SOIL : CAUSES OF REDUCTION IN SOIL FERTILITY PRIMARY 4 SECOND TERM AGRICULTURAL SCIENCE WEEK 4

Subject : AGRICULTURAL SCIENCE

Class : Primary 4

Term : Second Term

Week : Week 4

Topic :

SOIL : CAUSES OF REDUCTION IN SOIL FERTILITY

Previous Lesson: 

SOIL : CLASSIFICATION OF SOIL IN AGRICULTURE

Behavioural Objectives 

By the end of the lesson, pupils should be able to

• explain soil fertility;
• identify the causes of
  reduction in soil
  fertility;
• describe effects of
  reduction in soil
  fertility

Learning Objectives 

• Whole class brainstorm on
  the meaning of soil
  fertility.
• Pupils, visit the school
  farm, observe different soil
  samples and identify soil
  rich in nutrients from
  nutrients deficient soil.
• Pupils, in groups of five,
  observe crops at the farm
  and discuss the effect of
  soil fertility reduction.
• Pupils, in groups of two,
  collect three samples of
  sandy, loamy and clayey
  soil in a sealed nylon,
  label properly, paste on a
  cardboard paper and
  present to the class.

Embedded Core Skills 

• Communication and Collaboration
• Critical thinking and problem solving
• Leadership skills and Personal Development
• Creativity and Imagination
• Citizenship

Learning Resources 

• Display of different types of soil
• Web links

Content Development

Explain soil fertility

Soil fertility is a term that describes how healthy and nutritious the soil is for growing plants.

Good soil fertility means that plants can grow strong and healthy because the soil has all the nutrients they need to thrive.

Here are some examples to help explain soil fertility to grade 4 pupils:

• Imagine you’re trying to grow a flower in two different pots. In the first pot, you use soil that has lots of nutrients, like compost and fertilizer. In the second pot, you use plain soil from your backyard. The flower in the first pot will grow bigger and healthier than the one in the second pot because the soil in the first pot has better fertility.
• Another example is to think about a farm where crops are grown. Farmers will often use fertilizers and other nutrients to improve the soil fertility. This helps the crops to grow stronger and produce more fruits and vegetables for us to eat.
• Soil fertility can also be affected by things like pollution, erosion, and drought. If the soil is polluted or washed away by heavy rain, it can become less fertile and harder for plants to grow.

Soil fertility is really important for growing healthy plants and for providing us with the food we need to eat. We need to take care of our soil by using fertilizers and other nutrients, and by protecting it from pollution and erosion

The causes of reduction in soil fertility

There are several factors that can contribute to a reduction in soil fertility, which means that the soil becomes less healthy and less able to support plant growth. Here are some of the most common causes of a reduction in soil fertility:

1. Overuse or misuse of soil: If soil is overused or misused, it can become depleted of nutrients and lose its ability to support plant growth. For example, if the same crop is planted in the same field year after year, the soil may become exhausted and lose its fertility.
2. Erosion: Erosion is the process of soil being washed away by wind or water. When soil is eroded, the top layer is removed, taking with it valuable nutrients and organic matter. This can make the soil less fertile and less able to support plant growth.
3. Pollution: Pollution from chemicals and other sources can harm soil fertility. For example, if pesticides or other chemicals are used in excess, they can kill beneficial microorganisms in the soil that are necessary for healthy plant growth.
4. Lack of organic matter: Organic matter, such as compost and manure, provides nutrients to the soil and helps to retain moisture. If there is a lack of organic matter in the soil, it can become less fertile and less able to support plant growth.
5. Climate change: Climate change can also affect soil fertility. Extreme weather conditions, such as drought or heavy rain, can damage soil structure and deplete nutrients.

Effects of reduction in soil fertility.

Reduction in soil fertility can have several negative effects on plant growth, crop yields, and the environment. Here are some of the most common effects of a reduction in soil fertility:

1. Reduced plant growth: Soil fertility is essential for plant growth, as it provides the necessary nutrients and minerals for healthy plant growth. A reduction in soil fertility can lead to stunted growth, lower crop yields, and lower quality produce.
2. Decreased soil structure and stability: Soil fertility is also important for maintaining soil structure and stability. When soil becomes less fertile, it can become more compacted and less able to hold water, which can lead to erosion and loss of topsoil.
3. Increased need for fertilizers and pesticides: When soil fertility decreases, farmers may need to use more fertilizers and pesticides to maintain healthy crop growth. This can lead to increased costs, environmental pollution, and potential health risks.
4. Loss of biodiversity: Soil fertility is important for supporting a diverse range of plants and microorganisms. A reduction in soil fertility can lead to a decrease in biodiversity, which can have negative impacts on the environment and ecosystem services.
5. Reduced soil carbon sequestration: Healthy soils can sequester carbon, which helps to mitigate climate change. However, a reduction in soil fertility can lead to a decrease in soil carbon sequestration, which can contribute to climate change.

