RB 9 Science

RBSE Solutions for Class 9 Science Chapter 15 Natural Resources and Agriculture

RBSE Solutions for Class 9 Science Chapter 15 Natural Resources and Agriculture

Rajasthan Board RBSE Class 9 Science Chapter 15 Natural Resources and Agriculture

Natural Resources and Agriculture Textbook Questions Solved

Objective Type Questions

Question 1.
Growing of different crops in pre-planned succession is called as-
(A) Mixed Cropping
(B) Mixed Farming
(C) Crop rotation
(D) Intercropping
Answer: A

Question 2.
The average amount of CO2 in the atmosphere is:
(A) 0.03%
(B) 0.003%
(C) 0.0003%
(D) 0.3%
Answer: A

Question 3.
Which of the following causes acid rain?
(A) Air pollution
(B) Water pollution
(C) Soil pollution
(D) Sound pollution
Answer: A

Question 4.
Which one of the following nutrient is found in plants, by soil?
(A) Carbon
(B) Hydrogen
(C) Oxygen
(D) Nitrogen
Answer: D

Question 5.
Which one is Kharif crop?
(A) Soybean
(B) Wheat
(C) Gram
(D) Pea
Answer: A

Natural Resources and Agriculture Very Short Answer Type Questions

Question 6.
Name the instrument which is used to measure the movement of air?
Answer
Anemometer is used to measure the movement of air.

Question 7.
Define pollution?
Answer
The environment is affected by human activities. Discharge of any harmful substance into earth, water or air, which may change their natural composition is called pollution.

Question 8.
What are natural resources?
Answer
Natural resources are the stock of the nature, such as air, water, soil, coal, minerals, animals and plants, that are useful to mankind, in many ways.

Question 9.
What is Algal bloom?
Answer
The presence of sewage and fertilisers in polluted water provide a lot of nutrients to the algae present in water body. This excessive growth of algae is known as algal bloom.

Question 10.
What is sonic boom?
Answer
The experiments like rocket launching explosions and firing, produce deafening sound. The supper sonic jet left the sound waves, which are known as sonic boom.

Question 11.
What is mixed farming?
Answer
Mixed farming is the type of farming in which both crops and livestock are raised on the same farm.

Question 12.
Name the gas found in maximum percentage in the atmosphere? ‘
Answer
Nitrogen gas (78.09%) is found in maximum percentage in the atmosphere.

Question 13.
Which gas is used by plants in the respiration?
Answer
Oxygen.

Question 14.
What is the reason for the movement of air?
Answer
Movement of air is the result of changes that take place in our atmosphere, due to heating of air and the formation of water vapour.

Question 15.
Write the name of an exotic breed of poultry bird having high egg laying capacity?
Answer
White Leghorn.

Natural Resources and Agriculture Short Answer Type Questions

Question 16.
What is Humus? What are the advantages of Humus?
Answer
Humus is a dark coloured organic substance consisting of partially or wholly decayed plant or animal waste. It provides nutrient for plants and increases the ability of soil to retain water. Humus plays a major role in deciding the soil structure because it causes soil to become more porous and allows water and air to penetrate deep underground.

Question 17.
How acid rain is produced? Mention the harmful effects of acid rain?
Answer
Nitrogen and sulphur oxides present in the atmosphere are oxidised by the ozone and then dissolve in water vapours present in the atmosphere to form acid drops. The reaction occurs, according to the following equations.
NO + O3 → NO2 + O2
NO2+ O2→ NO + O2
No2 + No3→ N2O5
N2Os + H2O→ 2HNO3 (Nitric acid)
SO2 + O2 + 1/2H2O → H2SO4 (Sulphuric acid)
Acids formed in this way in the atmosphere fall back on the earth, along with the raindrops and this is called acid rain. Acid rain is rain which contains dissolved gases like nitrogen pentaoxide or sulphur di and tri-oxide in water present in the atmosphere, making nitric acid and sulphuric acid, respectively.
Harmful effects of Acid Rain:

  1. Acid rain kills fishes and other aquatic animals and plants.
  2. Acid rain causes irritation in the eyes and skin.
  3. Acid rain removes nutrients from plant leaves.
  4. Acid rain increases the acidity of soil and adversely affects the production of crops.
  5. Acid rain reacts with building materials such as marble, limestone and hence, weakens them by corrosion.
  6. Acid rain weakens the bridges and other such structures. There is a risk of their breaking, any time.
  7. Heavy metals such as cadmium, zinc, copper, nickel, etc. separate from mineral ores, due to acid rain. These metals pass into lakes and rivers, along with rainwater and cause water pollution.

Question 18.
What is BOD?
Answer
Biological Oxygen Demand indicates the quality of wastewater. BOD refers to the amount of dissolved oxygen needed by bacteria in decomposing the organic waste present in water. It is expressed in milligrams of oxygen per litre of water.

Question 19.
Describe the harmful effects of air pollution?
Answer
Following are the harmful effects of air pollution on health:

  1. Carbon dioxide, chlorine, ammonia, nitrous oxide, etc. gases coming out of factories cause irritation and burning in the throat and eye.
  2. The vapours which come out from chemical factories cause many diseases of lungs, such as a cough, asthma, etc.
  3. The gases coming out from the factories of aluminium and superphosphate cause diseases of teeth and bones.
  4. Smoke and dust particles present in the air cause cough, asthma and tuberculosis.
  5. Petrol and diesel vehicles produce gases such as carbon monoxide and tetramethyl lead, etc. If inhaled for long time continuously, these gases cause cancer, tuberculosis, etc.

