NCERT Solutions for Class 9 Science Chapter 15 Improvement in Food Resources

Chapter Name

NCERT Solutions for Class 9 Science Chapter 15 Improvement in Food Resources

Topics Covered

  • NCERT Intext Questions
  • NCERT Exercise Solutions

Related Study

  • NCERT Solutions for Class 9 Science
  • NCERT Revision Notes for Class 9 Science
  • Important Questions for Class 9 Science
  • MCQ for Class 9 Science
  • NCERT Exemplar Questions For Class 9 Science

NCERT Intext Questions

1. What do we get from cereals, pulses, fruits and vegetables?


  1. Cereals give carbohydrates which provide energy.
  2. Pulses give proteins which build our body.
  3. Vegetables and fruits provide vitamins and minerals.

2. How do biotic and abiotic factors affect crop production?


Factors responsible for loss of grains, during storage and production are :
(a) Biotic factors like rodents, pests, insects, etc.
(b) Abiotic factors like temperature, humidity, moisture, etc. These can affect seeds as :

  1. infestation of insects
  2. weight loss
  3. poor germination ability
  4. degradation in quality
  5. discolouration
  6. poor market price

3. What are the desirable agronomic characteristics for crop improvements?


Desirable agronomic characteristics for crop improvements are :

  1. Tallness and profuse branching are desirable characters for fodder crops.
  2. Dwarfness is desired in cereals.

4. What are macro-nutrients and why are they called macro-nutrients?


Macro-nutrients are the essential elements which are utilised by plants in large quantities. Many macro- nutrients are required by the plants for the following functions :

  1. As the constituent of protoplasm
  2. N, P, S are present in proteins
  3. Ca is present in cell wall
  4. Mg is important constituent of chlorophyll
The 6 micronutrients required by plants are : nitrogen, phosphorus, potassium, calcium, magnesium and sulphur.

5. How do plants get nutrients?


Plants get nutrients from air, water and soil. There are sixteen nutrients essential for the growth of plants. Carbon and oxygen are supplied by water and remaining thirteen nutrients are supplied by soil.

6. Compare the use of manure and fertilizers in maintaining soil fertility.


Effects of using manures on soil quality :

  1. The manures enrich the soil with nutrients and organic matter.
  2. Add humus to the soil
  3. Increase water retention capacity of sandy soils
  4. Increases soil fertility and helps in improving soil structure.
  5. In clayey soils, the large quantity of organic matter help in drainage and in avoiding water logging.
Effects of using fertilizers on soil quality :
  1. By the continuous use of fertilizers the rate of soil erosion increases.
  2. By the use of fertilizers porosity of soil decreases and the plant roots do not get oxygen properly.
  3. The nature of soil changes to acidic or basic.

7. Which of the following conditions will give the most benefits? Why?
(a) Farmers use high-quality seeds, do not adopt irrigation or use fertilizers.
(b) Farmers use ordinary seeds, adopt irrigation and use fertilizer.
(c) Farmers use quality seeds, adopt irrigation, use fertilizer and use crop protection measures.


(c) Farmers using good quality seeds, adopting irrigation, using fertilizers, and using crop protection measures will derive most benefits.

  1. The use of good quality seeds increases the total crop production. If a farmer is using good quality seeds, then a majority of the seeds will germinate properly and will grow into a healthy plant.
  2. Proper irrigation methods improve the water availability to crops.
  3. Fertilizers ensure healthy growth and development in plants by providing the essential nutrients such as nitrogen, phosphorus, potassium, etc.
  4. Crop protection measures include various methods to control weeds, pests, and infectious agents. If all these necessary measures are taken by a farmer, then the overall production of crops will increase.

8. Why should preventive measures and biological control methods be preferred for protecting crops?


Preventive measures and biological control methods should be preferred for protecting crops because excessive use of chemicals leads to environmental problems. These chemicals are also poisonous for plants and animals. Preventive measures include proper soil and seed preparation, timely sowing of seeds, intercropping and mixed cropping, usage of resistant varieties of crops, etc. On the other hand, biological control methods include the usage of bio- pesticides that are less toxic for the environment. An example of bio-pesticides is Bacillus thuringenesis, which is an insect pathogen that kills a wide range of insect larvae. Therefore, both preventive measures and biological control methods are considered eco- friendly methods of crop protection.

9. What factors may be responsible for losses of grains during storage?


During the storage of grains, various biotic factors such as insects, rodents, mites, fungi, bacteria, etc. and various abiotic factors such as inappropriate moisture, temperature, lack of sunlight, flood, etc. are responsible for losses of grains. These factors act on stored grains and result in degradation, poor germinability, discolouration, etc.

10. Which method is commonly used for improving cattle breeds? Why?


Cross breeding is a process in which indigenous breeds of cattle are crossed by exotic breeds to get a new breed which is high yielding. The desired characters are taken into consideration during cross breeding. The offspring should be high yielding and should be resistant to climatic conditions.

11. Discuss the implications of the following statement :
“It is interesting to note that poultry is India’s most efficient converter of low fibre food stuff (which is unfit for human consumption) into highly nutritious animal protein food.”


