natural resource1
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NATURAL RESOURCES
Natural resources (economically referred to as land or
raw materials) occur naturally within environments that
exist relatively undisturbed by mankind, in a natural
form. A natural resource is often characterized by
amounts of biodiversity existent in various ecosystems.
Natural resources are derived from the environment.
Many of them are essential for our survival while others
are used for satisfying our wants. Natural resources may
be further classified in different ways.
Classification
On the basis of origin, resources may be divided into:
y Biotic - Biotic resources are obtained from the
biosphere , such as forests and their products,
animals, birds and their products, fish and other
marine organisms. Mineral fuels such as coal and
petroleum are also included in this category becausethey formed from decayed organic matter.
y Abiotic - Abiotic resources comprise of non-living
things. Examples include land, water, air and ores
such as gold, iron, copper, silver etc.
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Considering their stage of development, natural
resources may be referred to in the following ways:
y P otential Resources - Potential resources are thosethat exist in a region and may be used in the future.
For example, petroleum may exist in many parts of
India, having sedimentary rocks but until the time it
is actually drilled out and put into use, it remains a
potential resource.
y Actual Resources are those that have been surveyed,
their quantity and quality determined and are being
used in present times. The development of an actual
resource, such as wood processing depends upon
the technology available and the cost involved. That
part of the actual resource that can be developed
profitably with available technology is called a
reserve.
With respect to renewability, natural resources can be
categorized as follows:
Reneweable resources are ones that can be
replenished or reproduced easily. Some of them, like
sunlight, air, wind, etc., are continuously availableand their quantity is not affected by human
consumption. Many renewable resources can be
depleted by human use, but may also be
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replenished, thus maintaining a flow. Some of these,
like agricultural crops, take a short time for renewal;
others, like water, take a comparatively longer time,
while still others, like forests, take even longer.
y Non-renewable resources are formed over very long
geological periods . Minerals and fossil fuels are
included in this category. Since their rate of
formation is extremely slow, they cannot be
replenished once they get depleted. Of these, the
metallic minerals can be re-used by recycling them.
But coal and petroleum cannot be recycled.
Examples
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The natural resource of wind powers these 5MW wind
turbines on this wind farm 28 km off the coast of
Belgium.
Some examples of natural resources include the
following:
y Agricultureagronomy is the science and
technology of using plants for food, fuel, feed, and
fiber.
y Air, wind and atmosphere
y Plants
y Animals
y Coal, fossil fuels, rock and mineral resources
y Forestry
y Range and pasture
y Soils
y Water, oceans, lakes, groundwater and rivers
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MAJOR NATURAL RESOURCES
y Forest Resources
y Water Resources
y Mineral Resources
y Food Resources
y Energy Resources
y Land Resources
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FOREST RESOURCES
y Covers earth like a green blanket
y Produce innumerable goods
y Provides several environmental services
y 1/3rd of the worlds land area is forested.
y Former USSR 1/5th
Brazil 1/7thCanada 6-7%
USA 6-7%
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y Regulation of Hydrological Cycle
y Soil Conservation
y Pollution Moderators.
OVER EXPLOITATION OF FORESTS &
DEFORESTATION
y
Increased Population
y Increased requirements
y Total forest area in
1900 7000 mha
1970 2890 mha
2000 2000 mha
y Deforestation rate is less in temperate
countries compared to tropical countries (40-50%).
CAUSES OF DEFORESTATION
y Shifting Cultivation300 million people living as shifting
cultivators.5 lakh ha of forests cleared annually.
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y Fuel Requirements Increase in fuel wood requirement
1945 ± 65 million tons
2001 ± 300-500 million tonsy Raw Materials for Industrial Use
wood for making boxes, furniture, railwaysleepers, plywood«
Pulp for paper industry.
y Development ProjectsHydroelectric power projects, Big dams,
Roads, Mining«
y Growing Food NeedsCreation of agricultural land and settlements
by clearing forests.
y Overgrazing.
CONSEQUENCES OF
DEFORESTATIONy It threatens the existence of many wild life
species due to destruction of their natural
habitat.
y
Biodiversity is lost and along with thatgenetic diversity is eroded.
y Hydrological cycle gets affected, thereby
influencing rainfalls.