Question 20.
What is biological magnification? Explain.
Answer
The pesticides and other chemicals used in the crop fields enter the water sources due to rain, e.g., DDT. These enter the food chain and keep on accumulating at each trophic level, as these chemicals cannot be decomposed. This increase in the concentration of toxicants with an increase in the trophic level is called biological magnification.

Question 21.
What is noise pollution? Explain the harmful effects of noise pollution?
Answer
Noise pollution: Any unwanted sound is called noise. High intensity sounds emitted by big machines, industries, factories, automobiles, aeroplanes, etc. are unwanted sound. Use of loudspeakers in public meetings, etc. a high volume of radio, TV and transistors increases the noise level. The pollution caused by it, is called noise pollution. The intensity of sound is measured in decibels. The intensity of sound in normal conversation is 30-50 decibels.

Effects of sound pollution on human beings:

  1. Audiological effects: Sounds of more than 90 dB intensity, causes fatigue in the ears and roaring in ears, continues. Persons living in the noise of 100 dB become hard of hearing or deaf. If the intensity of sound is very high and the source of loud sound is near the ears, the eardrum gets punctured and deafness is produced.
  2. Physiological effects: Harsh and unwanted sounds affect the physiological working of the human body. Sound pollution harms the vision of the eyes, and working of the heart, liver, respiratory system and brain. Sound pollution causes headache, nausea, irritation in skin, high blood pressure, vertigo and loss of memory.
  3. Psychological effects: Harsh sound causes anger, irritability and mental tension. It gives birth to quarrels and disputes among the people.
  4. Other effects: Sound pollution interferes in lectures, speech and normal talk with other persons. The working efficiency of persons goes down. Sound pollution disturbs sound sleep and peaceful study.

Question 22.
Write any four causes of Soil pollution?
Answer
Causes of Soil pollution are:

  1. Mixing of debris, waste products with the soil, causes soil pollution.
  2. By excessive use of pesticides and fertilisers, the soil is polluted.
  3. When industrial wastes are discharged in the soil, they also pollute the soil.
  4. Insecticides like, D.D.T. is very dangerous. When these enter the body of consumers from producers, their concentration is increased because these are non-degradable substances. Moreover, these can remain in the atmosphere for upto 15 years. DDT also causes soil pollution.

Question 23.
Write any four measures to control air pollution?
Answer
The following devices and measures should be adopted to control air pollution:

  1. Gas absorbing appliances should be used over the chimney of the factories, to absorb the harmful gases.
  2. Filters should be used to check up the big particles of refuse matter, so that the big particles may not mix in the atmosphere.
  3. Suitable fuel should be used in vehicles. Combustion engines of vehicles should be checked from time to time.
  4. The fuel should be as such, that on oxidation there may be minimum smoke and less harmful gases are given out.

Question 24.
Write the differences between Manures and Fertilisers.
Answer

Manures Fertilisers
1. Manure is semi-decomposed organic matter. 1. The fertiliser is a chemical formulation.
2. It is prepared from natural materials,like plant residues & animal residues. 2. It is synthetic, being formed from chemical salts.
3. It contains only a small quantity of mineral salts. 3. Fertilisers contain pure mineral salts or their precursors.
4. It is not nutrient specific. 4. It is nutrient specific.
5. It adds organic matter to the soil. 5. There is no addition of organic matter.
6. It is required in large quantity.  6. It is required in small quantity.
7. Nutrient availability is moderate and they are released slowly. 7. Fertiliser possesses readily available easily releasable plant nutrients.
8. Manure is bulky. It is very difficult to transport to longer distances. 8. It has smaller bulk. Fertilisers can therefore, be transported easily to long distances
9. Manure cannot be stored for long duration. 9. Fertilisers can be stored for long duration.
10. It helps in maintaining soil texture, its hydration and aeration 10. It can harm soil texture and other soil characteristics.
11. Excess manure is not much harmful. It does not cause pollution. 11. Excess fertiliser is harmful for plants. It also causes pollution.

Question 25.
What is vermicomposting? Explain.
Answer
Vermicomposting is the degradation of organic wastes through the consumption by the earthworms. Earthworms increases the fertility of soil in several ways, physically, they are reactors, crushers and mixers, chemically, they are degraders of organic wastes and biologically they are stimulators of decomposition. In India, many species of earthworms are used in vemicomposting, such as Dichogaster bolani, Drawida willsi, etc.

Question 26.
Explain. Organic farming?
Answer
Organic farming: It is a farming system with minimal or no use of chemicals, like fertilisers, herbicides, pesticides, etc. and with maximum input from organic manures, recycled farm wastes, use of bio-agents such as culture of blue-green algae in preparation of biofertilisers, neam leaves or turmeric, specifically in grain storage as bio-pesticides, with healthy cropping systems.

Question 27.
How does artificial rearing done?
Answer
For the production of honey, on a commercial basis, Italian variety of honey bee is reared. Apis mellifera is commonly used for honey production, throughout the country. This variety has been domesticated in India, due to its various good characters such as gentleness in nature, good honey collection capacity prolific queen production. with less swarming and a good ability to protect itseb from enemies. For the purpose of commercial production of honey, apiaries are established.

For artificial rearing of bees, artificial hive is required. Artificial hive consists of a large brood chamber, wax coated metal plates and plastic plates. These plates form the base of artificial hive. These hives are kept in garden, to attract the bees. Blooming period is the most suitable time for artificial rearing.

Drone bees are introduced. Drone bees secrete wax from their abdomen, producing glands. They start secreting wax on plates coated with toad. Drones prepare wax chambers on wax coated plates. When the honey chambers are filled completely, then plates are taken out and honey is collected. The wax deposited on these is also separated.

