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8/7/2019 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.



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



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



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



MAJOR NATURAL RESOURCES

y Forest Resources

y Water Resources

y Mineral Resources

y Food Resources

y Energy Resources

y Land Resources



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%



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.



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.



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.



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



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,



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



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



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«



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



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.



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



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



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



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



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.



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.



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)



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



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.



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



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



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.



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



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.



TERRACING

STRIP CROPPING



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



Causes

Deforestation, Overgrazing, Mining

Conservation of Natural Resources

- Role of an individual

Equitable use of Resources for

Sustainable Lifestyle .

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