RBSE Class 9 Science Chapter 15 Natural Resources And Agriculture Solutions help students to master all the concepts of the chapter well and gain high scores in the exams. It is also considered as the most important resource used by students to revise the chapter completely. Solving these solutions will help them to comprehend the subject matter and master it properly. Meanwhile, these questions from the RBSE Class 9 Solutions for Chapter 15 Science include all the highlights from the topics from the chapter. These chapterwise important topics and questions from the RBSE Class 9 Science help students to prepare most competently for the RBSE Class 9 exams.
Additionally, in order to master the concepts taught in class, students are also advised to improve their performance by implementing a strategic learning process. Here, we have attempted to list out the important questions from Chapter 15, Natural Resources and Agriculture of RBSE Class 9 Science Textbook. Practising these questions will help the students to score high marks as they get more familiar with the question types. Students who have mastered the subject will be able to have a proper foundation of the subject before moving to higher classes and it will also help them to score high marks.
Rajasthan Board Class 9 Science Chapter 15- BYJU’S Important Questions & Answers
RBSE Class 9 Science Chapter 15 Objective Questions-Important Questions and Solutions
1. Growing different crops in a field in a planned manner is known as :
(a) Mixed cropping
(b) Mixed farming
(c) Crop cycle
(d) Intra cropping
Answer: (c) Crop cycle
2. According to the volume, the amount of carbon-di-oxide present in the atmosphere is :
Answer: (a) 0.03%
3. Acid rain results from :
(a) Air pollution
(b) Water pollution
(c) Soil pollution
(d) Sound pollution
Answer: (a) Air pollution
4. Of the following which nutrient is obtained by the plants from the soil :
Answer: (d) Nitrogen
5. Which of the following is a Kharif crop :
Answer: (a) Soyabean
RBSE Class 9 Science Chapter 15 Very Short Answer Questions-Important Questions and Solutions
1. Name the device used to measure the speed of wind.
Answer: Anemometer is the device used to measure the velocity of wind.
2. What is pollution?
Answer: The unwanted-for or undesired change in the chemical or biological properties of air, water and soil that is very harmful for human life ecology and natural resources is termed as Pollution.
3. What are the natural resources?
Answer: All the substances that are obtained from nature used by other organisms, along with humans are natural resources. Air, water, soil, minerals, fossil fuel, plants and animals are all natural resources.
4. What are algal blooms?
Answer: Algal blooms are the excessive growth of algae in water bodies.
5. What is a sonic boom?
Answer: The supersonic jet that moves at a speed faster than sound, leaves a trail of sound waves as it moves ahead. This is known as the Sonic boom. Sonic boom weakens the buildings when it collides with the earth surface.
6. What is mixed farming?
Answer: All the needs of the farmer cannot be fulfilled by the produce of small patches of land. Hence, in order to increase productivity the farmer adopts other methods that include animal husbandry, fisheries, horticulture and agriculture. This practice not only boosts the farmer’s income but also enables the use of the land available to the maximum. This system of farming that involves the growing of crops along with raising the livestock is known as Mixed farming.
7. What is the name of the gas present in the maximum amount in the atmosphere?
Answer: In dry atmosphere, Nitrogen is the gas present in the maximum amount making up 79%.
8. Which gas is used by plants during respiration?
Answer: Oxygen is the gas used by the plants during respiration.
9. What is the reason for wind movement?
Answer: The movement of air is dependent on several factors such as the geographical position, topography, height and distance from the sea, density of vegetation and so on.
10. Write the name of fowl with maximum production.
Answer: The name of the fowl with maximum production is White Leghorn.
RBSE Class 9 Science Chapter 15 Short Answer Questions-Important Questions and Solutions
11. What is humus? What are its benefits?
Answer: The black organic substances that are produced by the decay of dead parts of plants and animals by the microorganisms are termed as Humus. Solid pollutants such as the sewage, animal and plant remains and so on that are buried deep under the soil in large pits degrade to form the humus. It can be used for agricultural purposes. The plant nutrients are stored in the humus.
12. How does acid rain occur? Write the side effects of acid rain.
Answer: When Nitrogen-di-oxide (NO2) is released from the burning of fossil fuels, it oxidises to form Nitrate (NO3) that produces nitric acid with water (HNO3). The nitric acid 3 then comes down to the earth along with rain water. The rain that has nitric and sulphuric acids dissolved in its water is known as the Acid Rain. Acid rain increases the acidity of soil and goes on to destroy its fertility. It also harms buildings, rail-roads, monuments, statues and so on by corroding them.
