Class 8 Social Science Notes Chapter 2 (Land; Soil; Water; Natural Vegetation and Wildlife Resources) – Resource and Development (Geography) Book

Alright class, let's focus on Chapter 2: 'Land, Soil, Water, Natural Vegetation and Wildlife Resources'. This chapter is crucial as it deals with the fundamental resources that support life and development. Understanding these resources, their distribution, importance, and conservation is vital, not just for your exams but also for responsible citizenship. We will break down each resource systematically.

Chapter 2: Land, Soil, Water, Natural Vegetation and Wildlife Resources - Detailed Notes

1. Land Resources

• Importance: Land is among the most critical natural resources. It covers only about 30% of the total area of the Earth's surface. Not all parts of this small percentage are habitable.
• Uneven Population Distribution: The uneven distribution of population globally is mainly due to varied characteristics of land and climate.
  • Sparsely Populated/Uninhabited Areas: Rugged topography, steep slopes, low-lying areas susceptible to water-logging, desert areas, and thickly forested areas.
  • Densely Populated Areas: Plains and river valleys offering suitable land for agriculture.
• Land Use: Land is used for various purposes such as:
  • Agriculture
  • Forestry
  • Mining
  • Building houses, roads
  • Setting up industries
  • This is commonly termed Land Use.
• Factors Determining Land Use:
  • Physical Factors: Topography, soil, climate, minerals, availability of water.
  • Human Factors: Population density, technological capability, cultural traditions.
• Classification of Land (Based on Ownership):
  • Private Land: Owned by individuals.
  • Community Land: Owned by the community for common uses like collection of fodder, fruits, nuts, or medicinal herbs. These are also called Common Property Resources (CPR).
• Land Degradation: The decline in the productive capacity of land. Major threats include:
  • Expansion of agriculture and construction activities.
  • Causes: Deforestation, overgrazing, mining, quarrying, overuse of chemical fertilizers and pesticides in agriculture.
• Conservation of Land Resources: Methods to check land degradation:
  • Afforestation: Planting trees.
  • Land Reclamation: Restoring degraded land.
  • Regulated use of chemical pesticides and fertilizers.
  • Checks on overgrazing.

2. Soil Resources

• Definition: The thin layer of grainy substance covering the surface of the earth is called soil. It is closely linked to landforms and is made up of organic matter (humus), minerals, and weathered rocks.
• Soil Formation:
  • The right mix of minerals and organic matter makes the soil fertile.
  • Weathering: The breaking up and decay of exposed rocks by temperature changes, frost action, plants, animals, and human activity. This is the primary process.
  • It takes hundreds of years to make just one centimetre of soil.
• Factors Influencing Soil Formation:
  • Parent Rock: Determines colour, texture, chemical properties, mineral content, permeability.
  • Climate: Temperature and rainfall influence the rate of weathering and humus formation.
  • Relief (Altitude and Slope): Determines the accumulation of soil. Steep slopes usually have thinner soil cover.
  • Flora, Fauna, and Micro-organisms: Affect the rate of humus formation. Dead plants and animals contribute organic matter.
  • Time: Determines the thickness of the soil profile. Older soils are generally deeper.
• Soil Profile: A vertical section through the soil showing its different layers or horizons. (Simplified for Class 8: Topsoil with humus and vegetation, Subsoil with sand, silt, clay, Weathered rock material, Parent rock).
• Soil Degradation: Major threats include soil erosion and depletion.
  • Causes: Deforestation, overgrazing, overuse of chemical fertilizers or pesticides, rain wash (sheet erosion), landslides, floods, wind erosion (in arid regions), faulty farming methods (e.g., ploughing up and down the slope creating channels - gully erosion).
• Soil Conservation Methods: Protecting the soil layer from erosion and depletion.
  • Mulching: Covering the bare ground between plants with a layer of organic matter like straw. Helps retain soil moisture.
  • Contour Barriers: Building barriers along contours using stones, grass, soil. Trenches are made in front to collect water.
  • Rock Dam: Piling up rocks to slow down the flow of water, preventing gullies and further soil loss.
  • Terrace Farming: Making broad flat steps or terraces on steep slopes so that flat surfaces are available to grow crops. Reduces surface run-off and soil erosion. (Common in mountainous regions).
  • Intercropping: Growing different crops in alternate rows, sown at different times to protect the soil from rain wash.
  • Contour Ploughing: Ploughing parallel to the contours of a hill slope instead of up and down. Forms a natural barrier for water to flow down.
  • Shelter Belts: Planting rows of trees in coastal and dry regions to check wind movement and protect soil cover.

