JAC Board Class 9th Science Solutions Chapter Chapter 15 Improvement in Food Resources
JAC Class 9th Science Improvement in Food Resources InText Questions and Answers
What do we get from cereals, pulses, fruits and vegetables?
Cereals provide us carbohydrates which give energy. Pulses provide us proteins which build our body. Vegetables and fruits provide vitamins and minerals.
How do biotic and abiotic factors affect crop production?
- Factors responsible for loss of grains, during storage and production are:
- Biotic factors like rodents, pests, insects, etc.
- Abiotic factors like temperature, humidity, moisture, etc.
- Combination of both biotic and abiotic factors causes:
- infestation of insects
- weight loss
- poor germination ability
- degradation in quality
- poor market price
What are the desirable agronomic characteristics for crop improvements?
Desirable agronomic characteristics for crop improvements are as follows:
- Tallness and profuse branching are desirable characters for fodder crops.
- Dwarfness is desired in cereals so that less nutrients are consumed by these crops.
What are macronutrients and why are they called macronutrients?
Macronutrients are the essential elements which are utilised by plants in large quantities. Many macronutrients are required by the plants for the following functions:
- As the constituent of protoplasm
- N, P, S are present in proteins
- Ca is present in cell wall
- Mg is an important constituent of chlorophyll
How do plants get nutrients?
Plants get nutrients from air, water and soil. There are sixteen nutrients essential for the growth of plants. Carbon and oxygen are supplied by air. Hydrogen is supplied by water. The remaining thirteen nutrients are supplied by soil.
Compare the use of manures and fertilisers in maintaining soil fertility.
- 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 restore water retention capacity of sandy soils and drainage in clayey soils.
- The addition of manures reduces soil erosion.
- They provide food for soil organisms, like soil friendly bacteria.
- Effects of using fertilisers on soil quality:
- By the continuous use of fertilisers, the soil becomes powdery, dry and the rate of soil erosion increases.
- By the use of fertilisers, the organic matter decreases which further decrease the porosity of soil and the plant roots do not get oxygen properly.
- The nature of soil changes to acidic or basic.
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, use fertilisers.
(c) Farmers use quality seeds, adopt irrigation, use fertilisers and use crop protection measures.
Use of any quality seeds is not sufficient until they are properly irrigated, enriched with fertilisers and protected from biotic factors. Hence, option (c) will give the most benefits.
Why should preventive measures and biological control methods be preferred for protecting crops?
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, economical and minimise pollution without affecting the soil quality.
What factors may be responsible for losses of grains during storage?
The factors responsible for the 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.
Which method is commonly used for improving cattle breeds and why?
Cross breeding is a process in which indigenous varieties of cattle are crossed by exotic breeds to get a breed which is high yielding. During cross – breeding, the desired characters are taken into consideration. The offspring should be high yielding, should have early maturity and should be resistant to climatic conditions.
Discuss the implications of the following statement: “It is interesting to note that poultry is India’s most efficient converter of low fibre foodstuff (which is unfit for human consumption) into highly nutritious animal protein food”.
The basic aim of poultry farming is to raise domestic fowl for egg production and chicken for meat. These poultry birds are not only the efficient converters of agricultural by – products, particularly cheaper fibrous wastes (which are unfit for human consumption but can be formulated into cheaper diets for poultry birds) into high – quality meat but also help in providing eggs, feathers and nutrient – rich manure. For this reason, it is said that, “poultry is India’s most efficient converter of low fibre foodstuff into highly nutritious animal protein food”.
What management practices are common in dairy and poultry farming?
Management practices are common in dairy and poultry farming:
- Shelter: Dairy animals and poultry birds require proper shelter, i.e., well – designed, dairy and hygienic shelter.
- Feeding: To get good yield of food production, proper feed is provided to dairy animals and poultry birds.
- Caring for animal health: Animals and birds must be protected from diseases caused by viruses, bacteria or fungi.
What are the differences between broilers and layers and in their management?
The poultry bird groomed for obtaining meat is called broiler. The egg laying poultry bird is called layer. The housing, nutritional and environmental requirements of broilers are somewhat different from those of egg layers. The ration (daily food requirement) for broilers is protein- rich with adequate fat. The level of vitamins A and K is kept high in the poultry feeds. Layers require enough space and proper lightning. They are vaccinated against various diseases. Broilers are taken care of to avoid mortality and to maintain feathering and carcass quality.
How are fish obtained?
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.
What are the advantages of composite fish culture?
