Class 9 Science Notes Chapter 16 (Chapter 16) – Examplar Problem (English) Book
Alright class, let's focus on Chapter 16, 'Improvement in Food Resources'. This chapter is crucial not just for your school exams but also forms a base for various government exams, as it deals with fundamental aspects of agriculture and animal husbandry which are vital for our country. We'll break down the key concepts systematically.
Chapter 16: Improvement in Food Resources - Detailed Notes
1. Introduction: Why Improve Food Resources?
- Need: India's population is constantly growing, requiring more food production from limited, and sometimes decreasing, arable land.
- Objective: To increase the efficiency of crop and livestock production to meet the rising demand for food grains, vegetables, fruits, milk, eggs, meat, etc.
- Historical Context:
- Green Revolution: Focused on significantly increasing the production of food grains (especially wheat and rice) through the use of High Yielding Varieties (HYVs), fertilizers, pesticides, and improved irrigation.
- White Revolution: Aimed at increasing milk production (Operation Flood) through better management of dairy animals and cooperative systems.
2. Improvement in Crop Yields
This involves three main scientific approaches:
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(A) Crop Variety Improvement:
- Goal: To develop crop varieties with desirable traits.
- Methods:
- Hybridisation: Crossing genetically dissimilar plants to obtain offspring (hybrids) with combined desirable characters.
- Intervarietal: Between different varieties of the same species.
- Interspecific: Between different species of the same genus.
- Intergeneric: Between different genera.
- Genetic Modification (GM): Introducing a gene that provides a desired characteristic, resulting in Genetically Modified Crops (GMCs). Example: Bt Cotton (resistance to bollworm).
- Hybridisation: Crossing genetically dissimilar plants to obtain offspring (hybrids) with combined desirable characters.
- Desirable Agronomic Traits for Selection:
- Higher Yield: Increased productivity per acre.
- Improved Quality: Varies with crop (e.g., protein quality in pulses, oil quality in oilseeds, baking quality in wheat, preserving quality in fruits/vegetables).
- Biotic Resistance: Resistance to diseases (caused by fungi, bacteria, viruses), insects, and nematodes.
- Abiotic Resistance: Tolerance to stress conditions like drought, salinity, waterlogging, heat, cold, and frost.
- Change in Maturity Duration: Shorter duration allows multiple rounds of cropping per year, reducing overall costs.
- Wider Adaptability: Ability to grow well under different environmental conditions (soils, climates).
- Desirable Agronomic Characteristics: Tallness and profuse branching for fodder crops; dwarfness for cereal crops (less nutrient consumption, prevents lodging).
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(B) Crop Production Management:
- Involves managing the resources and practices during cultivation to maximize yield. Depends on financial conditions (input capacity) – leading to 'no cost', 'low cost', or 'high cost' production practices.
- Nutrient Management: Plants require nutrients for growth, supplied by air (Carbon, Oxygen), water (Hydrogen, Oxygen), and soil (remaining 13 nutrients).
- Macronutrients (Required in large quantities): Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), Sulphur (S).
- Micronutrients (Required in small quantities): Iron (Fe), Manganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), Molybdenum (Mo), Chlorine (Cl).
- Sources of Nutrients:
- Manures: Decomposed animal excreta and plant waste. Rich in organic matter, improves soil structure and water retention. Supply small quantities of nutrients slowly. Types:
- Farmyard Manure (FYM): Cattle dung, urine, litter.
- Compost: Decomposed farm/domestic waste in pits. Vermi-compost uses earthworms for faster decomposition.
- Green Manure: Growing and then mulching fast-growing plants (like sunn hemp, guar) into the soil before sowing the main crop; enriches soil with nitrogen and phosphorus.
- Fertilizers: Commercially produced plant nutrients. Supply specific nutrients (N, P, K) in high concentrations. Ensure quick availability but can cause water pollution (eutrophication) if used excessively and harm soil microbes/structure over long term. Examples: Urea (N), DAP (Diammonium Phosphate - N, P), Superphosphate (P), Potash (K).
- Organic Farming: Farming system with minimal or no use of chemicals (fertilizers, herbicides, pesticides). Employs organic manures, recycled farm wastes, bio-agents (for pest control), healthy cropping systems (mixed cropping, intercropping, crop rotation).
- Manures: Decomposed animal excreta and plant waste. Rich in organic matter, improves soil structure and water retention. Supply small quantities of nutrients slowly. Types:
- Irrigation: Artificial supply of water to crops.