13. What is Biological Oxygen Demand (BOD)?
Answer: Biological Oxygen Demand (BOD) is the measurement for the amount of oxygen used in volume of water in the specified time, from which the quantity of organic pollutants are inferred.
14. Describe the negative effects of air pollution.
Answer: Man is the main cause of atmospheric pollution and the chief air pollutants include carbon monoxide, sulphur-di-oxide, hydrocarbon mixture, the suspended particulate matter present in the air, smoke and dust particles. Also, the source of all these pollutants are coal burnt in industries and households, petrol, gas ovens, automated vehicles and so on.
The smoke that is released on burning of coal and other natural fuels contain many oxides of sulphur. Sulphur-di-oxide is a harmful pollutant and it affects the mucous membrane of eyes,
lungs and throat and causes many diseases. Also, the particulate contents of smoke such as the soot, tar, dust particles and so on reduces light. They gradually deposit on the earth, thus entering the animal body during respiration leading to various diseases of the respiratory tract including lungs. At the same time, oxides of nitrogen released on burning automobile petroleum cause irritation in the nose and the respiratory tract. Also, the sewage released from leather
industries, animal slaughter-houses, passenger-ships and boats and more contain many infections, microorganisms that cause various diseases among the human population like – Cholera, typhoid, jaundice and so on.
15. What is biomagnification? Explain.
Answer: Chemicals like- pesticides (like DDT), fungicides, bactericides and herbicides are used on a large scale to protect plants from pathogens, diseases, weeds and so on, which do not decompose and remain in the soil. Plants, at times, absorb them and they reach the higher trophic levels by means of the food chain. In this process, there is biomagnification of these substances and they become toxic for human consumption. This increase in the toxicity along with the rise in trophic level is termed biomagnification.
16. What is noise pollution? Explain the negative effects of noise pollution.
Answer: Sound that is undesirable and annoying is termed as noise and when the sound intensity reaches levels that irritates us, we call it noise pollution. The sound of intensity more than 80 db is a pollutant that is harmful for our hearing. Sound of 100 db intensity makes us feel restless and disturbed by sound, while that of 120 db or more produces a severe headache. It also hinders smooth conversation and reduces our hearing power and disturbs our mental peace. People residing in areas with intense noise pollution lose their ability to listen at a very young age. Mental tension and heart beat is also increased with noise. It is also bad for brain and liver functioning. We also find many harmful physiological effects to our body such as the pupil expands due to intense noise, the yellowing of skin is observed, voluntary muscles may contract, secretion of digestive enzymes is hampered, blood pressure increases, the quantity of adrenalin in the blood increases. All this leads to increased tension in nerves and increased restlessness.
17. Write four reasons for soil pollution.
Answer: Soil pollution was caused by modern lifestyle, and the human activities related to industries and agriculture. Given here are the reasons for soil pollution. Solid and liquid effluent from industries are spread on the soil without any type of pre-treatment. The fly-ash that spreads for miles harms the soil to a great extent. The minerals, chemicals, toxins and so on of the effluents pollute the soil and make it barren. Further, urban effluents or solid urban waste such as paper, glass, metallic boxes, plastic, fibres, food-waste, rubber, dyes, paint and more pollute the soil to a large extent. The liquid urban waste, meanwhile includes the organic and inorganic chemicals, oil, grease, toxic substances and so on. These spread on the soil and pollute it. These effluents have pathogens that cause various diseases. Also, in-judicious,
unforeseen use of chemical fertilizers in excess and excessive irrigation makes the soil waterlogged and removes the essential nutrients from the soil, thus making it barren.
18. Write four methods to control air pollution.
Answer: Using the resources limitedly and in a judicious manner helps to control air pollution. Find here the few strategies to control it:
- Adsorption : a physical process that depends upon the surface properties of some substances. In it the flow of liquid and gas is coupled with a solid, so that the solid holds a thin film of the liquid or gas on the outside surface-thus entrapping it. Activated charcoal, silica gel. Resin and so on are utilized as adsorbents. Since the adsorbents are reused it is an economic thrift process.
- Absorption : a physical process, in which the gases are allowed to dissolve in fluids. Water is the best solvent or medium for absorption.
- Condensation : the best method for removing the hydrocarbons that have very low vapour pressure at ambient temperature, (i.e. air temperature of the surroundings). Air pollution can be satisfactorily controlled by using water or air cooled condensers.
- By chemical reactions : Pollutants can be removed from the air using various chemical reactions.