In composite fish culture, a combination of five or six fish species is cultured in a single fish pond. These species are selected so that they do not compete for food among themselves and have different types of food habits. As a result, the food available in all the parts of the pond is used. For example, Catlas are surface feeders, Rohus feed in the middle – zone of the pond, Mrigals and common carps are bottom feeders and grass carps feed on the weeds. Together, these species can use all the food in the pond without competing with each other. This increases the fish yield from the pond.
What are the desirable characters of bee varieties suitable for honey production?
The desirable characters of bee varieties suitable for honey production:
- The variety of bee should be able to collect a large amount of honey.
- The bees should stay in a given beehive for a longer period.
- The bees should have capacity of breeding well.
- The variety of bee should be disease resistant.
What is pasturage and how is it related to honey production?
Pasturage means the flowers available to the bees for nectar and pollen collection. In addition to adequate quantities of pasturage, the kind of flowers available will determine the taste of the honey.
JAC Class 9th Science Improvement in Food Resources Textbook Questions and Answers
Explain any one method of crop production which ensures high yield.
One method used for crop production which ensures high yield is plant breeding. It is the science involved in improving the varieties of crops by breeding plants. The plants from different areas/places are picked up with desired traits and then hybridisation or cross-breeding of these varieties is done to obtain a plant/crop of desired characteristics. The high – yielding crop variety shows the following characteristics. High yield, early maturation, less water for irrigation, better quality seeds are produced, less fertiliser required, adapts itself to the environmental conditions.
Why are manure and fertilisers used in fields?
Manures and fertilisers are used in fields to enrich the soil with the required nutrients, to improve fertility of the soil, crop yield and quality. Manure helps in enriching the soil with organic matter and nutrients. This improves the fertility and structure of the soil. On the other hand, fertilisers ensure a healthy growth and development in plants. They are a good source of nitrogen, phosphorus and potassium. A balanced combination of manures and fertilisers in the soil should be used to get an optimum yield.
What are the advantages of intercropping and crop rotation?
Both Intercropping and crop rotation are used to get maximum benefit on limited land:
- Intercropping ensures maximum utilisation of the nutrients supplied by the soil. It helps in preventing pests and diseases to spread throughout the field. It also increases soil fertility.
- Crop rotation prevents soil depletion, increases soil fertility, and reduces soil erosion. Both these methods reduce the need for fertilisers. These also help in controlling weeds and control the growth of pathogens and pests in the crops.
What is genetic manipulation? How is it useful in agricultural practices?
Genetic manipulation is a process of incorporating desirable (genes) characters into crop varieties by hybridisation. Hybridisation involves crossing between genetically dissimilar plants. This is done for production of varieties with desirable characteristics like profuse branching in fodder crops, high – yielding varieties in maize, wheat, etc.
Genetic manipulation is useful in developing varieties which show:
- increased yield
- better quality
- shorter and early maturity period
- better adaptability to adverse environmental conditions
- desirable characteristics
How do storage grain losses occur?
The storage grain losses can occur due to the following reasons:
- Biotic factors: Like insects, rodents, fungi, mites and bacteria These organisms infect the grains and degrade the quantity and quality of the grains.
- Abiotic factors: Various factors, like inappropriate moisture and temperature, can lead to the loss of grains and their discolouration, loss in weight, etc.
How do good animal husbandry practices benefit farmers?
Good animal husbandry practices produce draught animals that can be used for the agricultural purposes like tilling, irrigation and carting. The draught animals perform these works and make the work easy for the farmer.
What are the benefits of cattle farming?
Cattle farming is beneficial in the following ways:
- Milk production is increased by high – yielding animals.
- Good quality of meat, fibre and skin can be obtained.
- Good breed of draught animals can be obtained.
For increasing production, what is common in poultry, fisheries, and bee-keeping?
Proper management technique is a common factor in increasing production in poultry, fisheries, and beekeeping. Management techniques like regular cleaning of farms are of utmost importance. Maintenance of temperature, prevention, and cure of diseases of the farmed organisms are also required to increase the number of animals and the yield.
How do you differentiate among capture fishing, mariculture and aquaculture?
- Capture fishing is the method of obtaining fishes from natural resources.
- Mariculture is the culture of marine fishes for commercial use. It is the farming of marine fishes of high economic value in seawater. For example, the farming of finned fishes like mullets, bhetki, pearl spots, etc.
- Aquaculture involves the production of aquatic animals that are of high economic value such as prawns, lobsters, fishes, crabs, etc.