NCERT Solutions For Class 9 Science Chapter 12 Improvement in Food Resources

 Chapter 15 Improvement in Food Resources

Q1. What do we get from cereals, pulses, fruits and vegetables?

Answer: Cereals give carbohydrates which provide energy.
Pulses give proteins which build our body.
Vegetables and fruits provide vitamins and minerals which protect our body.

Q2. How do biotic and abiotic factors affect crop production ?

Answer: A variety of biotic factors such as pests, nematodes, diseases, etc. can reduce the net crop production. A pest causes damage to agriculture by feeding on crops. 

Similarly, abiotic factors such as salinity, humidity, moisture, temperature, etc. affect the net crop production. Some natural calamities such as droughts and floods have a great impact on crops sometimes, destroying the entire crop.

 Q3. What are the desirable agronomic characteristics for crop improvements?

Answer: Desirable agronomic characteristics for crop improvements are:

(a) Tallness and profuse branching are desirable characters for fodder crops.
(b) Dwarfness is desired in cereals, so that less nutrients are consumed by these crops.

Q4. What are macro-nutrients and why are they called macro-nutrients?

Answer: Macro-nutrientsare nutrients required in relatively large quantities for growth and development of plants. They are six in number. Since they are required in large quantities, they are known as macro-nutrient. The six macro-nutrients required by plants are nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur.

Q5. How do plants get nutrients?

Answer: Plants require sixteen essential nutrients from nature for their growth and development. All these nutrients are obtained from air, water, and soil. Soil is the major source of nutrients. Thirteen of these nutrients are available from soil. The remaining three nutrients carbon, oxygen, and hydrogen are obtained from air and water.

 Q6. Compare the use of manures and fertilisers in maintaining soil fertility.

Answer: Manures increase soil fertility by enriching the soil with organic matter and nutrients as it is prepared by the decomposition of animal excreta and plant wastes. On the other hand, fertilizers are mostly inorganic compounds whose excessive use is harmful to the symbiotic micro-organisms living in soil. Their excessive use also reduces soil fertility. Hence, fertilizers are considered good for only short term use.

Q7.  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.

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

(i) 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.

(ii)  Proper irrigation methods improve the water availability to crops.

(iii)   Fertilizers ensure healthy growth and development in plants by providing the essential nutrients such as nitrogen, phosphorus, potassium, etc.

(iv) 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.

Q8.  Why should preventive measures and biological control methods be preferred for protecting crops?

Answer: Diseases in plants are caused by pathogens. To get rid of pathogens, some preventive measures and biological control methods are used as they are simple, economic and minimise pollution without affecting the soil quality.

Q9. What factors are responsible for losses of grains during storage ?

Answer: 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.

Q10.  Which method is commonly used for improving cattle breeds and why?

Answer: 

1. The method of cross-breeding is widely used to improve cattle breeds.
2. Cross-breeding two good cattle varieties will lead to a new, improved variety.
3. Crossbreeding indigenous breeds with exotic breeds. Foreign or exotic breeds have higher milk yield and longer lactation period as compared to indigenous breeds.
4. Therefore, indigenous breeds should be cross-bred with exotic breeds. The local breeds are hardy and resistant to several diseases. 

Q11. 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”.

Answer: Poultry in India is the most efficient converter of low fibre food stuff into highly nutritious animal protein food. In poultry farming, domestic fowls are raised to produce eggs and chicken. For this, the fowls are given animal feeds in the form of roughage, which mainly consists of fibres. Thus, by feeding animals a fibre rich diet, the poultry gives highly nutritious food in the form of eggs and chicken.

Q12. What management practices are common in dairy and poultry farming?

Answer: Common management practices in dairy and poultry farming are:

(i)        Proper shelter facilities and their regular cleaning.

(ii)       Some basic hygienic conditions such as clean water, nutritious food, etc.

(iii)       Animals are kept in spacious, airy, and ventilated place.

(iv)       Prevention and cure of diseases at the right time is ensured.

 

Q13.  What are the differences between broilers and layers and in their management?