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y Problems of soil erosion and loss of soil fertility
increases.
y
In hilly areas it often leads to landslides.
CASE STUDY 1
y Desertification of Hilly regions of the
iHimalayas
Deforestation in Himalayas, involving clearance of natural forests and plantations of monocultures
like P inus Rox bhurgi, Eucalyptus Camadulenses
etc. have upset the ecosystem by changing the
various soil and biological properties. Nutrient
cycling has become poor, original germplasm is
lost and the area is invaded by exotic weeds.
These areas are not able to recover and are
losing their fertility. The entire west Khasi hill
district of Meghalaya in North-East Himalayas,
Ladakh and Parts of Kumaon and Garhwal are
now facing the serious problem of desertification.
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CASE STUDY 2
y Waning rainfall in Udhagamandalam (Ooty)
The sub normal rainfall during 1965-1984 at Ootyin Nilgiri Mountains has been found to be closely
associated with declining forest cover in this
region in the past 20 years. The rainfall pattern
was found to fluctuate with wooded land area in
the hills. When the NIlgiri mountains had
luxuriant forest cover annual rainfall used to be
much higher.
MAJOR ACTIITIES IN FORESTS
y Timber Extraction
y Mining
Effects of Timber Extraction
y poor logging results in degraded forests.
y soil erosion, especially on slopes.
y sedimentation of irrigation systems.
y loss biodiversity.
y
climatic changes, such as lower precipitation.
y new logging roads permit shifting cultivators
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and fuel wood gatherers to gain access to logged
areas.
y loss of non-timber products
WATER RESOURCES
Water resources are sources of water that are useful or
potentially useful to humans. Uses of water includeagricultural, industrial, household, recreational and
environmental activities. Virtually all of these human
uses require fresh water.
97% of water on the Earth is salt water, leaving only 3%
as fresh water of which slightly over two thirds is frozen
in glaciers and polar ice caps. The remaining unfrozen
freshwater is mainly found as groundwater, with only a
small fraction present above ground or in the air.
Fresh water is a renewable resource, yet the world's
supply of clean, fresh water is steadily decreasing. Water
demand already exceeds supply in many parts of theworld and as the world population continues to rise, so
too does the water demand. Awareness of the global
importance of preserving water for ecosystem services
has only recently emerged as, during the 20th century,
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more than half the worlds wetlands have been lost along
with their valuable environmental services. Biodiversity-
rich freshwater ecosystems are currently declining faster
than marine or land ecosystems. The framework for
allocating water resources to water users (where such a
framework exists) is known as water rights.
A graphical distribution of the locations of water onEarth.
WATER USE AND OVER EXPLOITATION
y Increased Human Population + Rapid
Development Increased water withdrawal
demands + Wastagedue to Pollution(anthropogenic activities)
y Globally, 70% of water withdrawn is used for
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agriculture
India 93% water for agriculture sector
Water Poor Countries 4% for watering crops
y Global Industrial Usage 25%
Developed Countries 70%
Less Developed Countries 5%
y Per Capita Usage of water - wide variations
In USA an average family of 4 members consumes
1000M 3 of water every year.
Ground Water vs Surface Water
y Ground Water Aquifers
A layer of sediment or rock that is highly permeable
and contains water is called as an aquifer.
