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Important Questions for CBSE Class 7 Science Chapter 9 - Soil

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Last updated date: 13th Jul 2024
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CBSE Class 7 Science Chapter-9 Important Questions - Free PDF Download

Free PDF download of Important Questions with solutions for CBSE Class 7 Science Chapter 9 - Soil prepared by expert Science teachers from the latest edition of CBSE(NCERT) books. Register Online for NCERT Solutions Class 7 Science tuition on Vedantu.com to score more marks in CBSE board examination. Vedantu is a platform that provides free CBSE Solutions (NCERT) and other study materials for students. Maths Students who are looking for the better solutions ,they can download Class 7 Maths NCERT Solutions to help you to revise complete syllabus and score more marks in your examinations.



Study Important Questions for Class 7 Science Chapter 9 - Soil

Very Short Answer Questions: (1 Marks)

Define the Following Terms:

1. Soil

Ans: Soil is the dark brown to the black upper layer of the ground that contains a mixture of humus and stony particles and is where plants thrive.


2. Soil Profile

Ans: The soil profile is a vertical segment of the soil that represents all of the layers.


3. Weathering

Ans: Weathering is the progressive disintegration of rocks and minerals into smaller soil particles as a result of environmental influences such as wind, water, and temperature.


4. Humus

Ans: The dead and decaying plant materials that make up the organic element of the topsoil. It is created when plant matter decomposes under the influence of soil microbes.


5. Erosion

Ans: Erosion is the progressive wearing down and loss of the land's surface caused by wind, water, and other factors.


Short Answer Questions: (3 Marks)

6. What are the factors that cause soil erosion?

Ans: Erosion is the progressive wearing down and loss of the land's surface caused by wind, water, and other factors. Erosion can be induced by both natural and man-made environmental conditions.

1. Wind: When soil is exposed to the wind on a regular basis, the finer topsoil particles are swept away by the wind, resulting in erosion.

2. Water: As water flows above land, it eliminates the top layers of soil, causing erosion.

3. Cattle Overgrazing and Deforestation: Cattle overgrazing and deforestation both deplete plant roots in the soil. These roots are unable to hold on to soil particles as a result. Soil deteriorates as it becomes loose and degraded.


7. What is the percolation rate of the soil?

Ans: The passage of water through the soil is known as percolation. The rate at which water moves through the soil is referred to as the percolation rate. The amount of water percolated per minute can be calculated. The percolation rate is a measure of the soil's ability to retain water. Water retention capacity decreases as water percolates faster through the soil, and vice versa. The highest percolation rate is found in sandy soil, whereas the lowest is found in clayey soil.


8. What is meant by water retention of the soil?

Ans: Water retention refers to the amount of water retained by the soil. After the rest of the water has percolated, this is the water that stays in the soil. This is a measurement of how much water will be available to plants and other organisms in the soil. It is calculated by subtracting the percolated water from the total water added to the soil. The amount of water per kilogramme of soil can be calculated. Clayey soil holds the most water, whereas sandy soil holds the least.


9. How can we prevent soil erosion?

Ans: Soil erosion can be controlled and prevented in the following ways: 

1. Planting/Vegetation: Planting vegetation can control and prevent soil erosion by holding on to soil particles and preventing them from being eroded.

2. Fertilizer Use: Fertilizers can stop soil from eroding by adding an extra layer of protection.

3. Retaining Walls: Constructing retaining walls around places where soil erosion is a problem can help to reduce the amount of soil eroded.

Permeable fabric materials, such as coir, can be used to strengthen the soil and prevent erosion.


10. How is soil important for plant growth?

Ans: Plants cannot grow without soil.

1. Soil gives a surface for plant roots to anchor to and helps them stand upright.

2. The soil offers essential minerals for plant growth.

3. Soil is a vital source of water for plant growth.

4. Humus and essential bacteria in the soil aid in nitrogen fixation and availability to plants.


Long Answer Questions: (5 Marks)

11. Explain the soil profile with a diagram.

Ans:


Soil profile


The vertical part of a soil profile represents the many layers of soil on the planet.

The colour, texture, depth, and chemical makeup of each layer vary. Horizons are the names given to these levels.

O Horizon: The humus layer on topsoil is known as the O horizon. Because microbes decompose plant stuff, it is high in organic matter. It has a dark colour and a velvety texture. It contributes to the soil's fertility.

A Horizon: The topsoil is the topmost layer on the land surface and is referred to as A horizon. The surface of the A-horizon, or topsoil, is known as the humus or O horizon. A horizon is more permeable and made up of fine soil particles. Microorganisms and other organisms such as worms, rodents, moles, and beetles live there because it holds more water. The little plants' roots are completely encased in topsoil.

B Horizon: It's smaller and deeper than A horizon. It has a lower proportion of organic stuff and a higher proportion of hard mineral components.