Honey is very useful for health. It is also used in ayurvedic medicines. Wax obtained from bees is called bee wax, which is used in the preparation of polish, creams and shoe polish. Apiculture is used professionlly in these days. Khadi Gram Udhyog is encouraging apiculture, nowadays.

Question 28.
Write the names of high milk yielding breeds of cows and buffaloes?
Answer
Breed of Cows: Indigenous (Desi) high milk yielding breeds are:(a) Gir
(b) Sahiwal
(c) Red Sindhi
(d) Devli
Exotic (foreign) varieties are:
(a) Jersey
(b) Reddane
(c) Holstein and
(d) Karan Swiss.
All these are reared to get more milk. Their bulls help in farming and for transport purpose. They are Nageri, Malvi and Hallikar. Bregus type of breed is prepared by crossing method.

Breed of Buffaloes: Indigenous (Desi) breeds of good milk yielding buffaloes are:
(a) Nagauri
(b) Jaffarbadi
(c) Mehsana
Murrah and Surati are foreign imported breeds of buffalo.

Question 29.
Name the various disease in dairy animals?
Answer
Diseases of daily animals can be broadly classified into:
Parasitic Diseases: The parasites of cattle may be both external and internal. External parasites include fleas, lice, ticks and mites. Internal parasites include worms and flukes.
Infectious diseases: These are mainly caused by viruses and bacteria. They are contagious and spread easily.
For Example Viral diseases: Foot and mouth disease, Cowpox and Rinderpest. Bacterial diseases: Anthrax, Haemorrhagic septicemia, etc.

Question 30.
What is Mixed Cropping? Write its advantages.
Answer
Mixed cropping is the practice of growing two or more crops simultaneously on the same piece of land.
Some mixed cropping practices are:
(a) Soyabean + Pigeon pea
(b) Wheat + Mustard

Advantages of mixed cropping:
The risk of total crop failure, due to uncertain monsoon, is reduced.
Farmers tend to harvest a variety of products such as cereals, pulses, vegetables or fodder, to meet the various requirement of family or of agricultural farms.

Natural Resources and Agriculture Long Answer Type Questions

Question 31.
What is sustainable agriculture? Describe the various methods of sustainable agriculture.
Answer
Sustainable Agriculture: The science of cultivating land to raise crops is called agriculture. Sustainable agriculture means successful management of resources for agriculture to satisfy the changing human needs, while maintaining or enhancing the quality of environment and conserving natural resources. Due to steady increase of human population, it is necessary to increase the crops production, that can be achieved by efficient management of natural resources, such as soil, water, forest, fertilisers, pesticides, etc.

Various method of sustainable agriculture: Mixed farming is the crop production including horticulture and rearing of farm animals, poultry and piggery, etc.

Types of mixed crop farming are:

Food-fodder, horticulture-pastoral, agro-forestry and mixed cropping-cereal crops and milch animals, etc. Mixed cropping is the practice of growing two or more crops simultaneously on the same piece of land.
Some mixed cropping practices are:
(a) Soybean + Pigeon pea
(b) Wheat + Mustard

Advantages of mixed cropping:
(a) The risk of total crop failure due to uncertain monsoon is reduced.
(b) Farmers tend to harvest a variety of produce, such as cereals, pulses, vegetables or fodder, to meet the various requirements of family or of agricultural farms. Crop rotation: One method of crop production which ensures high yield is crop rotation. Crop rotation is defined as the practice of growing of different crops on a piece of land, in a preplanned succession. Depending upon the duration, crop rotation is done for different crop combinations. If crop rotation is done properly, then two or three crops can be grown in one year with good harvests.

Advantages of crop rotation:
(a) Crop rotation helps in the replenishment of soil fertility.
(b) It enhances the production, by increasing the soil fertility.
(c) It prevents building up of diseases and pests of a particular crop.
(d) It prevents depletion of selective nutrients.

  1. One year rotation-Rice – Wheat; Maize – Mustard.
  2. Two-year rotation-Maize – Potato; Sugarcane – pea.
  3. Three-year rotation-Rice, Wheat-Mung, Mustard, Sugarcane, Burseem.

Question 32.
Name the products formed by Fishery? Describe the steps of fishery?
Answer
Fish is an important food, which is quite rich in proteins.
The main products formed by fishery are: Oil with vitamins, proteins, fats, fins, skin and scales.

Fishery or Pisciculture is a combination of agriculture and animal husbandry. Providing natural food to fishes, rearing in ponds comes under agriculture. The term pisciculture is the production, breeding and management of fishes on a large scale, under controlled conditions. As India has vast freshwater resources, there is a great scope of improvement in fish production. India ranks 7th among the leading fish producing countries of the world. Development and production of fish in freshwater is more than marine water (salt water).

Many people living near coastal areas depend on fishes for their food requirement. The main aim of Pisciculture is to produce fishes for food and secondly, it provides employment opportunities.
Varieties (types) of fishes used for piscicultures.
Selected Fresh water species: Catla, Rohu, Mrigal.
Foreign (exotic) fishes: Silver carp, common carp, Grass carp, Hilsa, Salmon, Singhara.

Activities for Pisciculture: Construction of pond: Appropriate pond or tank is required for pisciculture. The pond should be constructed on land, containing clay soil. Sunlight should reach on the bottom of the pond. Inlet and outlet of water in the pond should be proper.

