Land, Soil, Water, Natural Vegetation and Wildlife Resources Class 8 Geography Chapter 2 Notes are available here. These notes are prepared by the subject experts of our team.
Land, Soil, Water, Natural Vegetation and Wildlife Resources Class 8 Geography Chapter 2 Notes
Land
- Land is among the most important natural resources.
- It covers only about thirty per cent of the total area of the earth’s surface, and all parts of this small percentage are not habitable.
- The uneven distribution of population in different parts of the world is mainly due to varied characteristics of land and climate.
- The rugged topography, steep slopes of the mountains, low-lying areas susceptible to water logging, desert areas, and thick forested areas are normally sparsely populated or uninhabited.
- Plains and river valleys offer suitable land for agriculture.
- Hence, these are the densely populated areas of the world.
- Ninety per cent of the world population occupies only thirty per cent of land area.
- The remaining seventy per cent of the land is either sparsely populated or uninhabited.
Land Use
- Land is used for different purposes such as agriculture, forestry, mining, building houses, roads, and setting up industries.
- This is commonly termed as Land use.
- The use of land is determined by physical factors such as topography, soil, climate, minerals, and availability of water.
- Human factors such as population and technology are also important determinants of land use pattern.
- Land can also be classified on the basis of ownership as private land and community land.
- Private land is owned by individuals, whereas community land is owned by the community for common uses like collection of fodder, fruits, nuts, or medicinal herbs.
- These community lands are also called common property resources.
- People and their demands are ever growing, but the availability of land is limited.
- The quality of land also differs from place to place.
- People started encroaching on common lands to build commercial areas, housing complexes in urban areas, and to expand agricultural land in rural areas.
- Today, the vast changes in the land use pattern also reflect the cultural changes in our society.
- Land degradation, landslides, soil erosion, and desertification are the major threats to the environment because of the expansion of agriculture and construction activities.
Conservation Of Land Resources
- Growing population and their ever-growing demand have led to large-scale destruction of forest cover and arable land and have created a fear of losing this natural resource.
- Therefore, the present rate of degradation of land must be checked.
- Afforestation, land reclamation, regulated use of chemical pesticides and fertilizers, and checks on overgrazing are some of the common methods used to conserve land resources.
Soil
- Soil is the thin layer of grainy substance covering the surface of the earth.
- Soil is closely linked to land.
- Landforms determine the type of soil.
- Soil is made up of organic matter, minerals, and weathered rocks found on the earth.
- Soil formation occurs through the process of weathering.
- The right mix of minerals and organic matter makes the soil fertile.
Weathering:
- Weathering is the breaking up and decay of exposed rocks.
- Causes of weathering include temperature changes, frost action, plants, animals, and human activity.
Landslides
- Landslides are defined as the mass movement of rock, debris, or earth down a slope.
- They often occur in conjunction with earthquakes, floods, and volcanoes.
- Prolonged rainfall can cause heavy landslides that block river flow for some time.
- River blocks caused by landslides can create havoc for downstream settlements upon bursting.
- In hilly terrain, landslides are a major natural disaster that affects life and property and are a major concern.
A Case Study:
- A massive landslide hit Pangi village near Reckong Peo in Kinnaur district of Himachal Pradesh.
- The landslide damaged a 200-meter stretch of the old Hindustan-Tibet road, National Highway – 22.
- The landslide was triggered by intense blasting at Pangi village.
- Blasting caused the weak zone of the slope to collapse, damaging the road and nearby villages.
- Pangi village was completely vacated to avoid any possible loss of life.
Mitigation Mechanism:
- Advancement in scientific techniques helps understand and manage landslides.
- Mitigation techniques include:
- Hazard mapping to locate areas prone to landslides, which can be avoided for building settlements.
- Construction of retention walls to prevent land from slipping.
- Increasing vegetation cover to arrest landslides.
- Surface drainage control works to manage landslide movement with rainwater and spring flows.
Factors Of Soil Formation
Parent Rock: Determines the color, texture, chemical properties, mineral content, and permeability of the soil.
Climate: Temperature and rainfall influence the rate of weathering and humus formation.