Answer: 

Broilers	Layers
Broilers have fast growth rate, therefore they need protein rich food with sufficient fat.	Layers need less proteins and fats in their food
Vitamin A and K are provided in larger quantities.	Sufficient nutrients, minerals and vitamins have to be provided.
Do not require much space and lighting.	They need enough space and lighting.

Q14. How are fish obtained?

Answer: Fish can be obtained by two ways:

(i)  Capture fishing: It is the process of obtaining fish from natural resources.

(ii)  Culture fishery: It is the practice of farming fishes. Farming can be done in both freshwater ecosystem (which includes river water, pond water) and marine ecosystem. 

Q15. What are the advantages of composite fish culture?

Answer: An advantage of composite fish culture is that it increases the yield of fish. In a composite fish culture, five or six different species are grown together in a single fish pond. Fishes with different food habitats are chosen so that they do not compete for food among themselves. Also, this ensures a complete utilization of food resources in the pond. As a result, the survival rate of fish increases and their yield also increases.

Q16. What are the desirable characters of bee varieties suitable for honey production?

Answer: Bee varieties having the following desirable characters are suitable for honey production:

(i) They should yield high quantity of honey.

(ii) They should not sting much.

(iii) They should stay in the beehive for long durations.

(iv)  They should breed very well.

(v) The variety of bee should be disease resistant.

Q17. What is pasturage and how is it related to honey production?

Answer: Pasturage is the availability of flowers from which bees collect nectar and pollen. It is related to the production of honey as it determines the taste and quantity of honey.

Q18. Explain any one method of crop production which ensures high yield.

Answer: One of the method of crop production that ensures high yield is intercropping. This method is beneficial because more than two types of crops having different nutrient requirement can be grown in a definite pattern of land. Intercropping helps in preventing pests and avoid the spread of diseases throughout the field. So with crop rotation, soil fertility is increased, reduces soil erosion is reduced, and soll depletion is prevented.

Q19.  Why are manure and fertilizers used in fields?

Answer: 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.

Q20. What are the advantages of inter-cropping and crop rotation?

Answer: Inter-cropping and crop rotation both play an important role in increasing the yield of crops. Inter-cropping helps in preventing pests and diseases to spread throughout the field. It also increases soil fertility, whereas crop rotation prevents soil depletion, increases soil fertility, and reduces soil erosion. Both these methods reduce the need for fertilizers. It also helps in controlling weeds and controls the growth of pathogens and pests in crops.

Q21. What is genetic manipulation? How is it useful in agricultural practices?

Answer:  Genetic manipulation is a process where the desired genes are isolated from one organism  and transferred to the other organism by using the hybridization technique.

 Genetic manipulations help in obtaining traits which are not possible naturally such as dwarfness in cereals, tall and profuse branching in fodder crops. It helps in obtaining higher yield, resistance to pests, less maturity period, resistance to severe environmental conditions such as droughts, high alkalinity, floods etc.

Q22. How do storage grain losses occur?

Answer: Biotic and abiotic factors both play an important role in the spoilage of the stored seeds. Biotic factors such as insects, rodents and abiotic factors such as moisture present in the food grains due to improper drying, humidity and temperature can affect the grains by causing discolouration, loss of ability to germinate and degradation.

Q23 .  How do good animal husbandry practices benefit farmers?

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

(i) It results into improved breeds of the domesticated animals
(ii) It increases the yield of foodstuffs such as milk, eggs and meat
(iii) Proper management of domestic animals in terms of shelter, feeding care and protection against diseases results in good yield and healthy products.

Q24 . What are the benefits of cattle farming?

Answer: Benefits of cattle farming: 

i)Good quality and quantity of milk can be produced. 

ii)Draught labour animals can be produced for agricultural work. 

iii)New variety that are resistant to diseases can be produced by crossing two varieties with the desired traits.

iv) Wastes from the cattle can be used to enrich the soil as well as can be used in the biogas production. 

Q25. For increasing production, what is common in poultry, fisheries and bee-keeping

Answer: For increasing production in poultry, fisheries and bee-keeping, the following things are common:

1. Maintaining temperature and hygenic environmental conditions

2. Prevention and protection from diseases and pests.

3. Giving proper and nutritious food

4. Avoid overcrowding of animals in their shelter.

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