Improvement in Food Resources

Class 9 – NCERT Science Solutions

Intext Questions 1

Question 1

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

Answer

Cereals — Carbohydrates

Pulses — Proteins

Fruits and vegetables — vitamins and minerals in addition to small amounts of proteins, carbohydrates and fats.

Intext Questions 2

Question 1

How do biotic and abiotic factors affect crop production?

Answer

The crop production depends upon many biotic and abiotic factors that affect the plant growth and productivity.

Biotic factors — Some of the biotic factors are type of variety, insects and pests, diseases caused by plant pathogens etc. Varieties are designed to increase yield, increase disease resistance and wider adaptability. Insects, pests and diseases are responsible for harming crops and decrease productivity.

Abiotic factors — Abiotic factors like drought, salinity, water logging, heat, cold and frost, humidity, wind, sunshine (photoperiod) affect the crop production. Every crop requires a fix set of abiotic condition required for its optimum production. Any deviation in any of the factor can lead to decrease in production. For instance, increase in temperature during flowering may decrease the pollination and grain formation in wheat.

Question 2

What are the desirable agronomic characteristics for crop improvements?

Answer

The desirable agronomic characteristics for crop improvements are different for different crops. Some of them are:

1. Tallness and profuse branching are desirable characters for fodder crops.
2. Dwarfness is desired in cereals, so that less nutrients are consumed by these crops and also to avoid crop lodging.
3. High sugar content in sugarcanes and sugarbeets.
4. Long awns and broader leaves to increase photosynthesis in wheat.
5. Increased number of tillers in paddy.

Intext Questions 3

Question 1

What are macro-nutrients and why are they called macronutrients?

Answer

The nutrients like nitrogen, phosphorus, potassium, calcium, magnesium and sulphur that are required by the crop in large quantity are called macro-nutrients. They are called so because they are consumed in large amount by the crops.

Question 2

How do plants get nutrients?

Answer

Plants get nutrients from soil, air and water. Air supplies carbon and oxygen, hydrogen comes from water, and soil supplies the other thirteen nutrients to plants. These nutrients are absorbed by the plants through their roots along with water.

Intext Questions 4

Question 1

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

Answer

Manure	Fertilizers
Consists of large quantity of organic matter.	Consists of compounds containing nutrient and no organic matter.
Supplies small quantities of nutrients to the soil.	Supplies large quantity of nutrient to the soil.
Prepared by the decomposition of animal excreta and plant waste; some times green plants.	Commercially produced plant nutrients.
The bulk of organic matter in manure helps in improving the soil structure, water holding capacity and fertility.	It can hamper soil structure and fertility if not used in optimum amount.
They do not affect pH of soil.	They can make the soil acidic or alkaline.
They do not cause pollution.	They cause air pollution during their manufacture and water pollution when used excessively in fields.
Examples: Compost, Green manure	Example: Urea, SSP

Intext Questions 5

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 use quality seeds, adopt irrigation, use fertilizer and use crop protection measures.

The above conditions will give the most benefits because it will fullfil all the requirements of plant for high yield. Quality seeds alone cannot give good yield if not provided with irrigation and fertilizers. Also, crop protection measures protect the crop from the damage due to diseases, competition of weeds and insect-pests and thus prevent loss of yield.

Intext Questions 6

Question 1

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

Answer

Preventive measures and biological control methods should be preferred for protecting crops because

1. Biological control of weeds and insects occurs naturally in nature if we do not use chemicals like herbicide and insecticide.
2. They do not cause any pollution and ecological disturbance as done by chemicals.
3. This also helps to minimize bio-magnification.
4. Insects and weeds slowly adapt or mutate to become stronger and immune to chemicals.

Question 2

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

Answer

Factors responsible for losses of grains during storage are biotic— insects, rodents, fungi, mites and bacteria, and abiotic— inappropriate moisture and temperatures in the place of storage. These factors cause degradation in quality, loss in weight, poor germination, discolouration of produce, all leading to poor marketability.

Intext Questions 7

Question 1

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

Answer

Cross breeding of exotic breeds with indigenous breeds is the method commonly used for improving cattle breeds. Exotic or foreign breeds (for example, Jersey, Brown Swiss) are selected for long lactation periods, while local breeds (for example, Red Sindhi, Sahiwal) show excellent resistance to diseases. The two can be cross-bred to get animals with both the desired qualities.

