Class 9 Science Chapter 12 Improvement In Food Resources

Key Concept: Manure Classification

c) Vermi-compost

[Solution Description] Vermi-compost is prepared by using earthworms to hasten the process of decomposition of plant and animal refuse. This process enriches the soil with organic matter and nutrients, making it a sustainable method for improving soil fertility.

Key Concept: Livestock Management, Sustainable Practices

c) Implementing rotational grazing and balanced feeding schedules

[Solution Description]

To improve livestock productivity sustainably, the farmer should focus on proper care and management practices, including shelter, feeding, breeding, and disease control. Implementing sustainable practices such as rotational grazing, balanced feeding schedules, and regular health check-ups can enhance productivity without causing environmental harm. Additionally, integrating livestock with other farming activities like agriculture, poultry, or fisheries can provide a diversified and sustainable income source.

Key Concept: Fertilizers, Soil Fertility, Environmental Impact

c) Water pollution

[Solution Description]

Excessive use of fertilizers can lead to their leaching into nearby water bodies due to excessive irrigation or rainfall. This results in water pollution, particularly eutrophication, where the excessive nutrients cause algal blooms, deplete oxygen levels, and harm aquatic life. Hence, the direct consequence of overusing fertilizers is water pollution.

Key Concept: Animal Husbandry

b) To manage and care for livestock for products like milk and meat

[Solution Description]

The primary purpose of animal husbandry is to manage and care for animals, especially livestock, to obtain products like milk, meat, eggs, etc., and to ensure their health and well-being.

Key Concept: Broiler production, Nutritional requirements

b) Increasing protein content

[Solution Description]

According to the syllabus, broiler chickens require a protein-rich diet with adequate fat for good growth rate and better feed efficiency. While vitamin-rich supplementary feed is important, the primary issue here is likely insufficient protein content. Protein is essential for muscle development and overall growth in broilers. Therefore, the farm should prioritize increasing the protein content in the feed to improve growth rate and feed efficiency.

Key Concept: Cross-breeding, Summer Adaptation

c) Summer adaptation capacity/tolerance to high temperature

[Solution Description]

Cross-breeding programs aim to combine desirable traits from different breeds. For enhancing summer adaptation capacity, the focus should be on selecting birds that can tolerate high temperatures efficiently. This trait is critical for survival and productivity in hot climates, as it reduces heat stress and maintains growth rates even during peak summer months.

Key Concept: Food Security and Agriculture

c) Enhancing the purchasing power of people

[Solution Description]

Food security depends on both the availability of food and access to it. Simply increasing grain production for storage does not solve malnutrition and hunger. People need money to purchase food. Therefore, increasing the incomes of people working in agriculture is necessary to combat hunger and ensure food security.

Key Concept: Genetic Modification

c) To introduce a specific desirable characteristic

[Solution Description]

The primary purpose of introducing a desired gene into a crop plant is to provide the plant with a specific characteristic that improves its performance, such as disease resistance, higher yield, or tolerance to abiotic stresses like drought or salinity.

Key Concept: Crop Variety Improvement

c) Hybridisation

[Solution Description]

Hybridisation is a method used to incorporate desirable characters into crop varieties. It involves crossing between genetically dissimilar plants, which can be intervarietal, interspecific, or intergeneric. This process helps in combining useful characteristics such as disease resistance, high yield, and improved quality into new crop varieties.

Key Concept: Egg production, Management practices

d) Ensuring optimal temperature in housing

[Solution Description]

During summer, high temperatures can stress the birds, leading to reduced egg production. Therefore, maintaining optimal temperature in the housing through proper ventilation, cooling systems, or shading is crucial. Hygienic conditions, nutritional feed, and pest control are essential but secondary to ensuring the birds are not stressed by heat. Thus, the priority should be to maintain a comfortable environment for the layers.

Key Concept: Green Revolution, White Revolution, Environmental Balance

c) They have led to overuse of natural resources, causing environmental degradation

[Solution Description] The Green Revolution and White Revolution have led to increased food production but at the cost of intensive use of natural resources like water, soil, and fertilizers. This overuse can degrade the environment, leading to issues such as soil erosion, water depletion, and loss of biodiversity. While these revolutions have addressed immediate food needs, they have compromised the environmental balance required for long-term sustainability.

Key Concept: Fish Seed Production

c) Use of hormonal stimulation for breeding

[Solution Description]

A major problem in fish farming is the lack of availability of good-quality fish seed. Many fish species breed only during the monsoon season, and collecting fish seed from the wild can result in mixed species. To address this issue, hormonal stimulation techniques have been developed to breed fish in ponds, ensuring a supply of pure fish seed in desired quantities.

