Solutions 9. Soil - Additional Questions With Solutions | Class 7 Science - Toppers Study

Additional Questions With Solutions

Ques: What is humus?
Ans: The rotten death material presence in soil is known as humus.

Ques: what is weathering?
Ans: The breaking down of rocks by the action of wind, water, and climate. This process is called weathering.

Ques: which are those factors which influence the nature of soil?
Ans:
(i)   Rocks from which it has been formed.
(ii)  Vegetation that grows in it.

Ques: What is soil profile?
Ans: A vertical section through different layers of the soil is called the soil profile.

Ques: What are Horizons?
Ans: Each layer differ in feel (texture), colour, depth and chemical composition. These l-ayers are referred to as horizons.

Ques: why is the uppermost horizon generally dark in colour?
Ans: As it is rich in humus and minerals.

Ques: Name the layer of the soil which makes the soil fertile.
Ans: Humus.

Ques: What is topsoil?
Ans: The upper layer is generally soft, porous and can retain more water; it is called the topsoil or the A-horizon.

Ques: In how many layers has soil profile been divided?
Ans: Soil profile has been divided in four layers.
(i)   topsoil or A-horizon
(ii)  B-horizon

1. C-horizon
2. Bedrock

Ques: What is called the layer of soil profile which is hard and difficult to dig?
Ans: Bedrock

Ques: What is soil?
Ans: The mixture of rock particles and humus is called the soil.

Ques: What are various classifications of soil?
Ans: The classifications of soil.

1. Sandy soil.
2. Clayey soil.
3. Loamy soil.

Ques: Write three properties of sandy soil.
Ans:

1. Sandy soils tend to be light.
2. It is well aerated.
3. It is rather dry.

Ques: Name the some important climatic factors which affect the soil profile and bring changes in the soil structure.
Ans: Soil is affected by the wind, rainfall, temperature, light and humidity etc.

Ques: What is percolation?
Ans: Absorbing water by the soil is known as percolation.

Ques: What is soil erosion?
Ans: The removal of land surface by water wind or ice is known as soil erosion.

Ques: Explain how soil is formed?
Ans: The soil is formed by the breaking down of rocks by the action of wind, water and climate.

Ques: List the differences between clayey soil and sandy soil.
Ans:

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Ques: How is clayey soil useful for crops?
Ans: Clayey soil is useful for crops, because they are rich in humus and are very fertile.