Chapter 15 Improvement in Food Resources

Class 9 Science Chapter 15
Improvement in Food Resources NCERT Solutions 

Page 204

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

Answer Cereals give us carbohydrates.

Pulses gives us proteins.

Fruits and vegetables gives us vitamins.

Page 205

Question 1. How do biotic and abiotic factors affect crop production?

Answer Biotic factors such as pests, insects and diseases can reduce the crop production.A pest cause damage to agriculture by feeding on crops.Weeds also reduce crop productivity by competing with the main crop for nutrients, space, and sunlight.

Abiotic factors such as temperature, salinity etc effect the crop production.Some natural calamities such as droughts and floods destroys the entire crop.

Question 2. What are the desirable agronomic characteristics for crop improvements?

Answer The desirable agronomic characteristics for crop improvement are:

1) Tallness and profuse branching in fodder crop.

2) Dwarfness in cereals.

Page 206

Question 1. What are macro-nutrients and why are they called macronutrients?

Answer Those nutrients which are required in large quantities for growth and development of plant are called macro-nutrients.The six macro nutrients are Nitrogen, phosphorus, Sulphur, Potassium, Calcium and magnesium.Since these nutrients are required in large quantities, they are called macro-nutrients.

Question 2. How do plants get nutrients?

Answer Plants obtain nutrients from air, water and soil.Plants require 16 main nutrients for their growth and development.Thirteen of these nutrients are obtained from soil whereas the remaining three nutrients i.e. oxygen, hydrogen and carbon are obtained from air and water.

Page 207

Question 1. Compare the use of manure and fertilizers in maintaining soil fertility.

Answer A manure is a natural substance obtained by decomposition of animal waste, human waste, plant residue by the action of micro-organism.They increases soil fertility by enriching the soil with organic matter and nutrients as it supplies essential elements and humus to the soil. Fertilisers are inorganic substances added to the soil to increase its fertility and enhance plant growth.The excessive use of fertilisers is harmful for symbiotic micro-organism living in soil.They are good only for short term use.

Page 208

Question 1. 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 quality seeds, adopting irrigation, using fertilizer and using crop protection measures will derive most benefits.

The use of good quality seeds increases the crop production. If a farmer is using good quality seeds then most of the seeds will germinate properly, and will grow into a healthy plant. Proper irrigation methods will improve the availability of water to the crops. Fertilisers are inorganic substances added to the soil to increase its fertility and enhance plant growth. They provide essential nutrients to soil such as Nitrogen, Phosphorus, potassium etc. Methods to control weeds, pests and infectious agents are taken by the farmer to protect crop and increase its production.

Page 209

Question 1. Why should preventive measures and biological control methods be preferred for protecting crops?

Answer Preventive measures and biological control methods are preferred for protecting crops because excessive use of chemical leads to environmental problems.These chemicals are harmful for plants, animals, humans ,soil etc.Biological control methods include usage of bio-pesticides that are less toxic for the environment.They neither harm crop nor environment.

Question 2. What factors may be responsible for losses of grains during storage?

Answer The factors responsible for loss of grains during storage are:

1) Biotic factors: Insects, rodents, fungi, bacteria

2) Abiotic factors: moisture content, temperature, lack of sunlight

Page 210

Question 1. Which method is commonly used for improving cattle breeds and why? 

Answer Cross breeding is a process commonly used for improving cattle breeds.In this method indigenous variety of cattle is crossed with exotic breed to get a breed which is high yielding.During cross breeding , the desired characters are taken into consideration.The purpose of cattle breeding is to increase the production of milk and draught labour for agricultural work.For example: Cross breeding between Jersey brown and Sahiwal, Red Sindhi produces a new variety having good qualities of both the breeds.

Page 211

Question 1. 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 farming in India is the most effective converter of low fibre food stuff into highly nutritious animal protein food. In poultry farming, domestic fowls are raised to produce eggs and chicken.These fowls can efficiently convert low-quality fibrous food materials, which cannot be consumed by humans, into an animal protein food that is highly nutritious 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

Page 211 

Question 1. What management practices are common in dairy and poultry farming?

Answer The management practices common in diary 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.

Question 2. What are the differences between broilers and layers and in their management?