Unconfined Aquifer overlaid by permeable and
is rechargeable
Confined Aquifer sandwiched between two
impermeable layers of rock or sediments,
recharged only where aquifers intersects with the
land
y Surface Water Streams, ponds, lakes
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y Water conservation measures in agriculture,such as
using drip irrigation
y Implementing methods to retain moisture and
re-vegetate the degraded areas
MINERAL RESOURCES
y Minerals ± Naturally occurring, inorganic,crystalline solids having definite chemicalcomposition and characteristic physicalproperties
y e.g., Quartz, Feldspar, Biotite, Dolomite,Calcite, Leterite«
y Composed of elements like silicon, oxygeniron, magnesium, calcium, aluminum«
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Uses and Exploitation
y Development of industrial plants and machinery
y Generation of energy Coal, Liginite, Uranium
y Construction, Housing and other Settlements
y Transportation means
y Communication Telephone wires, cables,
y Electronic devices
y Medicinal uses
y Formation of alloys
y Agriculture as fertilizers, seed
dressings,fungicides
y Jewellery
MINERALS
y
Non-Metallic Minerals
graphite, diamond, quartz, feldspar
y Metallic Minerals
Bauxite, Laterite, Hematite
y Critical Minerals essential for the economy of
a nation e.g., iron, aluminum, copper, gold
y Strategic Minerals required for the defence
of the country e.g., Manganese, Cobalt,
Platinum, Chromium
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Impacts of Mining
y Devegetation and Defacing of Landscape
y Subsidence of Land
y Ground water Contamination
y Surface water Pollution
y Air Pollution
y Occupational Health Hazards
RemedialM
easuresy It is desirable to adopt eco-friendly mining
technology.
y The low grade ores can be better utilized byusing microbial leaching technique.Thiobacillus ferroxidans has been successfullyand economically used for extracting gold
embedded in iron sulfide oresy Restoration of mined areas by re-vegetating
them with appropriate plant species.
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FOOD RESOURCES
y The main food resources wheat, rice, maize,
barley, oats, pulses, sugarcane, other fruits and
vegetables, meat milk
y The FAO estimation minimum calorific intake
on a global scale is 2,500 calories/day.
Undernourished - < 90% of min requirementseriously under nourished - < 80%
y Deficiency or lack of nutrition malnutrition
World Food ProblemsLast 50 years
y
world grain production increased threetimes increase in per capita production by
about 50%
y population growth (mostly in less developed
countries)
y Every year 40 million people die of under
nourishment and malnutrition
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Impacts of Overgrazing
y Land Degradation
Overgrazing removes the vegetal cover over the soil
and the exposed soil gets compacted due to which
the operativesoil depth declines
Roots cannot go deep into the soil
Adequate soil moisture is not available
Organic recycling also declines in the ecosystem
Because not enough detritus or litter remains on the
soil to be decomposed The humus content of the soil decreases and
overgrazing leads to organically poor, dry,
compacted soil
Due trampling by cattle the soil loses infiltration
capacity,which reduces percolation of water into the
soil and as aresult of this more water gets lost fromthe ecosystem alongwith surface runoff
Thus overgrazing leads to multiple actions resulting in
loss of soil structure, hydraulic conductivity and soil
fertility
Soil Erosion Due to overgrazing by cattle, the cover of
vegetation almost gets removed from the land
The soil becomes exposed and gets eroded by the
action of strong wind, rainfall etc
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The grass roots are very good binders of soil
When the grasses are removed, the soil becomes
loose and susceptible to the action of wind and water.
Agriculture1. Slash and burn cultivation or shifting
cultivation
2. Modern agriculture
The types of agriculture are very different in their
process and their outputs in terms of yield as
well as their impacts on the environment.
Traditional Agriculture and its Impacts
y It usually involves a small plot, simple tools,
naturally
available water, organic fertilizers and a mix of crops
y It is more near to natural conditions and usually it
results in low production
The main Impacts of this type of agriculture arey Deforestation
The slash and burn of trees in forests to clear the land for
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cultivation and frequent shifting results in loss of forest
cover
y Soil Erosion
Clearing of forest cover exposes the soil to wind, rain and
storms, thereby resulting in loss of top fertile layer of soil
y Depletion of Nutrients
During slash and burn the organic matter in the soil gets
destroyed and most of the nutrients are taken up by the
crops within the short period, thus making the soil
nutrient poor which makes the cultivator to shift to newarea.
Modern Agriculture and its Impacts
y It makes use of hybrid seeds of selected single crop
variety, high-tech equipments and lots of energy
subsidies in the form of fertilizers, pesticides andirrigation water
y The food production has increased tremendously,
evidenced by the green revolution
The Impacts
y Impacts related to high yielding varietiesy Fertilizer related problems
y Pesticide related problems
y Water logging
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y Salinity problems
Fertilizer related problems
y Micronutrient Imbalance
Most of the chemical fertilizers used in modern
agriculture have
nitrogen, phosphorus and potassium which are essential
macronutrients
Farmers use these indiscriminately to boost up crop
growth.
y Nitrate Pollution
Nitrogenous fertilizers applied in the fields often leach
deep into soil and ultimately contaminate the ground
water.