- Need: Essential for plant growth, nutrient absorption, germination. Crucial in areas with inadequate or irregular rainfall.
- Sources: Wells (Dug wells, Tube wells), Canals (from rivers/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: Methods to maximize yield and minimize risk from the same piece of land.
- Mixed Cropping: Growing two or more crops simultaneously on the same land (e.g., Wheat + Gram, Groundnut + Sunflower). Reduces risk of total crop failure; insurance against drought/pest attack on one crop. Seeds are mixed before sowing.
- Intercropping: Growing two or more crops simultaneously in the same field in definite row patterns (e.g., 2 rows Soyabean + 1 row Maize). Prevents pests/diseases from spreading easily; ensures better use of resources (nutrients, light, water) as crops often have different needs. Facilitates specific fertilizer/pesticide application.
- Crop Rotation: Growing different crops on a piece of land in a pre-planned succession. Helps control pests, weeds, and diseases specific to one crop; improves soil fertility (especially if legumes are included, as they fix atmospheric nitrogen). Duration depends on the crops (e.g., Maize - Potato - Sugarcane).
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(C) Crop Protection Management: Protecting crops from threats during growth and after harvest.
- Threats during Growth:
- Weeds: Unwanted plants competing for nutrients, light, space (e.g., Xanthium (Gokhroo), Parthenium (Congress grass), Cyperinus rotundus (Motha)). Methods: Mechanical removal (uprooting, tilling), Chemical control (Herbicides like 2,4-D), Biological control (using insects/organisms that feed on weeds), Proper seed bed preparation, Intercropping, Crop rotation.
- Insect Pests: Damage crops by cutting (root, stem, leaf), sucking cell sap, boring into stems/fruits. Methods: Pesticides (insecticides - can be harmful), Resistant varieties, Summer ploughing, Biological control (predators/parasites of pests).
- Diseases: Caused by pathogens (bacteria, fungi, viruses). Transmitted through soil, water, air, seed. Methods: Fungicides, Bactericides, Resistant varieties, Seed treatment.
- Storage of Grains: Protecting harvested produce from losses.
- Loss Factors:
- Biotic: Insects, Rodents, Fungi, Mites, Bacteria.
- Abiotic: Inappropriate moisture content, Temperature fluctuations.
- Effects: Degradation in quality, weight loss, poor germinability, discolouration, market value reduction.
- Preventive Measures: Proper cleaning of produce before storage, thorough drying (reducing moisture content, especially in sunlight), Fumigation (using chemicals like Aluminium Phosphide to kill pests in storage structures), use of gunny bags, metallic bins, silos, granaries with controlled atmosphere and temperature.
- Loss Factors:
- Threats during Growth:
3. Animal Husbandry
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Scientific management of livestock. Includes feeding, breeding, shelter, and disease control.
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(A) Cattle Farming:
- Purposes: Milk production (Milch animals/Dairy animals) and Farm labour (Draught animals - for ploughing, irrigation, carting).
- Breeds:
- Indigenous (Desi): Good disease resistance. Examples: Red Sindhi, Sahiwal (good milch breeds).
- Exotic (Foreign): Long lactation periods. Examples: Jersey, Brown Swiss.
- Cross Breeding: Crossing exotic and indigenous breeds to get offspring with desired qualities (e.g., high milk yield + disease resistance + acclimatization).
- Management:
- Shelter: Well-ventilated roofed sheds, protected from rain, heat, cold. Cleanliness is vital. Sloping floors for easy cleaning.
- Food: Balanced ration containing:
- Roughage: Mainly fibre (e.g., fodder, legumes like berseem, oats).
- Concentrates: Low fibre, high protein and other nutrients (e.g., cotton seeds, oil cakes, grain). Food supplements (minerals, vitamins).
- Disease Control: Protection from parasites (external - ticks, mites; internal - worms). Vaccination against viral and bacterial diseases (e.g., Foot and Mouth Disease, Anthrax). Regular cleaning, isolation of sick animals.
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(B) Poultry Farming: Rearing domestic fowl for egg and meat production.
- Types: Layers (for eggs), Broilers (for meat).
- Breed Improvement: Cross-breeding indigenous (Aseel) and exotic (Leghorn) breeds to develop varieties with desirable traits: number/quality of chicks, dwarf broilers (less feed), summer adaptation, low maintenance, high egg/meat production.
- Management:
- Housing & Temperature: Proper sanitation, ventilation, temperature regulation crucial for high production.
- Feed: Broilers need protein-rich feed with adequate fat, vitamins A & K. Layers require specific nutrients for egg production.
