PRIMARY 4: AGRIC SCIENCES – THIRD TERM | WEEK 9

TOPIC: WEEDS

A: TEACHING AND LEARNING MATERIALS

1. Samples of common weeds.
2. Pictures of weeds.
3. Pictures of crops growing with weeds.
4. Hand lens.
5. Flashcards.
6. School garden.

B: REFERENCE MATERIALS

1. Scheme of work.
2. Recommended Agric Sciences textbook for Primary 4.
3. Online educational resources.

C: PREVIOUS KNOWLEDGE

The pupils have seen unwanted plants growing among crops, in gardens and around their homes.

D: PERFORMANCE OBJECTIVES

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

1. Explain weeds.
2. Identify common weeds.
3. Differentiate weeds from cultivated crops.
4. State harmful effects of weeds.
5. Explain how weeds compete with crops.

E: CONTENT

Meaning of Weeds

Weeds are unwanted plants growing where they are not needed. For example, grasses growing among maize plants may be weeds. 🌽🌿🌿

Examples of Common Weeds

Examples include:

• spear grass
• goat weed
• nut grass
• stubborn grass
• tridax

Difference Between Weeds and Crops

A crop is a plant deliberately grown by a farmer. A weed is an unwanted plant growing among crops or in unwanted places.

Harmful Effects of Weeds

1. Competition for Water

Weeds use water needed by crops.

2. Competition for Nutrients

Weeds take nutrients from the soil.

3. Competition for Sunlight

Tall weeds may block sunlight from reaching crops.

4. Competition for Space

Weeds occupy space that crops need.

5. Harbouring Pests

Some weeds provide hiding places for insects and other pests.

6. Reducing Crop Yield

Too many weeds can make crops grow poorly and produce less food.

7. Making Harvesting Difficult

Dense weeds can make harvesting more difficult.

F: LESSON PRESENTATION

F1: Teachers’ Activities

1. Explains weeds.
2. Displays common weed samples.
3. Takes pupils to observe weeds where possible.
4. Compares crops with weeds.
5. Explains competition for resources.
6. Discusses the harmful effects of weeds.

F2: Pupils’ Activities

1. Explain weeds.
2. Identify common weeds.
3. Observe weeds around the school.
4. Differentiate weeds from crops.
5. State harmful effects of weeds.

G: CONCLUSION

The teacher revises the meaning, examples and harmful effects of weeds on crops. The teacher encourages pupils to identify unwanted plants in gardens and understand why farmers remove them.

H: EVALUATION GUIDE

Pupils should be able to answer the following questions:

1. What are weeds?
2. Name four common weeds.
3. State one difference between a crop and a weed.
4. Name four things weeds compete with crops for.
5. State four harmful effects of weeds.
6. How can weeds reduce crop yield?