3. Water Resources

• Importance: Water is a vital renewable natural resource. Essential for life, agriculture, industries, and generating electricity.
• Availability:
  • Three-fourths of the Earth's surface is covered with water (hence, called the 'water planet').
  • Most water is saline (oceans and seas) and not fit for direct human consumption.
  • Freshwater: Accounts for only about 2.7% of the total water.
  • Accessibility: Nearly 70% of this freshwater occurs as ice sheets and glaciers in Antarctica, Greenland, and mountain regions – inaccessible.
  • Only about 1% of freshwater is available and fit for human use (found as groundwater, surface water in rivers and lakes, and water vapour in the atmosphere).
• Water Cycle: The constant movement of water through evaporation, condensation, and precipitation. Water can neither be added nor subtracted from the Earth.
• Water Scarcity: Shortage of water. Major problem in many parts of the world.
  • Causes:
    • Increasing population leading to rising demand.
    • Growing demand for food and cash crops, increasing urbanization, rising standards of living.
    • Over-exploitation and wastage of water resources.
    • Unequal access to water among different social groups.
    • Contamination of water sources by discharge of untreated/partially treated sewage, agricultural chemicals, and industrial effluents.
    • Variations in seasonal or annual precipitation (Drought prone areas).
• Conservation of Water Resources: Protecting water from pollution and wastage.
  • Treating Effluents: Discharging treated sewage, agricultural chemicals, and industrial waste into water bodies.
  • Afforestation: Forest and other vegetation cover slow surface runoff and replenish underground water.
  • Rainwater Harvesting: Collecting rainwater on rooftops and directing it to storage tanks or allowing it to percolate into the ground.
  • Efficient Irrigation: Using canals properly, minimizing seepage losses. Using sprinklers (for uneven land, sandy soil) and drip or trickle irrigation (in dry regions) to conserve water.
  • Water Consciousness: Promoting wise use of water in households and communities.

