CLASS 9 SCIENCE NCERT SOLUTION FOR CHAPTER – 15 Improvement in Food Resources

Improvement in Food Resources

IN TEXT Questions

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

Solution:
Cereals give carbohydrates which provide energy. Pulses give proteins which build our body. Vegetables and fruits provide vitamins and minerals in addition to small quantities of carbohydrates, fats and proteins.

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

Solution:
Factors responsible for loss of grains, during storage and production are of two types:

  1. Biotic factors like rodents, pests, insects, etc.
  2. Abiotic factors like temperature, humidity, moisture, etc.

Combination of biotic and abiotic factors causes –

  • Infestation of insects
  • Weight loss
  • Poor germination ability
  • Degradation in quality
  • Discolouration
  • Poor market price.

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

Solution:
Desirable agronomic characteristics for crop improvement are as follows :

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

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

Solution:
Macro-nutrients are the essential elements which are utilized by plants in large quantities. As they are required in large quantities they are called macro-nutrients e.g., carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, etc.

Question 5.
How do plants get nutrients ?

Solution:
Nutrients which are found in the soil get dissolved in the water and is absorbed by the roots of the plants. The conducting tissue, xylem transport this water to different parts of the plant.

Question 6.
Compare the use of manures and fertilisers in maintaining soil fertility.

Solution:

Effects of using manures on soil quality:

  • The manures enrich the soil with nutrients.
  • They provide a lot of organic matter (humus) to the soil and thus restores water retention capacity of sandy soils and drainage in clayey soil.
  • The addition of manures reduces soil erosion.
  • They provide food for soil organisms, like soil friendly bacteria and help in the increase of natural microflora.

Effects of using fertilisers on soil quality:

  • By the continuous use of fertilisers, the soil becomes powdery, dry and rate of soil erosion increases.
  • By the use of fertilisers, the organic matter decreases which further decreases the porosity of soil and consequently the plant roots do not get oxygen properly.
  • The nature of soil changes to acidic or basic.

Question 7.
Which of the following conditions will give the most benefits ? Why ?

(a) Farmers use high-quality seeds, do not . adopt irrigation or use fertilisers.
(b) Farmers use ordinary seeds, adopt irrigation and use fertiliser.
(c) Farmers use quality seeds, adopt irrigation, use fertilisers and use crop protection measures.

Solution:
(c) : The condition where, farmers are using quality seeds, adopting irrigation, using fertilizers and crop protection measures, will be the most beneficial. Use of good quality seeds is not sufficient until they are properly irrigated, enriched with fertilisers and protected from biotic factors.

Question 8.
Why should preventive measuresand biological control methods be preferred for protecting crops ?

Solution:
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.

Question 9.
What factors are responsible for losses of grains during storage ?

Solution:
The factors responsible for the loss of grains during storage are:

  • Abiotic factors like moisture (present in food grains), humidity (of air) and temperature.
  • Biotic factors like insects, rodents, birds, mites, bacteria and fungi.

Question 10.
Which method is commonly used for improving cattle breeds and why ?

Solution:
Cross-breeding is a process in which indigenous varieties of cattle are crossed by exotic breeds to get a breed which is high yielding. During cross-breeding, the desired characters are taken into consideration.

The progeny resulting from cross-breeding contains the desirable traits of both indigenous and exotic breeds. The, progeny should be high yielding, should have early maturity and should be resistant to adverse climatic conditions.

Question 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 into highly nutritious animal protein food.”

Solution:
The basic aim of poultry farming is to raise domestic fowl for egg production and chicken meat. These poultry birds are not only the efficient converters of agricultural by-products, particularly cheaper fibrous wastes (which is unfit for human consumption but can be formulated into cheaper diets for poultry birds) into high quality meat but also help in providing eggs, feathers and nutrient rich manure.

For this reason, it is said that, “poultry is India’s most efficient converter of low fibre food stuff into highly nutritious animal protein food.”

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

Solution:

  • Shelter : Dairy animals and poultry birds require proper shelter, i.e., well designed diary and hygienic shelter.
  • Feeding : To get good yields of food products, proper feed is provided to dairy animals and poultry birds.
  • Caring for animal health : Animals and birds must be protected from diseases caused by viruses, bacteria or fungi.