Food material for fishes:
Two types of food are needed for the fishes:

  1. Natural food,
  2. Artificial food.

1. Natural food consists of small aquatic plants and animals. For a continuous supply of this food, bio fertilisers and birds excreta are added. Lime (CaO) is added to water, to reduce the acidity of water.

2. Artificial food is also needed for the rapid development of fishes. Crushed grains, powdered wheat, soyabean, yeast, rice bran, etc. are included in artificial food.

3. Removal of fishes from a pond: Fishes are taken out, once in a year. All the fishes should not be taken out. Partial removal of fishes increases the production of fishes and it should be done early in the morning.

4. Precautions of pisciculture:

  1. Pollution of water causes great harm to the fishes. So, the pond should be cleaned regularly and non-beneficial plants should be removed.
  2. Fishes suffer from many types of diseases, caused by bacteria and viruses, so fishes should be checked at regular interval of time and treated, accordingly.
  3. Introduction of small fishes should be done early in the morning.
  4. During thunder, lightening and raining, fishing should not be done.
  5. Fish food should be palatable.

Question 33.
What is Irrigation? Describe the various modem systems of Irrigation?
Answer
Irrigation is the process of supplying water to crop plants in the fields, by means of canals, reservoirs, wells, tube-wells, etc.
It depends on the following two factors:

  1. Crop-based irrigation, i.e., on the nature of crop plants.
  2. Soil-based irrigation, i.e., on the nature of soil of the crop fields.

The various irrigation systems in India are as follows:
The common method of irrigation in India is well, tube wells, pumps, canals, tanks, river-valley system and river-lift systems. Irrigation is essential at various levels of crop production, such as sowing, tilting, flowering and fruiting.
(a) Wells: Wells are bored at such places, where groundwater is enough.

These are of two types:

  1. Dug wells: Dug wells have their bottom surface below the ground water table. Water accumulates here from surroundings. Water is lifted for irrigation by mechanical means, e.g., Persian wheels operated by bullocks, horses and camels
  2. Tube wells: Tube wells are dug very deep. Water is lifted from these wells by diesel or electric run pumps.

(b) Tanks: These are small storage reservoirs. They store run-off water from the surrounding catchment areas. Small dams are constructed below the catchment areas, to regulate the flow of water for agriculture.

(c) Canal system: Canals mostly get water from large rivers. Doors are .fitted at the mouth of canal joining the river to regulate the flow of water. A canal is distributed into branch canals, distributaries or field channels. These field channels irrigate the fields. For irrigation, the fields of various farmers, a rotation system is followed, so that each and every farmer may irrigate his field.

(d) River valley system: In the western ghat mountains for South India, are present many steep and narrow riverine valleys. In this region, rainfall is very heavy during June to September and again in November and December. On the slopes and in the valleys, perennial crops, like supari are cultivated. Rice crop is also grown in the bottomlands of the valley.

(e) River lift system: Water is lifted directly from the river for irrigation of nearby fields. It is done due to inadequate flow of water in canal or due to insufficient release of water from the river reservoir.

(f) Sprinkler irrigation system: It is introduced in canal irrigated areas of Haiyana, Rajasthan and Madhya Pradesh. Drip irrigation system is in use in Maharashtra, Karnataka, Andhra Pradesh, Orisa and Tamil Nadu. It is in practice with the help of Isral technical, known Indian Agricultural Research Institute, New Delhi. They are also providing training to the people of various states. Here, they are cultivating different varieties of roses, tomatoes, capsicum of yellow and red colour, gourd, etc.

Question 34.
Describe the various aims of improved cropping?
Answer
Aims of improved cropping:

  1. The main aims of crop improvement are to increase the productivity of economic product, which is possible by developing high yielding varieties.
  2. The plant crops are subjected to many biotic stresses, such as disease, insects, pests, nematode as well as abiotic stresses, such as draughts, water logging, salinity, heat, cold, etc.
  3. Better quality of crop regarding economic value, protein quality of pulses, oil quality in oil seeds and preservity of vegetables and fruits.
  4. Photo-in sensitive and thermo insensitive varieties of some crops can be cultivated in large areas, as they are not affected by light and temperature.
  5. Crop production, under different environmental conditions, can be stabilised by developing improved varieties of crops.
  6. Desired agronomic traits give higher produce, such as high tillering, tall professedly branching characters of fodder crops, and dwarf character of cereals.
    Examples of the high yielding variety of wheat are: Sonara 64, Hira, Moti, Kalyan Sona and Sharbati sonara.
    High yielding variety of paddy are: Pusa 205, IR 8, Padma and Jaya.

Question 35.
What is water pollution? Describe its various sources and harmful effects.
Answer
Water pollution: Spoiling the quality of water by any natural or human activity is called water pollution.
Causes of water pollution:

  1. Waste products, industrial wastes and chemical wastes are thrown in rivers, lakes, etc. as such pollute the water bodies.
  2. Sewerage and dirty waste water of villages, towns and cities is drained to fall into rivers or any other water body.
  3. People wash their dirty clothes, take bath, clean their utensils and bath their pet animals in the water of the pond, lake, river, etc.
  4. Oil slick in the sea due to leakage, from ship, causes pollution. Water is also polluted, due to atomic explosions in seas.
  5. Atomic explosion experiments inside the sea, and dumping of nuclear waste in oceans.