Intext Questions 8

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

The fowls that are reared in the poultry farms are fed with the leftover fibres from the cereals that are left after the grains are removed. These are low fibre food that the fowl intake to grow and they produce the eggs and meat finally. Thus, poultry converts the low nutrition and cheap food stuff into good quality protein rich food. Thus, it verifies the above statement.

Intext Questions 9

Question 1

What management practices are common in dairy and poultry farming?

Answer

The management practices common in dairy and poultry farming are:

1. Proper cleaning, sanitation, and spraying of disinfectants at regular intervals.
2. Appropriate vaccination to prevent the occurrence of infectious diseases.
3. Providing need based ration.

Question 2

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

Answer

Differences between the management of broilers and layers:

Broilers	Layers
Broiler chickens are fed with feed rich in protein, fat, vitamin A and K.	Layers need less protein and fats in their diet but it should be rich in micronutrients.
Broilers do not require much space and lighting.	Layers need enough space and lighting.

Intext Questions 10

Question 1

How are fish obtained?

Answer

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 2

What are the advantages of composite fish culture?

Answer

In a composite fish culture, five or six local and imported fish species are cultured together in a single fish pond. Fishes with different food habitats are chosen so that they do not compete for food among themselves. This ensures a complete utilization of food resources in the pond and thus total yield increases.

Intext Questions 11

Question 1

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

Answer

The desirable characters of bee varieties suitable for honey production are:

1. High honey collection capacity
2. Less sting
3. Stay in a given beehive for long periods
4. Breed well

Question 2

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

Answer

Pasturage or bee forage are crops that yield pollen and nectar for bees. They are grown within flight range of the bees. The quality, taste and yield of honey depends upon the type and quantity of pasturage available to the bees for nectar and pollen collection.

Exercises

Question 1

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

Answer

Inter-cropping is one of the methods of crop production that ensures high yield. It is the method of growing two or more varieties of crops on the same land in a definite pattern. These crops are so selected that they have different nutrient requirements at different times. It ensures least competition among crops. It ensures high yield as it provides extra harvest over sole crop.

Question 2

Why are manure and fertilizers used in fields?

Answer

Manure and fertilizers are used in fields in order to increase fertility of soil. They provide nutrition to standing crops for their proper growth.

Question 3

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

Answer

Advantages of inter-cropping:

1. Crops give better return.
2. Spread of insect-pest is less.
3. Weed infestation is less.
4. Maintain soil health.
5. Reduced need of fertilizers.

Advantages of crop rotation:

1. Prevents soil nutrition loss or replenishes nutrition.
2. Maintains soil texture.
3. Prevents infestation of weeds, insects and pests.
4. Gives better return.

Question 4

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

Answer

Genetic manipulation is a process in which genes of desirable characters are transferred from a plant to another plant by the technique of hybridisation. Genetic manipulation helps in obtaining desirable agronomic characters liked dwarfness in cereals, tallness and profuse branching in fodder crops. It is useful in developing varieties with higher yield, good quality, biotic and abiotic resistance, short maturity period, wider adoptability and other desirable agronomic characteristics.

Question 5

How do storage grain losses occur?

Answer

During the storage of grains both biotic and abiotic factors cause losses to the grain. Biotic factors such as insects, rodents, mites, fungi etc. and various abiotic factors such as moisture, temperature, lack of sunlight, etc. are responsible for losses of grains. These factors cause loss in weight, degradation in quality and poor germination rate.

Question 6

How do good animal husbandry practices benefit farmers?

Answer

Rearing of animals and following good animal husbandry practices provide farmer with:

• Ample of milk, meat, manure (decomposition of dung)
• Fuel in the form of dung cakes.
• It also adds to farmers income as he can sell animal products like milk.
• Farmer can also improve his cattle breeds by selective breeding.

Question 7

What are the benefits of cattle farming?

Answer

Following are the benefits of cattle farming:

1. Milch animals provide us milk.
2. Draught animals are used as labour in farm.
3. Their dung is used as fuel in villages.
4. Their dung is used for making manure.

Question 8

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

Answer

For increasing production, common practices in poultry, fisheries and bee-keeping are:

1. Quality species should be selected.
2. Provide quality food, pasturage in case of bees.
3. Proper disease management.
4. Cross breeding should be done.
5. Hygenic shelter condition.

Question 9

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

Answer

Capture fishing	Mariculture	Aquaculture
Catching fishes from natural resources.	Culture of marine fishes.	Culture of all economically important aquatic animals such as prawns, lobsters, fishes, crabs, etc.
Fish grows naturally, seeding is not done.	Seeding is done in sea.	Rearing is done manually.