Lesson Presentation

Materials Needed:

• Pictures of healthy and unhealthy soil
• Samples of different types of soil (if available)
• Chart paper and markers
• Video on soil fertility (optional)

Introduction:

• Begin by showing pictures of healthy and unhealthy soil, and ask students to identify the differences between the two.
• Ask students to share what they know about soil and why it’s important for plant growth.
• Introduce the topic of soil fertility and explain that it’s the term used to describe how healthy and nutritious the soil is for growing plants.

Body:

• Explain to students that good soil fertility means that plants can grow strong and healthy because the soil has all the nutrients they need to thrive.
• Discuss the different factors that can contribute to a reduction in soil fertility, such as overuse or misuse of soil, erosion, pollution, lack of organic matter, and climate change.
• Show samples of different types of soil (if available) and discuss the differences between them in terms of their fertility.
• Ask students to brainstorm ways to maintain soil fertility, such as adding organic matter to the soil, reducing the use of harmful chemicals, and practicing crop rotation.
• Create a chart with the students to summarize the main points of the lesson.

Conclusion:

• Wrap up the lesson by reviewing the importance of soil fertility for healthy plant growth, and the negative effects of a reduction in soil fertility.
• Ask students to share what they learned from the lesson and how they can apply this knowledge to their own lives.
• Optional: Show a video on soil fertility to reinforce the lesson content.

Assessment:

• Have students complete a worksheet or quiz on soil fertility to assess their understanding of the topic.
• Alternatively, have students write a short paragraph or draw a picture that summarizes the main points of the lesson.

Extension:

• Encourage students to conduct their own experiments on soil fertility, such as testing different types of soil and adding different types of organic matter to see how they affect plant growth.
• Ask students to research the impact of soil fertility on agriculture, the environment, and society, and present their findings to the class.

Weekly Assessment

1. What is soil fertility? a. The amount of water in the soil b. The amount of sunlight the soil receives c. The health and nutrient content of the soil d. The type of plants that can grow in the soil
2. Why is soil fertility important for plant growth? a. It provides the necessary nutrients for healthy plant growth b. It helps to regulate the temperature of the soil c. It prevents erosion and loss of topsoil d. It ensures that plants receive enough sunlight
3. Which of the following is NOT a factor that can contribute to a reduction in soil fertility? a. Overuse or misuse of soil b. Use of organic matter and fertilizers c. Pollution d. Climate change
4. What is erosion? a. The process of soil becoming more compacted b. The process of soil losing its nutrient content c. The process of soil being washed away by wind or water d. The process of soil becoming contaminated with chemicals
5. How can farmers maintain soil fertility? a. Reduce the use of harmful chemicals b. Practice crop rotation c. Add organic matter to the soil d. All of the above
6. How does a reduction in soil fertility affect plant growth? a. It leads to stunted growth and lower crop yields b. It increases the need for fertilizers and pesticides c. It can result in lower quality produce d. All of the above
7. What is organic matter? a. Matter that contains carbon b. Matter that contains minerals c. Matter that is found in the ocean d. Matter that is harmful to the soil
8. Which of the following is a common cause of a reduction in soil fertility? a. Using organic matter in the soil b. Overuse of pesticides c. Heavy rainfall d. Planting a variety of crops
9. How can a reduction in soil fertility impact the environment? a. It can lead to a decrease in biodiversity b. It can result in soil erosion and loss of topsoil c. It can contribute to climate change d. All of the above
10. Why is it important to take care of our soil? a. To support healthy plant growth b. To protect the environment c. To ensure sustainable food production d. All of the above

Weekly Test

1. Soil fertility refers to how healthy and ____________ the soil is for growing plants.
2. Good soil fertility means that plants can grow strong and healthy because the soil has all the ____________ they need to thrive.
3. Overuse or misuse of soil, erosion, pollution, lack of organic matter, and climate change are all factors that can contribute to a ____________ in soil fertility.
4. ____________ is the process of soil being washed away by wind or water.
5. Organic matter, such as compost and manure, provides ____________ to the soil and helps to retain moisture.
6. A reduction in soil fertility can lead to stunted growth, lower crop yields, and lower ____________ produce.
7. Soil fertility is important for supporting a diverse range of ____________ and microorganisms.
8. Practices such as adding organic matter to the soil, reducing the use of harmful chemicals, and practicing crop rotation can help to ____________ soil fertility.
9. Healthy soils can sequester ____________, which helps to mitigate climate change.
10. It is important to take care of our soil to support healthy plant growth, protect the environment, and ensure ____________ food production.

Assignment

1. What is soil fertility, and why is it important for plant growth?
2. What are some factors that can contribute to a reduction in soil fertility?
3. How does erosion affect soil fertility, and what can be done to prevent it?
4. What is organic matter, and why is it important for maintaining soil fertility?
5. How can farmers maintain soil fertility, and what are the benefits of doing so?
6. What are some negative effects of a reduction in soil fertility on plant growth and crop yields?
7. Why is biodiversity important for soil fertility, and how can it be supported?
8. What is soil carbon sequestration, and how does it relate to soil fertility?
9. What are some strategies for protecting soil fertility in the face of climate change?
10. Why is it important to take care of our soil, and what are the consequences of neglecting soil fertility?