Time: Determines the thickness of the soil profile.
Flora, Fauna, and Micro-organisms: Affect the rate of humus formation.
Relief: Altitude and slope determine the accumulation of soil.
Degradation of Soil and Conservation Measures
- Soil erosion and depletion are major threats to soil as a resource.
- Both human and natural factors can lead to soil degradation.
Factors contributing to soil degradation include:
- Deforestation
- Overgrazing
- Overuse of chemical fertilizers or pesticides
- Rain wash
- Landslides
- Floods
Methods of Soil Conservation:
1. Mulching: The bare ground between plants is covered with a layer of organic matter like straw to retain soil moisture.
2. Contour Barriers: Stones, grass, and soil are used to build barriers along contours, with trenches made in front of the barriers to collect water.
3. Rock Dam: Rocks are piled up to slow down the flow of water, preventing gullies and further soil loss.
4. Terrace Farming: Broad flat steps or terraces are made on steep slopes to create flat surfaces for growing crops, reducing surface runoff and soil erosion.
5. Intercropping: Different crops are grown in alternate rows and sown at different times to protect the soil from rain wash.
6. Contour Ploughing: Ploughing is done parallel to the contours of a hill slope to form a natural barrier for water flow.
7. Shelter Belts: In coastal and dry regions, rows of trees are planted to check wind movement and protect soil cover.
Water
- Water is a vital renewable natural resource.
- Three-fourths of the earth’s surface is covered with water, earning it the name “water planet.”
- Life began in the primitive oceans almost 3.5 billion years ago.
- Oceans cover two-thirds of the earth’s surface and support a rich variety of plant and animal life.
- Ocean water is saline and not suitable for human consumption.
- Freshwater accounts for only about 2.7% of the total water on earth.
- Nearly 70% of freshwater is in ice sheets and glaciers in Antarctica, Greenland, and mountain regions, which are inaccessible.
- Only 1% of freshwater is available and fit for human use, found as groundwater, surface water in rivers and lakes, and as water vapor in the atmosphere.
- Freshwater is the most precious substance on earth.
- The total volume of water on earth remains constant; it cannot be added or subtracted.
- Water abundance seems to vary due to its constant motion through the water cycle: evaporation, precipitation, and runoff.
Humans use large amounts of water for:
- Drinking and washing
- Agriculture
- Industrial processes
- Generating electricity through reservoirs and dams
Factors leading to freshwater shortages include:
- Increasing population
- Rising demands for food and cash crops
- Increasing urbanization
- Rising standards of living
- Drying up of water sources
- Water pollution
- Water consumption for human use was 3,850 cubic kilometers per year in 1975, soaring to more than 6,000 cubic kilometers per year in 2000.
- A dripping tap wastes 1,200 liters of water in a year.
Problems of Water Availability
- There is scarcity of water in many regions of the world.
Regions facing freshwater shortages include:
- Most of Africa
- West Asia
- South Asia
- Parts of the western USA
- Northwest Mexico
- Parts of South America
- Entire Australia
- Countries in climatic zones susceptible to droughts face significant water scarcity problems.
Water shortage may result from:
- Variation in seasonal or annual precipitation
- Over-exploitation and contamination of water sources.
Conservation of Water Resources
- Access to clean and adequate water sources is a major global problem.
- Conservation steps are necessary to preserve dwindling water resources.
- Water, though renewable, becomes unfit for use due to overuse and pollution.
Major contaminants in water include:
- Untreated or partially treated sewage
- Agricultural chemicals
- Industrial effluents
- These contaminants pollute water with nitrates, metals, and pesticides, which are often non-biodegradable and enter human bodies through water.
Water pollution can be controlled by:
- Treating effluents properly before releasing them into water bodies.
Forests and other vegetation cover help:
- Slow surface runoff
- Replenish underground water
- Water harvesting is a method to save surface runoff.
- Proper lining of canals used for irrigation can minimize water loss through seepage.
- Sprinklers effectively irrigate areas by reducing water loss through seepage and evaporation.
- In dry regions with high evaporation rates, drip or trickle irrigation is very useful.
