Chapter 15 Improvement in Food Resources

India is second largest populated country to fulfil the daily need like food many improvement programme are launched so that demand can be completely solved and food should be supplied to each one. Different modern technologies are implemented to avoid chemical dependency with high yielding effects. Biotechnology is area where researches are going better and better so that quality and quantity of both animal and plant products can be enhanced.

Download pdf of NCERT Solutions for Class Science Chapter 15 Improvement in Food Resources

Download pdf of NCERT Examplar with Solutions for Class Science Chapter 15 Improvement in Food Resources

Exercise 1

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

    i. From cereals like wheat, rice, maize, we get carbohydrates which provide energy.
    ii. Pulses like pea, gram, soybean give us proteins.
    iii. Fruits and vegetables are a rich source of vitamins and minerals. A small amount of proteins, carbohydrates, and fats are also present in them.

Exercise 2

  • Q1 How do biotic and abiotic factors affect crop production?

    Biotic factors such as pets, insects and diseases reduce the crop production. A pest causes damage to our crops by feeding. Weeds also reduce crops productivity by competing with the main crop for nutrients and light.

    Similarly, abiotic factors such as temperature, wind, rain etc. affect the net crop production. For example droughts and floods have a great impact on crops sometimes, destroying the entire crop.

    Q2 What are the desirable agronomic characteristics for crop improvements?

    The desirable agronomic characteristics for crop improvements are:

    i. Tallness and profuse branching are desirable characters for fodder crops.
    ii. Dwarfness is desired in cereals. This way they consume less nutrients.

    These desirable agronomic characteristics help in increasing crop productivity.

Exercise 3

  • Q1 What are macro-nutrients and why are they called macro-nutrients?

    Nutrients required in large quantities are called Macro-nutrients. 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.

    Q2 How do plants get nutrients?

    Plants get nutrients through soil, water, and air. Plants require sixteen essential nutrients from nature for their growth and development. Soil is the major source of nutrients. Soil supplies 13 nutrients to plants and remaining three nutrients (carbon, oxygen, and hydrogen) are obtained from air and water.

Exercise 4

  • Q1 Compare the use of manure and fertilizers in maintaining soil fertility.

    Manure contains large quantities of organic matter and also supplies small quantities of nutrients to the soil. Manure is prepared by the decomposition of animal excreta and plant wate. On the other hand, fertilizers are commercially produced plant nutrients. Fertilizers supply nitrogen, phosphorus and potassium. They are used to ensure good vegetative growth giving rise to healthy plants. Fertilizers are a factor in the higher yields of high cost farming.

Exercise 5

Exercise 6

  • Q1 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 these methods are safe ecologically and do not harm other life forms. These chemicals are also poisonous for plants and animals. Excessive use of chemicals can lead to many environmental problems and cause pollution. 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 thuringiensis, which is an insect pathogen that kills a wide range of insect larvae . Hence , these are completely safe for other life forms.

    Q2 What factors may be responsible for losses of grains during storage?

    Biotic and abiotic factors are responsible for the loss of stored grains. 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 affect the quality, cause a loss in weight, discoloration of produce, thereby making the grains unfit for the market.

Exercise 7

  • Q1 Which method is commonly used for improving cattle breeds and why?

    Cross breeding is a method commonly used for improving cattle breeds. It is a process in which indigenous varieties of cattle are crossed by exotic breeds to get a crossbreed which is high yielding. Cross breeding between two good varieties of cattle will produce a new improved variety. For example, the cross between foreign breeds such as Jersey Brown, Swiss (having long lactation periods) and Indian breeds such as Red Sindhi, Sahiwal (having excellent resistance power against diseases) produces a new variety having qualities of both breeds.

Exercise 8

Exercise 9

  • Q1 What management practices are common in dairy and poultry farming?

    Common management practices in dairy and poultry farming are:

    (i) Proper shelter facilities having hygienic conditions are given to the dairy and poultry animals.
    (ii) Proper and nutritious feed is provided to dairy animals and poultry birds to get a good yield to products.
    (iii) Animals are kept in spacious, airy, and ventilated places.
    (iv) Proper prevention and protection from diseases and pests are given to the animals.

    Q2 What are the differences between broilers and layers and in their management?

    Broilers have fast growth rates, therefore they need protein rich food with sufficient fat and vitamin A and k are provided in larger quantities. They do not require much space and lighting. On the other hand, Layers need less proteins and fats in their food and sufficient nutrients, minerals and vitamins have to be provided. They need enough space and lighting.

