SOIL
AGRICULTURAL SCIENCE FIRST TERM
E NOTES FOR SS 2
FIRST Term Agricultural Science
SS 2
Senior Secondary School 2
Subject : AGRICULTURAL SCIENCE
Topic : SOIL
Class : SS 2
TERM : FIRST TERM
WEEK : WEEK 1
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 meaning of soil
2. Explain types of soil
3. Say the composition of soil
Content :
SOIL
WEEK ONE
TOPIC: SOIL
CONTENT
- Meaning of Soil
- Types of Soil
- Composition of Soil
- Properties of Soil
MEANING OF SOIL
Soil can be defined as the unconsolidated weathered materials found in the upper most layer of the earth surface on which plants grow. It provides support and nutrients for the plants.
TYPES OF SOIL
The three types of soil are; Sandy Soil, Clay Soil and Loamy Soil.
SANDY SOIL
A soil is said to be sandy if the proportion of sand particles in a sample of the soil is high. The particles are mainly quartz (SiO2).
PROPERTIES OF SANDY SOIL
- Sandy soil is coarse, grained and gritty.
- It is loose with large pore spaces.
- It absorbs and loses water easily.
- It is not sticky when wet and cannot form a cast or ribbon.
- It is well aerated with low water holding capacity.
- Percolation in sandy soil is high but capillarity is low.
- Sandy soil heats up easily during the day and cools down quickly in the night.
- It supports leaching, hence it is low in plant nutrients.
- It does not support water logging and erosion.
- Sandy Soil has grey or brownish colour.
METHODS OF IMPROVING SANDY SOIL
- Planting of cover crops
- Application of compost manure
- Application of farm yard manure
- Mulching the soil
- Avoidance of bush burning
ECONOMIC IMPORTANCE OF SANDY SOIL
- It is good for cultivation of cassava, cotton, groundnut etc.
- It is good for building construction when mixed with cement.
CLAY SOIL
A soil is said to be clayed if the proportion of clay in a sample of the soil is very high.
PROPERTIES OF CLAYED SOIL
- The particles are fine, powdery and smooth when dry.
- The parties are sticky and moody when wet.
- The particles are tightly bound together with little pore (air) spaces.
- It has a high water holding capacity.
- It is poorly aerated.
- Percolation in clay is low but capillarity is high.
- It does not support leaching, hence it contain plant nutrients.
- It is hard when dry and sticky when wet.
- It can easily form a ribbon or cast when molded.
- It supports water – logging and erosion.
- It has a grey or brownish colour.
METHODS OF IMPROVING CLAYED SOIL
- Liming
- Addition of organic manure
LOAMY SOIL
Loamy soil is a mixture of sand and clay particles with high proportion of organic matter.
PROPERTIES OF LOAMY SOIL
- Loamy Soil is moist, loose with moderate sized pore space.
- The structure breaks easily when wet and friable when dry.
- It has non-powdery and non-sticky texture.
- It can easily be worked or cultivated.
- It contains lots of organic matter (humus).
- It does not support erosion and water logging.
- It was well aerated and it can hold water.
- It is the best soil for cultivation of crops.
- It is dark brown or black in colour.
COMPONENT/COMPOSITION OF THE SOIL
The composition of the soil by percentage are:
- Soil mineral matter 45%
- Soil water 25%
- Soil air 25%
- Soil living Organisms 5%
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
- What is soil?
- List the three types of Soil and state three characteristics of sandy soil.
- What is clay soil?
- In a tabular form, give five differences between sandy and Clay soil.
- What is loamy soil?
- List four properties of loamy soil.
- List two methods of improving clay soil.
- List the component of soil and their respective percentage composition.
- List three ways of improving sandy soil.
- List five properties of sandy soil.
- List five properties of clay soil
- (a) What is a soil? (b) List the four component of soil.
- 2. (a) State four characteristics of clay soil. (b) What is weathering?
Objectives
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
- Particles of soil care closely packed together in ____ soil (a) sandy (b) clay
- (c) loamy (d) silt
- Quartz is the major composition of ____ soil (a) clay (b) loamy (c) sand (d) silt
- The soil which mostly which mostly support leaching is ____ (a) sand (b) clay
- (c) loamy (d) silt
- The soil which supports water logging is ____ (a) sand (b) silt (c) clay (d) loamy
- The best soil for agriculture is ______ (a) sand (b) clay (c) silt (d) loamy
- 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
