NCERT Solutions for Class 9 Science Chapter 12 Improvements in Food Resources provides detailed answers for all in-text and exercise Questions. These solutions contain an in-depth explanation of each topic involved in the chapter. Students studying in class 9 can access these solutions for free in PDF format.
All these solutions are prepared by expert teachers and updated for the current academic session. NCERT Solutions for Class 9 Science Chapter 12 Improvements in Food Resources help students to understand the fundamental concepts given in class 9 Science textbook. We have prepared the answers to all the questions in an easy and well-structured manner. It helps students to grasp the chapter easily.
Class 9 Science Improvements in Food Resources Intext Questions (Solved)
PAGE NO. 141
Question 1: What do we get from cereals, pulses, fruits and vegetables?
Answer 1: (a) Cereals provide us with carbohydrates. Also, they are a rich source of energy.
(b) Pulses give us proteins.
(c) Fruits and vegetables are a rich source of vitamins and minerals. A small amount of proteins, carbohydrates, and fats are also present in them.
PAGE NO. 142
Question 1: How do biotic and abiotic factors affect crop production?
Answer: Biotic and abiotic factors both play a role in crop production:
Biotic Factors: These are related to living things. Pests like insects can damage crops, while diseases from fungi or bacteria can harm or kill plants. Weeds compete with crops for nutrients and water. On the positive side, helpful insects like bees can pollinate plants, improving crop yields.
Abiotic Factors: These involve non-living environmental elements. The weather, including temperature and rainfall, affects how well crops can grow. Soil quality, which involves nutrient levels, pH balance, and texture, is crucial for healthy crops. Other factors like the amount of sunlight and water availability are important for plant growth.
Question 2: What are the desirable agronomic characteristics for crop improvements?
Answer: The desirable agronomic characteristics for crop improvements are:
(i) Tallness and profuse branching in any fodder crop.
(ii) Dwarfness in cereals.
These desirable agronomic characteristics help in increasing crop productivity.
PAGE NO. 143
Question 1: What are macro-nutrients and why are they called macro-nutrients?
Answer: Macro-nutrients are nutrients required in relatively large quantities for growth and development of plants. 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.
Question 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.
OR
Plants get nutrients mainly from the soil through their roots. The roots absorb water and dissolved nutrients from the soil and transport them to different parts of the plant. Nutrients like nitrogen, phosphorus, and potassium, along with others, are taken up from the soil as the plant needs them for growth and development. Additionally, plants make their own food through photosynthesis using sunlight, carbon dioxide from the air, and water.
PAGE NO. 144
Question 1: Compare the use of manure and fertilizers in maintaining soil fertility.
Answer: Manures increase soil fertility by enriching the soil with organic matter and nutrients as it is prepared by the decomposition of animal excreta and plant wastes. On the other hand, fertilizers are mostly inorganic compounds whose excessive use is harmful to the symbiotic micro-organisms living in soil. Their excessive use also reduces soil fertility. Hence, fertilizers are considered good for only short term use.
OR
Manure and fertilizers both help in maintaining soil fertility, but they do so in different ways:
Manure:
- Organic in nature, made from decomposed plant and animal waste.
- Improves soil texture, making it more porous and enhancing its water-retaining capacity.
- Adds a wide range of nutrients to the soil, but in lower concentrations than fertilizers.
- Releases nutrients slowly, providing long-term nutrition to plants.
- Enhances the biological activity and health of the soil by adding organic matter.
Fertilizers
- Chemically synthesized or inorganic materials.
- Provide specific nutrients like nitrogen, phosphorus, and potassium in high concentrations.
- Nutrients are available to plants quickly.
- Used for immediate improvement in crop yield.
- Does not improve soil structure or add organic matter.
While manure is more about improving overall soil health and providing nutrients slowly, fertilizers are focused on supplying specific nutrients quickly to boost plant growth. The best approach often involves using both in a balanced way to maintain soil fertility and plant health.
