Week 4
Subject: Agricultural Science
Class: JSS 3
Week of the Term: 4th Week
Topic: Practical Agriculture
Sub-Topic: Identification of common weeds, identification of weed control chemicals and equipment, classification and uses of weeds.
Objectives
At the end of the lesson, students should be able to:
- Identify at least five common weeds found in agricultural fields.
- Describe different weed control methods and the chemicals used.
- Classify weeds based on their growth habits and potential uses in agriculture.
Entry Behaviour
Students should understand the importance of crops and how weeds can affect agricultural productivity.
Instructional Materials
- Samples of common weeds
- Charts displaying weed control chemicals
- Equipment for weed control (e.g., hoes, sprayers)
Reference Materials
- L. A. Are, A. A. Adegbola, T. I. Ashaye, E. Nwogu (2015). Agriculture, Junior Secondary, Secondary Schools, University Press Plc, Lagos.
- Dairo S. D., Akande A. S., Akindele F. Y., Muazu I., Uzowanne C. (2010). Agricultural for Junior Secondary School 3 Textbook (BEC Edition). Spectrum Books Limited, Lagos.
Content
Identification of Common Weeds
Identifying common weeds is a critical skill for any aspiring farmer or agricultural practitioner, as these unwanted plants can significantly impact crop health by competing for nutrients, light, and water. Students will learn to recognize various weeds that are prevalent in local agricultural settings. Key weeds to focus on include:
- Speargrass (Imperata cylindrica): A fast-growing perennial grass that can form dense mats, making it difficult for crops to thrive.
- Waterleaf (Talinum triangulare): Known for its succulent leaves and rapid growth, it often invades vegetable gardens and crops.
- Pigweed (Amaranthus spp.): Characterized by its broad leaves and ability to grow tall, pigweed can overshadow smaller crops, leading to yield reduction.
- Bindweed (Convolvulus spp.): A climbing perennial vine that wraps around plants, choking their growth and inhibiting sunlight exposure.
To reinforce their learning, students will participate in field observations where they will identify and document various weeds found in local agricultural settings. They may engage in hands-on activities, such as collecting samples of different weeds for classroom analysis and discussion.
Weed Control Methods
Understanding effective weed control methods is essential for successful agricultural practice. Students will explore various strategies to manage weeds, including:
- Cultural Control: This involves practices that promote healthy crop growth and minimize weed competition. Examples include crop rotation, where different crops are planted in succession to disrupt weed life cycles, and using cover crops to suppress weed growth during off-seasons.
- Mechanical Control: Physical methods of weed management, such as manual weeding using hand tools (hoes, rakes) or mechanical tillage, will be discussed. Demonstrations on how to use these tools safely and effectively will be provided.
- Chemical Control: Students will learn about herbicides, chemicals specifically designed to control unwanted plants. They will study various types of herbicides, such as:
- Non-selective Herbicides: Such as glyphosate, which kill all plant material it comes into contact with.
- Selective Herbicides: Such as atrazine, which target specific types of plants while leaving others unharmed.
Safety precautions for handling herbicides will be emphasized, including the importance of wearing protective gear, understanding label instructions, and adhering to local regulations regarding chemical use.
Classification and Uses of Weeds
Weeds can be classified based on their life cycles into three main categories:
- Annual Weeds: These complete their life cycle within one growing season (e.g., crabgrass, pigweed).
- Biennial Weeds: These take two years to complete their life cycle, often producing a rosette of leaves in the first year and flowering in the second year (e.g., wild carrot).
- Perennial Weeds: These can live for several years and may regenerate from their root systems (e.g., dandelions, bindweed).
Step 1: Introduction
Lesson Presentation (Step-by-Step Procedure)
Others removed.
