Soil - Class 4 Science - New St. Mery English School

Soil is one of the most important natural resources on Earth. It is the upper layer of the land where plants grow and many living organisms live. Without soil, life on Earth would not be possible because plants get water, nutrients, and support from it.

Soil is made up of tiny particles of rocks, minerals, air, water, and dead plants and animals. Different types of soil such as sandy soil, clayey soil, and loamy soil are found in different places, and each type is useful for different kinds of plants.

In this chapter, Class 4 students will learn what soil is, how it is formed, its types, and why it is important for plants, animals, and humans. This lesson helps children understand how soil supports life and how we should take care of this precious natural resource. 🌱 

Soil - Class 4 Science - New St. Mery English School

What is Soil?

Ans:- Soil is the top layer of the Earth in which plants grow. It is made of tiny rock particles, air, water, and organic matter like humus.

How does soil form?

Ans:- soil is formed when rocks breakdown into tiny pieces due to continuous drying, heating and cooling by the sun, rain and wind. this is called weathering. this repeated weathering over thousands of years break the rock into small pieces and thus, soil is formed. soil formation is very slow, long and continuous process.

What is pedology?

Ans:- The science that deals with study of soil is called as pedology.

What is pedologist?

Ans:- The scientists who study soil are called pedologist.

What is composition of soil?

Ans:- Soil is made up of different sized particles. Three main particles of the soil are Sand, Silt and Clay.

Sand- The largest soil particles

Silt- These particles are smaller than sand but larger than clay

Clay- The smallest soil particles 

How many types of soil on the basis of the ratio of different soil particle.

Ans:- There are three types of soil on the basis of the ratio of different soil particle.

1- Sandy Soil

2- Clayey Soil

3- Loamy Soil

                                          What is Sandy soil?

Ans:- A type of soil that has big particles and trap a lot of air between the particles. It is rough and does not hold water is called Sandy soil. This soil contains more of sand particles. It is non-sticky. It is found in desert or at seashores.

                                           

                                          What is Clayey soil?

Ans:- A type of soil that is very fine and does not have space for air between the particles and it can hold lot of water is called Clayey soil. It is sticky and good for making pots and toys.

                                           What is loamy soil?

Ans:- A type of soil that is the mixture of sandy soil, clayey soil and silt in equal proportion is called loamy soil. It is brown in colour and rich in humus, nutrients and moisture. It contains the right amount of air and water. It is the best soil for plants to grow.

Soil Profile

What is Soil Profile?

Ans:- Soil is made up of different layers. The vertical section of the soil that shows different layers from the upper surface to underlying rocks is called Soil Profile. 

In how many levels is the Soil Profile divided?

Ans:- Soil Profile is divided into three levels.

1- Top Soil

2- Sub Soil

3- Bed Rock

Write about Top Soil.

Ans:- It is uppermost layer of the soil.

          It is rich in nutrients.

          It contains humus.

          It contains air.

          It is dark in colour.

         It is home of some animals.

Write about Sub Soil.

Ans:- It is just below the top soil.

          It is made of broken pieces of rocks.

          It contains some humus and water.

          It contains lesser air.

         It is less fertile.

         It contains only few organisms live here.

Write about Bed Rock

Ans:- It is the deepest layer  of the soil.

          It is found below the sub soil.

         It contains mostly rocks.

        There is no humus here.

        It contains very little water.

What is Soil Erosion?

Ans:- Soil erosion is the process of removal, wearing away, or washing away of the top layer of soil by natural forces like wind, water, or human activities.

Causes of Soil Erosion

1. Heavy Rainfall – washes away soil.

2. Strong Winds – blow loose soil.

3. Floods – carry away soil with water.

4. Deforestation – cutting trees removes roots that hold soil.

5. Overgrazing – animals eat plants and expose soil.

6. Poor farming methods – loosen and expose soil.

Soil Conservation

Soil Conservation means protecting the soil from being damaged, lost, or washed away. It includes all the methods that help save soil, improve soil quality, and prevent soil erosion.

Write five ways by which we conserve soil.

Ans:- The five ways by which we conserve soil are

1- By afforestation

2- By building bunds or embankments along river banks

3- By growing plants in farm lands

4- By avoiding overgrazing

5- By step farming in Hilly areas