Chapter 2

NATURAL RESOURCES AND THEIR CONSERVATION

Chapter - 2

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© 2009 Cengage Learning India Pvt. Ltd. All rights reserved

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Natural Resources

Any substance that is obtained from nature and which can be transformed into a form that becomes valuable and useful for human beings is termed as a natural resource. Examples of natural resources are trees, crops, soil, water, etc.

Natural resources can be classified on the basis of their origin as biotic resources and abiotic resources, and on the basis of their continual utility as renewable resources and non-renewable resources.


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Classification of Natural Resources

Resources whose continual harvest is possible with proper planning and management, such as plants, animals, solar energy, wind energy, etc., are known as renewable resources.

Renewable Resources

Those resources which once gone have very little chance of recovery or resynthesis are called non-renewable resources. Examples of non-renewable resources are coal, minerals, and petroleum.

Non-renewable Resources


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Forest Resources

A forest is a biotic community with a predominance of trees; it is an important renewable resource.

Forests restore oxygen in our atmosphere through photosynthesis and also provide solvents, medicines, fuels, and many other products that are important for our health and comfort.

India is rich in forest resources with a great diversity of flora and fauna.


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Importance of Forests

•Forests provide timber for construction of buildings and furniture.

•They provide raw material for a number of large- and small-scale industries.

•They provide a variety of edible products for human beings and animals.

•They provide natural habitat to tribal people.

•They make manure and fuel wood available to humans.

•They are an important source of national income.

•They provide various medicinal plants.

•They increase the beauty of landscape and attract tourists.

•They are extremely helpful in generating employment opportunities.

Direct Benefits


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Indirect Benefits

•Forests help in minimizing natural hazards.

•They help in reducing soil erosion and siltation of downstream water bodies.

•They help in reducing desertification and land degradation.

•They help in maintaining biodiversity by providing habitat to wild animals.

•They help in regulating hydrological cycle.

•They help in regulating the gases in atmosphere.


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Deforestation

Causes of Deforestation •Encroachment of forest land for agricultural use

•Expansion of cities to accommodate the growing population •Construction of dams, canals, and highways

•Establishment of industrial areas

•Demand for firewood

•Mining

•Shifting cultivation

•Submergence of forests in river valley projects

The term deforestation refers to the removal or reduction of forest cover.


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Effects of Deforestation

•Loss of natural habitat of wild animals and plants•Increased intensity and frequency of floods•Land degradation•Loss of forest products •Change in climatic conditions•Siltation of rivers and lakes •Loss of revenue •Change in hydrological cycle and reduced rainfall •Increased socio-economic problem in the long run


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Control of Deforestation

•Mining activities should be prohibited in areas declared as protected forests.

•Cutting of trees should be followed by massive plantation.

•The environmental laws and legal provisions should be strictly enforced.

•Forest extension should be carried out through social forestry, agro forestry, recreation forestry, extension forestry, etc.

•Public awareness should be created regarding medicinal and other economic and environmental significance of forests.


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Water Resources

Importance of Water

•Water is the basic component of every living cell.

•It is the basic input required for agriculture.

•Hydel power can be used for generating hydroelectricity.

•It provides habitat to aquatic flora and fauna.

•Common salt can be obtained from water.


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Sources of Water

Ground Water

Surface Water

Water that is hidden underground in spaces between soil and rock particlesis known as ground water.

After precipitation, the amount of water that does not percolate down into the ground or does not return to the atmosphere by evaporation or transpiration and enters the rivers, streams, lakes, ponds, wetland, or artificial reservoirs constitutes surface water.


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Effects of Over-utilization of Ground Water

•Reduced flow of surface water

•Lowering of water table

•Water logging

•Subsidence

•Degradation of water quality

•Increased salt content

•Increased power costs


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Dams: Benefits and Problems

Advantages of Dams

•Irrigation

•Production of electricity

•Promotion of navigation

•Recreation

•Control of floods

•Increase in the availability of water for domestic as well as

industrial purposes © 2009 Cengage Learning India Pvt. Ltd. All rights reserved

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Disadvantages of Dams

•Deforestation and loss of biodiversity •Sinking of agricultural and forest land •Displacement of tribal people from their homes•Unchecked growth of aquatic weeds •Siltation of reservoirs due to degraded catchments conditions •Change in microclimate •Increase in water-borne and soil-borne diseases •Increase in flash floods •Increase in frequency of earthquakes •Increase in water logging and salinity •Changes in Earth's rotation •Emission of greenhouse gases


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Mineral Resources

Types of Minerals

•Metallic minerals (iron ore, lead, zinc, etc.)

