Soil Class 7 Extra Questions and Answers Science Chapter 9

Soil Class 7 Extra Questions and Answers Science Chapter 9 PDF are solved by experts and will guide students in the right direction. Students can get how to tackle different questions easily by solving the Extra Questions for Class 7 Science Question bank on a regular basis.

Class 7 Science Chapter 9 Extra Questions and Answers Soil

Extra Questions for Class 7 Science Chapter 9 Soil with Answers

Soil Class 7 Extra Questions Very Short Answer Type

Question 1.
What is soil?
Answer:
The uppermost layer of land area of earth, which is a mixture of rock particles and humus is called soil.

Question 2.
What is soil profile?
Answer:
A vertical section through different layers of the soil is called the soil profile.

Question 3.
Write the formula for percolation rate.
Answer:
Percolation rate (mL/min)
= \(\frac{\text {amount of water(mL)}}{\text {percolation time(min)}}\)

Question 4.
Name the climatic factors affecting soil properties.
Answer:
Soil is affected by wind, rainfall, temperature, light and humidity.

Question 5.
What is the ideal soil for paddy?
Answer:
For paddy, soils rich in clay and organic matter, having a good capacity to retain water, are ideal.

Question 6.
Which soil is suited for lentils?
Answer:
For lentils (masoor) and other pulses, loamy soils, which drain water easily, are required.

Question 7.
Which soil is suitable for cotton?
Answer:
For cotton, sandy-loam or loam, which drain water easily and can hold plenty of air, are more suitable.

Question 8.
What is soil erosion?
Answer:
The removal of fertile topsoil by water, wind or ice is known as soil erosion.

Soil Class 7 Extra Questions Short Answer Type 1

Question 1.
Why is there a demand to ban polythene bags?
Answer:
Polythene bags and plastics pollute the soil. They also kill the organisms living in the soil. That is why, there is a demand to ban polythene bags and plastics.

Question 2.
Name the layers of soil formed when soil is dissolved in water and left undisturbed.
Answer:
Humus, water, clay, sand and gravel.

Question 3.
What is soil horizon?
Answer:
Each layer of soil differs in feel (texture), colour, depth and chemical composition. These layers are referred to as horizons.

Question 4.
What is B-horizon?
Answer:
The second layer of soil has a lesser amount of humus but more of minerals. This layer is generally harder and more compact and is called the B-horizon or the middle layer.

Question 5.
Write about C-horizon.
Answer:
The third layers of soil is the C-horizon, which is made up of small lumps of rocks with cracks and crevices. Below this layer is the bedrock, which is hard and difficult to dig with a spade.

Soil Class 7 Extra Questions Short Answer Type 2

Question 1.
Draw the different horizons of soil.
Answer:

Question 2.
Write briefly about the topsoil.
Answer:
The uppermost horizon is generally dark in colour as it is rich in humus and minerals. The humus makes the soil fertile and provides nutrients to growing plants. This layer is generally soft, porous and can retain more water. It is called the topsoil or the A-horizon.

This provides shelter for many living organisms such as worms, rodents, moles and beetles. The roots of small plants are embedded entirely in the topsoil.

Question 3.
Write briefly about loamy soil.
Answer:
The best topsoil for growing plants is loam. Loamy soil is a mixture of sand, clay and another type of soil particle known as silt. Silt occurs as a deposit in river beds. The loamy soil also has humus in it. It has the right water holding capacity for the growth of plants.

Question 4.
Write about soil erosion.
Answer:
The removal of fertile topsoil by water, wind, or ice is known as erosion. Plant roots firmly bind the soil. In the absence of plants, soil becomes loose. So it can be moved by wind and flowing water. So, cutting of trees and deforestation should be prevented and efforts should be made to increase the green areas.

Soil Class 7 Extra Questions Long Answer Type

Question 1.
Discuss the dependence of crop on soil type.
Answer:
The climatic factors, as well as the components of soil, determine the various types of vegetation and crops that might grow in any region.

Clayey and loamy soils are both suitable for growing cereals like wheat and gram. Such soils are good at retaining water. For paddy, soils rich in clay and organic matter and having a good capacity to retain water, are ideal. For lentils (masoor) and other pulses, loamy soils, which drain water easily, are required.

For cotton, sandy-loam or loam, which drain water easily and can hold plenty of air, are more suitable. Crops such as wheat are grown in the fine clayey soils, because they are rich in humus and are very fertile.

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