Key Concept: Vaccinations, Poultry health

b) Implementing a rigorous vaccination schedule for all birds

[Solution Description]

In poultry farming, outbreaks of viral diseases can lead to high mortality rates. The most effective long-term strategy to minimize such losses is implementing a comprehensive vaccination program. This ensures that the birds develop immunity against the virus, reducing the severity and spread of the disease during future outbreaks. Proper sanitation and biosecurity measures also play a supporting role.

Key Concept: Cross-breeding, Desirable Traits

c) Aseel and Leghorn

[Solution Description]

To achieve a breed that is tolerant to high temperatures and can utilize fibrous cheaper diets, the farmer should consider cross-breeding an indigenous breed like Aseel, which is known for its adaptability, with an exotic breed like Leghorn, which is known for its efficiency in feed utilization. This combination would likely result in a breed that has both the desirable traits of summer adaptation capacity and the ability to utilize more fibrous cheaper diets.

Key Concept: Sustainable practices, Food security

b) Adopting mixed farming and integrated practices

[Solution Description] Sustainable practices aim to increase food production without harming the environment. These practices include mixed farming, intercropping, and integrated farming, which combine agriculture with livestock, poultry, fisheries, or bee-keeping. By adopting these methods, we can ensure higher yields while maintaining ecological balance. Additionally, increasing the incomes of people working in agriculture ensures they have access to food, thereby addressing food security.

Key Concept: Inter-cropping, Crop Rotation

c) Inter-cropping and crop rotation together ensure better nutrient utilization and pest control

[Solution Description]

Inter-cropping of soyabean and maize ensures maximum utilization of nutrients since the nutrient requirements of these crops are different. This practice also reduces the risk of pests and diseases spreading to all plants of one crop. Additionally, crop rotation with wheat helps in maintaining soil fertility and prevents the buildup of pests and diseases specific to soyabean or maize. Thus, this strategy ensures better returns and sustainable farming.

Key Concept: Irrigation

c) River Lift Systems

[Solution Description]

River Lift Systems are most suitable for areas where canal flow is insufficient or irregular due to inadequate reservoir release. In this system, water is directly drawn from rivers to supplement irrigation.

Key Concept: Composite Fish Culture

b) To consume detritus and organic matter

[Solution Description]

Bottom feeders such as Mrigal (Cirrhinus mrigala) and Common Carp (Cyprinus carpio) play a crucial role in composite fish culture by consuming detritus and organic matter that settles at the bottom of the pond. This helps in maintaining the cleanliness of the pond and ensures efficient utilization of food resources.

Key Concept: Rainwater Harvesting, Watershed Management

c) Light soils have poor water retention capacity

[Solution Description] The farmer has implemented rainwater harvesting and watershed management techniques, which have increased groundwater levels and reduced soil erosion. However, during prolonged dry spells, the crops may still suffer due to insufficient water retention in light soils. Light soils have poor water retention capacity, which means they cannot hold water for long periods, leading to drought-like conditions even with increased groundwater levels. Therefore, the most likely reason for the low crop yield is the poor water retention capacity of light soils.

Key Concept: Sustainable Practices in Agriculture

b) Integrated farming

[Solution Description]

Sustainable farming practices aim to increase food production while minimizing environmental degradation. Integrated farming combines agriculture with livestock, poultry, fisheries, or bee-keeping, which helps in efficient resource utilization and reduces environmental impact.

Key Concept: Crop Variety Improvement

b) Hybridisation

[Solution Description]

Hybridisation is a method used to incorporate desirable characteristics into crop varieties. It involves crossing genetically dissimilar plants, which can be intervarietal, interspecific, or intergeneric. This process helps in developing new varieties with improved traits such as disease resistance, higher yield, and better quality.

Key Concept: Weed Control

c) Xanthium

[Solution Description]

Weeds are unwanted plants in cultivated fields that compete with crops for nutrients, space, and light. Examples include Xanthium (gokhroo), Parthenium (gajar ghas), and Cyperinus rotundus (motha). Therefore, Xanthium is an example of a weed.

Key Concept: Desirable characters of bee varieties, Pasturage

d) High honey collection capacity and availability of diverse flowers

[Solution Description]

The desirable characters of bee varieties suitable for honey production include high honey collection capacity, less frequent stinging, long stay in beehives, and good breeding. Additionally, the quality of honey depends on pasturage, which refers to the flowers available for nectar and pollen collection. Therefore, the beekeeper should consider both the characteristics of the bee variety and the availability of diverse flowers.

Key Concept: Canals, Water Distribution Efficiency

b) 2000 $m^3$/hr

[Solution Description]

The total flow rate of the main canal is 5000 $m^3$/hr. It is divided into two branch canals in the ratio 3:2. To find the flow rate of the second branch canal, follow these steps:

1. Calculate the total parts of the ratio: $3 + 2 = 5$.

2. Determine the flow rate corresponding to one part: $\frac{5000}{5} = 1000$ $m^3$/hr.

3. The second branch canal has 2 parts, so its flow rate is $2 \times 1000 = 2000$ $m^3$/hr.

Key Concept: Cropping Seasons

c) Gram

[Solution Description]

The rabi season runs from November to April, and crops grown during this period are called rabi crops. Wheat, gram, peas, mustard, and linseed are examples of rabi crops.