- Disease Prevention: Vaccination against viral/bacterial diseases (e.g., Ranikhet disease), sanitation, spraying disinfectants.
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(C) Fish Production (Pisciculture): Important source of animal protein.
- Sources:
- Marine Fisheries: Catching fish from seas and oceans.
- Capture Fishing: Using fishing nets from boats. Common coastal fish: Pomfret, Mackerel, Tuna, Sardines, Bombay Duck. High-value fish (Mullets, Bhetki, Pearl spots), shellfish (Prawns, Mussels, Oysters - also farmed via Mariculture), and seaweed are also harvested. Modern methods use echo-sounders and satellites to locate fish schools.
- Inland Fisheries: Catching fish from freshwater (rivers, canals, ponds, lakes) and brackish water (estuaries, lagoons) resources. Yield is generally lower than marine fisheries.
- Aquaculture: Farming of fish under controlled conditions. Pisciculture specifically refers to fish farming.
- Marine Fisheries: Catching fish from seas and oceans.
- Composite Fish Culture: Intensive farming of 5-6 compatible fish species with different food habits in a single pond. Ensures full utilization of food resources at different levels of the pond, increasing overall yield.
- Species Example:
- Surface feeders: Catla
- Middle-zone feeders: Rohu
- Bottom feeders: Mrigal, Common Carp
- Weed feeders: Grass Carp
- Challenge: Lack of good quality seed (fish eggs/larvae) of all species at the same time. Hormonal stimulation is now used for synchronised breeding.
- Species Example:
- Sources:
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(D) Bee-keeping (Apiculture): Rearing honeybees for honey and wax.
- Importance: Honey is widely used (nutritional, medicinal value). Beeswax used in cosmetics, polishes. Bees are also important pollinators for many crops (e.g., sunflower, brassica, apple, pear). Requires low investment.
- Bee Varieties Used:
- Indigenous: Apis cerana indica (Indian bee), Apis dorsata (Rock bee - difficult to domesticate), Apis florae (Little bee).
- Exotic: Apis mellifera (Italian bee) - commonly used commercially due to high honey collection capacity, prolific breeding, less stinging nature, ability to stay in beehives longer.
- Pasturage: The availability and quality of flowers/nectar for bees. Influences the quantity and taste of honey. Apiaries (bee farms) are often set up near orchards or fields with flowering plants.
Multiple Choice Questions (MCQs)
-
Which of the following is a micronutrient required by plants?
(a) Nitrogen
(b) Phosphorus
(c) Potassium
(d) Zinc -
Growing wheat and gram together in the same field without a definite row pattern is an example of:
(a) Intercropping
(b) Crop Rotation
(c) Mixed Cropping
(d) Organic Farming -
Parthenium is an example of a:
(a) Fungal disease
(b) Insect pest
(c) Weed
(d) Bacterial disease -
Which of the following is an exotic breed of cattle known for its long lactation period?
(a) Sahiwal
(b) Red Sindhi
(c) Jersey
(d) Aseel -
The practice of farming fish like Catla, Rohu, and Mrigal together in a pond is called:
(a) Mariculture
(b) Aquaculture
(c) Capture Fishing
(d) Composite Fish Culture -
Vermi-compost is prepared using:
(a) Fungi
(b) Bacteria
(c) Earthworms
(d) Farmyard waste only -
Which revolution is associated with a significant increase in milk production in India?
(a) Green Revolution
(b) White Revolution
(c) Blue Revolution
(d) Golden Revolution -
Broilers in poultry farming are primarily raised for:
(a) Egg production
(b) Meat production
(c) Draught purposes
(d) Manure production -
Apis mellifera is preferred in commercial apiculture mainly because it:
(a) Is an indigenous Indian bee
(b) Stings very frequently
(c) Has a high honey collection capacity and is gentle
(d) Primarily produces beeswax -
Abiotic factors responsible for losses during grain storage include:
(a) Insects and rodents
(b) Fungi and bacteria
(c) Inappropriate moisture and temperature
(d) Weeds and nematodes
Answer Key for MCQs:
- (d) Zinc
- (c) Mixed Cropping
- (c) Weed
- (c) Jersey
- (d) Composite Fish Culture
- (c) Earthworms
- (b) White Revolution
- (b) Meat production
- (c) Has a high honey collection capacity and is gentle
- (c) Inappropriate moisture and temperature
Make sure you understand the 'why' behind each concept and practice applying these ideas. This chapter connects biology with practical applications vital for our food security. Good luck with your preparation!