Answer

Broilers	layers
Broilers are the poultry birds that are raised for meat	Layers are poultry birds raised for eggs
Their daily food is rich in proteins and vitamin A and K.	They require calculated feed with vitamins, minerals and micronutrients.

Page 213

Question 1. How are fish obtained?

Answer Fishes can be obtained in two ways:

1) Capture fishing: It is the process of obtaining fish from natural resources.
2) Culture fishery: It is the practice of farming fishes. Farming can be done in both fresh water ecosystem (which includes river water, pond water) and marine ecosystem.

Question 2. What are the advantages of composite fish culture?

Answer 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 them and are having different types of food habits. As a result, the food available in all the parts of the pond is used.An advantage of composite fish culture is to increase the yield of fish.

Page 213

Question 1. What are the desirable characters of bee varieties suitable for honey production?

Answer

1) The variety of bee should be able to collect a large amount of honey.

2) The bees should stay in a given beehive for a longer period.

3) The bees should have capacity of breeding well.

4) The variety of bee should be disease resistant.

Question 2. What is pasturage and how is it related to honey production?

Answer Pasturage is the availability of flowers to bees for nectar and pollen collection.It is related to the production of honey as it determines the taste and quality of honey. 

Exercise Page 214, 215

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

Answer The method which ensures high yield is crop rotation.It is a method of growing two or more varieties of crop on the same land in sequential seasons. A crop utilises particular nutrients in larger quantities from the soil.Then if the same crop is grown in subsequent season those nutrients will be depleted in the soil.Therefore, crops having different nutrients requirements are rotated.

Foe example: Legumes are included in the crop rotation programme. They are used to increase soil fertility. Those crops which require high fertility level (e.g. wheat) may be grown after growing legumes (e.g., pea).

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

Answer They are used to enrich the soil with the required nutrients.Manures enrich the soil with organic matter and nutrients. Fertilizers help in proper growth and development of plant.They are good source of nitrogen, phosphorus and potassium.

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

Answer Advantages of Inter-cropping

 1) It makes better use of the natural resources of sunlight, land and water.

2) Soil erosion is effectively arrested.

3) Since the seeds of the two crops are not mixed before sowing, fertilizers can be placed as per the need of the crops.

4) Since the seed maturity period of these crops vary, the different crops can be harvested and threshed separately.

5) The produce of each crop can be marketed and consumed separately. 

Advantages of Crop Rotation

1) It controls pests and weeds. Most pathogens survive on crop residue, but only for a limited time, and most pathogens do not infect multiple crops.

2) Crop rotation reduces the need of fertilizers.

3) Several Crops may be grown in succession with only one soil preparation.

4) By alternation between deep and shallow rooted crops, the soil may be utilised more completely.

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

Answer Genetic manipulation means the incorporation of desirable characters in an organism (crop plant) by various methods such as hybridization, mutation, polyploidy and DNA recombinant technology.

Genetic manipulation is useful in developing varieties which shows:

1) Higher yields

2) Improved quality

3) Shorter and early maturity period

4) Better adaptability to adverse environmental conditions

5) Insect resistant crops

Question 5. How do storage grain losses occur?

Answer During storage damage of grains can take place by following two main types of factors:

1) Biotic factors such as insects , rodents( house rat, house mouse, lesser bandicoot rat), birds (e.g, parakeet, sparrow, bulbul, blue rock pigeon, crow, etc), mites and bacteria.

2) Abiotic factors such as moisture contents and temperature.

Combination of biotic and abiotic factors causes infestation of insects, degradation in quality, loss in weight, poor germinability, discolouration of produce, poor marketability and economic loss.

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

Answer Good animal husbandry practices benefit 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.

Question 7) What are the benefits of cattle farming?

Answer The benefits of cattle farming are:-

1) Milk production is increased by high yielding animals.

2) Good quality of meat, fibre and skin can be obtained.

3) Draught labour animals can be obtained.

4) New variety that are resistant to diseases can be produced.

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

Answer Through cross-breeding, regular cleaning of farms, maintenance of temperature and prevention and cure of diseases.

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

Answer

Capture Fishing	Mariculture	Aquaculture
It is the fishing in which fishes are captured from natural resources like pond, sea water and estuaries.	It is the culture of fish in marine water for commercial use.	It is the production of aquatic animals that are of high economic values.It is done both in fresh water and marine water.