Harmful effects of polluted water on human life:

  1. Water plants and animals are destroyed, due to polluted water by industrial wastes.
  2. Sewerage, garbage and organic materials dumped into water bodies, kill the fishes, because of reduction in oxygen concentration, causing their suffocation.
  3. Many diseases are caused by drinking polluted water, e.g., typhoid, cholera, dysentery, jaundice, hepatitis and polio.
  4. Eggs of hookworms, roundworms, etc. enter into our bodies through polluted water and make us ill.
  5. Parasites penetrate the skin of human beings while bathing in polluted water, it becomes the cause of diseases such as schestomiosis, laptospisosis, etc.
  6. Water discharged from some industries may contain metals like copper, chromium, zinc, cadmium. These metals are harmful to human beings and cause diseases.
    For example, Minamata disease is caused due to mercury metal. This disease harms the liver and kidneys.
  7. Fluorine ions present in water causes fluorosis of teeth and bones, Problems of kidney and thyroid gland are produced, due to the high concentration of fluorine.

Natural Resources and Agriculture Additional Questions Solved

Multiple Choice Questions (MCQs)

Question 1.
The compound responsible for the depletion of ozone layer is-
(A) Sulphur dioxide
(B) Chlorofluoro carbon
(C) Alkyl halide
(D) Organo-Mercuiy compounds
Answer: B

Question 2.
The polluted water can cause-
(A) Typhoid
(B) Kidney trouble
(C) Malaria
(D) Pulmonary disease
Answer: A

Question 3.
Which gas is present in the air in the highest proportion?
(A) Oxygen
(B) Nitrogen
(C) Carbon dioxide
(D) Argon
Answer: B

Question 4.
The main cause of a cough, asthma and tuberculosis is-
(A) Air pollution
(B) Water pollution
(C) Noise pollution
(D) All the above
Answer: A

Question 5.
Which is helpful in checking air pollution-
(A) Animals
(B) Factories
(C) Means of Transport
(D) Trees
Answer: D

Question 6.
The pollutant which dissolves in rain water to form acid rain is-
(A) Carbon monoxide
(B) Sulphur dioxide
(C) Nitrogen pentoxide
(D) Both (B) and (C)
Answer: D

Question 7.
The purest form of water is-
(A) distilled water
(B) sea water
(C) rain water
(D) well water
Answer: A

Question 8.
The improved variety of rice is-
(A) Kranti
(B) Pusa Basmati
(C) Pusa Jwala
(D) Pusa Bold”
Answer: B

Question 9.
Plants get hydrogen from-
(A) Air
(B) Water
(C) Soil
(D) Sun
Answer: B

Question 10.
Out of the following, which is a micro­nutrients for plants-
(A) Nitrogen
(B) Boron
(C) Phosphorus
(D) Potassium
Answer: B

Question 11.
The organism which prepare vermi- compost is-
(A) Earthworm
(B) Cockroach
(C) Grasshopper
(D) Bacteria
Answer: A

Question 12.
One of the following is a variety of wheat-
(A) HD – 2687
(B) Ganga-S
(C) Vikram
(D) PNR-S91-18
Answer: A

Question 13.
When two or more crops are grown in the field in succession, the practice is called-
(A) Multiple cropping
(B) Mixed cropping
(C) Mono cropping
(D) None of the above”
Answer: C

Question 14.
The HYV of wheat is-
(A) Pusa Basmati
(B) Villas
(C) C – 306
(D) Navjot
Answer: C

Question 15.
Main cereal crop of our country
(A) Rice
(B) Wheat
(C) Maize
(D) Millet
Answer: B

Natural Resources and Agriculture Very Short Answer Type Questions

Question 1.
Give the name of two air pollutants which are responsible for acid rain.
Answer
(a) Sulphur dioxide
(b) Nitrogen pentoxide

Question 2.
Name a disease caused by coal dust?
Answer
Lung cancer.

Question 3.
Which gases cause eye bum?
Answer
Sulphur dioxide,Chlorine and Ammonia.

Question 4.
Name the class of compounds which destroy the atmospheric ozone layer.
Answer
Chlorofluoro carbons.

Question 5.
What diseases are produced by dust particles?
Answer
Coryza, cough, asthma and tuberculosis.

Question 6.
What is air pollution?
Answer
Any qualitative or quantitative change in the composition of air, that produce an undesirable or harmful effect on living beings is called air pollution.

Question 7.
Name two air pollutants which cause acid rain.
Answer
(a) Sulphur dioxide (SO2)
(b) Nitrogen dixode (NO2)

Question 8.
Name two causes of air pollution
Ans.
(a) Smoke emitted by various automobiles.
(b) Burning of fuels, like wood, coal and petrol.

Question 9.
What gases are emitted by burning of petrol?
Answer
Carbon monoxide (CO), carbon dioxide (CO2) and nitrogen oxides (N2O, NO2) are emitted by burning of petrol.

Question 10.
What is water pollution?
Answer
The contamination of water with harmful chemicals and radiations is called water pollution.

Question 11.
Name four diseases caused by water pollution.
Answer
1. Cholera
2. Dysentery,
3. Typhoid and
4. Jaundice.

Question 12.
Explain why fishes in some river, pond or along sea shore are sometimes found dead.
Ans.
Toxic chemicals present in waste material thrown from factories and industries into river water, on large scale, kill the fishes.

Question 13.
Name the two gases which together constitute 99% of the atmosphere.
Answer
Oxygen (20.946%) and nitrogen (78.084%).

Question 14.
What is the percentage of oxygen in gases present in the atmosphere?
Answer
20.946%.

Question 15.
What is smog?
Ans.
Smog is a combination of smoke, water droplets of fog and fumes discharged into air from homes, factories and automobiles.

Question 16.
Write the name of the gas produced in Mathura Refineries which can damage the great historical monument, Taj Mahal.
Answer
Sulphur dioxide gas.

