Class 9 Science Notes Chapter 15 (Chapter 15) – Examplar Problem (English) Book

Alright class, let's focus on Chapter 15, 'Improvement in Food Resources'. This is a crucial chapter, not just for your exams but also for understanding how we sustain our large population. We'll break down the key concepts methodically.

Chapter 15: Improvement in Food Resources - Detailed Notes

1. Introduction: Why Improve Food Resources?

• Growing Population: India's population is continuously increasing, leading to a higher demand for food grains, vegetables, fruits, milk, eggs, meat, etc.
• Limited Land: Land available for cultivation is limited and, in some cases, decreasing due to urbanization and industrialization.
• Need for Increased Efficiency: To meet the growing demand from limited land, we need to increase the efficiency of crop and livestock production. Past efforts like the Green Revolution (increasing food grain production) and White Revolution (increasing milk production) highlight this need.

2. Improvement in Crop Yields

This involves three main stages:
a) Crop Variety Improvement
b) Crop Production Management
c) Crop Protection Management

(a) Crop Variety Improvement:

• Goal: To develop crop varieties with desirable traits.
• Desirable Agronomic Traits:
  • Higher Yield: Increase productivity per acre.
  • Improved Quality: Quality considerations vary (e.g., protein in pulses, oil in oilseeds, preserving quality in fruits/vegetables, baking quality in wheat).
  • Biotic Resistance: Resistance to diseases (caused by fungi, bacteria, viruses), insects, and nematodes.
  • Abiotic Resistance: Tolerance to stresses like drought, salinity, waterlogging, heat, cold, frost.
  • Change in Maturity Duration: Shorter duration allows farmers to grow multiple crops per year (multi-cropping), reducing costs.
  • Wider Adaptability: Ability to grow well under different environmental conditions (soils, climates).
  • Desirable Agronomic Characteristics: Traits like tallness and profuse branching for fodder crops, dwarfness for cereals (less nutrient consumption).
• Methods:
  • Hybridisation: Crossing genetically dissimilar plants.
    • Intervarietal: Between different varieties of the same species.
    • Interspecific: Between different species of the same genus.
    • Intergeneric: Between different genera.
  • Genetic Modification: Introducing a gene that provides the desired characteristic, resulting in Genetically Modified (GM) crops (e.g., Bt Cotton).

(b) Crop Production Management:

• Goal: To ensure optimal conditions for crop growth and yield. This depends on financial conditions (input capacity) and farming practices. Practices include 'no cost', 'low cost', or 'high cost' production.
• Nutrient Management:
  • Plants require nutrients for growth, supplied by air (Carbon, Oxygen), water (Hydrogen, Oxygen), and soil (remaining 13 nutrients).
  • Macronutrients (Required in large quantity): Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulphur (S).
  • Micronutrients (Required in small quantity): Iron (Fe), Manganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), Molybdenum (Mo), Chlorine (Cl).
  • Sources of Nutrients:
    • Manure: Decomposed animal excreta and plant waste.
      • Types: Farmyard Manure (FYM), Compost (including Vermi-compost - using earthworms), Green Manure (growing and mulching leguminous plants like sun hemp or guar).
      • Advantages: Adds organic matter (humus) improving soil structure and water retention, provides nutrients slowly, recycles farm waste, avoids pollution.
      • Disadvantages: Bulky, low concentration of specific nutrients.
    • Fertilisers: Commercially produced plant nutrients (N, P, K).
      • Advantages: Nutrient-specific, concentrated, easy to transport and apply, ensure high yields in intensive farming.
      • Disadvantages: Expensive, cause water pollution (eutrophication) if used excessively, can harm soil microorganisms and structure over long term.
    • Organic Farming: Farming system with minimal or no use of chemicals (fertilisers, herbicides, pesticides). Uses organic manures, recycled farm wastes, bio-agents (for pest control), healthy cropping systems.
• Irrigation: Supplying water to crops.
  • Need: Essential for plant growth, nutrient absorption, dealing with insufficient or untimely rainfall.
  • Sources: Wells (Dug wells, Tube wells), Canals (from rivers or reservoirs), River Lift Systems (drawing water directly from rivers), Tanks (small storage reservoirs). Rainwater harvesting and watershed management increase groundwater levels.
  • Modern Methods (Water-Efficient): Sprinkler system, Drip system.
• Cropping Patterns: Ways to maximize yield and minimize risk.
  • Mixed Cropping: Growing two or more crops simultaneously on the same land (e.g., Wheat + Gram, Groundnut + Sunflower). Advantage: Reduces risk of total crop failure.
  • Intercropping: Growing two or more crops simultaneously in a definite row pattern (e.g., Soyabean + Maize, Finger millet + Cowpea). Advantages: Prevents pest/disease spread, better use of resources (nutrients, light, water).
  • Crop Rotation: Growing different crops on a piece of land in a pre-planned succession. Often includes a legume crop to replenish soil nitrogen. Advantages: Controls pests and weeds, improves soil fertility, reduces fertilizer need. Choice depends on moisture, irrigation, duration.

