NCERT Solutions for Class 9 Science Chapter 15 Improvement in Food Resources

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NCERT Solutions for Class 9 Science Chapter 15 Improvement in Food Resources help you understand concepts better and also improve your problem-solving skills. These has been designed by the expert panel of Gkrankers.com keeping in mind the latest CBSE syllabus and pattern.

The solutions are detailed and easy to understand. Chapter 15 CBSE Class 9 Science NCERT Solutions provide step-by-step explanations for each concept in the book, which makes it easier for students to understand and learn the material.

Chapter 15 Improvement in Food Resources Class 9 Science NCERT Solutions

In Text Questions

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

Solution

We get carbohydrates from cereals, proteins from pulses, vitamins and minerals from fruits and vegetables.

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

Solution

Biotic factors such as diseases and insects, and abiotic factors such as drought, salinity, heat, cold results in decrease of crop production.

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

Solution

Desirable agronomic characteristics for crop improvements are:
(i) Tallness and profuse branching are desirable characters for fodder crops.
(ii) Dwarfness is desired in cereals.

1. What are macronutrients and why are they called macronutrients?

Solution

A macronutrient is an element that plants require in a large quantity and includes carbon, hydrogen, oxygen, nitrogen, potassium, and sulphur.

2. How do plants get nutrients?

Solution

Plants get nutrients from air, water and soil. Nutrients are also absorbed by the roots of plants from the soil. The absorbed water is transported by the tissue throughout the plant body. Air provides carbon, hydrogen and oxygen to plants.

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

Solution

Effects of using manures on soil quality:
(i) Manure is rich in organic matter but is poor supplier of nutrients.
(i) It add humus to the soil
(iii) It increase water retention capacity of sandy soils
(iv) It increases soil fertility and helps in improving soil structure.
(v) In clayey soils, the large quantity of organic matter help in drainage and in avoiding water logging.

Effects of using fertilizers on soil quality:
(i) By the continuous use of fertilizers the rate of soil erosion increases.
(ii) By the use of fertilizers porosity of soil decreases and the plant roots do not get oxygen properly.
(iii) The nature of soil changes to acidic or basic.

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.

Solution

Conditions given in option (c) are the most beneficial for farmers due to the following reasons:
(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.

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

Solution

Preventive measures and biological control methods should be preferred for protecting crops because excessive use of chemicals leads to environmental problems. These chemicals are also poisonous for plants and animals. Preventive measures include proper soil and seed preparation, timely sowing of seeds, intercropping and mixed cropping, usage of resistant varieties of crops, etc.

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

Solution

(i) Biotic factors such as insects, fungi, bacteria, rodents, birds, mites, etc.
(ii) Abiotic factors such as inappropriate moisture content and temperature in the place of storage.

1. Which method is commonly used for improving cattle breeds? Why?

Solution

Cross breeding is a process in which indigenous breeds of cattle are crossed by exotic breeds to get a new breed which is high yielding. The desired characters are taken into consideration during cross breeding. The offspring should be high yielding and should be resistant to climatic conditions.

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.”

Solution

Poultry farming is raised for domestic fowl for egg production and chicken meat. Poultry birds are not only the efficient converters of agricultural by products, into high quality meat but also help in providing egg, feathers and nutrient rich manure. Due to this reason, it is said that, “poultry is India’s most efficient converter of low fibre food stuff into highly nutritious animal protein food.”

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

Solution

(i) Proper housing and hygienic conditions
(ii) Vaccination for prevention of infectious diseases
(iii) Selection of good quality breeds
(iv) Enough space, proper light intensity and duration and maintenance of adequate temperature
(v) Proper feeding management

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

Solution

Grooming the poultry bird for obtaining meat is called broiler. The egg laying poultry bird is called layer. The housing, nutritional and environmental requirements of broilers are different from those of egg layers. Protein rich with adequate fat food is the daily food requirement for broilers. The level of vitamins A and K is kept high in the poultry feeds while layers require enough space and proper lighting.

1. How are fish obtained?

Solution

There are two ways of obtaining fish.
(i) Capture fishing is obtaining fish from natural resources.
(ii) The other way is by fish farming or culture fishery.

2. What are the advantages of composite fish culture?

Solution

The fish species in composite fish culture are selected based on their food habits, so that they do not compete for food among themselves. It involves combining five or six fish species in a single pond. This results in fishes consuming all of the food available in the pond without competing. They help each other grow, which increases the fish yield.

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

Solution

Desirable characters in bee varieties for honey production are:
(i) They should be able to produce a large amount of honey.
(ii) They should have good breeding capacity and prolific egg production.
(iii) The variety of bee should be disease resistant.
(iv) They should stay in beehives for a longer time.

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

Solution

Pasturage refers to the flowers available to bees for nectar and pollen collection. In addition to adequate quantities, the type of flowers available determines the taste of the honey.

Exercises

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

Solution

In intercropping, two or more crops are grown simultaneously on the same field in a definite pattern, with a few rows of one crop alternated with a few rows of the other crop to produce a high yield. In order to maximize the use of nutrients supplied, the crops selected must have different nutrient requirements. By doing so, pests and diseases are prevented from spreading to all the plants in a field belonging to one crop.

2. Why are manure and fertilisers used in fields?

Solution

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. Plants require fertilizers for healthy growth and development. Fertilizers contain nitrogen, phosphorus, and potassium.

3. What are the advantages of intercropping and crop rotation?

Solution

Advantages of intercropping:
(i) It provides additional yield income per unit area and minimises chances crop failure.
(ii) It helps to maintain soil fertility
(iii) It controls weeds and reduces soil runoff.
(iv) Both the crops can be harvested and threshed separately.

Advantages of using crop rotation:
(i) It improves the soil fertility.
(ii) It avoids depletion of a particular nutrient from soil.
(iii) It minimises pest infestation and diseases.
(iv) It helps in weed control.
(v) It prevents change in the chemical nature of the soil.

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

Solution

In genetic manipulation, desirable genes are transferred from one plant to another, such as profuse branching in fodder crops, high yields in grain crops, short maturity periods, and tolerances, etc. Hybridisation or the introduction of desired genes are methods of genetic manipulation. It is useful in agricultural practices:
(i) It helps in increasing yield and quality of crops.
(ii) It provides varieties that are better adapted to adverse environmental condition and have desirable features.

5. How do storage grain losses occur?

Solution

(i) Abiotic factors like moisture, humidity and temperature.
(ii) Biotic factors like insects, rodents, birds, mites and bacteria are responsible for loss of grains during storage.

6. How do good animal husbandry practices benefit farmers?

Solution

Animal husbandry is the scientific management and care of farm animals. It also includes developing genetic qualities and behaviour that are advantageous to human beings. It benefits farmers by:
(a) Producing improved breeds of domestic animals
(b) Increasing production of animal-based products such as milk, egg and meat
Healthy farm animals that provide good yield of commercially- viable products leads to increased income and opportunities of growth for farmers.

7. What are the benefits of cattle farming?

Solution

(i) Milk production is increased by high yielding animals
(ii) It provides good quality meat, fibre and hide.
(iii) It also provides good breed of draught animals.

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

Solution

The production of poultry, fisheries and bee-keeping can be increased by cross breeding.

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

Solution

(i) Capture fishing: It is the fishing in which fishes are captured from natural resources like pond, sea water and estuaries.
(ii) Mariculture: It is the culture of fish in marine water. Varieties like prawns, oysters, bhetki and mullets are cultured for fishing.
(iii) Aquaculture: It is done both in freshwater and in marine water. Fish can be located easily and caught using fishing nets.

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