- Adopting these irrigation methods can conserve valuable water resources.
Natural Vegetation and Wildlife
1. Natural Vegetation:
- Exists in the biosphere, a narrow zone of contact between the lithosphere, hydrosphere, and atmosphere.
- In the biosphere, living beings are interrelated and interdependent, forming an ecosystem.
- Vegetation and wildlife are valuable resources.
- Plants provide timber, shelter to animals, oxygen, soil protection, shelter belts, underground water storage, fruits, nuts, latex, turpentine oil, gum, medicinal plants, and paper.
2. Wildlife:
- Includes animals, birds, insects, and aquatic life forms.
- Provides milk, meat, hides, and wool.
- Insects like bees provide honey, help pollinate flowers, and play a role as decomposers in the ecosystem.
- Birds feed on insects and act as decomposers.
- Vultures feed on dead livestock and are considered vital environmental cleansers.
- Animals, big or small, are integral to maintaining ecosystem balance.
3. Additional Information:
- Rainwater harvesting is the process of collecting rainwater from rooftops and storing it for future use. One spell of rain for two hours can save 8,000 liters of water.
- Vultures in the Indian subcontinent were dying of kidney failure after scavenging livestock treated with diclofenac, a painkiller similar to aspirin or ibuprofen. Efforts are being made to ban the drug for livestock use and breed vultures in captivity.
Distribution of Natural Vegetation
- The growth of vegetation depends primarily on temperature and moisture.
Major vegetation types of the world include:
- Forests
- Grasslands
- Scrubs
- Tundra
In areas of heavy rainfall:
- Huge trees may thrive.
- Forests are associated with abundant water supply.
As moisture decreases:
- The size and density of trees reduce.
- Short, stunted trees and grasses grow in regions of moderate rainfall, forming the grasslands.
In dry areas with low rainfall:
- Thorny shrubs and scrubs grow.
- Plants have deep roots and leaves with thorny and waxy surfaces to reduce moisture loss through transpiration.
- Tundra vegetation in cold Polar Regions consists of mosses and lichens.
- The world population has increased significantly over the past two centuries.
- To feed the growing population, large areas of forests have been cleared for agriculture.
- Forest cover worldwide is rapidly vanishing, creating an urgent need for conservation.
Conservation of Natural Vegetation and Wildlife
Forests:
- Forests are valuable resources that provide shelter to animals and help maintain the ecosystem.
- Climate changes and human interference can cause loss of natural habitats for plants and animals.
- Many species have become vulnerable or endangered, and some are on the verge of extinction.
Factors accelerating extinction include:
- Deforestation
- Soil erosion
- Construction activities
- Forest fires
- Tsunamis
- Landslides
Poaching:
- Poaching leads to a sharp decline in the number of certain species.
- Animals are poached for hides, skins, nails, teeth, horns, and feathers.
Species affected by poaching include:
- Tiger
- Lion
- Elephant
- Deer
- Black buck
- Crocodile
- Rhinoceros
- Snow leopard
- Ostrich
- Peacock
Conservation Measures:
- Increasing awareness is crucial for conservation.
- National parks, wildlife sanctuaries, and biosphere reserves are established to protect natural vegetation and wildlife.
- Conservation of creeks, lakes, and wetlands is necessary to prevent resource depletion.
- Maintaining environmental balance requires avoiding disturbances to species populations.
- Human activities have disturbed natural habitats, leading to extinctions or endangerment of several species.
- Awareness programs like social forestry and Vanamohatsava should be promoted.
- School children should be encouraged to engage in bird watching and nature camps to appreciate varied species.
Legal and International Efforts:
- Laws against the trade and killing of birds and animals exist in many countries.
- In India, killing lions, tigers, deer, great Indian bustards, and peacocks is illegal.
- The international convention CITES lists species of animals and birds whose trade is prohibited.
- Conservation of plants and animals is considered an ethical duty of every citizen.
National Parks:
- Designated to protect the ecological integrity of ecosystems for present and future generations.
Biosphere Reserves:
- A series of protected areas linked through a global network, demonstrating the relationship between conservation and development.