DAV Class 8 SST Chapter 2 Question Answer – Natural Resources: Land, Soil and Water

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DAV Class 8 SST Ch 2 Question Answer – Natural Resources: Land, Soil and Water

DAV Class 8 SST Ch 2 Solutions – Natural Resources: Land, Soil and Water

Something to Know

A. Tick (✓) the correct option.

Question 1.
Which type of erosion leads to desertification?
(a) soil erosion
(b) wind erosion
(c) water erosion
(d) wave erosion
Answer:
(a) soil erosion

Question 2.
Which one of the following is suitable for restoring soil fertility?
(a) terrace fanning
(b) contour ploughing
(c) shifting agriculture along the hill slopes
(d) rotation of crops
Answer:
(b) contour ploughing

Question 3.
Which of the following is not in favour of multipurpose river valley projects?
(a) control floods
(b) generate hydroelectricity
(c) large scale displacement of people
(d) provide water for irrigation
Answer:
(c) large scale displacement of people

Question 4.
Maintenance of lakes and ponds is essential for-
(a) increasing surface water runoff
(b) increasing water table
(c) increasing soil fertility
(d) recycling of water
Answer:
(b) increasing water table

Question 5.
Which factor is more responsible for the quick formation of soil in Rajasthan?
(a) soluble rocks
(b) vegetation cover
(c) extreme difference in day and night temperature
(d) rainfall
Answer:
(c) extreme difference in day and night temperature

B. Fill in the blanks.

Question 1.
Earth’s surface is divided into ________ and ________ zones.
Answer:
land; water

Question 2.
To maintain ecological balance, ________ % of the land should be under forest.
Answer:
33

Question 3.
Planting of trees is commonly known as ________ .
Answer:
afforestation

Question 4.
The main source of fresh water is ________ .
Answer:
rainfall

Question 5.
Earth is known as planet due to the presence of water on it.
Answer:
blue

C. Write a technical term or an appropriate word for each of the following statements.

Question 1.
It is formed by decomposed parts of plants and animals.
Answer:
humus

Question 2.
The original rock from which the soil is formed.
Answer:
Parent rock

Question 3.
It is formed as a result of long continued weathering process of rocks.
Answer:
Soil

Question 4.
A project which serves various purposes at the same time.
Answer:
Multipurpose River Valley Project

Question 5.
The process in which the top layer of the soil is removed by the natural and human activities.
Answer:
Soil erosion

D. Answer the following questions in brief.

Question 1.
Why is soil considered an important resource? Give any these reasons.
Answer:
Soil is considered an important resource because

• Agricultural production is mainly dependent upon the fertility of soil.
• Animals also depend upon the soil to satisfy their basic needs as soil gives nutrients to plants.
• It is also used for making brikcs and pottery.

Question 2.
Highlight any three causes of soil erosion.
Answer:
The causes of soil erosion include both human and natural activities. Natural agencies such as water, wind, glacier, etc. cause soil erosion. But at the same time, mankind’s unwise actions such as deforestation, over-grazing and mining are also responsible for soil erosion. It has been observed that the fertility of soil is severely damaged by soil erosion.

Question 3.
Explain hydrological cycle with the help of a diagram.
Answer:
The main source of fresh water is rainfall. This rain water continuously gets recycled in nature through evaporation, condensation and precipitation. This process is called hydrological cycle.

Question 4.
How does river water get polluted? Explain.
Answer:
River water gets polluted as the untreated industrial waste and urban waste is dumped into them. This makes the river water unsuitable for consumption. It also disturbs the ecosystem.

Question 5.
Identify any three ecological problems caused by building large dams.
Answer:

• Extensive forests get submerged under water.
• River water gets diverted.
• Auatic life gets affected.

E. Answer the following questions.

Question 1.
Explain any five factors which are responsible for the formation of soil.
Answer:
The five factors responsible for soil formation are:
(i) Parent rock: The original rock, from which soul is formed by the process of weathering is known as the parent rock. It determines colour, texture, chemical, properties, mineral, content and permeability of the soil. For example, the black soil of India is derived from the lava rock.

(ii) Topography: The location of a soil on a landscape can affect how the climate processes affect it. Variations in the relief, such as mountains, plains and plateaus determine the thickness of the soil. For example, the northern plains have thick soil cover than the Himalayas. Even within mountains, river valleys have thick soil cover.