Key Concept: Irrigation, Drought Tolerance

c) Use of drought-tolerant crops and rainwater harvesting

[Solution Description]

In drought-prone areas, the focus should be on reducing water dependency and improving water use efficiency. Farmers should opt for drought-tolerant crop varieties that require less water. Additionally, rainwater harvesting can help store scarce rainfall for future use, and drip irrigation ensures efficient water delivery to crops, minimizing wastage. These practices together provide a sustainable solution for crop production in drought-affected regions.

Key Concept: Desirable agronomic traits, Dwarf cereals, Tall fodder crops

c) Dwarf cereals and tall fodder crops

[Solution Description]

To maximize the yield of cereals and fodder crops, the farmer needs to focus on specific desirable agronomic traits. For cereals, dwarfness is preferred as it reduces nutrient consumption and increases grain production. For fodder crops, tallness and profuse branching are desirable as they enhance biomass production. Therefore, the farmer should select varieties with dwarfness for cereals and tallness for fodder crops.

Key Concept: Mixed Cropping, Crop Variety Improvement

b) 17.5 quintals

[Solution Description]

Let the total area be 1 hectare. Initially, the entire area is used for wheat, yielding 20 quintals. If 25% of the wheat area is replaced with gram, then 0.75 hectares will be under wheat and 0.25 hectares under gram. The yield from wheat will be $0.75 \times 20 = 15$ quintals, and the yield from gram will be $0.25 \times 10 = 2.5$ quintals. Therefore, the total yield per hectare will be $15 + 2.5 = 17.5$ quintals.

Key Concept: Disease Prevention, Cross-Breeding Programs

c) Combine cross-breeding programs with regular vaccination and sanitation practices

[Solution Description]

To balance cross-breeding programs and disease prevention, it is essential to implement both strategies simultaneously. Cross-breeding focuses on developing desirable traits, while disease control involves proper cleaning, sanitation, spraying disinfectants, and vaccination. Combining these approaches ensures both genetic improvement and reduced disease-related losses.

Key Concept: Cross-Breeding in Cattle Farming

c) Cross-breeding

[Solution Description] Cross-breeding is commonly used to improve cattle breeds. It involves breeding exotic breeds (like Jersey, Brown Swiss) known for long lactation periods with local breeds (like Red Sindhi, Sahiwal) that show excellent resistance to diseases. This results in offspring that inherit both desirable qualities.

Key Concept: Composite Fish Culture, Income Diversification

c) Catla: 1251, Rohu: 834, Mrigal: 417

[Solution Description]

The total number of fish to be stocked can be calculated by multiplying the pond area by the optimal stocking density. Total fish = 500 $m^2$ $\times$ 5 fish/$m^2$ = 2500 fish.

The ratio of Catla:Rohu:Mrigal is given as 3:2:1. To find the number of fish for each species:

– Let the common multiplier be $x$. Then, Catla = 3$x$, Rohu = 2$x$, and Mrigal = $x$.

– Total fish = 3$x$ + 2$x$ + $x$ = 6$x$ = 2500.

– Solving for $x$, we get $x$ = 416.67. Since the number of fish must be an integer, we round $x$ to the nearest whole number, which is 417.

Therefore:

– Number of Catla = 3 $\times$ 417 = 1251

– Number of Rohu = 2 $\times$ 417 = 834

– Number of Mrigal = 417

Key Concept: Desirable agronomic characteristics, Biotic and abiotic resistance

b) Dwarfness and pest resistance

[Solution Description]

For a cereal crop in regions with frequent water logging and pest issues, desirable agronomic characteristics include dwarfness to reduce nutrient consumption and resistance to both biotic (pests) and abiotic (water logging) stresses. Dwarfness helps in efficient nutrient use, while resistance ensures the crop can thrive despite adverse conditions.

Key Concept: Intercropping, Pest Management

b) The alternating rows create a physical barrier for pests

[Solution Description]

In intercropping, different crops are grown in alternate rows. Pests that target one crop (e.g., maize) find it difficult to spread to the other crop (e.g., soybeans) due to the physical barrier created by the alternating rows. This reduces the overall pest population and limits the spread of diseases.

Key Concept: High-cost farming

d) Use of advanced technology and hybrid seeds

[Solution Description]

High-cost farming involves the use of advanced technology and hybrid seeds, which require significant financial investment but can lead to higher yields. This practice aims to maximize crop productivity through technological advancements and genetically improved seeds.

