AP Board 7th Class Science Solutions Chapter 15 Soil: Our Life

AP State Syllabus AP Board 7th Class Science Solutions Chapter 15 Soil: Our Life Textbook Questions and Answers.

AP State Syllabus 7th Class Science Solutions 15th Lesson Soil: Our Life

7th Class Science 15th Lesson Soil: Our Life Textbook Questions and Answers

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Question 1.
How can you say soil is a precious resource? Give reasons.
Answer:

1. Soil is a precious resource.
2. It is the basis for growth of plants.
3. It is habitat for micro organism, animals, reptiles etc.
4. Soil is used for various purposes.
5. Almost all the things in our surroundings directly or indirectly depend on soil.

Question 2.
Which type of soil is suitable for growing cotton?
Answer:

1. Black soil is suitable for growing cotton.
2. Black soil is sticky in nature. It retains water for a long time.
3. This soil is suitable for the growth of cotton, sugarcane and paddy.

Question 3.
Give reasons for low percolation rate of clayey soil as compared to sandy soil.
Answer:

1. Clayey soil mainly contains clay.
2. Only small percentage of sand and slit are present in the clayey soil.
3. Humus is also present in this soil.
4. The components having good percolation capacity are not present in the clayey soil in the desired proportion.
5. So clayey soil has low percolation rate as compared to sandy soil.

Question 4.
Why is top soil more useful for us?
Answer:

1. The top organic layer of soil, made up mostly of leaf litter and humus (decomposed organic matter).
2. This layer is soft and porus. It contains nutrients which help in the growth of plants.
3. To soil is capable of retaining water in it.
4. It is a good habit at for many living organism.

Question 5.
What types of soils are there in your village? Make a. list of crops grown on these soils.
Answer:

1. Types of soil differ from village to village.
2. For guidance, a village in Krishna District is identified and details are given here.
3. There is black soil in the village. This soil can retain water for a long time.
4. Here farmers grow cotton, sugarcane and paddy.

Question 6.
If a farmer wants to improve water holding capacity of his sandy soil field what will you suggest to him?
Answer:

1. In sandy soi] the proportion of larger sized particle is more.
2. This soil will have more percolation rate.
3. If a good proportion of fine particles are added to the sandy soil, these fine particles hold the water.
4. So the farmer is advised to mix clay soil, having fine particles, with the sandy soil, to improve water holding capacity.

Question 7.
Do you think rotting vegetation and animal remains are important for the soil? In what way?
Answer:

1. Rotting vegetation and animal remains make up the humus rich in fertility.
2. They contain nutrients, natural manure which give good support to the growth of plants.

Question 8.
Roots of grasses hold soil particles. This conserves the
Answer:
Soil

Question 9.
Which of the following statements is correct? Correct the wrong one.

• Soil form from sand.
• Crop rotation protects soil fertility.
• Clay soil can’t hold water for a long time.
• Upper layers ofsoild are made of rocks.

Answer:

• Soil form from sand. …….. This, is wrong.
• Crop rotation protects soil fertility. ……… This is correct.
• Clay soil can’t hold water for a long time. …….. This is wrong.
• Upper layers of soild are made of rocks. …….. This is wrong.

Correct statements:
a) Soil is formed slowly as rock erodes into tiny pieces near the Earth’s surface.
b) Statement is correct.
c) Clay soil contains more fine particles. So its water holding capacity is more.
d) The upper layers of soil is made up of humus mixed with mineral particles.

Question 10.
Collect soil from your school ground. Try to make a ring with that soil. Write down your observations. What type of soil is it?
Answer:
The student can do it.
The soil changes from school to school. So the student with the help of the teacher can make the observations.

Question 11.
Take a boiling tube. Put two spoons of soil in it. Heat it on a spirit lamp and cover it.
a) Do this experiment and write your findings.
b) Do you find any moisture in the soil?
c) How can you say that?
Answer:
a)

1. This soil is found to contain minerals like salts of sodium, calcium and magnesium.
2. Traces of potassium chlorides, sulphates and carbonates are also observed.

b) I found moisture in the soil.
c)

1. As the boiling tube is covered, on the bottom of the cover, water drops condensed
   are found.
2. Due, to heat the moisture in the soil got evaporated and the vapours were condensed on the bottom of the cover.

Question 12.
Nazmal’s grandmother said “Human beings always depends on soil”. Is she correct? How do you support her statement?
Answer:

1. Nazmal’s grandmother is correct. I support her statement.
2. Soil is one of the most important natural resources. It supports the existence of living organisms.
3. We use soil for different purposes in our daily life. Almost all things in our surroundings directly or indirectly depend on soil.
4. The soil supports all plants, animals and microorganism.
5. We grow our food components in this soil.

Question 13.
“If you sow a seed in the soil it will give birth to a tiny plant which grows bigger and bigger. “It is the wonder of soil” Swetha said. How do you express your appreciation of soil like Swetha?
Answer:

1. Soil always support plants to grow.
2. It is plants that grow life long.
3. Soil supplies the necessary water and nutrients to the plant throughout its life period.
4. The plant makes it own food using, solar energy and the gases in the atmosphere with the help of water supplied by the soil.
5. It is one of the wonderful things we observe in the nature.

Question 14.
Write a dialogue between seed and soil and perform a small play using your own script.
Answer:
Soil : Who are you?
Seed : I am as eed.
Soil : What do you want from me?
Seed : I want water, minerals and nutrients.
Soil : Why do you need all those things?
Seed : As I want to germinate and become a big tree I need all those things.
Soil : Definitely I will supply all that things needed to you to become a big tree.

Question 15.
If you have a chance to talk with a soil scientist, what questions would you like to ask him about soil?
Answer:
I shall ask the following questions.

1. How can you test the soil for its acidity?
2. Is it possible to change the basic nature of the soil?
3. How can the water holding capacity of the soil be increased at a low cost.
4. Suggest methods to improve the fertility of the soil.
5. What can be done with the black cotton soil when a building is to be constructed?
6. As black cotton soil yields, and the building cracks, suggest preventive measures for it.

Question 16.
Do you find any relationship between the chapters “Soil” and “Nutrition in plants”. What are they?
Answer:

1. Plants get their nutrition from the soil where they grow.
2. All plants cannot grow in every soil. We have to select plants to seed suited to the soil available.
3. By taking proper steps, we can improve the quality of soil for a good growth of the plants.