(iii) Climate: Climatic factors like temperature and rainfall affect the soil formation. In the areas of high rainfall and extreme temperature, rocks are easily weathered which affect the soil formation.

(iv) The Vegetation Cover: Cracks disintegrate into smaller pieces and help in the soil formations. Remains of dead or decomposed plants and animals provide humus to the soil, which enriches the fertility of the soil.

(v) Time: It takes thousands of years to develop a very thin layer of soil on the earth’s surface. Example; the Nile Delta and delta formed by the Ganga and Brahmaputra rivers have very deep and fertile soil.

Question 2.
What is meant by land use pattern? Why is it important to study the land use pattern? List the factors influencing the utilisation of land.
Answer:
The use of land for various purposes such as for cultivation of crops, building of houses, roads, railways, grazing of animals, etc. is commonly known as land use pattern. It is important to study the land use pattern because the percentage of land used for various purposes various from one region to another. The utilisation of land is determined by the continuous interplay of the physical factors, such as relief, soil, climatic conditions, mineral resources, etc., and the human factors like density of population and the technological and social requirements of the people.

Question 3.
What are Multipurpose River Valley Projects? Nahie any two such projects. List the main objectives of a multipurpose river valley project.
Answer:
Multipurpose River Valley Projects are large scale hydro projects which have been developed’all over the world to utilise water. Under them, a dam or series of dams are constructed across the river for storing water.
Two multipurpose river valley projects-

• Hirakud
• Bhakra Nangal

A multipurpose river valley serves many objectives at the same time. The stored water is used for several purposes, such as providing irrigation, generating hydro electricity, afforestation, control floods, navigation, etc

Question 4.
Suggest any five steps to conserve soil.
Answer:
Soil is an important natural resource. Therefore, its conservation must be given top priority. Various methods of soil conservation are:

1. Afforestation: It is the process of planting more trees and seeds on land. It reduces the surface runoff and kinds the soil.
2. Shelter belts: Rows of trees are planted in desert regions to protect the fields from wind erosion.
3. Rock dams: This prevents gullies and further soil loss since rocks are piled up to slow down the flow of water.
4. Terrace farming: Terrace farming 1 should be encouraged across the hill slope. Terraces reduce run-off and soil erosion.
5. Contour ploughing: Ploughing parallel to the contours of a hill slope to form a natural barrier for water to flow down a slope is called contour ploughing.
6. Overgrazing by animals like sheep and goats must be checked. Fodder crops should be raised. The free movement of animals in the fields should be restricted.
7. Reckless cutting of trees should be checked.

Question 5.
Suggest any five methods for the conservation of water.
Answer:
Water is an indispensable resource of life. We cannot imagine life in its absence. The sources of water are limited and are reducing every year. Therefore, its conservation is essential. Various methods of water conservation are given below:

1. Rainwater harvesting: It is a method of collecting water while it rains so that it may come of use in the future.
2. Improving underground storage: The surface run-off can be minimised by having vegetation cover to improve underground storage.
3. Making dams across the rivers: The rainwater can be impounded by making dams across the rivers.
4. Drip irrigation system: Water can be saved by adopting modern methods of irrigation, such as drip or trickle irrigation techniue and sprinkler method of irrigation.
5. The demand of water for industries can be met by the recycled water.
6. The domestic demand can also be reduced by using modern method of recycling. The already used water can be reused for watering plants, flushing toilets.
7. Maintenance of lakes and ponds also helps in increasing the auifer or water table of underground water.
8. Water can be conserved by educating and sensitising people towards the urgent need to conserve water so that they do not waste fresh water.