Key Concept: Pest Control Methods

c) Summer ploughing

[Solution Description]

The question asks for a method that involves ploughing fields deep during summer to destroy pests. This method is known as summer ploughing. It helps in exposing pests to sunlight and heat, thereby killing them. The correct answer is summer ploughing.

Key Concept: Food Security

b) Increasing the incomes of people working in agriculture

[Solution Description]

Food security depends on both the availability of food and the ability of people to access it. Simply increasing food production is insufficient if people lack the financial means to purchase food. Therefore, increasing the incomes of those dependent on agriculture, through better yields and diversified farming practices, is crucial for ensuring food security.

Key Concept: Nutrients from Fruits and Vegetables

c) Vitamins and Minerals

[Solution Description]

Fruits and vegetables are primarily known for providing vitamins and minerals, which are essential for maintaining health and preventing deficiencies of essential nutrients.

Key Concept: Check dams, Groundwater recharge

b) 4,320 $m^3$

[Solution Description]

First, calculate the total rainwater that falls per hectare. 1 hectare = 10,000 $m^2$, and 1200 mm = 1.2 m. So, total rainwater = $10,000 \times 1.2 = 12,000$ $m^3$. Next, calculate the runoff: Runoff = Total rainwater $\times$ Runoff coefficient = $12,000 \times 0.4 = 4,800$ $m^3$. The remaining water after runoff is $12,000 – 4,800 = 7,200$ $m^3$. Now, calculate the infiltrated water: Infiltrated water = $7,200 \times 0.6 = 4,320$ $m^3$. Therefore, the groundwater recharge per hectare annually is 4,320 $m^3$.

Key Concept: Balanced diet for dairy animals

b) Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.

[Solution Description]

The assertion states that dairy animals need a balanced diet of roughage and concentrates for health and milk production. This is true because roughage aids in proper digestion due to its high fibre content, and concentrates provide essential nutrients like proteins that are crucial for milk production. However, the reason explains why roughage and concentrates are important separately but does not directly explain why they must be combined in a balanced diet. Therefore, both the assertion and reason are true, but the reason does not correctly explain the assertion.

Key Concept: Tanks, Rainwater Harvesting, Watershed Management

c) 500 cm

[Solution Description]

The total water stored in the check-dam is 5000 cubic meters for a catchment area of 10 hectares. To find the average depth of water stored per hectare, we divide the total volume of water by the area: $5000 / 10 = 500$ cubic meters per hectare. Since 1 cubic meter of water over 1 hectare corresponds to a depth of 0.0001 meters, the calculation remains straightforward as it is already given in cubic meters per hectare.

Key Concept: Rainwater harvesting

c) Stop rainwater flow and reduce soil erosion

[Solution Description]

The primary purpose of building check-dams in rainwater harvesting is to stop the rainwater from flowing away, increasing groundwater levels and reducing soil erosion. This helps in making more water available for agriculture.

Key Concept: Categories of Food Crops

c) Rice

[Solution Description]

Cereals such as wheat, rice, maize, millets, and sorghum provide us with carbohydrates, which are essential for meeting our energy requirements.

Key Concept: Storage Losses

b) Insects

[Solution Description]

Biotic factors are living organisms that cause storage losses in grains. These include insects, rodents, fungi, mites, and bacteria. Among these, insects, rodents, and fungi are the most common biotic factors responsible for degradation in quality, loss in weight, poor germinability, and discolouration of grains.

Key Concept: Cross-breeding, desirable traits

b) Cross-breeding an indigenous breed with an exotic breed

[Solution Description]

The farmer should cross-breed Indian breeds like Aseel with exotic breeds like Leghorn. According to the syllabus, cross-breeding programs focus on developing new varieties with desirable traits such as summer adaptation capacity and low maintenance requirements. Indian breeds are known for their adaptability, while exotic breeds contribute to improved traits.

Key Concept: Animal feed requirements

b) Maintenance requirement and milk-producing requirement

[Solution Description] Dairy animals have two main types of food requirements: maintenance requirement and milk-producing requirement. The maintenance requirement supports the animal’s healthy life, while the milk-producing requirement is necessary during the lactation period to ensure proper milk production.

Key Concept: Maintenance of temperature, Hygienic conditions

b) Install an efficient heating system in the poultry house

[Solution Description]

During extreme winter, the ambient temperature drops significantly, which can lead to hypothermia in broilers, increasing mortality rates. To maintain optimal body temperature, broilers require a controlled environment with proper heating systems. Additionally, ensuring proper ventilation while retaining heat is crucial to prevent respiratory issues. Hygienic conditions must also be maintained to avoid infections that can exacerbate stress due to cold. Thus, the most effective solution is to install an efficient heating system in the poultry house.