Exercise 10

Exercise 11

  • Q1 What are the desirable characters of bee varieties suitable for honey production?

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

    (i) They should yield high quantities of honey. The bee varieties reared should produce more honey.

    (ii) They should not sting much. Bees reared should sting less so that they can reared easily and the honey can be obtained easily.

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

    (iv) They should breed very well.

    Q2 What is pasturage and how is it related to honey production?

    Pasturage is the availability of flowers from which bees collect nectar and pollen then it will stay in honey where it is mixed with the enzymes and proteins of bees to convert into honey.

Exercise 12

  • Q1 Explain any one method of crop production which ensures high yield.

    One of the methods of crop production that ensures high yield is crop rotation. This method involves growing two or more varieties of crop in the same fertile land in a sequential and seasonal order in a definite pattern. A crop utilises some particular nutrients in larger quantities from the soil and thus the soil gets enriched in this process. Therefore, crops having different nutrient requirements are rotated. For example, legumes which have nitrogen-fixing bacteria in their root nodules supply the soil with nitrogen.

    Q2 Why are manure and fertilizers used in fields?

    Manures and fertilizers are added to the soil to increase the fertility of soil by replenishing essential nutrients. Manure is organic matter derived from animal faeces and plant waste. On the other hand, fertilizers ensure a healthy growth and development in plants. Thus, manure and fertilizers are used to provide nutrients to the soil due to which the cop yield is enhanced.

    Q3 What are the advantages of inter-cropping and crop rotation?

    Inter-cropping and crop rotation both play an important role in increasing the yield of crops. Inter-cropping helps to maintain soil fertility and prevents pests and diseases from spreading throughout the field. It increases productivity per unit area. Crop rotation improves the soil fertility and avoids depletion of a particular nutrient. It minimizes the pest infestation and diseases. Both these methods reduce the need for fertilizers. It also helps in controlling weeds and controls the growth of pathogens and pests in crops.

    Q4 What is genetic manipulation? How is it useful in agricultural practices?

    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.

    For example, let us assume there is a wild plant that produces small fruits. If the gene responsible for a larger fruit size is introduced in this plant, this plant becomes transgenic, and starts producing larger fruits. 

    Therefore, genetic manipulation is useful in agricultural practices by developing varieties having higher yield, better quality, shorter maturity period and wider adaptability to adverse environment conditions.

    Q5 How do storage grain losses occur?

    Both biotic and abiotic factors play an important role in the spoilage of the stored seeds. Biotic factors such as insects or pests that cause direct damage by feeding on seed. Abiotic factors such as temperature, light, moisture, etc., also affect the seed. They decrease the germinating ability of the seeds and make them unfit for future use by farmers. Unpredictable occurrence of natural calamities such as droughts and floods also causes destruction of crops.

    Q6 How do good animal husbandry practices benefit farmers?

    Good animal husbandry practises are beneficial to the farmers in the improvement of breeds of the domesticated animals and 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.

    Hence, good animal husbandry practices increase the production of animal products which increases the profit of farmers.

    Q7 What are the benefits of cattle farming?

    Benefits of cattle farming:

    (i) You can have fresh milk from the milch cattle , the value addition of milk in producing various products can be sold.
    (ii) The dung of the animal can be used as manure to the crops.
    (iii) Drought cattle can be used for agricultural activities.
    (iv) Calves when born can be sold there by the gang a fair amount of money.

    Q8 For increasing production, what is common in poultry, fisheries and bee-keeping?

    Production of poultry, fisheries and bee keeping can be increased by adopting new scientific ways of management. Regular cleaning of farms is of utmost importance and giving proper & nutritious food. Prevention and protection from diseases and pests. Avoid overcrowding of animals in their shelter. Hence, increasing production on poultry, fisheries and bee keeping the following things are common.

    Q9 How do you differentiate between capture fishing, mariculture and aquaculture?
    Capture fishing Mariculture Aquaculture
    It is one of the most common forms of fishing. It is a type of fishing where the fishes are obtained from natural resources like rivers, lakes or seas . Fish farming or culture fishing in marine waters is called mariculture. Varieties like tuna and prawns are cultivated in this method. Fish culture done in brackish water where seawater and freshwater mix together is known aquaculture.


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