Map Skill

On an outline political map of the world, show the following multipurpose river valley projects-
(a) Aswan dam in Egypt
(b) Hoover dam in USA
(c) Damodar River Valley Project in India
(d) Hirakud dam in India
Answer:

Something to Do

Question 1.
Collect information about some Multipurpose River Valley Projects of India and then complete the following table.
Answer:

Name of the project	River	Beneficiary States
1. The Hirakud Project	Mahananda	Chhattisgarh, Odisha
2. The Bhakra-Nangal Project	Satluj	Punjab, Haryana, Himachal Pradesh, Rajasthan
3. Sardar Sarovar	Narmada	Madhya Pradesh, Gujarat
4. Nagaijuna Sagar	Krishna	Andhra Pradesh
5. Rihand Project	Son	Madhya Pradesh and Chhattisgarh
6. Tehri	Bhagirathi	Uttarakhand
7. Chambal	Chambal	Rajasthan, Madhya Pradesh
8. Farakha	Ganga	West Bengal
9. Rihand	Son	Uttar Pradesh, Madhya Pradesh, Bihar
10. Beas	Beas	Himachal Pradesh

Question 2.
Find out the causes of water pollution in the River Yamuna or a river of your state.
Answer:
Do yourself

DAV Class 8 Social Science Chapter 2 Question Answer – Natural Resources: Land, Soil and Water

A. Tick (✓) the correct option.

Question 1.
The most appropriate method to check soil erosion on steep slopes is
(a) afforestation
(b) shelter belts
(c) terrace farming
(d) None of these
Answer:
(d) None of these

Question 2.
Land covers about of the total surface area of the earth.
(a) 70%
(b) 50%
(c) 40%
(d) 30%
Answer:
(d) 30%

Question 3.
The area under forest is highest in
(a) India
(b) Japan
(c) France
(d) America
Answer:
(b) Japan

Question 4.
The percentage of cultivated land in India is
(a) 57%
(b) 41%
(c) 33%
(d) 28%
Answer:
(a) 57%

Question 5.
Soil erosion is caused by mankind’s unwise actions which include.
(a) deforestation
(b) overgrazing
(c) deforestation and mining
(d) deforestation, overgrazing and mining
Answer:
(d) deforestation, overgrazing and mining

Question 6.
The most appropriate method to check soil erosion in desert regions is
(a) afforestation
(b) shelter belts
(c) terrace farming
(d) contour ploughing
Answer:
(b) shelter belts

Question 7.
Hirakud Dam built over the river
(a) Mahanadi
(b) Narmada
(c) Damodar
(d) Son
Answer:
(a) Mahanadi

Question 8.
Hoover Valley Project is located in
(a) Egypt
(b) USA
(c) Russia
(d) Japan
Answer:
(b) USA

Question 9.
The colour, texture etc. of soil is determined by
(a) time
(b) climate
(c) parent rock
(d) relief
Answer:
(c) parent rock

Question 10.
The percentage of fresh water on the earth is
(a) 2.0%
(b) 2.50%
(c) 3%
(d) 3.1%
Answer:
(c) 3%

Question 11.
Why are trees planted in rows in a desert region?
(a) To prevent flood
(b) To prevent soil erosion
(c) To prevent wind erosion
(d) To prevent water erosion
Answer:
(b) To prevent soil erosion

B. Very Short Answer Type Questions

Question 1.
How is land the most important natural resource?
Answer:
Land is the most important natural resource because almost all human activities related to food, shelter and clothing take place on it.

Question 2.
What is soil?
Answer:
Soil is combination of organic and inorganic matter.

Question 3.
How is the inorganic component of soil formed?
Answer:
The inorganic component of soil is formed by rock particles and minerals such as lime, calcium, etc.

Question 4.
How is soil formed?
Answer:
Soil is formed as a result of the long continued weathering process of rocks. It also contains water and air, which occupy its pore spaces.

Question 5.
Which type of people are found in areas of high altitudes, deserts and equatorial forests?
Answer:
People engaged in hunting, gathering, fishing and shifting cultivation are found in these areas.

Question 6.
Where are thin and infertile soils found?
Answer:
Thin and infertile soils are found in 30 areas of high altitudes, deserts, and euatorial forests.

Question 7.
What are the human factors that determine land use pattern?
Answer:
The human factors affecting land use pattern are density of population and the technological and social reuirement of the people.

Question 8.
What are the physical factors that determine land use pattern?
Answer:
The physical factors that determine land use pattern are relief, soil, climatic conditions, mineral resources, etc.

Question 9.
What is parent rock?
Answer:
The original rock from which soil is formed by the process of weathering is called parent rock.

Question 10.
What is the advantage of fertile soil?
Answer:
Fertile soil is important for agriculture.
It helps in maintaining food security of the world.

