NCERT Solutions Class 9 Science
The NCERT Solutions in English Language for Class 9 Science Chapter – 15 (Improvement in Food Resources) has been provided here to help the students in solving the questions from this exercise.
Chapter – 15 (Improvement in Food Resources)
Questions
1. What do we get from cereals, pulses, fruits and vegetables?
Answer – Cereals give carbohydrates which provide energy.
Pulses give proteins which build our body.
Vegetables and fruits provide vitamins and minerals.
Questions
1. How do biotic and abiotic factors affect crop production?
Answer – Factors responsible for loss of grains, during storage and production are:
(a) Biotic factors like rodents, pests, insects, etc.
(b) Abiotic factors like temperature, humidity, moisture, etc.
Combination of both biotic and abiotic factors causes :
1. infestation of insects
2. weight loss
3. poor germination ability
4. degradation in quality
5. discolouration
6. poor market price
2. What are the desirable agronomic characteristics for crop improvement?
Answer – The essential agronomic features required for crop improvement are:
- Profuse branching along with tallness in any fodder crop.
- Dwarfness in any cereals.
Questions
1. What are macro-nutrients, and why are they called macronutrients?
Answer – Macro-nutrients are the fundamental elements that are used by plants in more quantity. Macro-nutrients needed by the plants are :
- Macro-nutrients as the constituent of protoplasm.
- Phosphorus, Nitrogen, and Sulphur are present in proteins.
- Calcium exists in the cell wall.
- Magnesium is a significant component of chlorophyll.
2. How do plants get nutrients?
Answer – Plants require sixteen essential nutrients from nature for their growth and development. All these nutrients are obtained from air, water, and soil. Soil is the major source of nutrients. Thirteen of these nutrients are available from soil. The remaining three nutrients (carbon, oxygen, and hydrogen) are obtained from air and water.
Questions
1. Compare the use of manure and fertilisers in maintaining soil fertility.
Answer – 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.
The effects of fertilisers are
- By the continuous use of fertilizers, the soil becomes powdery, dry and rate of soil erosion increases.
- By the use of fertilizers, the organic matter decreases which further decreases the porosity of soil and the plant roots do not get oxygen properly.
- The nature of soil changes to acidic or basic.
Questions
1. 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 fertiliser and use crop protection measures.
Answer – Option (c) will give the most benefits because the use of good quality seeds is not only sufficient until the soil is properly irrigated, enriched with fertilisers and protected from biotic factors.
Questions
1. Why should preventive measures and biological control methods be preferred for protecting crops?
Answer – 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.
2. What factors may be responsible for the losses of grains during storage?
Answer – The factors responsible for losses 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.
Questions
1. Which method is commonly used for improving cattle breeds and why?
Answer – Cross Breeding is commonly used for improving cattle breeds.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 and Indian breeds such as Red Sindhi, Sahiwal produces a new variety having qualities of both breeds.
Questions
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 in India is the most efficient converter of low fibre food stuff into highly nutritious animal protein food. In poultry farming, domestic fowls are raised to produce eggs and chicken. 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.
Questions
1. What management practices are common in dairy and poultry farming?
Answer – Common management practices in dairy and poultry farming are:
- Proper shelter facilities and their regular cleaning.
- Some basic hygienic conditions such as clean water, nutritious food, etc.
- Animals are kept in spacious, airy, and ventilated place.
- Prevention and cure of diseases at the right time is ensured.
2. What are the differences between broilers and layers and their management?
Answer –
Broilers – The poultry bird raised for meat purposes is called a broiler. Broilers feed on protein-rich adequate-fat food. The level of vitamins A and K is kept high in poultry feeds.
Layers – The egg-laying poultry bird is called a layer. The housing, environmental and nutritional requirements of broilers vary from those of egg layers. Layers require proper lighting and enough space.
Questions
1. How are fish obtained?
Answer – Fishes are obtained in two ways:
- Capture fishing – Obtaining fish from natural resources.
- Culture Fishery – Culturing of fishes in freshwater ecosystems, like rivers, ponds and lakes, also including marine.
2. What are the advantages of composite fish culture?
Answer – The advantages of composite fish culture are
- Fish can be grown in crop fields especially paddy.
- Intensive Fish farming is possible because plenty of water is available during crop seasons.
- In this system both local and imported fish species can be cultivated.
Questions
1. What are the desirable characteristics of bee varieties suitable for honey production?
Answer – Bee varieties having the following desirable characters are suitable for honey production:
- They should yield high quantity of honey.
- They should not sting much.
- They should stay in the beehive for long durations.
- They should breed very well.
2. What is pasturage, and how is it related to honey production?
Answer – Pasturage is the availability of flowers from which bees collect nectar and pollen. It is related to the production of honey as it determines the taste and quantity of honey.
Exercise
1. Explain any one method of crop production which ensures high yield.
Answer – Inter cropping is a method of crop production which ensures high yield. It is a practice of growing two or more crops simultaneously. in the same field in rows. In inter cropping definite row patterns are followed such as one row of main crop of is followed by two row of intercrop.
In inter cropping there is greater utilisation of the interspaced area, light, nutrients, water and air. As a result productivity per unit area increased.
2. Why are manure and fertilisers used in fields?
Answer – They are used to ensure good vegetative growth (leaves, branches and flowers), giving rise to healthy plants, that results in high crop production.
3. What are the advantages of inter-cropping and crop rotation?
Answer –
Inter-cropping
- Checks pests and rodents and hence decreases the chances of the spoiling of whole crops
- Decreased chances of soil erosion
- Reduced loss of crops with high yield
- Less water requirement
Crop rotation
- Farmers can grow two or three crops annually
- Pulses take nitrogen directly from the atmosphere and hence require a minimal amount of fertilisers
- Both fruits and vegetables can be grown easily
- Best use of land with a proper supply of nutrients
4. What is genetic manipulation? How is it useful in agricultural practices?
Answer – Genetic manipulation is a process in which the transfer of genes takes place from one organism to another. Here, a gene of a particular character is introduced inside the chromosome cell, resulting in a transgenic plant.
Example: BT Cotton is a genetically modified crop which carries bacterial genes that protect this plant from insects. These are used in plants like brinjal, cabbage, rice, cauliflower, and maize crops to get protection from insects.
5. How do storage grain losses occur?
Answer – The factors responsible for loss of grains during storage are:
1. Abiotic factors like moisture (present in foodgrains), humidity (of air) and temperature.
2 Biotic factors like insects, rodents, birds, mites and bacteria.
6. How do good animal husbandry practices benefit farmers?
Answer – Good practice of animal husbandry benefits farmers in the following ways:
- Yields in good quality cattle
- Better quality of milk production
- Use in agriculture for carting, irrigation and tilling
7. What are the benefits of cattle farming?
Answer – The benefits of cattle farming are
- Cattle are used for agricultural purposes
- Generation of good quality cattle
- Milking and meat purpose
- The skin of cattle is used for the leather and wool industry
8. For increasing production, what is common in poultry, fisheries and bee-keeping?
Answer – Through cross breeding, the production of poultry, fisheries and bee-keeping can be increased.
9. How do you differentiate between capture fishing, mariculture and aquaculture?
Answer – Capture fishing – It is a technique in which fish are captured from various sources of natural resources like sea, rivers, lakes and ponds.
Mariculture – Culturing of fish in marine fishes like prawns, oysters, bhetki and mullets in marine water for commercial use.
Aquaculture – Involved in culturing of fish in both marine and freshwater.