Question 17.
Write the name of the improved variety of wheat?
Answer
HD 2687.

Question 18.
Name the manure which is formed with the help of earthworm.
Answer
Vermicompost.

Question 19.
Mention the best way to protect plants from the irus.
Answer
The best way to protect plants from virus disease, TMV resistant varieties must be grown. Infected plant should be removed and burnt from field.

Question 20.
How a pathogen entry can be prevented in a crop field?
Answer
We should stop the entrance of pathogens by preferable preventive measures, e.g., selection of optimum time of cropping, use of pest and disease resistant hybrid varieties, crop rotation, clean cultivation.

Question 21.
Define Inter-cropping?
Answer
Inter cropping is retailored and improved version of traditional mixed cropping, in which two or more crops are grown simultaneously in the same field, but in a definite row pattern.

Question 22.
What is sustainable agriculture?
Answer
It refers to the successful management of resources to satisfy human needs, while conserving natural resources, using renewable resources.

Question 23.
What do you understand by rotation of crops.
Answer
Rotation of crop is repeated cultivation of a cereal crop and a legume crop in successive seasons.

Question 24.
What are primary nutrients?
Answer
Primary nutrients are the most important minerals, required for plant growth.
They are: Nitrogen, Phosphorus and Potassium.

Question 25.
Write one advantage of crop rotation.
Answer
Crop rotation minimises attraction by pathogens and pest, controls weeds, improves fertility of soil.

Question 26.
What are weedicides? Name one weedicide.
Answer
The chemical substances which are used to kill weeds are called weedi­cides. An example of weedicide is 2, 4 – D (i.e. 2, 4-Dichlorophenoxy acetic acid).

Question 27.
Write the name of two fungal diseases of plants.
Answer
(a) Late blight of potato.
(b) Green ear disease of

Question 28.
Write names of two bacterial disease in plants.
Answer
(a) Angular leaf spot of tobacco.
(b) Red stripe of sugar cane.

Natural Resources and Agriculture Short Answer Type Questions.

Question 1.
What are the different kinds of environ­mental pollution?
Answer
Following are the different kinds of pollution-

  1. Water pollution
  2. Air pollution
  3. Land pollution
  4. Noise pollution
  5. Radioactive pollution
  6. Thermal pollution

Question 2.
Which sources emit carbon dioxide in the atmosphere?
Answer
Following are sources which release carbon dioxide into the atmosphere-

  1. When fossil fuels such as wood, coal oil, etc. are burnt in furnaces, then carbon dioxide is released to the atmosphere.
  2. When petrol or any fuel is burnt in automobiles, railway engine, ships, aeroplanes, etc., carbon dioxide is discharged and sent to the atmosphere.
  3. When living beings respire, CO2 is sent to the atmosphere.

Question 3.
Why a long exposure to carbon monoxide is fatal for human beings?
Answer
Carbon monoxide has affinity for haemoglobin, 200 times more than oxygen. If a person inhales carbon monoxide for 6 to 8 hours, then carbon monoxide has poisonous effect. Carbon monoxide binds with haemoglobin and forms carboxy- haemoglobin, which can not absorb oxygen. Thus, red blood corpuscles lose the capacity of carrying oxygen to various parts of the body. As a result of which, the person dies for want of oxygen.

Question 4.
Why the use of polythene bags should be stopped?
Answer
Use of polythene bags should be stopped and banned, because of the following reasons.

  1. Biodegradation of polythene bags does not occur. So, polythene bag remain permanently in the soil and is an obstacle in the development of plants.
  2. Polythene bags thrown in drains chock the drain-pipe, as a result of which dirty waste water spreads out on the land. So, insects, bacteria and germs are produped in that stagnating water, which spread many diseases such as cholera, malaria, etc.
  3. People throw used polythene bags containing refuge and wastage of food, fruits and vegetables in it. Cows and other animals swallow these bags along with the food contents. These bags accumulate in the stomach of the cows and cause diseases and even death of the cows.

Question 5.
How noise pollution can be controlled during festivals and social functions?
Answer
Control of noise pollution during festivals and social functions:

  1. Use of noise pollution produced by loud speakers during festivals, social and religious functions should be restricted.
  2. Burning of crackers and other fire­works should be stricktly prohibted from 10 O’clock in night, till 6 O’clock in the morning.
  3. Crackers with high sound intensity should not be allowed.
  4. Crackers and fire works should not be allowed near hospitals, educational institutions.

Question 6.
What are macro-nutrients and why are they called macro-nutrients?
Answer
Macronutrients are essential inorganic elements, which are required in comparatively larger quantities for growth and reproduction of plants. They are called macronutrients because they are required in relatively larger quantities e.g. carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium etc.

Question 7.
What management practices are common in dairy and poultry farming?
Answer
The principles of feeding, breeding and weeding are same in both.

  • Proper shelter, its hygiene aeration and lighting
  • Proper feed and feed additives.
  • Selective breeding.
  • Health care including vaccination.
  • Proper drinking water.

Question 8.
Why are manures and fertilizers used in fields?
Answer
Manures and fertilisers are added to fields mainly to replenish minerals, which get depleted due to withdrawal by crop plants and reaching down to lower strata of soil.

  1. Manures add a small quantity of all minerals to the soil. They improve soil hydration, soil aeration and activity of soil micro-organisms, some of which are required for solubilisation of heavy minerals.
  2. Fertilisers are nutrient specific which contain one or more minerals in concentrated form. They meet the immediate and complete minerals requirement of high yielding varieties. However, they harm soil structure and cause pollution of crops, soil, groundwater and nearby surface water. A combination of both manure and fertilizer is highly useful.

