines to cut weeds.
• Slashing – Using a cutlass to cut weeds.
• Tillage – Ploughing and harrowing the land.

2. Chemical Weed Control

• Using herbicides – Spraying chemicals to kill weeds.
• Types of herbicides:
  • Selective herbicides – Kill only certain weeds (e.g., Atrazine, Simazine).
  • Non-selective herbicides – Kill all plants (e.g., Glyphosate, Roundup).
  • Systemic herbicides – Absorbed by the plant and kill it completely.
  • Contact herbicides – Work on contact, burning weeds quickly.

3. Cultural Weed Control

• Mulching – Covering the soil with dry grass to prevent weed growth.
• Crop rotation – Changing crops every season to stop weeds from growing.
• Flooding – Watering the field to drown weeds.
• Burning – Destroying weeds with fire.
• Cover cropping – Planting fast-growing crops to prevent weeds.

4. Biological Weed Control

• Using natural enemies like insects or animals to control weeds.

5. Preventive Weed Control

• Quarantine – Preventing the spread of weeds by inspecting imported seeds and plants.

6. Integrated Weed Management (IWM)

• A combination of two or more weed control methods for better results.

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Class Activity Discussion (FAQs)

1. What are weeds? → Weeds are unwanted plants.
2. Why do farmers remove weeds? → To prevent them from competing with crops.
3. Give two examples of weeds. → Elephant grass, spear grass.
4. Mention one use of weeds. → Weeds can be used as animal feed.
5. What is the meaning of weed control? → It means removing weeds from the farm.
6. Name two methods of weed control. → Mechanical control and chemical control.
7. What are herbicides? → Chemicals used to kill weeds.
8. Name one selective herbicide. → Atrazine.
9. How does mulching help control weeds? → It prevents sunlight from reaching the weeds.
10. What is cultural weed control? → Using farming practices to reduce weeds.

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Presentation Steps

Step 1: Revising the Previous Topic

• The teacher asks pupils to mention examples of weeds they know.

Step 2: Introducing the New Topic

• The teacher displays pictures of weeds and asks pupils what they see.

Step 3: Teacher Explains the Topic

• The teacher explains the definition, characteristics, uses, and control of weeds.

Step 4: Learners’ Contributions

• Pupils discuss different weeds and their control methods.

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Teacher’s and Learners’ Activities

Teacher’s Activities	Learners’ Activities
Shows pictures and samples of weeds	Observe and describe the weeds
Explains weed characteristics	Ask and answer questions
Demonstrates weed control methods	Participate in discussions
Organizes group activities	Work in groups to list weed control methods

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Evaluation Questions

1. Define weeds.
2. List three characteristics of weeds.
3. Mention five uses of weeds.
4. What is herbicide?
5. Name two methods of weed control.
6. What is the meaning of biological weed control?
7. Differentiate between selective and non-selective herbicides.
8. State two examples of cultural weed control.
9. What is integrated weed management?
10. Mention one economic importance of weeds.

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Conclusion

• The teacher summarizes the lesson.
• Pupils copy notes and correct mistakes.
• The teacher marks pupils’ notes and provides feedback.

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Assignment

• Read about Classification of Weeds in preparation for the next lesson.

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Effects of Weeds to farmers Primary 5 Second Term Lesson Notes Week 3