19. What is the difference between manure and fertilizer?
Answer: Different types of manure and fertilizers are used in order to supply nutrition to the soil. Plant nutrients are prepared commercially, Fertilizers provide nitrogen, phosphorus and potassium. They also result in good vegetative growth of plants and keep them healthy. Fertilizers are used to boost the production. Manure is prepared by the decomposition of dead plant parts and animal wastes. Bio-waste is used to manufacture manure. Manure replenishes the soil with organic substances and nutrients, thus increasing its fertility. More quantity of organic substances in manure improves the structure of soil. Green manure, compost and veri-compost are types of manure. Dung manure, compost, vermi-compost and green manure are used as manure-Urea, while di-ammonium phosphate, super phosphate, ammonium sulfate and calcium ammonium nitrate are used as fertilizers.
20. How is vermi-compost prepared?
Answer: For composting, the agricultural wastes like the feaces of animals, dung, vegetable rind and trash, weeds and so on are filled in pits and decomposed with the help of micro-organisms. This decomposed material is used as manure. Compost is said to be rich in organic matter as well as various nutrients. Meanwhile, to prepare vermi-compost, plant and animal wastes are degraded with the help of earthworms.
21. What is Organic Farming? Explain.
Answer: A technique of farming, where chemical fertilizers, insecticides, weedicides and so on are not used at all or if in case of need is used only in very small quantities is called Organic Farming. Instead of fertilizers, in organic farming, organic manure recycled agricultural wastes and cattle wastes, biological agents like blue-green algal cultures, bio-fertilizers and the likes are used. Neem leaves and turmeric powder are used as bio-insecticides during storage.
22. How is artificial apiculture done?
Answer: For artificial apiculture, artificial hives in the shape of closed boxes with larger egg chambers and plates of metal or plastic are prepared. The plates have a coating of wax and they form the support for the formation of hives. The closed box also sports many perforations, so that the honey bee can enter the hives.The artificial hives are put in gardens or near the fields from where the bee can get the nectar. The worker bees collect the nectar and convert it into honey. Honey is collected in the cells of the artificial hive and is obtained by removing the plates from the hive.
23. Write the name of the breeds of cow and buffalo. Which produces more milk?
Answer: Buffalo is preferred for more milk production. Find here the varieties of buffalo most preferred for more milk production. They include the murrah, jafarabaadi, surti and so on. Meanwhile, desi varieties of cow includes Sahiwaal, Sindh, Gir, Devli, Hariyanawi and more. At the same time, the foreign breeds of cow are Redden, Holstein, Jerry etc.
24. Write the names of a few cattle diseases.
Answer: Animals may suffer from diseases caused by virus, bacteria, fungi and worms. The main diseases of animals are given here. The diseases include Khurpka Poly vaccine Every year (paw festering) and Muhpka (festering of mouth), Diphtheria, Glandular Disease (Gilte-rog), Tuberculosis and Smallpox.
25. What is Mixed Cropping? What are its benefits?
Answer: If only one type of crop is grown in a field, the requirements of all the crop plants will be alike.That is, it will use up some of the nutrients and it may reduce in quantity over time, while others are not used at all. Hence, in order to avoid this nutrient imbalance, two or more crops are grown together in the field. This cropping pattern is called mixed cropping. In mixed cropping, the normal crop groups used together are like wheat and gram, wheat and mustard groundnut and sunflower and so on. One benefit of the mixed cropping is that if one of the crops fails as a result of adverse weather conditions or due to any other reasons, at least the produce of the other will be available.
RBSE Class 9 Science Chapter 15 Essay Questions-Important Questions and Solutions
26. What is long term cultivation? Explain the various methods of long term cultivation.
Answer: Land often becomes barren with continuous use of chemicals, fertilizers, insecticides and so on. Hence, there is a need for long term cultivation. Techniques that can be used for crop cultivation, on a continuous basis, without harming natural resources is called long term agriculture. Methods such as mixed farming, mixed cropping and crop-rotations are used for long-term agriculture.
27. Write the name of the products of fisheries and explain the various steps of culturing fishes.
Answer: Fishes are a good source of nourishment and they are also used as food material. Fishery, now is a combined form of agriculture and animal husbandry as fishery is a type of
animal husbandry while producing food from fishes in the water reservoir is agriculture. See here the steps involved in fish-culture:
- Dwelling: While mostly, fishes are cultured in natural water sources such as sea, lakes, ponds and river, it is also done in artificial water reservoirs. Places that have clay-rich soil are considered good to construct water reservoirs.