Question 9.
What are the benefits of cattle farming?
Answer
The cattle farmers are benefited in the following ways:

  1. They use cattle for various draught purposes in agricultural operations like ploughing, harrowing etc.
  2. They get milk for cattle.
  3. Provide extra income.
  4. They provide manure and fuel. Agriculture and cattle farming is complementary to each other.
  5. They are used in the driving cart for the transportation of materials and men.

Question 10.
List out some useful traits in improved crop?
Answer
Useful traits of improved crops are as follows:

  1. Higher yield
  2. Improved nutritional quality
  3. Resistance to biotic and abiotic stresses.
  4. Change in maturity
  5. Wide range of adaptability.
  6. Desired agronomic characteristics.

Question 11.
Explain the different factors that are to be considered before deciding the nature of feed for cattle and poultry birds.
Answer
The food requirements of cattle and poultry birds vary according to the age, health, nature of work and special conditions, like lactation period.

  1. The optimal food requirements of a cattle can be worked out, by studying the internal structure and functioning of the rumen and nutritional quality of their feeds and fodder. The milk yield of an animal is largely determined by the kind of feed given to it.
  2. A calf needs more food and nutrition than an old cow.
  3. The feed of poultry birds also needs essential nutrients like carbohydrates, proteins and minerals. The feed for larger poultry farm contains mashed cereals, like bajra, wheat and maize, rice, beans and groundnut cake.

Question 12.
Describe the role of fertilisers and irrigation in improving crop yield. Mention any one effect of each if it is used in excess.
Answer
Role of fertilisers are as follows:

  1. They provide macronutrients like N, P, K, S and Mg and micronutrients like Cu, B, Mn required for the proper growth and development of plants.
  2. They are readily soluble in water and immediately absorbed by the plants.
  3. They provide these nutrients in a specific quantity.

Role of irrigation are as follows:

  1. It is applied in certain frequency and quantity for specific crops, e.g. Paddy needs more water.
  2. It provides water supply to the plants which is very much essential for life processes, like photosynthesis.
  3. It is applied in certain frequency and quantity for a specific type of soils, e.g. sandy soil needs more frequent irrigation.

The effect, when fertilisers are used in excess:
Excess of nitrogenous fertilisers from the soil is washed away into water bodies like a pond, encourages more algal growth and oxygen depletion. This is called eutrophication.

The effect when irrigation is used in excess:
Excess irrigation affects the respiration of roots if it is done before harvesting.

Question 13.
What are the desirable traits for which improved varieties are developed by cross-breeding programmes between indigenous and exotic breeds? What are the advantages of exotic breeds?
Answer
The desirable traits are as follows:

  1. Dwarf broiler parent, for commercial chick production.
  2. Number and quality of chicks.
  3. Improvement in the hen, housed for egg production and reduction in the size of the layer, with the ability to utilise a more fibrous diet, formulated using agricultural by-products.
  4. Low maintenance requirements.
  5. Summer adaptation tolerance to, high temperature.

Advantages of exotic breeds:

  1. They mature easily.
  2. They yield more eggs and meat.
  3. They are small in size and eat less, as compared to indigenous variety.

Question 14.
What is inter-cropping? How does it differ from mixed cropping? State its two advantages?
Answer
Inter-cropping is the process of growing two or more crops simultaneously, on the same field in a definite pattern. A few rows of one crop, alternate with a few rows of a second crop.
For example: Soyabean + maize or finger millet (bajra) + cowpea (lobia).

Difference between mixed cropping and Inter-cropping are as follows:

Mixed cropping Intercropping
1.  It has target to minimise risk of crop failure.

2.   It involves no set patterns of rows of crops.

3.   Seeds of two crops are mixed before sowing.

 1.  It has target toin- crease productivi­ty per unit area.

2.   It involves set patterns of rows of crops.

3.   Seeds of two crops are not mixed.

Advantages of inter-cropping are as follows:

  1. It prevents pests and diseases from spreading to all the plants, belonging to one crop in a field. In this way, both crops can give better returns.
  2. It ensures maximum utilisation of the nutrients supplied.

Question 15.
Why should preventive measures and biological control methods be preferred for protecting crops?
Answer
Prevention is always better than cure. Plants are harmed if attacked by pests. Preventive measures and biological control methods are preferred for protecting crop plants, because they not only prevent the stored food materials from getting, spoiled, getting infested by insects, bacteria and micro-organisms. These methods also protect crops from chemicals which are sometimes added, to control the pests attacking stored food grains. These chemicals are toxic. Some pesticides lead to biomagnification. Biological methods are eco-friendly too.

Natural Resources and Agriculture Long Answer Type Questions

Question 1.
What is sound pollution? What are the different sources of sound pollution? How pollution can be controlled?
Answer
Sound pollution: Production of undesirable loud and harsh sound at the wrong place and wrong time is called sound pollution. The sound of sirens of buses or trucks seems to be normal on a highway, but near a hospital, school or in residential colony the sound of siren takes the form of noise thus causing sound pollution. Unwanted sound is called noise. Following are the sources of sound pollution:

1. Sources of sound in homes:

  • Radio
  • Television
  • Mixers and grinders
  • Desert cooler
  • Transistor
    Air conditioner, etc. contribute to sound pollution, because these domestic appliances produce a variety of sound and noise.

2. Sources of sound in surroundings:

  • Loudspeakers used in religious place, on festive occasions, or public meetings
  • Exploding of crackers
  • crying of hawkers in streets
  • Fairs also contribute to noise pollution.