Question 11.
What is terrace farming?
Answer:
Terrace farming is a method of farming in which broad flat steps or terraces are made on the steep slopes so that flat surfaces are available to grow crops.

Question 12.
What does surface water mean?
Answer:
Surface water means water which is present above the earth’s surface in the form of rivers, streams, lakes, etc.

Question 13.
In which forms is fresh water found on the earth?
Answer:
Most of the fresh water on the earth is found in the rivers, streams, lakes, ponds, ice caps and underground water.

Question 14.
What do you know about the distribution of fresh water resources on the earth’s surface?
Answer:
Fresh water is in abundance at places which receive heavy rainfall, whereas availability of water is less in the areas where rainfall is low.

Question 15.
Mention the areas of high rainfall.
Answer:
The areas of high rainfall are euatorial regions in South America, Africa and South East Asia.

Question 16.
Mention the areas of low rainfall.
Answer:
The areas of low rainfall are tropical deserts such as Sahara, Arabian, Western Australia, Kalakari, Central Eurasia, Polar areas, etc.

Question 17.
Mention two serious effects of the polluted water.
Answer:
(i) The polluted water if consumed, causes severe diseases.
(ii) It also disturbs the ecosystem.

Question 18.
What method is used to save surface run-off?
Answer:
Water harvesting is a method to save surface run-off.

Question 19.
Give two reasons for land degradation today.
Answer:
(i) Ever growing demand of the growing population.
(ii) Destruction of forest cover.

C. Short Answer Type Questions

Question 1.
How does the vegetation cover influence soil formation?
Answer:
(i) At times, plants grow in the cracks existing in the rocks. With time, roots of the plants start penerating in the cracks and make it wider. As a result, it disintegrates it into smaller pieces and helps in the soil formation.

(ii) Remains of dead or decomposed plants and animals provide humus to the soil which enriches the fertility of the soil. The soil of densely forested area is generally very rich in humus content.

Question 2.
Why is it essential to conserve water?
Suggest any two suitable measures to conserve water. (DAV Board)
Answer:
Water is an indispensable resource of life. It serves the most basic purpose of drinking, without which life is impossible. But the sources of water are limited and are reducing every year. Due to the effects of global warming, the freuency of rain has also become unpredictable, therefore, it is very essential for us to conserve it. Note: Also see Textbook Q. No. E. 5.

Question 3.
Why is soil conservation essential? Mention the natural and human factors that cause soil erosion.
Answer:
Soil (fertile soil) is essential for agriculture. It helps in maintaining food security of the world. Its degradation or depletion would create serious constraint for agricultural production.

• Soil errosion is caused by both natural and human factors.
• Natural factors are water, wind, glacier.
• Human factors are deforestation, overgrazing, mining.

Question 4.
Mention three facts about water resources.
Answer:

1. Water is one of the most precious resources on the earth. Nearly 70% of the earth’s surface is covered with water.
2. About 77% of the earth’s total water is in oceans and seas. This is saline water which supports incredible biodiversity of marine life, but it is not suitable for human consumption or watering our crops.
3. Remaining 3% is fresh water that can be put to use. This fresh water is mainly obtained from surface run-off and groundwater that is continually being renewed and recharged through the hydrological cycle.

D. Long Answer Type Question

Question 1.
The land use pattern of a few countries of the world is given below in the table. Study the table and answer the questions that follow:
Land use in some selected countries (in percentage)

Country	Cultivated Land	Pastured	Forests	Other
Japan	12	2	67	19
UK	29	46	10	15
India	57	4	22	17
Australia	6	56	14	24

(i) What percentage of area is under pasture land in India?
(ii) Name the country that has the smallest cultivated area of land.
(iii) Which country has the highest percentage of area covered with forests?
(iv) How does an extensive forest cover benefit a country? (DAV Board)
Answer:
(i) 4% of the total land is under pastures in India.
(ii) Australia.
(iii) Japan has the highest percentage of area (67%) covered with forests.
(iv) An extensive forest cover benefits a country in a variety of ways:

• It preserves ecological diversify and our life support systems- water, air and soil.
• It preserves the genetic diversity of plants and animals for better growth of species and breeding.