- Various species of fish: Fresh water produces more fish as compared to saline water. Some of the indegenous fishes cultured in fisheries include Rohu, Mrigla, katla and so on, while exotic species of fishes that are cultured are common carp, silver carp and the likes.
- Food for fishes: Fishes living in natural water bodies feed on minute aquatic plants and microorganisms. Meanwhile, fishes in artificial water bodies are given rice husk, particles of cereals, wheat pieces, almond pomace, soyabean and so on as food.
- Fish production: Spawn, also known as the seeds of fish, are collected using nets from its breeding places of the rivers and fertilized eggs are obtained from them. The small fishes that emerge from these eggs are called the fry. After a period, the fry transform into fingerlings or parr and the fingerlings are then taken to the fish cultivation tanks. They are treated with bactericidal substances like copper sulphate, formalin, Potassium permanganate or salt to kill the infectious bacteria present there.
- Fish storage: When the fish is sufficiently big, they are caught with the nets in the water reservoirs or by passing current in the water body.
- Fish shielding: Fish are preserved by burying them in ice, in order to prevent their rotting.
28. What is irrigation? Explain the modern methods of irrigation.
Answer: Water is crucial for the growth and development of flowers, fruits and seeds. Water is absorbed, along with the dissolved minerals and fertilizers from the soil, by the roots. In order for the crop plants to grow healthy, the fields need to be watered on a regular basis. Irrigation is watering the fields at the different time intervals. Time and frequency of irrigation is dependent on the crop, soil type, season and so on. Water can be used economically by adopting modern methods of irrigation.These methods include sprinkler system and drip system.
- Sprinkler System: It is used for uneven land where less water is available. Rotating nozzles are fixed to the upper ends of vertical pipes that are at a definite distance from each other and are attached to the main pipe. When water is sent to the nozzles via the vertical pipes they rotate, sprinkling water over the crop plants in a manner similar to the rains, irrigating the crop.
- Drip System : Water, in this method, reaches down directly to the roots, drop by drop. It is the best irrigation method for fruit trees, gardens and other plantations. Water is not wasted in this method and the plant receives continuous supply of water, drop-by drop. This system is a boon for areas that face water scarcity.
29. Describe the aims of improvement in varieties of crop plants.
Answer: Good production of crops is dependent on the selection of varieties for cultivation. Several useful qualities (such as disease resistance, compatibility with fertilizers, quality of the produce and high production) of the crop varieties can be chosen by breeding. Desired traits can be introduced in the varieties via hybridization technique, where plants with different genetic properties are hybridized. Another method introduced for crop improvement is introduction of the desired genes that leads to producing genetically altered varieties. Good quality seeds germinate properly in favourable conditions. Crop production depends on the weather, the quality of soil and availability of water. Meanwhile, given are the objective of improving crop varieties. With the improvement in varieties of crop plants:
- High production: The production per hectare is increased.
- Improved varieties: The quality of the crop produce varies for every crop. For example, the quality of protein in pulses, quality of oil in oil crops, high quantity of vitamins and minerals in fruits and vegetables and so on.
- Biotic and Abiotic resistance: As a result of the several biotic (diseases, insects etc.)
and abiotic (drought, salinity, water logging, heat, cold, frost etc.) factors, the crop production may reduce. However, the varieties that are tolerant of these factors can boost the production under adverse conditions.
- Change in maturation period: It is economically beneficial to make use of varieties with reduced duration, from sowing to reaping. The farmers may then obtain more than one crop in the field yearly. Reduction in time also cuts down on the expenses of the crop production. If the crop maturation is simultaneous, the loss of produce will be less.
- Broad compatibility: Production of varieties that have broad compatibility is helpful to stabilize the produce in different environmental conditions. Some varieties are also used for cultivation under different environmental conditions.
- Optional qualities of the crop:The desired quality of fodder crops so that there will be more production using less nutrients is long and dense branching. In this way several improved varieties are used to boost the production.
30. What is water pollution? Describe the causes and negative impacts of water pollution.
Answer: Contaminating the source of water using various pollutants such as sewage, detergents, herbicides and insecticides dissolved in water, industrial effluents containing dissolved organic and inorganic chemicals, harmful microorganisms, soil sediments of rivers and rivulets deposited on the banks and so on is called water pollution. Learn here about the causes of water pollution and more about the effects of water pollution.