PAGE NO. 145
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: (c) Farmers using good quality seeds, adopting irrigation, using fertilizers, and using crop protection measures will derive most benefits because:
- 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.
- Proper irrigation methods improve the water availability to crops.
- Fertilizers ensure healthy growth and development in plants by providing the essential nutrients such as nitrogen, phosphorus, potassium, etc.
- Crop protection measures include various methods to control weeds, pests, and infectious agents. If all these necessary measures are taken by a farmer, then the overall production of crops will increase.
PAGE NO. 146
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 they are environmentally friendly and sustainable. Here’s why:
- They are less harmful to the environment than chemical pesticides, which can contaminate soil, water, and air.
- These methods reduce the amount of chemical residues in food, making it safer for human consumption.
- Biological control is sustainable as it uses natural mechanisms like predators or parasites to control pests, reducing reliance on chemicals.
- Pests can become resistant to chemical pesticides over time, making them less effective. Biological methods help prevent this resistance.
- Biological controls maintain the natural balance of the ecosystem, unlike chemicals which can kill beneficial organisms along with pests.
Question 2: What factors may be responsible for losses of grains during storage?
Answer: Several factors can be responsible for the loss of grains during storage:
- Moisture: High levels of moisture can lead to the growth of mold and fungi, which can spoil the grains.
- Insects and Pests: Insects, rodents, and other pests can eat the grains or contaminate them with their waste.
- Temperature: Extreme temperatures can either directly damage the grains or create conditions favorable for pests and mold.
- Improper Storage: Poorly ventilated or unclean storage facilities can increase the risk of spoilage and infestation.
- Exposure to Light: Direct sunlight or too much light can deteriorate the quality of grains over time.
These factors can significantly reduce the quantity and quality of stored grains, so proper storage conditions are essential to minimize losses.
PAGE NO. 147
Question 1: Which method is commonly used for improving cattle breeds and why?
Answer: Cattle farming is commonly used for improving cattle breeds. The purpose of cattle farming is to increase the production of milk and draught labour for agricultural work. Dairy animals (females) are used for obtaining milk and draught animals (males) are engaged in agricultural fields for labour work such as carting, irrigation, tilling, etc. Crossbreeding 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.
PAGE NO. 148
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: 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
PAGE NO. 148
Question 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.
Question 2: What are the differences between broilers and layers and in their management?
Answer: Layers are meant for egg production, whereas broilers are meant for poultry meat. Nutritional, environmental, and housing conditions required by broilers are different from those required by egg layers. A broiler chicken for their proper growth, requires vitamin-rich supplements especially vitamin A and K. Also, their diet includes protein-rich food and enough fat. They also require extra care and maintenance to increase their survival rate in comparison to egg layers.
PAGE NO. 149
Question 1: How are fish obtained?
Answer: Fish can be obtained by two ways:
- Capture fishing: It is the process of obtaining fish from natural resources.
- Culture fishery: It is the practice of farming fishes. Farming can be done in both freshwater ecosystem (which includes river water, pond water) and the marine ecosystem.
Question 2: What are the advantages of composite fish culture?
Answer: An advantage of composite fish culture is that it increases the yield of fish. In a composite fish culture, five or six different species are grown together in a single fish pond. Fishes with different food habitats are chosen so that they do not compete for food among themselves. Also, this ensures a complete utilization of food resources in the pond. As a result, the survival rate of fish increases and their yield also increases.
PAGE NO. 150
Question 1: What are the desirable characters 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.
Question 2: What is pasturage and how is it related to honey production?
Answer: Pasturage is the availability of Blowers from which bees collect nectar and pollen. It is related to the production of honey as it determines the taste and quantity of honey.
CBSE Class 9 Science Improvements in Food Resources Exercise Questions and Answers
Question 1: Explain any one method of crop production which ensures high yield.