Poultry farming is raised for domestic fowl for egg production and chicken meat. Poultry birds are not only the efficient converters of agricultural by products, into high quality meat but also help in providing egg, feathers and nutrient rich manure. Due to this reason, it is said that, “poultry is India’s most efficient converter of low fibre food stuff into highly nutritious animal protein food.”

12. What management practices are common in diary and poultry farming ?


(i) Shelter : Dairy animals and poultry birds require proper and hygienic shelter.
(ii) Feeding : To get good yield of food product, proper feed is provided to dairy animals and poultry birds.
(iii) Caring for animal health : Animals and birds must be protected from diseases caused by virus, bacteria or fungi.

13. What are the differences between broilers and layers and in their management?


Grooming the poultry bird for obtaining meat is called broiler. The egg laying poultry bird is called layer. The housing, nutritional and environmental requirements of broilers are different from those of egg layers. Protein rich with adequate fat food is the daily food requirement for broilers. The level of vitamins A and K is kept high in the poultry feeds while layers require enough space and proper lighting.

14. How are fish obtained ?


There are two ways of obtaining fish. Capture fishing is obtaining fish from natural resources. The other way is by fish farming or culture fishery.

15. What are the advantages of composite fish culture ?


A combination of five or six fish species is used in a single fish pond in composite fish culture. Selected species should not compete for food among them and should have different types of food habits. As a result, the food available in all the parts of the pond is used.
For example : Catlas are surface feeders, Rohus feed in the middle-zone of the pond, Mrigals and Common Carps are bottom feeders and Grass Carps feed on the weeds, together these species can use all the food in the pond without competing with each other. This increases the fish yield from pond.

16. What are the desirable characters of bee varieties suitable for honey production ?


Desirable characters of bee varieties suitable for honey production

  1. The bees should stay in a given beehive for a longer period.
  2. The bees should have capacity of breeding well.
  3. The variety of bee should be disease resistant.
  4. Variety of bee should be able to collect a large amount of honey.

17. What is pasturage and how is it related to honey production?


The available flowers to the bees for nectar and pollen collection is called pasturage. In addition to adequate quantities of pasturage, the kind of flowers available will determine the taste of the honey.

NCERT Exercise Solutions

1. Explain any one method of crop production which ensures high yield.


Plant breeding is one method used for crop production which ensures high yield. The plant from different areas is picked up with desired traits for hybridisation or cross-breeding. The high yielding crop shows the following characteristics : High yield, early maturation, less water for irrigation, better quality seeds, less fertilizer required, adaptation against environmental conditions.

2. Why are manure and fertilizers used in fields?


Manures and fertilizers are used in fields to enrich the soil with the required nutrients. Manure helps in enriching the soil with organic matter and nutrients. This improves the fertility and structure of the soil. On the other hand, fertilizers ensure a healthy growth and development in plants. They are a good source of nitrogen, phosphorus, and potassium. To get an optimum yield, it is instructed to use a balanced combination of manures and fertilizers in the soil.

3. What are the advantages of inter-cropping and crop rotation?


Advantages of using inter-cropping :

  1. It helps to maintain soil fertility.
  2. It increases productivity per unit area.
  3. Save labour and time.
  4. Both crops can be easily harvested and processed separately.
Advantages of using crop rotation :
  1. It improves the soil fertility.
  2. It avoids depletion of a particular nutrient from soil.
  3. It minimises pest infestation and diseases.
  4. It helps in weed control.
  5. It prevents change in the chemical nature of the soil.

4. What is genetic manipulation? How is it useful in agricultural practices?


A process of incorporating desirable (genes) characters into crop varieties by hybridisation is genetic manipulation. Hybridisation involves crossing between genetically dissimilar plants. This is done for production of varieties with desirable characteristics like high yielding varieties in maize, wheat, etc. Genetic manipulation is useful in developing varieties which shows :

  1. Increased yield.
  2. Better quality
  3. Shorter and early maturity period
  4. Better adaptability to adverse environmental conditions
  5. Desirable characteristics

5. How do storage grain losses occur?


The storage grain loss occur due to :

  1. Abiotic factors like moisture, humidity and temperature.
  2. Biotic factors like insects, rodents, birds, mites and bacteria are responsible for loss of grains during storage.

6. How do good animal husbandry practices benefit farmers?


Good animal husbandry practices are beneficial to the farmers in the following ways :

  1. Improvement of breeds of the domesticated animals.
  2. Increasing the yield of foodstuffs such as milk, eggs and meat.
  3. Proper management of domestic animals in terms of shelter, feeding, care and protection against diseases. Ultimately it helps the farmers to improve their economic condition.

7. What are the benefits of cattle farming ?


Cattle farming are beneficial in the following ways :

  • Milk production is increased by high yielding animals.
  • Good quality of meat, fibre and skin can be obtained.

8. For increasing production, what is common in poultry, fisheries and bee-keeping?


The production of poultry, fisheries and bee-keeping can be increased by cross breeding.

9. How do you differentiate between capture fishing, mariculture, and aquaculture?


(i) Capture fishing: It is the fishing in which fishes are captured from natural resources like pond, sea water and estuaries.
(ii) Mariculture: It is the culture of fish in marine water. Varieties like prawns, oysters, bhetki and mullets are cultured for fishing.
(iii) Aquaculture: It is done both in freshwater and in marine water.

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