|1 Crore+ students have signed up on EduRev. Have you?|
NATURAL RESOURCES AND THEIR CONSERVATION
The materials or any component, that can be utilised by man and are necessary for welfare of life, which is available in the natural environment in Atmosphere, Hydrosphere, Lithosphere is called natural resources. e.g. O2, Land, Soil water, Forest, Animals, Soil, microorganism.
Classification of natural resources :
1. Inexhaustible resources : Available in unlimited quantities, and the earth quantity may remain unchanged by human impact.
e.g. Solar Energy, Wind Power, Tidal power, Air, Geothermal Energy.
Its quality can be affected due to continuous increase in human population. e.g. Air pollution.
2. Exhaustible resources : These are likely to be finished by human use or unsustainable uses.
It is further divided in two groups:
(i) Renewable resources : Those which are being continuously consumed by man but renewed continuously by nature, always available if managed in a proper way, otherwise they may even get totally exhausted.
e.g. Biotic resources, forest, grazing animals, Rangeland, wild life, Agriculture crop system and fresh water yield, soil etc.
(ii) Non renewable resources : They are not renewable after use and are not replaced by nature, cannot be regained.
e.g. Fossil fuel (Coal, Petroleum), Natural Gas, Nuclear energy, Biotic species, Minerals etc. Nuclear energy is non renewable and unlimited resources.
HYDROSPHERE OR WATER RESOURCES:
1. Water is the major constituent of the hydrosphere and covers 3/4th of the earth's surface.
2. The total volume of water in the hydrosphere is 1.4 billion cubic kilometer [km3], about 97.5 % is the ocean water, unsuitable for human use. Only 2.5 % is available as fresh water. About 1.97 % is stored in ice ocean (Polar ice) and glaciers and 0.5 % is ground water and soil moisture (0.01 %). The rest [about 0.36 percent] is distributed in lakes swamps, river and streams.
3. About 84 % of the total global evaporation occurs from ocean surface and 16 % from land surface.
Conservation and management of water :
Main approach for conservation of water are :
1. Reducing agricultural water wastage by increasing efficiency of irrigation.
2. Reducing water wastage in industry by recycling the used water.
3. Reducing domestic water wastage by constructing waste water treatment.
4. Rainwater harvesting by employing practices to store rainwater and recharge ground water.
5. Afforestation and protection of water sheds to improve water economy. Approaches to provide a sustainable supply of high quality water are :
(i) Construction of dams and reservoirs to ensure year-round supply of water, in addition, controlling flood and generating electricity.
(ii) Desalinisation of sea water and saline ground water and making it fit for drinking and other purposes.
1. Earth's one-fourth area is formed by land.
2. About 4/5 of the land area is covered by soil.
3. At the beginning of 20th century, about 30 % of land in India was covered with forest but the end of the 20th century, the forest cover reduced to 19.4 %. Out of 19.4 %, only 12 % area covered by dense forest.
Per capita forest area available in India is = 0.06 hec.
Per capita forest area available in world is = 0.64 hec.
In India 33 % forest area is recommended by national forest policy (1988).
Soil is the mixture of living and non-living materials. Soil is only responsible for anchorage and sustenance of the plants. The fertility of soil is reduced due to growing of plants again and again. Natural factors like water, air etc. are also responsible for transporting the top soil and decrease fertility. This is called soil erosion.
The structure of soil is different at the different depths of land. Its some upper part is called top soil. This region is very essential for the growth of the plants. Its thickness is about 15-20 cm. This top soil contains humus and various micro-organisms which increase the fertility of the soil. When this top soil gets removed by fast wind, fast rain, cyclone and running water then it is called soil erosion. The following reasons are responsible to minimise the fertility power of soil in nature.
(i) Shortage of mineral substance.
(ii) Leaching : The dissolved minerals go into the depth (lower layers) with water. Roots of the plants usually remain in top soil so the minerals are not available to the plants.
Some management measures are essential to check the soil erosion. According to this some principle are as follows :-
(i) To protect the soil form the drops of rainy water.
(ii) To stop the accumulation of water as well as stop the flow of water on the slopes.
(iii) To prevent the transportation of soil particles.
(iv) To slow down the wind velocity on the surface of the earth.