Class 9 Science Chapter 13: Improvement in Food Resources

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Chapter 13: Improvement in Food Resources

The core idea of this chapter is to understand how we can increase the production of food (from both plants and animals) using scientific methods and sustainable practices to feed our growing population.

Part 1: Improvement in Crop Yields

Crops are plants of the same kind cultivated on a large scale. They are classified based on the season and the product they provide.

A. Types of Crops:

1. Based on Season:
   • Kharif Crops: Grown in the rainy season (June to October). Example: Paddy, Soybean, Maize, Cotton.
   • Rabi Crops: Grown in the winter season (November to April). Example: Wheat, Gram, Mustard, Pea.
2. Based on Product:
   • Cereals: Provide carbohydrates (Wheat, Rice, Maize).
   • Pulses: Provide proteins (Gram, Pea, Lentil).
   • Oil Seeds: Provide fats (Mustard, Groundnut, Soybean).
   • Vegetables, Fruits & Spices: Provide vitamins and minerals.

B. Practices for Improving Crop Yield (Crop Production Management):

1. Nutrient Management (Fertilisers & Manures):
   • Manure: Organic substance obtained from the decomposition of plant or animal waste. It is bulky, less rich in nutrients, but improves soil texture and fertility.
   • Fertiliser: Inorganic, commercially produced chemicals rich in specific nutrients (N, P, K). They are nutrient-specific but can make the soil barren if used excessively.
   • Organic Farming: A farming system with no or minimal use of chemicals like fertilisers and pesticides.
2. Irrigation: Supplying water to crops.
   • Sources: Wells, tubewells, ponds, lakes, rivers, dams, canals.
   • Methods: Traditional (moat, chain pump, dhekli) and modern (sprinklers, drip system – highly efficient for water conservation).
3. Cropping Patterns:
   • Mixed Cropping: Growing two or more crops simultaneously on the same piece of land (e.g., Wheat + Gram). Reduces risk of crop failure.
   • Inter-cropping: Growing two or more crops simultaneously in a definite row pattern (e.g., Soybean + Maize). Maximises resource use.
   • Crop Rotation: Growing different crops on a piece of land in a pre-planned succession. Helps in soil fertility management.

C. Crop Protection Management:

• Weeds: Unwanted plants that compete with the crop for resources. Control: Mechanical removal, use of weedicides (2,4-D).
• Pests: Insects, rodents, etc., that can damage crops. Control: Pesticides, biological controls.
• Diseases: Caused by pathogens like fungi, bacteria, viruses. Control: Use of disease-resistant varieties, fungicides, etc.

D. Storage of Grains:
Grains must be stored properly to protect them from:

• Biotic factors: Insects, rodents, fungi, mites, bacteria.
• Abiotic factors: Inappropriate moisture (needs drying) and temperature.
• Methods: Storage in jute bags or metal bins. Large-scale storage in silos and granaries with strict chemical fumigation.

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Part 2: Animal Husbandry

The scientific management of animal livestock for their food, shelter, health, and breeding.

A. Cattle Farming: Done for milk (dairy) and draught labour (farming work).

• Breeds:
  • Milch Breeds (High milk-yielding): e.g., Gir, Sahiwal.
  • Draught Breeds (Good for labour): e.g., Malvi, Nageri.
• Animal Health: Diseases can be due to bacteria, viruses, fungi, or parasites. Proper shelter (clean, spacious, dry, ventilated) and vaccination are crucial.

B. Poultry Farming: Rearing of domestic fowl for eggs and meat.

• Importance: Provides high-protein food. Improved by cross-breeding indigenous (e.g., Aseel) with exotic (e.g., Leghorn) varieties to develop breeds that are disease-resistant and have better egg/meat yield.

C. Fish Production (Fisheries):

• Finned Fish (True Fish): e.g., Catla, Rohu, Mrigala, Salmon.
• Shellfish: e.g., Prawns, Mussels, Oysters (valued for their meat).
• Types:
  • Capture Fishing: Catching fish from natural resources (sea, rivers).
  • Culture Fishing: Fish farming (aquaculture). Marine Fisheries: Culture of fish in seawater (e.g., prawns, mussels). Inland Fisheries: Culture of fish in freshwater (canals, ponds, reservoirs) and brackish water (estuaries).

