Master Class 7 Science Chapter 8 Soil Oxford Book Solution

Class 7 Science Chapter 8 Soil Oxford Book Solution explains the formation, types, and layers of soil along with its importance in agriculture and daily life. This chapter also covers soil profile, percolation rate, and soil conservation methods. Here, you will find detailed and easy-to-understand solutions to all textbook questions from the Oxford book, helping students revise and prepare effectively.

Class 7 Science Chapter 8 Soil Oxford Book Solution Full Chapter

1. Objective type questions

A. Fill in the blanks with the correct words:

Soil erosion is fastest in hot and moist (Hot and moist/cold and dry) climate.
Answer: hot and moist
Bedrock (Subsoil/Bedrock) is rich in minerals that seep down along with water and contains compactly packed fine particles of soil.
Answer: Bedrock
Soil particles have empty spaces between them that are called pore spaces (Spores/pore spaces).
Answer: pore spaces
The rate at which water exits the soil is called soil percolation (Percolation/fertility).
Answer: percolation
A soil suitable for growing crops has to be fertile (fertile/dark in colour).
Answer: fertile
Terrace (Terrace/Limited) farming should be adopted in hilly areas.
Answer: Terrace

B. Write T for the True and F for the false statements. Correct the false statements:

Acid rain and acid water from factories and industries help in conserving the soil. – F
Correction: Acid rain and acidic waste harm the soil and lead to soil degradation, not conservation.
All soils are tight and compact. – F
Correction: All soils are not tight and compact; some are loose with good pore space.
The physical features of a place play a very important role in soil conservation. – T
The topsoil contains partly weathered pieces of rock. – F
Correction: The subsoil contains partly weathered pieces of rock. Topsoil contains humus and nutrients.
Larger the soil particles, lesser will be the pore space. – T
Loamy soil is good for cultivation of crops and gardening. – T

Class 7 Science Chapter 8 Soil Oxford Book Solution – MCQs

C. Choose the correct option.

11. Which of these factors affect soil formation?
a. Climate
b. Slope of land
c. Characteristics of the parent rock
d. All of these
✅ Answer: d. All of these
All these factors — climate, slope, and parent rock — contribute to the formation of soil.

2. Which of these layers of soil is usually characterized by cracks and crevices, and difficult to dig beyond it?
a. Topsoil
b. Subsoil
c. C Horizon
d. R Horizon
Answer: d. R Horizon
The R Horizon is the unweathered bedrock layer and is hard to dig due to cracks and compactness.

3. Which of these soils retains moisture and becomes very sticky when wet?
a. Sandy soil
b. Clayey soil
c. Loamy soil
d. Both a and b
Answer: b. Clayey soil
Clayey soil has very small particles, retains water well, and becomes sticky when wet.

4. Which of these adjustments help to make the soil fertile?
a. Alteration of pH
b. Aeration
c. Addition of fertilizers
d. All of these
Answer: d. All of these
Fertility of soil improves with proper pH balance, air circulation, and the use of nutrients/fertilizers.

5. Which of these measures will help to control soil pollution?
a. Acid rain and acid water
b. Improper dumping of garbage
c. Using organic pesticides
d. Spilling or leakage of chemical
Answer: c. Using organic pesticides
Organic pesticides are eco-friendly and help reduce soil pollution.

6. In which of these weathering processes, the characteristics of the original rock does not change?
a. Physical weathering
b. Chemical weathering
c. Biological weathering
d. All of these
Answer: a. Physical weathering
In physical weathering, rocks break down without changing their chemical composition.

7. In which of these climates is soil formation the fastest?
a. Hot and dry
b. Hot and moist
c. Cold and dry
d. Cold and moist
Answer: b. Hot and moist
Warm temperatures and moisture speed up weathering and the formation of soil.

8. In which of the following stages of soil formation does humus get formed by breakdown of plant or animal remains?
a. Stage I
b. Stage II
c. Stage III
d. None of these
Answer: c. Stage III
Humus forms in the final stage when organic matter like dead plants and animals decomposes.

9. Which of these special properties determine the soil type?
a. Absorption of water in soil
b. Moisture in the soil
c. Percolation rate of water in soil
d. All of these
Answer: d. All of these
All these factors help determine the type and usability of soil.

10. A soil sample is crumbly and dark, but not especially gritty or smooth and shiny. Which of these soils could it be?
a. Sandy
b. Clayey
c. Loamy
d. Gravel
✅ Answer: c. Loamy
Loamy soil is a balanced mix of sand, silt, and clay. It is crumbly, rich in nutrients, and ideal for plants.