(c) Crop Protection Management:

• Goal: Protecting crops from weeds, insect pests, and diseases.
• Weeds: Unwanted plants in the cultivated field (e.g., Xanthium (Gokhroo), Parthenium (Gajar ghas), Cyperinus rotundus (Motha)). They compete for food, space, and light.
  • Control Methods: Mechanical removal (uprooting, tilling), Preventive methods (proper seed bed preparation, timely sowing), Chemical control (herbicides/weedicides like 2,4-D), Biological control (using insects/organisms that feed on weeds).
• Insect Pests: Attack plants in three ways: cut root/stem/leaf, suck cell sap, bore into stem/fruits.
  • Control Methods: Using resistant varieties, summer ploughing (destroys eggs/pupae), pesticides (insecticides, herbicides, fungicides - but can be toxic), biological control.
• Diseases: Caused by pathogens like bacteria, fungi, and viruses. Transmitted via soil, water, air, insects.
  • Control Methods: Using resistant varieties, seed treatment, fungicides/bactericides, proper sanitation.
• Storage of Grains: Losses during storage can be high.
  • Factors Causing Loss:
    • Biotic: Insects, rodents, fungi, mites, bacteria.
    • Abiotic: Inappropriate moisture content, temperature.
  • Effects of Damage: Degradation in quality, loss in weight, poor germinability, discolouration, reduced market value.
  • Preventive Measures: Cleaning produce before storage, proper drying (reducing moisture), fumigation (using chemicals to kill pests), use of appropriate storage structures (gunny bags, granaries, silos).

3. Animal Husbandry

• The scientific management of livestock. Includes feeding, breeding, and disease control.
• Purposes: Milk, eggs, meat, fish, agricultural work (draught animals).

(a) Cattle Farming:

• Purposes: Milk production (dairy animals/milch animals) and farm labour (draught animals).
• Species: Bos indicus (cows), Bos bubalis (buffaloes).
• Breeds:
  • Indian Milch Breeds: Red Sindhi, Sahiwal (show resistance to diseases).
  • Exotic Milch Breeds: Jersey, Brown Swiss (long lactation periods).
  • Draught Breeds: Vary regionally.
• Cross Breeding: Indigenous breeds (e.g., Red Sindhi) crossed with exotic breeds (e.g., Brown Swiss) to get offspring with both high milk yield and disease resistance.
• Management:
  • Shelter: Well-ventilated, roofed shelters protecting from rain, heat, cold. Clean flooring.
  • Feeding: Balanced rations containing roughage (fibre, e.g., fodder, legumes) and concentrates (low fibre, high protein/nutrients, e.g., cotton seeds, oil cakes, grains). Feed additives (micronutrients, vitamins) promote health and milk output.
  • Health: Protection from diseases caused by parasites (external/internal) and infectious agents (bacteria, viruses). Vaccination against major viral and bacterial diseases.

(b) Poultry Farming:

• Rearing domestic fowl for egg production and chicken meat.
• Breeds:
  • Indigenous: Aseel.
  • Improved/Exotic: Leghorn (common layer).
• Cross Breeding: Done to develop varieties with desirable traits:
  • Number and quality of chicks.
  • Dwarf broiler parent (for commercial chick production, reduces feeding cost).
  • Summer adaptation/tolerance to high temperature.
  • Low maintenance requirements.
  • High egg and meat production.
• Egg Layers vs. Broilers:
  • Layers: Reared for egg production.
  • Broilers: Reared for meat production. Fed protein-rich diets with adequate fat, Vitamin A & K levels kept high.
• Management:
  • Housing & Temperature: Proper sanitation, hygiene, temperature control.
  • Feed: Balanced diet appropriate for growth (broilers) or egg production (layers).
  • Disease Prevention: Cleaning, spraying disinfectants, vaccination against viral/bacterial diseases.