Answer: Crop rotation is one of the methods of crop production that ensures high yield. It is the method of growing two or more varieties of crops on the same land in sequential seasons. A crop utilises some particular nutrients in larger quantities from the soil. Then, if the same crop is grown in subsequent seasons those nutrients will get depleted in the soil. Therefore, crops having different nutrient requirements are rotated. For example, legumes that have nitrogen-fixing bacteria in their root nodules supply the soil with nitrogen. Therefore, these legumes are rotated with nitrogen requiring cereals such as wheat and maize. This method reduces the need for fertilizers, thereby increasing the overall yield of crops.
Question 2: Why are manures and fertilizers used in fields?
Answer: Manures and fertilizers are used in fields to add essential nutrients to the soil, helping plants grow better. Manures, which are organic, improve soil health overall, while fertilizers provide specific nutrients like nitrogen, phosphorus, and potassium in concentrated forms. This helps increase crop yields, especially in soil that has become nutrient-depleted from repeated farming. To get an optimum yield, it is instructed to use a balanced combination of manures and fertilizers in the soil.
Question 3: What are the advantages of inter-cropping and crop rotation?
Answer: Inter-cropping and crop rotation both play an important role in increasing the yield of crops. Inter-cropping helps in preventing pests and diseases to spread throughout the field. It also increases soil fertility, whereas crop rotation prevents soil depletion, increases soil fertility, and reduces soil erosion. Both of these methods reduce the need for fertilizers. It also helps in controlling weeds and controls the growth of pathogens and pests in crops.
Question 4: What is genetic manipulation? How is it useful in agricultural practices?
Answer: Genetic manipulation is a process where the gene for a particular character is introduced inside the chromosome of a cell. When the gene for a particular character is introduced in a plant cell, a transgenic plant is produced. These transgenic plants exhibit characters governed by the newly introduced gene.
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. Similarly, genes for higher yield, disease resistance, etc. can be introduced in any desired plant.
Therefore, gene manipulation plays an important role in agricultural practices. It helps in improving crop variety. It ensures food security and insect resistant crops. It also improves the quality and yield of crops.
Question 5: How do storage grain losses occur?
Answer: Storage grain losses occur due to several factors:
- Moisture: Excessive moisture can lead to the growth of molds and fungi, which spoil the grains.
- Pests: Insects, rodents, and birds can eat the grains or contaminate them with waste.
- Improper Storage Conditions: Poor ventilation, unclean storage facilities, and inadequate protection can lead to spoilage and infestation.
- Temperature Fluctuations: Extreme or fluctuating temperatures can damage grains directly or create conditions favorable for pests and molds.
These factors can cause significant losses in stored grains, affecting both quantity and quality. Proper storage practices are essential to minimize these losses.
Question 6: How do good animal husbandry practices benefit farmers?
Answer: Good animal husbandry practices benefit farmers by improving animal health and increasing productivity, leading to more milk, eggs, and meat. Healthy animals also mean lower disease treatment costs and better-quality products, which can fetch higher prices. Efficient practices help save resources, making farming more cost-effective and profitable.
Question 7: What are the benefits of cattle farming?
Answer: Benefits of cattle farming:
- Good quality and quantity of milk can be produced.
- Draught labour animals can be produced for agricultural work.
- New variety that are resistant to diseases can be produced by crossing two varieties with the desired traits.
Question 8: For increasing production, what is common in poultry, fisheries and bee-keeping?
Answer: The common factor for increasing production in poultry, fisheries, and bee keeping is the proper management techniques that are to be followed. Regular cleaning of farms is of utmost importance. Maintenance of temperature and prevention and cure of diseases is also required to increase the number of animals.
Question 9: How do you differentiate between capture fishing, mariculture and aquaculture?
Answer:
| Capture fishing | Mariculture | Aquaculture |
| It is the method of obtaining fishes from natural resources. | It is the culture of marine fishes for commercial use. | It involves the production of aquatic animals that are of high economic value such as prawns, lobsters, fishes, crabs, etc. |