Lesson Notes By Weeks and Term - Junior Secondary School 1

Week: 9

Class: Junior Secondary School 1

Term: 2^nd Term

Age: 12 years

Duration: 40 minutes of 2 periods

Date:

Subject: Agriculture

Topic:-       Weeds

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Outline the classes of weeds, citing examples
2. Explain the mode of dispersal of weeds
3. Highlight the economic importance of weeds in agriculture

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION	TEACHER’S ACTIVITY	STUDENT’S ACTIVITY
STEP 1 INTRODUCTION	The teacher revises the previous lesson on weeds	Students pay attention
STEP 2 EXPLANATION	She outlines the classes of weeds, citing examples	Students pay attention and participates
STEP 3 DEMONSTRATION	She further explains the modes of weed dispersal. She also highlights the economic importance of weeds in agriculture	Students pay attention and participate
STEP 4 NOTE TAKING	The teacher writes a summarized note on the board	The students copy the note in their books

 

NOTE

CLASSIFICATION OF WEEDS

Weeds are classified based on the length of their life span.

1. Annual weeds: they are weeds that have their life cycle completed in one year

Examples are given in the table below

	Common name	Botanical name
1	Goat weed	Ageratum spp
2	Razor grass	Seleria pterosa
3	Fox-tail	Seleria barbata
4	Starbur	Acanthaspermum hispidum
5	Spiny amaranth	Amaranthus spinosus
6	Garden spurge	Euphobia hirta
7	Terongan	Solamum tervam
8	Broom weed	Sida acuta

 

2. Biennial weeds: these are weeds that complete their life cycle in more than one year but not more than two years e.g wild carrot
3. Perennial weeds: are weeds that complete their life cycle in more than two years or indefinite. Examples are given in the table below

	Common name	Botanical name
1	Spear grass	Imperata cylindrical
2	Guinea grass	Penicum maximum
3	Elephant grass	Pennistum purpurenum
4	PWD weed	Tridas Procummbens
5	African marigold	Aspilia africana

 

WEED DISPERSAL

Weed dispersal can be done using these agents

1. wind: this happens for seeds of grasses that are small, light and has wings e.g aspilia and tridax
2. Water: this happens for seeds which are water resistant, and have features that make them stay afloat for long times e.g wild cotton, water lily etc
3. animal and man: this happens for seeds that can stick or adhere to the cloth or skin of man and animals e.g mmimosa, desmodium, mistletoe, ageratum etc
4. explosive mechanism: this happens when there is an explosion e.g centrosema, mucuna, crotolaria etc

 

ECONOMIC IMPORTANCE OF WEEDS IN AGRICULTURE

1. some are eaten as food
2. some are used as feed
3. they cover the soil and protect it against erosion
4. some weeds are medicinal
5. they can be used as green manure
6. When they are ploughed into the soil, they could provide nutrients

EVALUATION:    1. State the classes of weeds, citing examples

2. Mention the methods of weed dispersal, citing examples
3. What are the economic importance of weeds to man?

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively