SEBA Class 9 Science: Improvement in Food Resources
INTEXT QUESTION
1. What do we get from cereals, pulses, fruits, and vegetables?
Answer: From cereals, we get carbohydrates, which provide energy.
From pulses, we get proteins.
Fruits and vegetables provide vitamins and minerals, along with small amounts of carbohydrates, proteins, and fats.
INTEXT QUESTION
1. How do biotic and abiotic factors affect crop production?
Answer: Biotic factors such as diseases, insects, pests, and nematodes reduce crop production by damaging plants. Abiotic factors like drought, salinity, water logging, heat, cold, and frost also affect crop growth and yield. Both biotic and abiotic stresses can lower crop productivity under different environmental conditions.
2. What are the desirable agronomic characteristics for crop improvements?
Answer: The desirable agronomic characteristics for crop improvements include tallness and profuse branching in fodder crops to increase yield. In cereals, dwarfness is desirable so that less nutrients are consumed by the plants, and higher productivity is obtained.
INTEXT QUESTION
1. What are macro-nutrients, and why are they called macro-nutrients?
Answer: Macro-nutrients are the nutrients that are required by plants in large quantities for their growth and development. They are called macro-nutrients because plants need them in greater amounts compared to other nutrients. Examples of macro-nutrients include nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur.
2. How do plants get nutrients?
Answer: Plants get nutrients from air, water, and soil. Air supplies carbon and oxygen, water supplies hydrogen and oxygen, and soil provides the remaining essential nutrients needed for plant growth and development.
INTEXT QUESTION
1. Compare the use of manure and fertilizers in maintaining soil fertility.
Answer: Manure and fertilisers differ in their role in maintaining soil fertility. Manure contains a large amount of organic matter and supplies small quantities of nutrients. It improves soil structure, increases water holding capacity in sandy soils, helps drainage in clayey soils, and maintains long-term soil fertility without harming soil micro-organisms.
Fertilisers are chemical substances that supply specific nutrients like nitrogen, phosphorus and potassium in concentrated form. They help in quick plant growth and increase crop yield in a short time. However, continuous use of fertilisers does not add organic matter to the soil, harms soil micro-organisms, and may reduce soil fertility in the long run.
INTEXT 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: The correct answer is (c).
Explanation:
Farmers will get the most benefits when they use quality seeds, adopt irrigation, use fertilisers, and apply crop protection measures. Quality seeds ensure better yield potential, irrigation provides water at the right stages, fertilisers supply essential nutrients, and crop protection measures prevent losses due to weeds, pests, and diseases. Together, these practices result in higher and more stable crop production.
INTEXT 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 excessive use of chemical pesticides can be harmful to plants, animals and the environment. Preventive methods like proper seed bed preparation, timely sowing, inter-cropping and crop rotation reduce pest attack naturally. Biological control methods are safer as they control pests without causing pollution or harming beneficial organisms, and help maintain ecological balance.
2. What factors may be responsible for losses of grains during storage?
Answer: Losses of grains during storage may occur due to both biotic and abiotic factors.
Biotic factors include insects, rodents, fungi, mites, and bacteria, which damage the stored grains.
Abiotic factors include unsuitable moisture and temperature conditions in storage places.
These factors cause loss in weight, poor germination, discolouration of grains, and a reduction in their quality and market value.
INTEXT QUESTION
1. Which method is commonly used for improving cattle breeds, and why?
Answer: The commonly used method for improving cattle breeds is cross-breeding.
Cross-breeding is used because it helps to combine the desirable qualities of two different breeds. Exotic breeds are selected for their long lactation period and higher milk production, while local breeds are resistant to diseases. By cross-breeding these two types, cattle with both high milk yield and good disease resistance are obtained.
INTEXT 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 statement means that poultry birds can convert low-fibre food materials, which humans cannot eat, into highly nutritious food like eggs and meat. Poultry feed often includes agricultural by-products and fibrous materials that are not suitable for human consumption. Poultry birds efficiently convert this feed into animal protein with high nutritional value. This makes poultry farming an important and economical source of protein. It also helps in better use of waste materials, increases food availability, and supports food security in India.
2. What management practices are common in dairy and poultry farming?
Answer: Common management practices in dairy and poultry farming include proper housing, feeding and disease control. Animals and birds are kept in clean, well-ventilated shelters to protect them from heat, cold and rain. Balanced and nutritious feed is provided according to their requirements to maintain good health and productivity. Regular cleaning, sanitation and proper disposal of waste are followed. Vaccination and timely treatment are done to prevent and control diseases. These practices help in maintaining animal health and increasing production.
3. What are the differences between broilers and layers and in their management?
Answer: Broilers and layers differ in their purpose and management.
Broilers are poultry birds reared for meat production. They are given protein-rich feed with adequate fat for fast growth and better feed efficiency. Their management mainly focuses on rapid growth and disease prevention.
Layers are poultry birds reared for egg production. They are given balanced feed rich in vitamins, especially vitamins A and K, to support egg laying. Their management focuses on proper nutrition, housing and health care.
