CBSE Class 9 Science Chapter-12 Important Questions Improvement in Food Resources - Free PDF Download
Class 9 CBSE Science Important Questions for Chapter 12 - Improvement in Food Resources
FAQs on Class 9 CBSE Science Important Questions for Chapter 12 - Improvement in Food Resources
1. What are the main objectives behind undertaking crop variety improvement for the 2025-26 CBSE exams?
Crop variety improvement is a critical topic, and its main objectives are to develop new crop varieties with desirable traits. For your exam, focus on these key goals:
- Higher Yield: To increase the production of the crop per acre.
- Improved Quality: To enhance nutritional value, such as protein in pulses or oil in oilseeds.
- Biotic and Abiotic Resistance: To create varieties resistant to diseases, insects (biotic factors) and tolerant to drought, salinity, or heat (abiotic factors).
- Change in Maturity Duration: To develop short-duration crops that allow farmers to grow multiple crops in a year.
- Desirable Agronomic Traits: To develop characteristics like dwarfness in cereals (so they consume fewer nutrients) or tallness and profuse branching in fodder crops.
2. Differentiate between manures and fertilisers. Which is considered better for long-term soil health and why?
This is a frequently asked question. The key differences are:
- Origin: Manures are natural organic substances obtained from the decomposition of animal and plant waste. Fertilisers are commercially produced inorganic compounds.
- Nutrient Content: Manures are rich in humus but have a lower concentration of specific plant nutrients. Fertilisers are nutrient-specific and highly concentrated in nitrogen, phosphorus, and potassium (NPK).
- Soil Health: Manures add humus to the soil, improving its structure and water-holding capacity. Fertilisers do not add humus and can degrade soil health with excessive use.
3. Explain the difference between broilers and layers and their management in poultry farming.
In poultry farming, birds are raised for two primary purposes:
- Layers: These are female fowl grown specifically for egg production. Their diet is managed to promote high-quality egg laying over a long period.
- Broilers: These are birds raised for meat production. Their diet is protein-rich with adequate fat to encourage rapid growth, and they are typically ready for market in 6-8 weeks.
4. What is composite fish culture? What is the main problem in this system and how is it overcome?
Composite fish culture is a system of growing five or six different species of fish together in a single fishpond. The key principle is that these species have different food habits and do not compete for food. For instance, Catlas feed on the surface, Rohu in the middle-zone, and Mrigals at the bottom. The main problem is that most of these fish breed only during the monsoon. A major challenge is the lack of good-quality fish seed. This problem is overcome by using hormonal stimulation to induce breeding, ensuring a supply of pure fish seed in desired quantities.
5. Why are crop rotation and intercropping considered important agricultural practices for high yields?
Both are crucial cropping patterns that enhance yield and soil health:
- Intercropping: This involves growing two or more crops simultaneously in the same field in a definite pattern (like alternate rows). This ensures maximum utilisation of nutrients, prevents pests from spreading to all plants, and increases productivity per unit area. Example: Soybean + Maize.
- Crop Rotation: This is the practice of growing different crops on a piece of land in a pre-planned succession. Growing a leguminous crop after a cereal crop, for example, helps replenish soil nitrogen naturally. This practice maintains soil fertility, controls weeds and pests, and prevents soil depletion.
6. What are the desirable agronomic characteristics that scientists aim for during crop improvement?
Agronomic characteristics refer to the traits that contribute to a higher yield and easier cultivation. Important examples for your exam include:
- Tallness and profuse branching: This is a desirable trait for any fodder crop as it provides more biomass to feed livestock.
- Dwarfness: This is a desirable trait for cereal crops (like wheat and rice). Shorter plants are stronger, can withstand strong winds, and consume fewer nutrients, allowing more resources to be diverted to grain production.
7. Why is animal husbandry essential for Indian farmers, and what are its two main components?
Animal husbandry is the scientific management of animal livestock. It is crucial for Indian farmers as it provides a secondary source of income and integrates with farming operations. Its two main components are:
- Cattle Farming: This is done for two purposes: obtaining milk from dairy animals (milch animals like cows and buffaloes) and for farm labour like tilling and carting (draught animals like bullocks).
- Poultry Farming: This involves raising domesticated fowl for the production of eggs and meat, which provides a quick return on investment for farmers.
8. What is green manure and how is it prepared? Provide two examples of plants used for it.
Green manure is an organic fertiliser created by growing specific plants and then ploughing them into the soil while they are still green. This process enriches the soil with nitrogen and phosphorus. The preparation involves:
- Cultivating fast-growing plants like Sunn hemp or Guar (cluster bean) before planting the main crop.
- Before these plants start to flower, they are ploughed and mixed into the soil.
- They then decompose in the soil, releasing valuable organic matter and nutrients.
9. What are the biotic and abiotic factors responsible for the loss of stored grains? How can they be prevented?
Losses of stored grains are a major concern. The factors responsible are:
- Biotic Factors: These are living organisms like insects, rodents, fungi, and bacteria that damage the grains.
- Abiotic Factors: These are non-living factors like improper moisture levels and unsuitable temperatures in the storage area, which encourage the growth of pests and moulds.
10. How does genetic manipulation contribute to agricultural improvement? Explain with an example.
Genetic manipulation is a technique where the genes of a plant are altered to introduce desirable characteristics. This results in genetically modified crops (GMCs). Its primary contribution to agriculture is creating varieties with:
- High yields
- Improved nutritional quality
- Resistance to pests and diseases
- Tolerance to environmental stress like drought or salinity
11. Why is beekeeping or apiculture considered a low-investment, high-return activity for farmers?
Beekeeping (apiculture) is highly beneficial for farmers for several reasons:
- Low Investment: It does not require large areas of land and has relatively low setup costs.
- Additional Income: It provides farmers with valuable products like honey, which has high market demand. Other products include beeswax, royal jelly, and bee venom.
- Crop Yield Improvement: Bees are excellent pollinators. Having beehives in or near a farm significantly increases the pollination of surrounding crops, leading to better yields, especially in fruits and certain vegetables. The quality of honey also depends on the flowers available for nectar collection, known as the pasturage.

















