 |
| Biosphere |
Land
The land is one of the most important resources of the Earth. It covers 29 per cent of the earth surface. More than 90 per cent of the human population live in 30 per cent of the available land and remaining land is either unhabitable or sparsely populated.
The uneven distribution of the human population can be attributed to topography, climate, soil, water and fuel availability. The river valleys and plains offer ideal conditions for agriculture and living are densely populated regions in the world.
Land Use
The use of land for different purposes such as agriculture, forestry, mining and urban construction is referred to as land use. It depends upon topography, climate, soil, water, mineral availability, human population and technology.
India has the highest cropland both in terms of land use and percentage. Australia leads the chart in terms of pasture lands. Suriname leads the chart in forest cover in terms of percentage and Russia leads forest cover in terms of total area.
Land use can be determined on the basis of ownership as private land and community land. Private land is owned by individuals whereas community land is owned by a community for the purpose of fodder, fruits and herbs.
Due to increased population and human greed, people have started encroaching on community lands. They are using community lands to construct new buildings in cities or expanding agriculture activities in rural areas.
Land degradation
Land degradation can be defined as the degradation of the quality of land. It is caused by deforestation, soil erosion and unchecked use of chemicals. Natural phenomena like landslides also degrade the quality of land. However, it can be checked by afforestation, land reclamation, better agriculture practices and controlled grazing.
Landslides
Landslides are common in mountain areas. It is a mass movement of rocks, debris and earth down the slope. Natural phenomena like earthquake, flood, volcanic activity and prolonged rain can cause landslides. However, human activities such as construction or drilling can also cause landslides. Sometimes heavy landslides lead to the formation of river block which blocks the river flow and causes havoc downstream.
Mitigation Mechanism
1. Hazard mapping of landslide-prone areas.
2. Construction of retention wall.
3. Afforestation.
4. Controlling drainage system in landslide-prone areas.
Soil
The upper layer of earth in which plants grow is known as soil. It is closely related to land as landforms regulate soil type. It is made up of organic material, mineral and weathered rocks. Soil fertility depends upon the right mix of mineral and organic material.
Soil Formation
The parent rock and climatic conditions are the two major factors behind soil formation. Other factors include relief type, the time taken and microorganisms.
 |
| Soil Formation/Source: NCERT |
Major factors behind soil degradation are deforestation, overgrazing and overuse of fertilisers. Natural phenomena like prolonged rain, landslides and floods add to the woes.
However, there are techniques to conserve and restore soil fertility. These are
1. Mulching: Covering the bare ground with organic materials such as straw. It helps in retaining soil moisture.
2. Contour barrier: Using a mix of stones, grass and soil to build a barrier along contours. In addition, trenches are made along with contour to collect water.
3. Rock dams: A rock pile is made to check water flow.
4. Terrace farming: Terrace like structures are made on a slopy area to check run-off and soil erosion.
5. Intercropping: A number of different crops grown in alternate rows to protect soil erosion and nutrient loss.
6. Shelterbelts: In coastal or dry areas, a belt of trees planted to check wind intensity.
Water
Water is essential for the survival of life. Around 71 per cent of the earth is covered by water. Oceans make up 97.3 per cent of overall water. Only 2.7 per cent is freshwater. Moreover, only 1 per cent of the total water is available for human consumption. Henceforth, the available fresh water becomes one of the most precious substances on earth. It is mostly found as groundwater, water from rivers, ponds and lakes and water vapour in the air. (Read Additional Notes on Water)
 |
| Distribution of Water/Source NCERT |
Humans need water for various reasons besides drinking such as water for agriculture, industries, power generation, and others. The average water usage per person has almost doubled from 3850 cu km/year in 1975 to 6000 cu km/year in 2000.
Moreover, with the increase in population, urbanisation and standard of living, there is soar in water demands. This has led to t shortage in water supply.
Water shortage and droughts are now common throughout the world. The problem can be attributed to overexploitation, seasonal variance and water pollution. Countries located in climatic zones are more likely to face droughts.
The water shortage has lead to new problems such as water mafia or water trade. Several places in India like Amreli (Gujarat) have water markets.
Water Conservation
Despite the fact that water is a renewable resource, its overuse and contamination he has lead to depletion in water quality. Clean and adequate water is one of the major problem the world is facing now.
Necessary Step for Conserving Water and Water Bodies
1. Sewage Treatment: Untreated sewage water, agricultural and industrial chemicals are the major source of water pollution. City and town administration should treat this sewage water before releasing into water bodies.
2. Afforestation: Forest and vegetation cover checks soil erosion and increases soil water retention capacity.
3. Water harvesting: Capturing rainwater and storing it for later use.
4. Better canal management: Canal should be lined to lessen the water loss.
5. Adopting new agricultural techniques: Adopting new techniques such as sprinklers or drip irrigation to minimize water wastage in fields.
6. Alternative farming: Switching to organic or less water intensive farming practices.
Natural Vegetation and Wildlife
Natural vegetation and wildlife exist in a small zone of contact between the lithosphere, hydrosphere and atmosphere known as the biosphere. Here, all living organisms are dependent on each other for survival. This co-dependent system is known as the ecosystem.
Both plants and animal play an important role in our environment. Plants not only provide us with oxygen to breathe but also provide us with food, timber and fuel. Insects such as bees provide us, honey. They also help in pollination which leads to the yield of fruits. Birds such as vulture feed on animal carcass and maintain the environment.
Distribution of Natural Vegetation
The growth of vegetation depends upon several factors such as topography, temperature and moisture. The major vegetations around the world are forest, grassland and scrubs.
Forests are found in heavy rainfall area. Grasslands are found in moderate rainfall regions. Shrubs and tundra vegetation are found in dry regions. Forest can be classified as 1. evergreen where trees do not shed their leaves once and 2. deciduous where trees shed their leaves in a particular season. These are again classified as tropical and temperate on the basis of their latitudinal position.
Read here: Notes on Natural Vegetation
Conservation of Natural Vegetation and Wildlife
The mindless exploitation of forests has made a severe impact on our environment. Due to human greed, many species like tiger, lion, elephant, snow leopard, deer, blackbuck, rhinoceros, crocodile and peacock are on the verge of extinction. These species are traded for their hides, skin, nails, and feathers. Several species such as Indian cheetah, Dodo and Passenger Pigeon have extinct due to human intervention. Here are few steps taken by the Governments across the world to save the biodiversity
1. Setting up national parks, wildlife sanctuaries and biosphere reserves to protect the biodiversity.
2. Setting up programmes to conserve creeks, lakes and wetlands. An international treaty to protect wetlands, Ramsar convention has been signed by several countries.
3. The ban on poaching and trading of animals and birds. An international convention CITES has been signed by many countries to ban illegal trade on several species of animals and birds.
4. Encouraging awareness programmes like Vanmahotsava or Social Forestry.