PHYSICAL PROPERTIES OF SOIL AGRICULTURAL SCIENCE PRIMARY 4 FIRST TERM LESSON NOTES WEEK 5
AGRICULTURAL SCIENCE THIRD TERM E NOTES FOR BASIC FOUR/ PRIMARY 4
Primary 4
Subject : AGRICULTURAL SCIENCE
Topic : PHYSICAL PROPERTIES OF SOIL
Class : BASIC FOUR / PRIMARY 4 / GRADE 4
TERM : FIRST TERM
WEEK : WEEK 5
LEARNING MATERIALS
- Whiteboard/Chalkboard
- Explanatory posters/pictures
- Explanatory videos
Instructional Materials :
- Lagos State Scheme of Work.
- Online Materials.
- Textbooks
- Workbooks
- Different types of soil
Previous Knowledge :
The pupils have been taught
in their previous lesson
PERFORMANCE OBJECTIVES
At the end of the lesson , pupils should be able to
1. say the physical properties of Soil
2. Explain what distinguish one type of soil from the other
3. List the determining factors that are used to classify soil such as mineral content, texture or porosity
Content :
Physical properties of soil
Each soil type has some physical properties. The property of any soil type is what makes it different from the others.
Sandy soil
This soil is different from clay and loam in many ways.
1. Sandy soil contains tiny stone particles.
2.It is rough when rubbed between the fingers, and it runs freely through the fingers when dry.
3.It is found mostly along footpaths, deserts and erosion areas. It is loose and not that fertile.
CLAYEY
1. Clayey soil is slippery and sticky when wet.
2.When dry, clayey soil is hard, very smooth, feels like powder, and it cracks. Have you seen a cracked soil before?
3.That is clay. Clay is a bit fertile.
LOAMY SOIL
1.This soil has properties that are different from sand and clay.
2.Loamy soil has a mixture of the properties of sand and clay.
3. It is very rich in humus. It is, therefore, fertile and the best for farming.
[mediator_tech]
Evaluation
1. Sandy soil contains tiny __________ particles.
a) water
b) stone
c) leaf
d) air
2. Sandy soil feels __________ when rubbed between the fingers.
a) smooth
b) sticky
c) rough
d) soft
3. Sandy soil is often found in __________ areas.
a) forest
b) farms
c) deserts
d) gardens
4. Clayey soil is __________ when wet.
a) smooth
b) slippery
c) rough
d) dry
5. When clayey soil is dry, it feels like __________.
a) rocks
b) powder
c) rubber
d) sandpaper
6. Clayey soil __________ when it dries and forms cracks.
a) turns into mud
b) stays the same
c) becomes smooth
d) cracks
7. Loamy soil is a mixture of the properties of __________ and clay.
a) sand
b) rocks
c) leaves
d) glass
8. Loamy soil is rich in __________, making it fertile.
a) water
b) air
c) humus
d) stones
9. Sandy soil runs freely through the fingers when __________.
a) wet
b) cold
c) dry
d) warm
10. Clayey soil is __________ when wet.
a) smooth
b) hard
c) loose
d) soft
11. Sandy soil is often found in __________ and erosion areas.
a) forests
b) farms
c) footpaths
d) rivers
12. Clayey soil is __________ and sticky when it’s wet.
a) smooth
b) rough
c) slippery
d) dry
13. Loamy soil has properties that are different from __________ and clay.
a) water
b) sand
c) stones
d) leaves
14. Loamy soil is the best for __________ because it is fertile.
a) building
b) farming
c) playing
d) painting
15. Sandy soil feels __________ when rubbed between the fingers.
a) rough
b) slippery
c) wet
d) cold
Note that the above physical properties of Soil is based on these major categories
- Soil texture : This deals with the varies sizes of particles that make up of the particular soil in question. Clay soil particles are closely packed together while sandy soil is loose
- Soil structure : This refers to the way particles of soil are arranged to allow space between them. It is used to refer to how individual particles are arranged or structured
- Soil porosity : This term is used to refer to how freely water can flow in soil particles. Good and healthy soil have many pores between and within the particles
- Soil colour : Clay soil is reddish in colour while sandy soil appears white
[mediator_tech]
Evaluation
1. Soil texture relates to the __________ of particles in soil.
a) shape
b) size
c) color
d) smell
2. Clay soil has __________ packed particles.
a) loosely
b) closely
c) colorful
d) large
3. Soil structure refers to how particles are __________ in soil.
a) hidden
b) organized
c) separated
d) floating
4. Soil structure allows for __________ between particles.
a) breaking
b) squeezing
c) space
d) noise
5. Soil porosity is about how __________ water can flow in soil.
a) quickly
b) slowly
c) freely
d) noisily
6. Healthy soil has __________ pores within and between particles.
a) colorful
b) empty
c) many
d) solid
7. Sandy soil often appears __________ in color.
a) green
b) red
c) white
d) black
8. Clay soil is known for its __________ color.
a) blue
b) reddish
c) yellow
d) brown
9. Soil texture relates to the __________ of particles in soil.
a) shape
b) taste
c) smell
d) sound
10. Sandy soil is characterized by its __________ particles.
a) closely packed
b) large
c) colorful
d) loose
11. Soil structure refers to the __________ of soil particles.
a) size
b) arrangement
c) color
d) taste
12. Healthy soil has __________ within and between particles.
a) few pores
b) tiny particles
c) many pores
d) no color
13. Soil porosity is about how __________ water can move in soil.
a) slowly
b) freely
c) noisily
d) tightly
14. Clay soil is often __________ in color.
a) green
b) brown
c) reddish
d) white
15. Sandy soil typically appears __________ in color.
a) red
b) blue
c) yellow
d) white
Causes of loss of soil fertility
Soil is said to be fertile when all the nutrients necessary for plant growth and development are present in it. Soil can lose its fertility in five main ways:
In some places, big forests and vast grasslands are set on fire to burn. Some of these areas are good farmlands. When this is done, dead and decaying leaves, grasses and living soil organisms are burnt. Dead leaves, grasses and soil organisms add fertility to the soil. Soil, therefore, loses its fertility when they are burnt.