3. Sources of sound in factories Industries: Machines in factories produce loud roaring noise and contribute to noise pollution.

4. Sources of sound due to traffic:

  • Noise produced by various automobiles vehicles
  • Noise produced by flying aeroplanes
  • Railway locomotives produce unwanted high-intensity sound.

Measures to control noise pollution:
1. Noise control in homes: Proper maintenance and necessary usage of television, radio, transistor, grinders, desert coolers, etc. bring down the noise level by keeping their volume level low.

2. Noise control on roads: Proper maintenance of the vehicles and use of low sound intensity of sirens, control the noise pollution. Law should be enforced to get rid of noisy vehicles.

3. Control on noise produce by industries and factories: Machines should be kept well lubricated and maintained properly, to bring down the level of noise. Factories should be set away from residential areas.
4. Trees and plants are good sound absorbers. So, trees should be planted on both the sides of the road to check the movement of sound towards homes, educational institutions, offices, etc.
5. People should be made aware of the fact that noise is injurious to health, through newspapers, television, radio, and magazines.

Question 2.
Why it is necessary to conserve water? What efforts should be made for the conservation of water?
Answer
Sources of water in the world are limited, whereas the population has increased tremendously. Consumption of water is more than available resources. The level of underground water has gone down. Lakes, rivers and ponds are polluted, so water should not be wasted at all. Due to deforestation, there is a shortage of rainfall. As such, conservation of water is necessary.
Following are the measures to be taken to conserve water:

  1. Do not let water flow uselessly. Leakage in pipes should be repaired.
  2. If the pipe-line distributing water is leaking and broken, the related officers should be informed so that pipes may be repaired or changed.
  3. Taps in public places should be kept closed, when not being used. Often children open the taps or sometimes elders also forget to close the tap, due to which water flows uselessly. So, close the taps before going from the house.
  4. Take care that water from the water reservoir kept on the roof of the house does not overflow. Keep the tanks always clean and covered.
  5. Wastewater of the kitchen should be collected in a tank and should be used for the kitchen garden or in washrooms. This saves drinking water.
  6. Every drop of water must be saved. Avoid wastage of water.
  7. Take every care that water resources do not get contaminated.

Question 3.
Explain the various methods of crop improvement. Name one improved variety of Rice, Maize, Soybean, Sunflower and Mustard?
Answer
The most important crop improve¬ment are as follows:
(1) Higher yield: The main aim of crop improvement is to improve the productivity of economic productivity, e.g. vegetables, grain and fodder. Quality seeds of improved varieties are used for their commercial production.

(2) Improved quality: Quality considera¬tions of crop products varies from crop to crop, e.g. protein quality in pulses, baking quality in wheat, oil quality in oil seeds and preserving the quality of fruits and vegetables.

(3) Photo insensitivity and thermoin¬sensitivity: Most of the plants are sensitive to certain abiotic factors such as light and temperature. Development of photo-insensitive and thermosensitivity crop varieties will help in crossing the cultivation boundaries, e.g. MACS 2469 can tolerate high temperature, a HYV of wheat.

(4) Wider adaptability: If we develop those varieties of crops which have wider adaptability, then it will help in stabilising the crop production, under different environmental conditions.
For example ICPH 8 is a hybrid pigeon pea plant, which takes a short duration to mature, escapes and diseases such as Fusarium, wilt and sterility mosaic will not and yields of 30 to 40 per cent more than the popular breed is obtained. It performs well under drought, as well as high- moisture conditions.

(5) Biotic and abiotic resistance: Under different situations, crop suffers due to biotic stresses and abiotic stresses. If we develop crop varieties, which are resistant to these stresses, then we can significantly improve crop production.
For example, MUW 318’is a HYV of wheat, which is released for cultivation in non-traditional areas such as Nilgiri and Palni hills and resistant to all the rusts.

(6) Desirable agronomic traits: If we develop those varieties of crops which contain desired agronomic traits, then it will help in setting higher production. Thus, tallness, high tillering and profuse branching are desirable characters for the fodder crops. Whereas, dwarfness is desired in cereals, as dwarf varieties provide protection from lodging.
For example, breeding for resistance to red root has led to sugarcane varieties such as CO 975 and CO 62399 which increase sugarcane production in problem areas. Likewise, new varieties of chicken pea, as BG 244 and ICC 34 grow erect, have many branches and has pods from base to tip.

Some improved varieties or high yielding varieties of crop plants are as follows:

  1. Rice – IR 8, Jaya.
  2. Maize – Gangs 5
  3. Mustard – Pusa Gold, Kranti
  4. Soybean – PK 262
  5. Sunflower – BSH 1

Question 4.
(a) What are the causes of crop disease?
(b) Explain the types of crop diseases.
(c) How does crop disease can be controlled?
Answer
(a) When the pathogens, such as bacteria, fungi and viruses get favourable conditions for growth and propagation, they spread and infect the crop plants causing crop diseases.
(b) Depending upon their mode of occurrence, crop diseases are of the following types:

  • Seed-borne diseases: These diseases are spread through seeds, e.g. leaf spot of rice.
  • Water borne diseases: Pathogens of these crop diseases are transmitted by water, e.g. Bacterial blight of rice.
  • Air borne diseases: These crop diseases are transmitted through the air, e.g. rust of wheat.
  • Soil-borne diseases: These diseases are spread through the soil mostly affecting roots and stems of crop plants, e.g. smut of bajra.

(c) All the seed and soil-borne diseases can be controlled, by treating the seed or soil and the airborne diseases are controlled by spraying fungicidal solution, on infected parts.

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