•Non-metallic minerals (asbestos, dolomite, and gypsum)

•Fuel minerals (coal, petroleum, and natural gas)

Minerals are naturally occurring chemical compounds, which are formedunder the crust of the Earth through inorganic processes.


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Environmental Effects of Extraction and Over-exploitation of Mineral Resources

•Destruction of forest and damage to the earth’s surface

•Soil erosion and reduction in soil fertility

•Generation of large amount of wastes which degrade the quality of land

•Pollution of air, water, and land

•Lowering of water table leading to ground subsidence and ground water pollution

•Destruction of natural ecosystems and creation of trenches and open pits

•Earthquakes and other volcanic events

•Occupational health hazards to miners

•Emission of radioactive pollutants, ash and trace metals by the combustion of coal and petroleum


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Food Resources

Types of Food Resources

• Agricultural crops

• Livestock

• Fish

Natural or artificially produced materials, which are used as food to derive metabolic energy, are called food resources.


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World Food Problems

•Insufficient production

•Lack of irrigation facility

•Undernutrition and malnutrition

•Hoarding and black-marketing


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Factors causing Food Problems

•Geographical conditions

•Lack of rainfall

•Population growth

•Natural hazards

•Inadequate distribution system

•Poor quality of soil

•Social disruption and terrorism


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Water-Logging and Salinity

Accumulation of water on land for longer period is known as water-logging.

Water logging causes moisture to percolate down, which dissolves the underground salts in it; these salts emerge on the surface of land after the water is evaporated. This leads to salinity in soils.

Regions enriched with canals and dams for irrigation are more prone to water logging which increases the accumulation of salt in the water-logged areas.


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Effects of Water-Logging

•Water-logging accelerates denitrification, which leads to loss of nitrogen.

•There is a lack of oxygen in water-logged areas.

•Because of the deficiency of nitrogen and oxygen, water-logged areas support the growth of only certain specific plant species.

•Water-logged areas support the growth of unwanted microorganisms causing rapid decomposition of accumulated organic matter. This creates a foul odour.

•Long term water-logging reduces the aesthetic value of the region.


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Effects of Chemical Fertilizers

• Chemical fertilizers cause loss of soil fertility and degradation of soil quality.

• They create nitrate pollution in groundwater when they dissolve in water and seep into the soil.

• Excess fertilizer from agricultural fields finds its way into ponds, lakes and rivers through run-off from water from the fields. These run-off fertilizers speed up the growth of algae in the pond, lake and river waters. This phenomenon is known as eutrophication.

• The nitrogen fertilizers lead to the accumulation of nitrate in the soil which are transformed to living organisms.


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Effects of Chemical Pesticides

• Most pesticides are not very specific and kill many non-target organisms as well.

• Pesticides adversely affect harmless species such as frogs, snakes, and birds, which are natural pest-control mechanisms.

• There is an increase in the resistance to pesticides in insects, pathogens, weeds, etc., because of indiscriminate use.

• Pesticides from agricultural lands run down with rain water and enter local streams or lakes.

• Pesticides adversely affect the health of farmers.

• Pesticides are retained in soil, and get concentrated in crops, vegetables, cereals, and fruits leading to bio-magnification; the magnified levels of toxins then enter the human body and cause serious damage.

• Excessive use of pesticides causes air, water, and soil pollution.


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Effects of Overgrazing

Overgrazing

• Elimination of sensitive palatable plant species and dominance of spiny, non-palatable, and alien species.

• Acceleration of soil erosion and decrease in soil fertility.• Accumulation of large quantity of animal wastes in downstream

water bodies causing problems of water pollution and eutrophication.

• Grazing animals sometimes bring seeds of weeds and pathogenic organisms which may often become harmful to other animals.

• Increase in reflectivity of land surfaces, which in turn, lowers surface temperature and reduce the quantity of rain and thereby increasing the chances of drought.