Key Concept: Desirable agronomic characteristics, Crop variety improvement

c) To reduce nutrient consumption

[Solution Description]

Dwarf varieties of cereal crops are developed primarily to reduce nutrient consumption. Taller plants tend to use more nutrients for stem growth, whereas dwarf plants allocate more resources to grain production. This characteristic leads to higher productivity as fewer nutrients are consumed by the plant structure, allowing more nutrients to be directed towards grain development.

Key Concept: Pesticide Usage

c) Environmental pollution

[Solution Description]

Pesticides, including herbicides, insecticides, and fungicides, are chemicals used to control weeds, insects, and diseases. However, their excessive use can be poisonous to many plant and animal species and cause environmental pollution. This includes contamination of soil, water, and air, leading to a loss of biodiversity and ecological imbalance.

Key Concept: Shorter maturity duration, Cost reduction

c) Lowered cost of production due to multiple cropping cycles

[Solution Description]

The primary economic benefit of selecting a crop variety with shorter maturity duration is that it reduces the cost of crop production. This is because shorter duration allows the farmer to grow multiple rounds of crops in a year, increasing overall productivity and reducing per-unit costs. Additionally, uniform maturity makes harvesting easier and reduces losses during the process.

Key Concept: Inter-cropping, Crop Rotation

b) Ensures maximum utilization of nutrients

[Solution Description]

Inter-cropping involves growing two or more crops simultaneously on the same field in a definite pattern. The main advantage of this method over mono-cropping is that it ensures maximum utilization of nutrients supplied to the soil. Since the crops have different nutrient requirements, they do not compete excessively for the same resources, leading to better overall utilization and improved yields.

Key Concept: Poultry Farming

b) To enhance the variety and improve productivity

[Solution Description]

Cross-breeding in poultry farming is done to combine the desirable traits of different breeds, such as high egg production from exotic breeds and disease resistance from local breeds. This improves the overall productivity and quality of poultry.

Key Concept: Hybridisation – Intervarietal crossing

d) Intervarietal crossing

[Solution Description]

The process of crossing between different varieties of the same species is called intervarietal crossing. This is a type of hybridisation where genetically dissimilar plants of different varieties are crossed to incorporate desirable characteristics.

Key Concept: Crop Variety Improvement, Wider Adaptability

c) Prioritizing varieties with wider adaptability

[Solution Description]

To ensure stable crop production under unpredictable and diverse climatic conditions, the farmer should prioritize developing or selecting crop varieties that exhibit wider adaptability. Wider adaptability allows a single variety to be grown successfully in different environmental conditions, such as varying temperatures, soil types, and water availability. This reduces the risk of crop failure due to sudden changes in weather, such as droughts or floods. Additionally, varieties with wider adaptability can stabilize production across different regions, making them more reliable for farmers facing uncertain climatic conditions.

Key Concept: River Lift Systems, Energy Consumption

b) $7.2

[Solution Description]

First, calculate the energy required to lift 1200 cubic meters of water. The system consumes 10 kWh to lift 1000 cubic meters, so the energy required to lift 1200 cubic meters is $(1200 / 1000) \times 10 = 12$ kWh. The system operates for 6 hours daily, so the daily cost of energy is $12 \times 6 \times 0.1 = $7.2$.

Key Concept: Crop Rotation Benefits

b) Reduced pest and disease buildup

[Solution Description]

Crop rotation helps in maintaining soil fertility, reducing pest and disease buildup, and improving soil structure. It also promotes efficient nutrient utilization and reduces soil erosion. The correct option should reflect one of these primary benefits.

Key Concept: Watershed Management

c) To stop rainwater from flowing away and increase ground water levels

[Solution Description] The primary purpose of building small check-dams in watershed management is to stop rainwater from flowing away, which helps in increasing the ground water levels and reducing soil erosion.

Key Concept: Hybridisation, Crop Variety Improvement

b) Interspecific hybridisation followed by intervarietal hybridisation

[Solution Description] To develop a new variety of black gram that is resistant to both drought and diseases, the farmer should use hybridisation techniques. Hybridisation allows for the combination of desirable traits from different varieties or species. Specifically, interspecific hybridisation (between two different species of the same genus) can introduce disease resistance, while intervarietal hybridisation (between different varieties) can enhance drought tolerance. Genetically modified crops could also be an option, but hybridisation is more practical and widely accepted in traditional farming. Therefore, the most effective method is hybridisation.

Key Concept: Sustainable Agriculture, Integrated Farming

b) Reduce pesticide use to protect bee populations

[Solution Description] To maintain sustainable practices, the farmer must balance agricultural productivity with environmental health. If pesticide use decreases beekeeping yield, it harms pollinators essential for crop production. The farmer should prioritize reducing pesticide use to protect bee populations, ensuring long-term sustainability of both agriculture and beekeeping.