RBSE Class 9 Science Chapter 15 Additional Questions-Important Questions and Solutions
31. What is the significance of Water?
Answer: Water is the most abundant of all the substances present on the earth’s surface. Over 70% of the earth’s atmosphere is submerged in water. A large portion of the earth’s surface is located in the oceans and seas. This water is saline. Meanwhile, non-saline or fresh water is found on the poles, as underground water, in the rivers, lakes, ponds and more. Water is also an important component of the protoplasm of the living cells. Water is a universal solvent in which various nutrients dissolve and enter the plant body. All the metabolic reactions occurring in the cell takes place in the aqueous media with all the life-processes of organisms dependent on water. Apart from this development, types of plant communities and their distribution are also controlled, to a large extent, by water.
32. What has increased the fear of corrosion of the marble of Taj Mahal?
Answer: Smoke is released on burning coal and other natural fuels. Smoke when with fog forms smog. In it the sulphur-di-oxide reacts with oxygen and forms higher oxides of sulphur forming sulphuric acid with water. This acid corrodes the stones and walls of buildings. The acid produced by the pollutants that are released from the petroleum refinery at Mathura has
increased the fear of corrosion of the marble of Taj Mahal.
33. What is responsible for 60% of the air pollution in today’s world?
Answer: Automobile exhaust containing all the air pollutants is responsible for 60% of the air pollution. On burning 1000 gallon of petrol, nearly 3200 pound CO, 200-400 pound carbonic vapour, 20.75 pound oxides of nitrogen, 2 pound carbonic acids, 2 pound ammonia and 0.3 pound solid carbon particles are released.
34. Chemical fertilizers in the form of pollutants. Explain.
Answer: Chemical fertilizers including urea, potash, diammonium phosphate and so on are used to boost agricultural production. These fertilizers flow down to the water bodies and create Algal blooms.
35. What is a decibel?
Answer: The unit used to measure the intensity of sound is called decibel. The unit proposed by Graham Bell, the famous scientist is also expressed by db.
36. What are ultraviolet rays and infra-red rays?
Answer: The radiations with the wavelength less than violet colour are called ultraviolet rays, while those having wavelength more than red are the infra-red radiations.
37. What is green manure?
Answer: Pod bearing, leguminous plants such as sunhemp, moong, gwar and so on are grown in the fields before growing the crops. After they get to sufficient height, they are ploughed down and mixed with the soil. These plants convert into green manure and are used to replenish the nitrogen and phosphorus content of the soil.
38. Name the macro and micro nutrients in soil.
Answer: Nitrogen, Phosphorus, Potassium, Calcium, Magnesium and Sulphur are the macronutrients of the soil. Likewise, the micronutrients in soil include Iron, Manganese, Boron,
Zinc, Copper, Molybdenum and Chlorine.
39. What are kharif and Rabi crops?
Answer: Crops that are sown during the rainy season are known as Kharif crops. In Bharat, the rainy season is June-September. Kharif crops include paddy, maize, soyabean, groundnut, moong and so on. Meanwhile, Rabi crops are grown during the winter season. Some of the major rabi crops are wheat, gram, pea, mustard and flex.
40. Explain crop rotation.
Answer: Fertility of the land is reduced because of continuous cropping of the same crop over the years. Production of the crop also reduces with lack of certain nutrients in the crop land, as they are being used regularly. Hence, to replenish the soil and maintain the balance of the nutrients, crop rotation is adopted. Crop rotation is the method of growing different crops in succession in the field in a planned manner. In this method, cereals are cultivated in rotation with pod-bearing leguminous plants in order to replenish the soil nitrogen.
41. What are the weeds and why should they be removed?
Answer: The unnecessary plants that grow along with the crop plants are called Weeds. Examples for weeds are Vilayati Gokhru (Xanthium), Motha (Cyperus rotundus), Carrot-grass (Parthenium) and so on. These weeds compete to get food, space and light and also absorb various nutrients from the soil, thus reducing the production. Hence, for the crop plants to grow healthy, the weeds should be removed from the fields.
42. What are the tips to follow while selecting crops for mixed cropping?
Answer: Given are the things to keep in mind while choosing the crops for mixed cropping to get the best results:
- Use one crop of a long period while another should be of a short period.
- One crop should be long and the other dwarf
- Use one crop with deep root system, while the other should have surface root
Studying effectively from the textbooks by revising all the concepts help students to score high marks in the subject. They can also depend on these RBSE Class 9 Science Solutions in order to comprehend all the topics completely. Other best resources that the students can find to prepare most competently for the exam are the RBSE textbooks and sample papers.
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