INTEXT QUESTION
1. How are fish obtained?
Answer: Fish are obtained in two ways. One way is from natural resources, which is called capture fishing. The other way is by fish farming, which is called culture fishery, where fish are cultured in marine and freshwater ecosystems such as seas, rivers and ponds.
2. What are the advantages of composite fish culture?
Answer: Composite fish culture has several advantages. In this system, different species of fish with different food habits are grown together in the same pond, so they do not compete for food. As a result, food available in all parts of the pond is fully utilised. This leads to better growth of fishes and increases the total fish yield from the pond.
INTEXT QUESTION
1. What are the desirable characteristics of bee varieties suitable for honey production?
Answer: The desirable characteristics of bee varieties suitable for honey production are high honey collection capacity, less stinging nature, ability to stay in a beehive for long periods, and good breeding capacity. These characters help in higher and efficient honey production.
2. What is pasturage, and how is it related to honey production?
Answer: Pasturage refers to the availability of flowers from which bees collect nectar and pollen. It is directly related to honey production because the quantity and quality of honey depend on the type and amount of flowers available to the bees. Adequate pasturage increases honey yield, and different kinds of flowers also determine the taste of honey.
EXERCISE QUESTIONS
1. Explain any one method of crop production which ensures high yield.
Answer: Inter-cropping is a method of crop production that ensures high yield. In this method, two or more crops are grown on the same field in a definite row pattern. Crops with different nutrient requirements are selected, which helps in better use of nutrients. It also reduces the spread of pests and diseases and results in higher crop yield.
2. Why are manure and fertilizers used in fields?
Answer: Manure and fertilisers are used in fields to supply essential nutrients required by plants for growth and development. Continuous cultivation reduces the nutrient content of the soil, so these nutrients need to be replenished. Manure adds organic matter to the soil, improves soil structure, and increases soil fertility. Fertilisers provide nutrients like nitrogen, phosphorus, and potassium in adequate amounts, which help in good vegetative growth and increase crop yield.
3. What are the advantages of inter-cropping and crop rotation?
Answer: Inter-cropping and crop rotation have several advantages.
Inter-cropping helps in better utilisation of nutrients because crops with different nutrient requirements are grown together. It reduces the spread of pests and diseases and gives better and more stable yield from the same field.
Crop rotation improves soil fertility by growing different crops in a planned sequence. It helps in efficient use of soil nutrients, reduces pest and disease problems, and allows two or three crops to be grown in a year with good harvests.
4. What is genetic manipulation? How is it useful in agricultural practices?
Answer: Genetic manipulation is the process of introducing a specific gene into a crop plant to obtain a desired characteristic. This method results in genetically modified crops.
Genetic manipulation is useful in agricultural practices because it helps in developing crop varieties with improved qualities such as higher yield, resistance to diseases and pests, and better tolerance to adverse environmental conditions. It allows crops to perform better under different situations and helps increase overall agricultural production.
5. How do storage grain losses occur?
Answer: Storage grain losses occur due to both biotic and abiotic factors. Biotic factors include insects, rodents, fungi, mites and bacteria that damage the stored grains. Abiotic factors include improper moisture and unsuitable temperature conditions in storage places.
These factors cause loss in weight, poor germination, discolouration of grains and reduction in quality, which finally leads to poor market value of the stored produce.
6. How do good animal husbandry practices benefit farmers?
Answer: Good animal husbandry practices benefit farmers by improving the health and productivity of livestock. Proper feeding, breeding and disease control help animals remain healthy and increase the production of milk, eggs and meat. Healthy animals also reduce losses due to diseases and death. These practices ensure better quality animal products and provide farmers with higher income and improved livelihood.
7. What are the benefits of cattle farming?
Answer: Cattle farming has several benefits. It provides milk, which is an important and nutritious food. Cattle are also used as draught animals for agricultural work such as ploughing fields, irrigation and pulling carts. Thus, cattle farming supports agriculture and helps farmers in their livelihood.
8. For increasing production, what is common in poultry, fisheries and bee-keeping?
Answer: For increasing production, proper management practices are common in poultry, fisheries and bee-keeping. These include selection of improved breeds or varieties, providing suitable food and shelter, and prevention and control of diseases. Scientific management helps in better growth, higher productivity and increased yield of eggs, meat, fish, honey and wax.
NOTE: Beeswax, the building material of honeycombs.
9. How do you differentiate between capture fishing, mariculture and aquaculture?
Answer: Capture fishing, mariculture and aquaculture differ in their methods and place of fish production.
Capture fishing is the method of obtaining fish from natural water bodies like seas, rivers and lakes without growing them. Fish are caught directly from natural resources.
Mariculture is the practice of farming marine fish and other organisms in seawater. It is done to increase fish production by culturing marine species in marine ecosystems.
Aquaculture is the practice of growing fish and other aquatic organisms in inland water bodies such as ponds, canals and reservoirs. It helps increase fish production under controlled conditions.