Class 7 Science Chapter 8 Soil Oxford Book Solution – 1 Mark

II. Very short answer type questions

Give one word for the following.

1. Breakdown of rocks due to exposure to natural forces

2. Dead and decayed plant and animal remains that increase fertility and porosity of soil

3. A vertical section of soil that shows the different layers of soil or horizons

4. The capacity of soil to provide nutrients in the right quantity for growth of plants

5. The removal of soil by running water and wind

6. Reduction or prevention of soil erosion

Class 7 Science Chapter 8 Soil Oxford Book Solution – 2 Marks

III. Short answer type questions

1. Breakdown of rocks due to exposure to natural forces
✅ Answer: Weathering

2. Dead and decayed plant and animal remains that increase fertility and porosity of soil
✅ Answer: Humus

3. A vertical section of soil that shows the different layers of soil or horizons
✅ Answer: Soil profile

4. The capacity of soil to provide nutrients in the right quantity for growth of plants
✅ Answer: Fertility

5. The removal of soil by running water and wind
✅ Answer: Erosion

6. Reduction or prevention of soil erosion
✅ Answer: Conservation

Class 7 Science Chapter 8 Soil Oxford Book Solution – 4 Marks

IV. Long answer type questions

1. Define weathering. Describe the different ways in which rocks undergo weathering and form soil.

Answer:
Weathering is the natural process by which rocks are broken down into smaller pieces by the action of wind, water, temperature, plants, and animals. It is the first step in the formation of soil.

Types of weathering:

Physical weathering: This occurs due to physical forces like temperature changes, freezing and thawing of water, and the action of wind and rain. It breaks rocks into smaller fragments without changing their composition.
Chemical weathering: In this process, the chemical composition of the rock changes due to reactions with water, oxygen, carbon dioxide, and acids. This leads to the weakening and breakdown of rocks.
Biological weathering: It is caused by the action of living organisms like plants, animals, bacteria, and fungi. Roots of plants can grow into cracks of rocks and break them apart.

These processes together contribute to the formation of soil over a long period.

2. Discuss the different kinds of soils.

Answer:
There are three main types of soil based on the size of the particles:

Sandy Soil: It has large particles and feels gritty. It has high percolation rate and does not retain moisture well. It is less fertile.
Clayey Soil: It has very small, tightly packed particles. It retains water and becomes sticky when wet. It is rich in minerals but lacks air spaces.
Loamy Soil: It is a balanced mixture of sand, silt, and clay. It is fertile, holds moisture well, and provides good aeration. Loamy soil is ideal for growing crops.

Each type of soil supports different types of vegetation and agricultural use.

3. Describe the three special properties of soil that determine its types.

Answer:
The three special properties of soil that help determine its type are:

Percolation rate: It refers to the rate at which water passes through the soil. Sandy soil has a high percolation rate, while clayey soil has a low percolation rate.
Moisture retention: It indicates how much water the soil can hold. Clayey soil retains more moisture compared to sandy soil.
Texture: It depends on the size and arrangement of soil particles. It can be gritty (sandy), smooth (clayey), or crumbly (loamy), which affects how suitable the soil is for plant growth.

These properties help identify the best use of different soils for farming, gardening, or construction.

4. Explain the causes and prevention of soil erosion.

Answer:
Soil erosion is the removal of the top fertile layer of soil by wind, water, or human activity.

Causes of soil erosion:

Heavy rainfall and flowing water
Strong winds in dry areas
Deforestation
Overgrazing by animals
Poor agricultural practices

Prevention methods:

Afforestation: Planting trees helps hold the soil together.
Terrace farming: Creating step-like fields on slopes reduces runoff.
Contour ploughing: Ploughing along the contour lines prevents water from flowing down directly.
Cover cropping: Growing cover plants like grasses helps protect the soil.
Avoiding overgrazing: Limiting the number of grazing animals helps preserve vegetation cover.

These steps help conserve soil and maintain fertility.

5. What is soil pollution? Describe the various measures that will help control soil pollution.

Answer:
Soil pollution is the degradation of soil quality due to the presence of harmful chemicals, waste, and pollutants that reduce its fertility and harm living organisms.

Causes of soil pollution:

Use of chemical fertilizers and pesticides
Industrial waste and acid water discharge
Improper disposal of garbage and plastic
Oil spills and heavy metals

Control measures:

Use of organic manure and bio-fertilizers instead of chemical fertilizers.
Proper waste management to prevent dumping of garbage and industrial waste into the soil.
Use of organic pesticides to reduce chemical impact.
Planting trees and maintaining vegetation to absorb pollutants.
Laws and regulations for safe disposal of hazardous waste by industries.

These measures help improve soil health and support sustainable agriculture.