The nitrates get concentrated in the water and when
their concentration exceeds 25 mg/L, they become thecause of aserious health hazard called Blue Baby
syndrome
y Eutrophication
Eutrophication means Over Nourishment
Due to eutrophication lakes get invaded by algal blooms;these algae grows very fast by rapidly using up the
nutrients, theyoften are toxic and badly affect the food
chain.
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get fully drenched with water and the soil-air gets
depleted
The water table rises while the roots of the plant do
not get adequate air for respiration
Mechanical strength of the soil declines, crop plants
get lodged and crop yield fails
Preventing excessive irrigation, sub-surface drainage
technology and bio-drainage with trees like Eucalyptus
are some of the remedial measures to prevent water
logging.
Salinity Problems At present rd of the total cultivable land area
of the world is affected by salts
In India about 7 million Hectares of land are
estimated to be salt affected Saline soils are characterized by the
accumulation of soluble salts like sodium
chloride, sodium sulphate, calcium chloride,
magnesium chloride
The most common method for getting rid of salts
is to flush them out by applying more goodquality water to such soils. Another method is
laying under ground network of perforated
drainage pipes for flushing out the salts slowly.
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ENERGY RESOURCES
Energy consumption is considered as an index
of its development
The first form of energy known was FIRE
Wind and Hydropower have been in use for the
last 10,000 years
The invention of steam engines replaced the
burning of wood by coal and coal was later
replaced to a great extent by oil.
In 1970s due to Iranian revolution and Arab oil
embargo the prices of oil shoot up, leading to
exploration and use of several alternate
sources of energy.
Energy SourcesA source of energy is one that can provide adequate
amount of energy in a usable form over a long period
of time
These sources are of two types: Renewable Resources which can be generated
continuously in nature and are inexhaustible
(also called as non-conventional energy sources)
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e.g., wood, solar energy, wind energy, tidal energy, hydro
power, bio-mass energy, bio-fuels, geo-thermal energy
and hydrogen
Non-renewable Resources which have
accumulated in nature over a long span of time and
cannot be quickly replenished when exhausted.
e.g., coal, petroleum, natural gas and nuclear fuels like
uranium thorium
Solar Energy Sun is the ultimate source of energy.
The nuclear fusion reaction taking place inside the
sunrelease enormous quantities of energy in the
form ofheat and light
The solar energy received by the near earth space is
approx. 1.4kJ/m2-s (solar constant) Traditional uses drying clothes and food grains,
preservation eatables, for obtaining salt from seawater
Techniques for harnessing Solar energy
Solar Heat Collectors Solar Cells
Solar Cookers Solar Water Heaters
Solar Furnaces Solar Power Plants
Solar Heat Collectors These can be passive or active in nature
Passive heat collectors are natural
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materials like stones, brickswhichabsorb heat during
day time and release itslowly at night
Active solar collectors pump a heat
absorbing medium (air or water) through a
small collector which is normally placed at
top of the building.
Solar Water Heater It consists of an insulated box painted black from
inside and having a glass lid to receive and storesolar heat
Inside the box it has black painted copper coil
through which cold water is made to flow in, which
gets heated and flows out into storage tank.
Solar Furnace Thousands of plane mirrors are arranged in concave
Reflectors , all of which collect the solar heat and
produce a high temperature.
Solar Power Plants Solar energy is harnessed on a large scale by using
concave reflectors which cause boiling of water to
produce steam; the steam turbine drives a generator to
produce electricity.
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Hydro Power Water enters the plant when an intake gate is
opened, and moves through the penstock. Gravity
and a narrowing scroll case increase the pressure of
the water as it enters the turbine. Water exits the
turbine and is returned to the river. The turbine
spins a rotor directly above it, and electricity
produced by the interaction of rotor and stator is
transmitted through a transformer at the station and
thence to the grid. Hydro power does not cause any pollution, it is
renewable and normally the hydro power projects
are multi purpose projects helping in controlling
floods, used for irrigation, navigation etc.