C Horizon: It's made up of little rock chunks with fractures and crevices.

Bedrock: The soil's deepest layer. It is made up of bigger rock fragments. Digging is extremely difficult and time-consuming.


12. Compare the Different Types of Soil.

Ans: The differences between types of soil are:

Sandy Soil

Loamy Soil

Clay Soil

It has a higher proportion of large soil particles.

There is an equal number of large and small soil particles in this mixture.

A higher proportion of fine soil particles are present.

Highly Porous

Moderately Porous 

Highly compact and least porous.

Water Retention: Low

Water Retention: Moderate

Water Retention: High

Percolation: High 

Percolation: Moderate

Percolation: Low

Air Spaces: High

Air Spaces: Moderate

Air Spaces: Low


13. Explain How Soil is Formed.

Ans: Weathering is the process that creates soil. Weathering is the progressive disintegration of rocks and minerals into smaller soil particles as a result of environmental influences such as wind, water, and temperature. Initially, there were enormous tracts of rocky ground. These massive rocks were exposed to extremes of temperature, rain, wind, and river flow, among other things. The surface of the rock slowly and gradually breaks down to smaller rock particles on the surface due to the constant and combined effect of all these forces. The C-horizon is thus produced from the bedrock. Further weathering of the smaller rock particles results in the formation of the B horizon, which consists of smaller rock particles packed more compactly. The weathering of the B horizon continues until the formation of the A horizon. The soil particles in a horizon are finer and softer. Microbial breakdown adds organic humus to the mix. Soil formation is a slow and gradual process that might take up to a million years.

Why are Important Questions for Class 7 Science Chapter 9 - Soil Necessary?

  • Vedantu’s Important Questions for Class 7 Science Chapter 9 - Soil are the finest material to understand and practice the topics in the best way.

  • The material carries all the information in detail and pointwise.

  • All the cases of the material are solved in the simplest way which explains the term clearly.

  • Vedantu’s Important Questions for Class 7 Science Chapter 9 - Soil provides all the main topics so that the student can focus on it and prepare for the exam. 


Conclusion

Exploring the essential questions from CBSE Class 7 Science Chapter 9, 'Soil,' leads to a deeper understanding of this vital natural resource. These questions delve into soil formation, its composition, and the crucial role it plays in sustaining life. Understanding these aspects enables students to appreciate soil's significance in agriculture, ecology, and the environment. Mastering these questions fosters a holistic understanding of soil science, empowering students to become responsible stewards of our Earth.

FAQs on Important Questions for CBSE Class 7 Science Chapter 9 - Soil

1. What is soil according to Chapter 9 of Class 7 Science?

The presence of natural resources is what makes our planet unique and soil is an important natural resource. It is a living natural resource. It anchors the roots of the soil and contains several microorganisms that help in the formation of humus and organic matter. It also provides water and nutrients to the plants and other natural vegetation. It enables the growing and cultivation of different types of crops. Soil is essential for agriculture which provides livelihood to more than 50% of our population.

2. What is the soil profile according to Chapter 9 of Class 7 Science?

Soil profile is the structuring of the soil in vertical layers. Soil comprises several layers that differ in composition as well as characteristics. Each layer has a different texture, colour, depth, and the chemical composition also differs. The layers are referred to as Horizons. The uppermost layer is called Horizon A. It is rich in minerals and humus. Horizon B contains less humus but more minerals. Horizon C includes lumps of rock and the last layer is the bedrock.

3. What are the different types of soil as explained in Chapter 9 of Class 7 Science?

The different types of soil are Sandy, Clayey, and Loamy. The soil type is characterized by the proportion of particles of different sizes. If the soil contains a higher proportion of big particles, it is called sandy soil. When the soil contains a larger proportion of fine particles, it is known as clayey soil. And when the proportion of bigger and fine particles is almost the same, the soil is called loamy soil. Each soil has distinct characteristics in terms of the space between the particles, whether they are well aerated or not etc.

4. What factors have an effect on soil as discussed in Chapter 9 of Class 7 Science?

Different types of soils are found in different climatic regions. There are various factors that affect the soil and its structure. These factors are wind, rainfall, temperature, light, and humidity. These factors play a significant role in the formation of the soil, its profile as well as on the maturing of the soil. These factors also bring about changes in the structure of the soil. The climate of a region and the soil and its characteristics determine the types of crops and plantations that might grow in the region.

5. Which website provides a good quality of important questions for Chapter 9 of Class 7 Science textbook?

Science is as much about applying the concept as about knowing the concept. It is imperative to attempt important questions to strengthen your understanding of the core concept. The PDF of important questions provided at Vedantu's website(vedantu.com) challenges you to be creative and boosts your creative thinking to find scientific solutions to problems. The PDF format allows you to study, prepare and practice the questions at your preferred pace and can be downloaded absolutely free of cost.