Key Concept: Micronutrients, Soil Enrichment

c) Bean

[Solution Description]

Molybdenum is crucial for nitrogen fixation and nitrate reduction in plants. Leguminous crops, such as beans, peas, and clover, rely heavily on these processes because they form symbiotic relationships with nitrogen-fixing bacteria. Therefore, a deficiency in molybdenum would severely impact leguminous crops, as it would hinder their ability to fix atmospheric nitrogen, leading to poor growth and yield.

Key Concept: Poultry Farming, Vaccination, Disease Control

c) 20 chickens

[Solution Description]

Calculate the number of chickens at risk: 20% of 500 = 0.2 $\times$ 500 = 100 chickens. The vaccination program reduces the risk by 80%, so 80% of these at-risk chickens will no longer be at risk: 0.8 $\times$ 100 = 80 chickens. Subtract this from the original number of at-risk chickens to find the remaining at-risk chickens: 100 – 80 = 20 chickens.

Key Concept: Nutrient Deficiency, Macronutrients, Micronutrients

c) Deficiency of macronutrients like nitrogen and phosphorus

[Solution Description]

Nitrogen and phosphorus are macronutrients essential for plant growth. Nitrogen is crucial for vegetative growth, while phosphorus is important for root development and flowering. A deficiency in these nutrients leads to stunted growth, yellowing of leaves (chlorosis), and poor flowering. Since the micronutrient levels are adequate, the symptoms are most likely due to the lack of macronutrients.

Key Concept: Green Revolution, White Revolution, Natural Resource Management

c) Increased risk of soil erosion and water depletion

[Solution Description]

The Green and White Revolutions have significantly increased food-grain and milk production, respectively. However, this intensive utilization of natural resources can lead to environmental degradation, such as soil erosion, water depletion, and loss of biodiversity. Over-reliance on chemical fertilizers and pesticides can disrupt ecological balances, making it essential to adopt sustainable practices that mitigate these risks while maintaining high productivity.

Key Concept: Composite Fish Culture, Marine Ecosystems

b) Efficient utilization of all available resources

[Solution Description]

In a composite fish culture system, different fish species occupy different ecological niches in the pond. Surface feeders consume algae and plankton, mid-water feeders consume detritus, and bottom feeders consume organic matter. This ensures efficient utilization of all available resources in the pond, leading to higher productivity and reduced competition among the species.

Key Concept: Marine Fisheries, Capture Fishing

b) 0.267 seconds

[Solution Description]

The echo-sounder sends a sound wave that travels down to the fish and then reflects back to the echo-sounder. The total distance traveled by the sound wave is twice the depth of the fish.

Distance = 2 $\times$ Depth = 2 $\times$ 200 meters = 400 meters

Speed of sound in seawater is given as 1500 m/s

Time is calculated using the formula: Time = Distance / Speed

So, Time = 400 meters / 1500 m/s = 0.2667 seconds

Therefore, the sound wave will take approximately 0.267 seconds to return to the echo-sounder.

Key Concept: Crop Variety Improvement

b) To improve crop production under different environmental conditions

[Solution Description]

Biotic stresses include diseases, insects, and nematodes, while abiotic stresses include drought, salinity, waterlogging, heat, cold, and frost. Developing crop varieties resistant to these stresses helps improve crop production by reducing losses due to these factors. Thus, the correct answer is to improve crop production under different environmental conditions.

Key Concept: Crop Protection Management, Nutrient Management

b) Use mechanical removal, crop rotation, and resistant varieties

[Solution Description]

The farmer should adopt integrated pest management practices, which include mechanical removal of weeds, proper seed bed preparation, timely sowing, intercropping, and crop rotation. Additionally, using resistant varieties and summer ploughing can help control pests and weeds without relying excessively on pesticides. These methods are environmentally friendly and help maintain soil fertility.

Key Concept: Nutrient Management

a) Nitrogen

[Solution Description]

Macro-nutrients are required by plants in large quantities for their growth and development. These include nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. Among these, nitrogen is one of the most essential macro-nutrients for plant growth.

Key Concept: Marine Fisheries, Mariculture

c) Using satellites and echo-sounders for fish location

[Solution Description]

To locate large schools of fish like tuna in the open sea, fishermen use advanced technologies such as satellites and echo-sounders. These technologies help in identifying the exact locations of fish schools, thereby increasing the efficiency and yield of fishing operations.

Key Concept: Crop Variety Improvement

d) All of the above

[Solution Description]

Crop variety improvement involves methods like hybridisation, which includes crossing between genetically dissimilar plants. This can be intervarietal, interspecific, or intergeneric. Another method is introducing a gene to create genetically modified crops.