D. Bee-Keeping (Apiculture): Rearing of honey bees for honey and wax.

• Importance: Honey has medicinal value, and bees are important pollinators.
• Common Indian Breeds: Apis cerana indica (Indian bee), Apis mellifera (Italian bee – most commonly used for commercial honey production).

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Important Questions & Answers

Very Short Answer Type Questions (1 Mark)

1. What are macronutrients?
   • Answer: Nutrients required by plants in large quantities. Example: Nitrogen, Phosphorus, Potassium, Calcium, etc.
2. Name two kharif crops.
   • Answer: Paddy (Rice) and Cotton.
3. What is the advantage of inter-cropping?
   • Answer: It helps to maximise the use of nutrients, water, and space, prevents pest spread, and reduces the risk of total crop failure.
4. Give one example of a milch breed of cattle.
   • Answer: Sahiwal or Gir.
5. Which species of honey bee is commonly used for commercial honey production?
   • Answer: Apis mellifera (Italian bee).

Short Answer Type Questions (2-3 Marks)

1. Differentiate between manure and fertiliser.
   • Answer:
     Manure Fertiliser
     Organic substance Inorganic salt
     Prepared by decomposition Commercially produced
     Less rich in nutrients Rich in specific nutrients (N, P, K)
     Improves soil texture Does not improve soil texture
     Environmentally friendly Causes water pollution if overused What are the advantages of composite fish culture? Answer: In this system, both local and imported fish species are cultured together in the same pond. Their food habits are different; some are surface feeders, some are middle-zone feeders, and some are bottom feeders. This ensures no competition for food and complete utilization of the pond’s resources, leading to a much higher fish yield. Why should preventive measures and biological control methods be preferred for protecting crops? Answer: Chemical pesticides and insecticides are toxic and poisonous. They can: Pollute soil and water. Kill useful microorganisms and insects. Harm consumers by leaving residues on crops.
     Biological control methods are specific, eco-friendly, and do not leave any harmful residues. Long Answer Type Questions (5 Marks)
     1. What are the different sources of irrigation? Also, explain two modern methods of irrigation that help in water conservation.
        • Answer: Sources of Irrigation: Wells, Tubewells, Ponds, Lakes, Rivers, Dams, Canals. Modern Methods:
          • Sprinkler System: A system of perpendicular pipes with rotating nozzles on top is connected to a main pipeline. Water flows through the main pipe under pressure and escapes from the nozzles, sprinkling water like rain. It is very useful for uneven land and sandy soil where water percolates quickly.
          • Drip System: In this system, water falls drop by drop directly near the roots of the plants. It is the most efficient method of irrigation as there is no wastage of water at all through evaporation or runoff. It is best suited for fruit plants, gardens, and trees.
     2. Discuss the role of hybridisation in improving poultry and cattle livestock.
        • Answer: Hybridisation refers to crossing between genetically dissimilar plants or animals to produce offspring (hybrids) with desirable traits.
          • In Poultry Farming: Indigenous breeds (like Aseel) are disease-resistant but lay fewer eggs. They are cross-bred with exotic breeds (like Leghorn) which are high egg-yielding. The resulting hybrids have desirable traits like (a) Number and quality of chicks, (b) Dwarf broilers for meat, (c) Low maintenance requirements, (d) Tolerance to high temperatures, and (e) Reduction in the size of the egg-laying bird.
          • In Cattle Farming: Cross-breeding between Indian (e.g., Sahiwal) and foreign (e.g., Jersey, Brown Swiss) breeds has resulted in varieties that have high milk-yielding potential and resistance to diseases.
     Quick Revision Mind-Map / Flowchart
     • Improvement in Food Resources
       • Crop Production
         • → Types (Kharif/Rabi, Cereals/Pulses)
         • → Practices (Nutrient Mgmt. – Manure/Fertiliser; Irrigation; Cropping Patterns – Mixed/Inter/Rotation)
         • → Protection (Weeds, Pests, Diseases)
         • → Storage (Drying, Fumigation)
       • Animal Husbandry
         • → Cattle Farming (Milch/Draught Breeds, Shelter, Disease)
         • → Poultry Farming (Cross-breeding for better yield)
         • → Fish Production (Capture/Culture, Marine/Inland)
         • → Bee-Keeping (Honey, Wax, Pollination)
     Good luck with your exams! Focus on understanding the concepts and the why behind each practice.