Leaching
This is the downward movement of nutrients from the top soil to the underground layers of the soil. Some nutrients dissolve in water for plants to absorb as food. When rain falls, some water collects in low-lying areas of the farm and stays there for some time. As this water sinks into the soil, it carries with it dissolved soil nutrients. These nutrients can no longer be available to the plants growing On the surface of the soil. The nutrients are lost or leached away.
Erosion
This is the gradual wearing away of the top soil by water or wind. When rain falls, water flows on the surface of the soil. The water carries the top soil along with it. The top soil contains nutrients dissolved in water. These nutrients are carried away by the flowing water and are no longer available for plants to use.
Wind blows and carries some soil particles from one place to another. This soil contains some nutrients which are also carried away by the wind.
Crop removal
The crops that farmers plant in their farms absorb nutrients from the soil for their growth and development. These nutrients, once taken up or absorbed, are no longer in the soil. Another crop planted in the same soil the following year may not have sufficient nutrients for its own growth and development.
Clean clearing
Leaves on forest trees drop on the soil. These leaves die and decay, and add nutrients to the soil. When these trees are removed and the forest under growths cut, the soil loses its regular supply of nutrients from the forest.
[mediator_tech]
Evaluation
1. Soil is considered fertile when it contains all the necessary __________ for plant growth.
a) water
b) sunlight
c) nutrients
d) air
2. One way soil loses its fertility is when forests and grasslands are set on __________.
a) water
b) fire
c) ice
d) wind
3. Burning forests and grasslands leads to the loss of fertility because it burns dead leaves, grasses, and __________ organisms.
a) tiny
b) living
c) colorful
d) old
4. Leaching is the downward movement of nutrients from the top soil to the __________ layers of the soil.
a) underground
b) surface
c) middle
d) aboveground
5. Some nutrients dissolve in water and are carried away when rainwater collects in __________ areas.
a) low-lying
b) high-lying
c) sunny
d) windy
6. Erosion occurs when the topsoil is gradually worn away by __________ or wind.
a) animals
b) sunlight
c) water
d) air
7. Water flowing on the soil’s surface can carry away the topsoil and the __________ nutrients it contains.
a) hidden
b) dissolved
c) colorful
d) dry
8. Nutrients carried away by wind are found in soil particles that are __________.
a) heavy
b) colorful
c) small
d) wet
9. Crop removal results in nutrient loss because crops absorb nutrients from the soil for their __________.
a) growth and development
b) decoration
c) hiding
d) noise
10. Once nutrients are absorbed by crops, they are __________ available in the soil.
a) more
b) still
c) no longer
d) rarely
11. Clean clearing involves the removal of trees and forest undergrowth, which reduces the soil’s regular supply of __________ from the forest.
a) water
b) nutrients
c) animals
d) sunlight
12. Soil loses its fertility when forests and grasslands are set on __________.
a) water
b) fire
c) ice
d) wind
13. Leaching leads to the downward movement of nutrients to __________ layers of the soil.
a) lower
b) upper
c) middle
d) outer
14. Erosion can occur due to the wearing away of the topsoil by __________.
a) plants
b) animals
c) sunlight
d) water or wind
15. Nutrients carried away by wind are found in small __________ particles.
a) colorful
b) heavy
c) wet
d) soil
Presentation
The topic is presented step by step
Step 1:
The class teacher revises the previous topics
Step 2.
He introduces the new topic
Step 3:
The class teacher allows the pupils to give their own examples and he corrects them when the needs arise
Evaluation:-
Answer the following questions
- The process whereby rocks are broken down to form soil is known as ______ (a) Transformation (b) Weathering (c) Osmosis
- The physical properties of Soil consists of ______ (a) solid, liquid and gas (b) solid and liquid (c) gas only
- The solid components of soil are also known as soil ______ (a) physical (b) particles (c) nutrients
- Soil pores are used by soil to ______ (a) retain water and air (b) produce pores (c) movements
- What percentage of soil is made up of air (a) 45 (b) 5 (c) 25
- What percentage of soil is made up of mineral matter? (a) 45 (b) 5 (c) 25
- Which soil type is having the highest porosity (a) clay (b) sandy (c) clay
- The parent materials of soil are ______ (a) Men (b) Rocks (c) Mineral resources
- The processes of breaking down rocks are physical, chemical and ______ (a) biological (b) systematic (c) Manually
- ______ makes the rock to expand, crack and break down into small pieces. (a) Rainfall (b) High temperature (c) Tension
Conclusion :
The teacher summarize the lesson. He or she gives out a board summary of the topic as note . He or she goes round to mark and does the necessary corrections
