Lesson Notes By Weeks and Term v4 - SHS 3

Lesson Video

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Performance objectives

• Identify common weeds in Ghana.
• Discuss different methods of weed control.
• Understand the advantages and disadvantages of each method.
• Learn safe practices for using herbicides.

Lesson summary

This lesson explores the critical practice of weed control in Ghanaian agriculture. Weeds are a major challenge for our farmers, from the small-scale vegetable grower in the Volta Region to the large-scale maize farmer in the Bono Region. They compete with our precious crops like maize, cassava, and yam for sunlight, water, and nutrients, drastically reducing yields and affecting the farmer's income and our nation's food security. Understanding how to manage them effectively and safely is essential for successful farming.

Lesson notes

A. What is a Weed?

A weed is simply a plant growing where it is not wanted. It is a plant "out of place." For example, a young maize plant growing in a yam field is considered a weed in that context. Common Ghanaian Examples: Spear Grass (*Imperata cylindrica*) - Very difficult to control due to its sharp, underground rhizomes. Guinea Grass (*Panicum maximum*) - Common in fields and along roadsides. Goat Weed / Agyenkwa (*Ageratum conyzoides*) - A common broadleaf weed. Wire Weed (*Sida acuta*) - A tough, woody weed found in pastures and crop fields. B. Why is Weed Control Necessary?

Weeds must be controlled because they: Compete with Crops: They fight with crops for essential resources like sunlight, water, soil nutrients, and space, leading to stunted growth and significantly lower yields. Harbour Pests and Diseases: Weeds can serve as alternative hosts for insects (like aphids) and pathogens (like fungi or viruses) that can later attack the main crop. Reduce Crop Quality: Weed seeds or parts can mix with harvested grains (e.g., maize, rice), lowering their market value. Interfere with Farm Operations: Dense weed growth can make it difficult to carry out activities like fertilizer application, pest control, and harvesting. Some are Poisonous: Certain weeds can be poisonous to livestock if consumed. C. Methods of Weed Control

There are four principal methods of controlling weeds. A modern, holistic approach called Integrated Weed Management (IWM) combines these methods. Cultural Weed Control

Evaluation guide

• Discuss the methods of weed control in Agricultural production.
• Inquiry -based learning: Learners in mixed -ability/mixed -gender groups surf th e
• internet for information on weed control.
• Managing talk for learning: Learners in mixed -ability groups discuss the methods of