(c) Fish Production (Pisciculture/Aquaculture):

• An inexpensive source of animal protein.
• Methods:
  • Capture Fishing: Harvesting fish from natural resources (marine and inland).
    • Marine Fisheries: Seas and oceans. Popular varieties: Pomfret, Mackerel, Tuna, Sardines, Bombay duck. Caught using fishing nets from boats. Echo-sounders and satellites help locate large schools. Over-exploitation is a risk.
    • Mariculture: Culturing marine fish (e.g., Mullets, Bhetki, Pearl spots), shellfish (Prawns, Mussels), and Oysters (for pearls) in coastal waters/estuaries.
    • Inland Fisheries: Rivers, canals, ponds, lakes, reservoirs (freshwater) and estuaries, lagoons (brackish water). Yield is generally lower than marine capture.
  • Culture Fishing (Aquaculture): Farming fish in controlled environments (ponds, tanks).
    • Composite Fish Culture: Rearing 5-6 different fish species together in a single pond.
      • Species Selection: Based on different food habits to utilize all food sources in the pond without competition.
        • Surface feeders: Catla
        • Middle-zone feeders: Rohu
        • Bottom feeders: Mrigal, Common Carp
        • Weed feeders: Grass Carp
      • Advantages: High yield, full resource utilisation.
      • Problem: Lack of availability of good quality fish seed (eggs/spawn) of desired species, as many species breed only during monsoon.
      • Solution: Hormonal stimulation (using pituitary extracts) to induce breeding ("induced breeding") for pure fish seed supply.

(d) Bee-keeping (Apiculture):

• Rearing bees for honey and beeswax.
• Importance: Honey is widely used (nutritional, medicinal value). Beeswax used in cosmetics, polishes. Bees are important pollinators. Requires low investment, provides additional income.
• Bee Varieties:
  • Indian: Apis cerana indica (Indian bee), A. dorsata (Rock bee - difficult to domesticate), A. florae (Little bee).
  • Exotic: Apis mellifera (Italian bee) - commonly used for commercial honey production.
• Advantages of Apis mellifera: High honey collection capacity, sting relatively less, stay in a given beehive for long periods, breed very well.
• Pasturage (Flora): The availability of flowers from which bees collect nectar and pollen. Quality and taste of honey depend on the pasturage available (e.g., almond honey, sunflower honey). Apiaries (bee farms) are established near abundant flora.

Multiple Choice Questions (MCQs)

1. Which of the following is NOT a macronutrient required by plants?
   (a) Nitrogen
   (b) Phosphorus
   (c) Iron
   (d) Potassium

2. Growing two or more crops simultaneously on the same field in a definite row pattern is known as:
   (a) Mixed cropping
   (b) Intercropping
   (c) Crop rotation
   (d) Monoculture

3. Xanthium and Parthenium are common examples of:
   (a) Insect pests
   (b) Fungal diseases
   (c) Weeds
   (d) Bacterial diseases

4. Which exotic breed of cattle is known for its long lactation period?
   (a) Sahiwal
   (b) Red Sindhi
   (c) Jersey
   (d) Aseel

5. Broilers in poultry farming are primarily raised for:
   (a) Egg production
   (b) Meat production
   (c) Draught purposes
   (d) Manure production

6. Which of the following is a surface feeder fish used in composite fish culture?
   (a) Rohu
   (b) Mrigal
   (c) Common Carp
   (d) Catla

7. The process of crossing genetically dissimilar plants to obtain improved varieties is called:
   (a) Grafting
   (b) Layering
   (c) Hybridisation
   (d) Organic farming

8. Vermi-compost is prepared using:
   (a) Fungi
   (b) Bacteria
   (c) Earthworms
   (d) Farm yard waste only

9. Which revolution is associated with a significant increase in milk production?
   (a) Green Revolution
   (b) White Revolution
   (c) Blue Revolution
   (d) Golden Revolution

10. The Italian bee variety, Apis mellifera, is preferred in apiculture mainly because of its:
    (a) Aggressive stinging behavior
    (b) Low honey collection capacity
    (c) Ability to swarm frequently
    (d) High honey collection and good breeding capacity

Answer Key:

1. (c) Iron (It's a micronutrient)
2. (b) Intercropping
3. (c) Weeds
4. (c) Jersey
5. (b) Meat production
6. (d) Catla
7. (c) Hybridisation
8. (c) Earthworms
9. (b) White Revolution
10. (d) High honey collection and good breeding capacity

Make sure you understand the 'why' behind each concept – why hybridisation is done, why nutrient management is essential, the pros and cons of fertilisers vs. manure, the logic behind composite fish culture, etc. This understanding is key for tackling application-based questions in exams. Let me know if any part needs further clarification!