Ocean Thermal Energy The energy available due to the difference in
temperature of water at the surface of the
tropical oceans and at deeper levels is called
ocean thermal energy
A difference of 20C or more is requiredbetween surface water and deeper water of
ocean for operating Ocean Thermal Energy
Conservation power plants
The warm surface water of ocean is used to
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boil a liquid like ammonia, the high pressure vapors of
the liquid are then used to turn turbine of a generator
and produce electricity.
Geothermal Energy The energy harnessed from the hot rocks
present inside the earth is called geothermal
energy
High temperature, high pressure steam fields
exist below the earths surface in many places,this heat comes from the fission of the
radioactive material naturally present in the
rocks
Holes are drilled artificially upto the hot rocks
and and pipes are put through which the steam
gushes out at high pressure which turns theturbine of a generator to produce electricity.
Bio-mass Energy Bio-mass is the organic matter produced by the
plants or animals which include wood, cropresidues, cattle dung, manure, sewage
The bio-mass is directly used as a fuel but the
efficiency of such furnaces is very low and it
produces lot of smoke causing air pollution
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LAND RESOURCES
Land is a finite and valuable resourceupon which we
depend for the basicamenities of life
Soil is classified as a renewable resource
The rate of regeneration of soil is very slow, about
200-1000 years are needed for the formation of 1
of soil, depending on the climate and soil type.
Land degradation With increasing population growth the demand
for arable land for producing food, fiber and fuelwood are also increasing
more and more pressure on the limited land
resource; degraded due to over exploitation
Soil degradation is a real cause of alarm
because soil formation is an extremely slow
process Soil erosion, water-logging, salinization and
contamination of the soil with the various
industrial wastes cause land degradation.
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Soil Erosion Soil erosion means wearing away of the soil; defined
as movement of soil components, especially surface
litter and top soil from one place to another
Soil erosion results in loss of fertility because it is the
top soil layer that is fertile.
Types
Normal erosion or geologic erosion
gradual removal of top soil by natural processes which
bring an equilibrium between physical, biological andhydrological activities and maintain a natural balance
between erosion and renewal
Accelerated erosion
caused by anthropogenic activities; the rate of erosion is
much faster than the rate of formation of soil;
Overgrazing,deforestation, mining accelerated erosion
Agents causing soil erosion
Climatic Agents Water and wind are the climatic agents of the soil
erosion.
Water effects soil erosion in the form of torrential rains,
rapid flow of
water along slopes, run-off, wave action and melting
andmovement of snow
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Wind affects soil erosion in the form of saltation
(verticalmovement of soil under the influence of direct
pressure of
stormy winds), suspension and surface creep
Biotic Agents Excessive grazing, mining and deforestation are the
major biotic agents responsible for soil erosion
Due to these processes the top soil is disturbed or
rendered devoid of vegetal cover.
Soil Conservation Practicesy Conservational till farming
y Contour farming
y Terracing
y
StripC
roppingy Alley Cropping
Conservation till farming Special tillers are used to break up and
loosen the subsurface soil without turning
up the top soil
The tilling machine make slits in the unploughed
soil and injects seeds, fertilizers, herbicides and a little
water in the slit, so that the seed germinates and
the crop grows.
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TERRACING
STRIP CROPPING
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Land Slides Various anthropogenic activities like hydro-electric
projects, large dams, reservoirs, construction of
roads and railway lines, construction of buildings,
mining are responsible for clearance of large
forested areas.
During the construction of roads, mining activities
etc., huge portions of fragile mountainous areas
are cut or destroyed by dynamite and thrown into
adjacent valleys and streams. These activitiesweaken the already fragile mountain slopes and
lead to land slides
They also increase the turbidity of various nearby
streams thereby reducing their productivity.
Desertification Desertification is a process whereby the
productive potential of a rid and semi-arid land
falls by 10% or more
Moderate desertification 10-25% drop
Severe desertification 25-50% drop
Very Severe desertification >50% drop Desertification is characterized by devegetation
and loss of vegetal cover, depletion of ground,
salinization ans severe soil erosion
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