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

Solution:
The poultry bird groomed of obtaining meat is called broiler. The egg laying poultry bird is called layer. The housing, nutritional and environmental requirements of broilers are somewhat different from those of egg layers.

The ration (daily food requirement) for broilers should be protein rich with adequate fat. The level of vitamins A and K is kept high in the poultry feeds and layers require enough space and proper lighting.

Question 14.
How are fish obtained ?

Solution:
There are two ways of obtaining fish. One is from natural resources, which is called capture fishing. The other way is by fish farming, which is called culture fishery.

Question 15.
What are the advantages of composite fish culture ?

Solution:
In composite fish culture, a combination of five or six fish species is used in a single fish pond. These species are selected so that they do not compete for food among themselves have different types of food habits. As a result, the food available in all the parts of the pond is used.

As Catlas are surface feeders, Rohu feeds 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.

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

Solution:

  • The variety of bee should be able to collect a large amount of honey.
  • They should stay in a given beehive for a longer period.
  • They should have capacity of breeding well.

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

Solution:
The pasturage refers to the available land area covered with green vegetation. In addition to adequate quantities of pasturage, the kind of flowers available will determine the taste of the honey.

Exercises

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

Solution:
One method used for crop production which ensures’high yield is plant breeding. It is the science involved in improving the varieties of crops by breeding plants. The plants with desired traits are picked up from different areas, places and then hybridisation or cross-breeding of these varieties is done to obtain a plant/crop of desired characteristics.

The high yield variety crop shows characteristics such as high yield, early maturation, less water requirement for irrigation, better quality of seeds less requirement of fertilisers, adaptations to the environmental conditions. ‘

Question 2.
Why are manure and fertilisers used in fields ?

Solution:
They are major sources of nutrients of plants. They are used to ensure good vegetative growth (leaves, branches and flowers) and production of healthy plants, that results in high crop yield.

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

Solution:
Advantages of using intercropping are as follows:

  • It helps to maintain soil fertility.
  • It increases productivity per unit area.
  • It saves labour and time.
  • Inter-eroping ensures maximum utilisation of the nutrients supplied, and also prevents pests and diseases from spreading to all the plants belonging to one crop in a field.

Advantages of using crop rotation are as follows:

  • It improves the soil fertility.
  • It avoids depletion of a particular nutrient from the soil.
  • It minimises pest infestation and diseases.
  • It helps in weed control.
  • It prevents change in the chemical nature of the soil.

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

Solution:
Genetic manipulation is a process of transferring of desirable characters (genes) from one plant to another plant. This is done for production of varieties with desirable characteristics like profuse branching in fodder crops, high yielding varieties in maize, wheat, etc.

Genetic manipulation is useful in developing varieties which have increased yield, better quality, shorter and early maturity period, better adaptability to adverse environmental conditions, well as desirable characteristics.

Agricultural practices of cultivation and yielding of crops are directly related to agronomic conditions. These conditions are based on weather, soil quality and availability of water resources. Since weather conditions are unpredictable such as drought and flooding situations, therefore, crop varieties have been developed that can be grown in diverse climatic conditions.

Question 5.
How do storage grain losses occur ?

Solution :

The factors responsible for loss of grains during storage are:

  • Abiotic factors like moisture (present in food grains), humidity (of air) and temperature.
  • Biotic factors like insects, rodents, birds, mites and bacteria.

Question 6.
How do good animal husbandry practices benefit farmers ?

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

  • Improvement of breeds of the domesticated animals.
  • Increasing the yield of foodstuffs such as milk, eggs and meat.
  • Proper management of domestic animals in terms of shelter, feeding care and protection against diseases is helpful in improving the quality as well as quantity of the products obtained from them.

Question 7.
What are the benefits of cattle farming ?

Solution:
Cattle farming is beneficial in the given ways:

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

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

Solution:
Through cross breeding, the production of poultry, fisheries and bee keeping can be increased.

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

Solution:
Capture fishing: It is the fishing in which fishes are captured from natural resources like pond, sea, estuaries.

Mariculture :
 It is the culture of fishes in marine water on commercial basis. Varieties like prawns, oysters, bhetki, mullets are cultured for fishing.

Aquaculture :
 It is the production of useful, i. e., high economic value, aquatic plants and animals such as fishes, prawns, crayfish, lobsters, crabs, shrimps, etc. and sea weeds by proper utilization of available waters in the country. It is done both in fresh water and in marine water.

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