The term overgrazing refers to the practice of grazing by a large livestock for a long period on a land without giving sufficient recovery time.


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Environmental Effects of Modern Agriculture

•Soil erosion and loss of fertility •Sedimentation •Change in land use patterns •Fertilizer problems •Pesticide problems •Irrigation related problems •Problems due to agriculture animals •Climate change •Effect on biogeochemical cycles •Loss of genetic diversity •Intensification of inequity


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Energy Resources

Renewable Energy Sources

Renewable sources of energy or flow sources, rely on natural energyflows and sources in the environment and thus have the potential of being continually replenished. These include firewood, petroplants, animal dung,solar energy, wind energy, geothermal energy, tidal energy, etc.

Non-renewable Energy Sources

Non-renewable energy sources are available in limited amount and develop over a longer period. Because of indiscriminate use they are likely to be exhausted in the near future. These include coal, mineral oil, natural gas, nuclear power, etc.


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Renewable Sources of Energy

•Solar Energy

•Wind Energy

•Tidal Energy

•Geothermal Energy

•Biomass Based Energy


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Non-Renewable Sources of Energy

•Coal

•Natural gas and oil

•Nuclear energy


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Land Resources

The Importance of Land

• The human civilization has thrived on land.

• Land is used for agriculture.

• Land contains huge amount of mineral deposits.

• It also contains water in the form of underground water.

• Most of the animals find their habitat on land.

• Land directly or indirectly provides all the resources required to fulfil the basic needs of humans: food, cloth, and shelter.


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Land Degradation

•Mining

•Urbanization

•Deforestation

•Overgrazing

•Construction of dams and canals

•Excessive use of fertilizers

•Dumping of industrial and domestic waste

Lowering of the quality of land is commonly referred to as land degradation.

Causes of Land Degradation


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Soil Erosion

Causes of Soil Erosion

•Large-scale deforestation for meeting commercial as well as day-to-day needs

•Heavy floods in rivers

•Overgrazing by cattle

•Dry violent winds

•Improper agricultural techniques

The detachment and transportation of the fertile layer of soil by water or air.


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Effects of Soil Erosion

•Decrease in productivity of land

•Desertification of land

•Reduction in the agricultural land at the banks of rivers

•Deposition of soil in river beds and canals causing diversion of

their natural flow and hence leading to disasters


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Methods of Controlling Soil Erosion

•Reduced tillage

•Contour bunding

•Vegetative bunds

•Strip cropping

•Terracing

•Afforestation on barren land

•Control of overgrazing

•Construction of small check dams

•Promotion of equitable use of water resources

•Prevention of excavation of rocks © 2009 Cengage Learning India Pvt. Ltd. All rights reserved

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Desertification

Causes of Desertification

Natural Factors

•Very low rainfall

•Excessive evaporation

•Vast difference in diurnal temperature extremes

•High salinity of soils

Anthropogenic Factors

•Continuous cutting of trees

•Overgrazing

•Over irrigation

•Excessive ploughing

•Conversion of pastures to arable lands

•Excessive use of fertilizers

Conversion of fertile land into an infertile desert land is called desertification.


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Effects of Desertification

•Rapid soil erosion

•Poor soil quality

•Unfavorable climate

•Low water table, salty and hard water

•Huge economic losses


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Control of Desertification

•Promoting large-scale plantation of trees

•Changing agricultural practices and promoting dry land farming

•Development of pasture lands and control of overgrazing

•Promoting equitable use of water resources

•Development of water catchment areas


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Role of an Individual in Conservation of Natural Resources•Energy Conservation Switch off electric lights and appliances whenever not neededRide a bicycle as often as possible

•Forest ConservationPlant a large number of treesMake equitable use of forest and forest products

•Water Conservation Repair leakagesSave water in agriculture and domestic activitiesAdopt rainwater harvesting techniques

•Land Conservation Do not dump agricultural, industrial, and domestic waste on land

•Sustainable FoodAdopt vegetarian food habits Use unpackaged food items such as vegetables and dry beans instead of canned or packaged food

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Chapter 2

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cengage learning india

examples of natural

abiotic resources

origin asbiotic resources

natural hazards

forest extension

forest resourceswith

termed asa natural resource