Quick Revision Notes & Formula Sheet

Class: 8th
Subject: Social Science (Geography)
Chapter: Land, Soil, Water, Natural Vegetation and Wildlife Resources

1. Introduction to Resources

• Resource: Anything that has utility and value is a resource. Natural resources are obtained from nature and used without much modification.
• Classification of Natural Resources:
  • On the basis of Development & Use: Actual Resources and Potential Resources.
  • On the basis of Origin: Biotic (living) and Abiotic (non-living).
  • On the basis of Renewability: Renewable Resources and Non-renewable Resources.

2. Land Resources

• Land Use: Land is used for different purposes such as agriculture, forestry, mining, building houses, roads, and setting up industries.
• Factors Affecting Land Use:
  • Physical factors: Topography, soil, climate, water availability, and minerals.
  • Human factors: Population and technology.
• Private Land vs. Community Land:
  • Private Land: Owned by individuals (e.g., houses, farmland).
  • Community Land: Owned by the community for common uses like collection of fodder, fruits, nuts, or medicinal herbs (also called common property resources).
• Major Threats to Land Resources: Land degradation, landslides, soil erosion, desertification, and deforestation.
• Conservation Measures: Afforestation, land reclamation, regulated use of chemical pesticides/fertilizers, and checking overgrazing.

3. Soil Resources

• Soil: The thin layer of grainy substance covering the surface of the earth is called soil. It is closely linked to land.
• Factors of Soil Formation:
  1. Parent Rock: Determines color, texture, chemical properties, mineral content, and permeability.
  2. Climate: Temperature and rainfall influence rate of weathering and humus formation.
  3. Relief: Altitude and slope determine accumulation of soil.
  4. Flora, Fauna and Micro-organisms: Affect the rate of humus formation.
  5. Time: Determines thickness of soil profile.
• Major Threats to Soil: Soil erosion and depletion of soil fertility.
• Methods of Soil Conservation:
  • Mulching: The bare ground between plants is covered with a layer of organic matter like straw to retain soil moisture.
  • Contour Barriers: Stones, grass, soil are used to build barriers along contours. Trenches are made in front of the barriers to collect water.
  • Rock Dam: Rocks are piled up to slow down the flow of water and prevent gullies and soil loss.
  • Terrace Farming: Broad flat steps or terraces are made on steep slopes so that flat surfaces are available to grow crops, reducing surface runoff and soil erosion.
  • Inter Cropping: Different crops are grown in alternate rows and sown at different times to protect the soil from rain wash.
  • Contour Ploughing: Ploughing parallel to the contours of a hill slope to form a natural barrier for water to flow down the slope.
  • Shelter Belts: In the coastal and dry regions, rows of trees are planted to check the wind movement to protect soil cover.

4. Water Resources

• Water Availability:
  • Earth is called the 'Watery Planet' (about 3/4th of the earth's surface is covered with water).
  • 97.3% of total water is oceans (saline, unfit for human consumption).
  • Only 2.7% is freshwater. Out of this, nearly 70% occurs as ice sheets and glaciers in Antarctica, Greenland, and mountain regions (inaccessible).
  • Only 1% of freshwater is available and fit for human use (found in groundwater, rivers, lakes, and water vapor).
• Water Scarcity: Caused by increasing population, rising demand for food and cash crops, increasing urbanization, and standard of living.
• Conservation of Water Resources:
  • Treating effluents before releasing them into water bodies.
  • Rainwater harvesting.
  • Lining irrigation canals to minimize seepage losses.
  • Sprinklers and drip/trickle irrigation in dry regions.

5. Natural Vegetation and Wildlife

• Interdependence: Natural vegetation and wildlife exist only in the narrow zone of contact between the lithosphere, hydrosphere, and atmosphere called the Biosphere. In the biosphere, living beings are inter-linked and interdependent on each other for survival (Ecosystem).
• Distribution of Vegetation: Mainly grouped into Forests, Grasslands, Shrubs, and Tundra.
• Major Threats to Forests & Wildlife:
  • Deforestation, soil erosion, constructional activities, forest fires, poaching, and climate change.
  • Extinct and Endangered Species: Indiscriminate killing has led to the sharp decline of many species. Tigers, lions, elephants, black bucks, etc., are protected.
• Conservation Measures:
  • National Parks, Wildlife Sanctuaries, and Biosphere Reserves are made to protect our natural vegetation and wildlife.
  • CITES (The Convention on International Trade in Endangered Species of Wild Fauna and Flora): An international agreement between governments to ensure that international trade in specimens of wild animals and plants does not threaten their survival.
  • Social forestry, Van Mahotsav, and creating awareness among school children (like bird watching, nature camps).