4. Natural Vegetation and Wildlife Resources

• Biosphere: The narrow zone of contact between the Lithosphere (land), Hydrosphere (water), and Atmosphere (air) where natural vegetation and wildlife exist.
• Ecosystem: In the biosphere, living beings are inter-related and interdependent on each other and their physical environment for survival. This life-supporting system is known as an ecosystem.
• Importance of Natural Vegetation (Plants):
  • Provide timber, shelter to animals.
  • Produce oxygen we breathe.
  • Protect soil essential for growing crops.
  • Act as shelter belts.
  • Help in storage of underground water.
  • Provide fruits, nuts, latex, turpentine oil, gum, medicinal plants, and paper.
• Importance of Wildlife:
  • Includes animals, birds, insects, as well as aquatic life forms.
  • Provide milk, meat, hides, and wool.
  • Insects like bees provide honey and help in pollination of flowers.
  • Birds feed on insects and act as decomposers.
  • Vultures, due to their ability to feed on dead livestock, are vital scavengers cleaning the environment.
  • All animals, big or small, are integral to maintaining balance in the ecosystem.
• Distribution of Natural Vegetation: Growth depends primarily on temperature and moisture. Major vegetation types are:
  • Forests: Associated with areas having abundant water supply. Can be dense or open based on temperature and rainfall.
    • Evergreen: Do not shed their leaves simultaneously in any season.
    • Deciduous: Shed their leaves in a particular season (usually dry season) to conserve moisture.
    • Further classified as Tropical or Temperate based on location.
  • Grasslands: Grow in regions of moderate rainfall.
    • Tropical Grasslands (e.g., Savanna in Africa).
    • Temperate Grasslands (e.g., Prairie in N. America, Pampas in S. America, Veld in S. Africa, Steppe in Asia, Downs in Australia).
  • Scrubs: Thorny shrubs and scrubs grow in dry areas of low rainfall.
  • Tundra: Found in cold Polar Regions, comprises mosses and lichens.
• Conservation of Natural Vegetation and Wildlife:
  • Threats: Climate change, human interference (deforestation, soil erosion, constructional activities, forest fires, poaching, hunting).
    • Poaching: Illegal hunting and trade of wildlife parts (hides, skins, nails, teeth, horns, feathers). Animals like tigers, lions, elephants, deer, black buck, crocodile, rhinoceros, snow leopard, ostrich, peacock are threatened.
    • Forest Fires: Can be natural (lightning) or human-induced (carelessness, arson).
    • Landslides, Tsunami: Natural disasters impacting habitats.
  • Conservation Methods:
    • Protected Areas: National Parks, Wildlife Sanctuaries, Biosphere Reserves are established to protect natural vegetation and wildlife.
    • Awareness Programmes: Social forestry and Vanamahotsava encourage planting trees at community and regional levels. School children encouraged for bird watching, nature camps.
    • Legal Protection: Laws against trade and killing of birds and animals. In India, killing lions, tigers, deer, great Indian bustards, and peacocks is illegal.
    • International Agreements: CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora) ensures that international trade in specimens of wild animals and plants does not threaten their survival. It lists species whose trade is prohibited or restricted.
    • Conservation of creeks, lakes, and wetlands is necessary to save precious resources from depletion.

Multiple Choice Questions (MCQs)

1. Which one of the following is NOT a factor influencing soil formation?
   (a) Parent Rock
   (b) Climate
   (c) Time
   (d) Population Density

2. Which method of soil conservation involves covering the bare ground between plants with organic matter like straw?
   (a) Terrace Farming
   (b) Mulching
   (c) Contour Ploughing
   (d) Shelter Belts

3. Land covers only about ______ percent of the total area of the Earth's surface.
   (a) 70%
   (b) 30%
   (c) 50%
   (d) 90%

4. Which of the following is a human factor determining land use pattern?
   (a) Topography
   (b) Soil
   (c) Technology
   (d) Climate

5. Which type of irrigation is most suitable for dry regions with high evaporation rates?
   (a) Sprinkler Irrigation
   (b) Canal Irrigation
   (c) Drip or Trickle Irrigation
   (d) Flood Irrigation

6. Community lands are also known as:
   (a) Private Property Resources
   (b) Common Property Resources
   (c) Government Property Resources
   (d) Individual Property Resources

7. The process responsible for breaking up rocks and initiating soil formation is called:
   (a) Erosion
   (b) Deposition
   (c) Weathering
   (d) Afforestation

8. What percentage of the world's freshwater is readily available and fit for human use?
   (a) About 10%
   (b) About 2.7%
   (c) About 70%
   (d) About 1%

9. CITES is an international agreement focused on:
   (a) Reducing air pollution
   (b) Conserving water resources
   (c) Regulating international trade in endangered species
   (d) Promoting organic farming

10. Which of the following is NOT a major threat to wildlife?
    (a) Poaching
    (b) Deforestation
    (c) Afforestation
    (d) Forest Fires

Answer Key for MCQs:

1. (d) Population Density
2. (b) Mulching
3. (b) 30%
4. (c) Technology
5. (c) Drip or Trickle Irrigation
6. (b) Common Property Resources
7. (c) Weathering
8. (d) About 1%
9. (c) Regulating international trade in endangered species
10. (c) Afforestation (Afforestation is a conservation method)

Study these notes thoroughly. Pay attention to definitions, factors, causes of degradation, and conservation methods for each resource. Remember the specific examples and data points mentioned, as they are often targeted in objective questions. Good luck with your preparation!