Key Concept: Disease prevention, Vaccination, Hygiene

c) Administering appropriate vaccination

[Solution Description]

Viral diseases in poultry can be highly contagious and lead to significant losses. Proper vaccination is the most effective measure to prevent such outbreaks. Regular cleaning, sanitation, and spraying of disinfectants also help, but vaccination specifically targets the prevention of infectious diseases.

Key Concept: Draught Animals

a) Cows

[Solution Description]

Draught animals are specifically used for agricultural tasks such as tilling, irrigation, and carting. According to the syllabus, Indian cattle belong to two species: Bos indicus (cows) and Bos bubalis (buffaloes). While cows can be used for both milk production and draught labour, buffaloes are also used for similar purposes.

Key Concept: Composite Fish Culture

b) Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.

[Solution Description]

The assertion states that composite fish culture increases fish yield by efficiently utilizing all available food resources in a pond. This is true because in composite fish culture, multiple species with different feeding habits are used to ensure that all parts of the pond are utilized. For example, Catla feeds on the surface, Rohu in the middle zone, and Mrigal and Common Carp at the bottom. This prevents competition for food and maximizes resource utilization, leading to higher yields.

The reason provided is also true as it explains that different species like Catla, Rohu, Mrigal, and Common Carp are selected because they occupy different feeding zones and do not compete for food. However, while the reason supports the assertion, it does not directly explain why this leads to increased yield. The increase in yield is due to the efficient utilization of all food resources, which is facilitated by the selection of non-competing species. Therefore, the reason is not the correct explanation of the assertion.

Key Concept: Mixed farming, Integrated farming practices

c) 30%

[Solution Description]

The total farm area is 10 hectares. The farmer allocates 4 hectares for crops and 3 hectares for livestock. The remaining area for poultry can be calculated as follows:

$\text{Area for poultry} = \text{Total area} – (\text{Area for crops} + \text{Area for livestock}) = 10 – (4 + 3) = 3 \text{ hectares}$

To find the percentage of land allocated for poultry, we use the formula:

$\text{Percentage for poultry} = \left( \frac{\text{Area for poultry}}{\text{Total area}} \right) \times 100 = \left( \frac{3}{10} \right) \times 100 = 30\%$

Therefore, the correct answer is 30%.

Key Concept: Milch Animals

c) Jersey

[Solution Description]

The question asks about an exotic breed of milch animal known for its long lactation period. According to the syllabus, exotic breeds like Jersey and Brown Swiss are selected for their long lactation periods. Therefore, Jersey is the correct answer.

Key Concept: Macronutrients, Micronutrients, Soil Fertility

b) Use compost to provide all necessary nutrients

[Solution Description]

Calcium is a macronutrient, while iron and boron are micronutrients. Using chemical fertilizers might provide a quick fix but can harm soil fertility in the long run due to their adverse effects on soil microorganisms and organic matter. Manure, especially compost, contains a balanced mix of macro- and micronutrients and improves soil fertility by adding organic matter. Thus, applying compost is the most effective and sustainable solution to address these deficiencies.

Key Concept: Fodder Crops – Oats

b) Livestock feed

[Solution Description] Oats are commonly grown as a fodder crop to provide nutritious food for livestock, making them an essential component in animal husbandry.

Key Concept: Crop Variety Improvement

c) To make harvesting easier

[Solution Description] Uniform maturity duration in crops allows for easier and more efficient harvesting processes. It reduces losses during harvesting and enables farmers to grow multiple crops in a year, making it economically beneficial.

Key Concept: Pasturage and Honey Quality

d) The flowers available for nectar and pollen collection

[Solution Description] The value or quality of honey depends on the pasturage, which refers to the flowers available to the bees for nectar and pollen collection. The kind of flowers available directly influences the taste and quality of the honey, along with the quantity of pasturage.

Key Concept: Food Security, Agricultural Income

c) Increasing agricultural incomes through scientific management practices

[Solution Description]

To address food security, it is essential to ensure people have sufficient income to purchase food. Increasing agricultural incomes through scientific management practices, such as adopting high-yield techniques and diversified farming, directly improves access to food. Building warehouses for grain storage alone does not solve the problem if people cannot afford to buy the stored food. Therefore, increasing agricultural incomes is the most effective measure.

Key Concept: Tanks, Check-Dams, Soil Erosion

c) 60%

[Solution Description]

To find the percentage reduction in soil erosion, we use the formula:

$\text{Percentage Reduction} = \frac{\text{Initial Erosion Rate} – \text{Final Erosion Rate}}{\text{Initial Erosion Rate}} \times 100$

Given: Initial Erosion Rate = 5 tons/hectare/year, Final Erosion Rate = 2 tons/hectare/year.

$\text{Percentage Reduction} = \frac{5 – 2}{5} \times 100 = 60\%$

Therefore, the percentage reduction in soil erosion is 60%.

Key Concept: Macronutrients

b) Nitrogen

[Solution Description]

Macronutrients are nutrients that plants require in large quantities for their growth and development. The primary macronutrients include nitrogen, phosphorus, potassium, calcium, magnesium, and sulphur.

Key Concept: Nutrient-rich feed, Animal Husbandry

c) 15 kg

[Solution Description]

The problem involves calculating the amount of roughage in the cow’s diet based on the given ratio. The total daily requirement is 20 kg, and the ratio of roughage to concentrates is 3:1. To find the amount of roughage, follow these steps:

1. The ratio of roughage to concentrates is 3:1, which means for every 3 parts of roughage, there is 1 part of concentrates.

2. The total parts are $3 + 1 = 4$.

3. The amount of roughage is calculated as $\frac{3}{4}$ of the total daily requirement.

4. Therefore, the roughage required is $\frac{3}{4} \times 20\, \text{kg} = 15\, \text{kg}$.

Thus, the cow should be given 15 kg of roughage daily.

Key Concept: Nutrient Management

b) Carbon

[Solution Description]

The question asks about the nutrient supplied to plants by air. According to the syllabus, air supplies carbon and oxygen to plants. These are essential nutrients required by plants for their growth and development.

Key Concept: Bee-keeping, Honey Quality, Pasturage

c) Type of flowers available

[Solution Description]

The quality or value of honey depends on the pasturage, which includes the flowers available to the bees for nectar and pollen collection. The kind of flowers available determines the taste of the honey. Therefore, the primary factor influencing the distinct flavors of honey in the two regions is the type of flowers available in each region.

Key Concept: Mariculture, Economic Value of Marine Fish

c) Using integrated multi-trophic aquaculture (IMTA)

[Solution Description] Sustainable mariculture practices involve balancing production with environmental conservation. The most effective practice would be to implement controlled breeding and harvesting cycles, ensuring that the marine ecosystem is not overexploited. Additionally, integrating species like seaweed can help maintain water quality by absorbing excess nutrients. Thus, the best approach is to use integrated multi-trophic aquaculture (IMTA), where multiple species are cultivated together to create a balanced ecosystem.

Key Concept: Desirable agronomic characteristics

c) They consume less nutrients

[Solution Description]

Developing dwarf varieties in cereals is advantageous because these varieties consume less nutrients, allowing more efficient use of resources and leading to higher productivity. Dwarfness in cereals also reduces the risk of lodging (falling over), which can damage the crop.

Key Concept: Improved Quality

c) Baking quality

[Solution Description]

In crop improvement, wheat is improved for its baking quality. This is because baking quality is crucial for making bread and other baked goods. Therefore, the correct answer is baking quality.

Key Concept: Milk Production

a) Increasing the lactation period

[Solution Description]

To increase milk production, the lactation period of dairy animals can be extended. This can be achieved by cross-breeding local breeds, which are disease-resistant, with exotic breeds that have long lactation periods.

Key Concept: Wider adaptability, Environmental conditions

b) Tolerance to high soil salinity

[Solution Description]

For a crop variety to succeed in regions with varying soil salinity levels, the most critical factor is its ability to tolerate high salinity. Wider adaptability ensures that the variety can perform well under different environmental conditions, including soil quality. The variety must have been specifically bred or modified to handle high salinity, as this directly impacts its growth and yield in such regions.

Key Concept: Inland Fisheries, Composite Fish Culture

c) Utilization of all available food resources in the pond

[Solution Description]

The primary advantage of a composite fish culture system is the efficient utilization of all available food resources in the pond. By stocking fish species with different feeding habits (surface feeders, middle-zone feeders, bottom feeders, and weed eaters), the system ensures that all parts of the pond’s ecosystem are utilized. This reduces competition for food among the fish species and maximizes the overall fish yield from the pond. Therefore, the main benefit is the optimization of food resource utilization, leading to higher productivity.

Key Concept: Cattle Farming

c) Both milk production and draught labour

[Solution Description]

Cattle farming is primarily done for two purposes: milk production and draught labour for agricultural work such as tilling, irrigation, and carting. Therefore, the correct answer is both milk production and draught labour.

Key Concept: Fresh Initiatives for Water Availability

b) Increase groundwater levels

[Solution Description]

The syllabus states that small check-dams are built to stop rainwater from flowing away, increase groundwater levels, and reduce soil erosion. Thus, the primary purpose of building small check-dams is to increase groundwater levels.

Key Concept: Storage Loss Factors, Preventive and Control Measures

a) Insects and high humidity

[Solution Description]

The problem arises due to biotic and abiotic factors. Biotic factors like insects, rodents, fungi, mites, and bacteria cause degradation in quality, discolouration, and loss in weight. Abiotic factors like inappropriate moisture and temperature also contribute to these issues. Since the grains were not cleaned or dried properly, both biotic and abiotic factors would be active in causing the observed damage.