unit vi air pollution

8/2/2019 Unit Vi Air Pollution

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Unit VI: Air Pollution

AIR POLLUTION

It is an atmospheric condition in which certain substances (including the normal

constituents in excess) are present in concentrations which can cause undesirable effects

on man and his environment. These substances include gases, particulate matter,

radioactive substances etc. Gaseous pollutants include oxides of sulphur (mostly SO2, SO3)

oxides of nitrogen (mostly NO and NO2 or NOx), carbon monoxide (CO), volatile organic

compounds (mostly hydrocarbons) etc. Particulate pollutants include smoke, dust, soot,

fumes, aerosols, liquid droplets, pollen grains etc. Radioactive pollutants include radon-

222, iodine-131, strontium- 90, plutonium-239 etc.

WHAT CAUSES AIR POLLUTION?

Air pollution may be caused by various natural and anthropogenic processes. Below are

listed some of the main air pollution causes.

NATURAL:

Volcanic activities volcanic eruptions emit a serious of toxic gases (includingsulfur and chlorine) as well as particulate matter (ash particles) but are usually

restricted to localized areas;

Winds and air currents can mobilize pollutants from the ground and transportthem over large areas;

Wildfires add to the atmosphere smoke, carbon monoxide as well as particulatematter (containing organic contaminants such as PAHs) and could affect significant

areas although in general are restricted and may be contained; Microbial decaying processes microorganisms which are present in any

environment have a major role in natural decaying processes of living organisms as

well as environmental contaminants; this activity results in the natural release of

gases especially methane gas;

Radioactive decay processes for example radon gas is emitted due to naturaldecay processes of Earths crust which as potential to accumulate in enclosed spaces

such as basements;

Increasing temperatures contribute to an increase in the amounts ofcontaminants volatilizing from pollution soil and water into air.

ANTHROPOGENIC:

Mining and smelting emit into the air a variety of metals adsorbed on particulatematter that is suspended in the air due to crushing & processing of mineralogical

deposits;


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Mine tailing disposal due to their fine particulate nature (resulting after crushingand processing mineral ores) constitute a source of metals to ambient air which

could be spread by wind over large areas;

Foundry activities emit into the air a variety of metals adsorbed on particulatematter that is suspended in the air due to processing of metallic raw materials

(including the use of furnaces);

Various industrial processes may emit both organic and inorganiccontaminants through the following mechanisms:

Accidental spills and leaks of stored chemicals Handling and storage of chemicals especially of volatile inorganic chemicals Transportation emits a series of air pollutants (gases including carbon

monoxide, sulfur oxides and nitrogen odides - and particulate matter) through the

tailpipe gases due to internal combustion of various fuels (usually gases such as

opxides of carbons, of sulfur, of nitrogen, as well as organic chemicals as PAHs)

Construction and Demolition activities pollute the air with various constructionmaterials. Of special threat is the demolishion of old buildings which may contain a

series of banned chemicals such as PCBs, PBDEs, asbestos. Coal Power Plants by burning coal they may emit a series of gases as well as

particulate matter with metals (such as As, Pb, Hg) and organic compounds

(especially PAHs);

Heating of buildings emits a series of gases and particulate matters due toburning of fossil fuels;

Waste Incineration depending on waste composition, various toxic gases andparticulate matter is emitted into the atmosphere;

Agriculture pollute the air usually through emissions of ammonia gas and theapplication of pesticides/herbicdes/insecticides which contain toxic volatile organiccompounds;

Military activities may introduce toxic gases through practices and training; Smoking emits a series of toxic chemicals including a series of organic and

inorganic chemicals, some of which are carcinogenic;

Effects of air pollution: Air pollution has adverse effects on living organisms and

materials.

Effects on Human Health: Human respiratory system has a number of mechanisms for

protection from air pollution. Bigger particles (> 10 m) can be trapped by the hairs andsticky mucus in the lining of the nose. Smaller particles can reach tracheobronchial system

and there get trapped in mucus. They are sent back to throat by beating of hair like cilia

from where they can be removed by spitting or swallowing. Years of exposure to air

pollutants (including cigarette smoke) adversely affect these natural defenses and can

result in lung cancer, asthma, chronic bronchitis and emphysema (damage to air sacs

leading to loss of lung elasticity and acute shortness of breath). Suspended particulates can


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cause damage to lung tissues and diseases like asthma, bronchitis and cancer especially

when they bring with them cancer causing or toxic pollutants attached on their surface.

Sulphur dioxide (SO2) causes constriction of respiratory passage and can cause bronchitis

like conditions. In the presence of suspended particulates, SO2 can form acid sulphate

particles, which can go deep into the lungs and affect them severely. Oxides of nitrogen

especially NO2 can irritate the lungs and cause conditions like chronic bronchitis and

emphysema. Carbon monoxide (CO) reaches lungs and combines with haemoglobin of

blood to form carboxyhaemoglobin. CO has affinity for haemoglobin 210 times more than

oxygen. Haemoglobin is, therefore, unable to transport oxygen to various parts of the body.

This causes suffocation. Long exposure to CO may cause dizziness, unconsciousness and

even death. Many other air pollutants like benzene (from unleaded petrol), formaldehyde

and particulates like polychlorinated biphenyls (PCBs) toxic metals and dioxins (from

burning of polythene) can cause mutations, reproductive problems or even cancer.

Effects on Plants: Air pollutants affect plants by entering through stomata (leaf pores

through which gases diffuse), destroy chlorophyll and affect photosynthesis. Pollutants also

erode waxy coating of the leaves called cuticle. Cuticle prevents excessive water loss and

damage from diseases, pests, drought and frost. Damage to leaf structure causes necrosis

(dead areas of leaf), chlorosis (loss or reduction of chlorophyll causing yellowing of leaf) or

epinasty (downward curling of leaf), and abscission (dropping of leaves). Particulates

deposited on leaves can form encrustations and plug the stomata. The damage can result in

death of the plant.

Effects on aquatic life: Air pollutants mixing up with rain can cause high acidity (lower

pH) in fresh water lakes. This affects aquatic life especially fish. Some of the freshwater

lakes have experienced total fish death.

Effects on materials: Because of their corrosiveness, particulates can cause damage to

exposed surfaces. Presence of SO2 and moisture can accelerate corrosion of metallic

surfaces. SO2 can affect fabric, leather, paint, paper, marble and limestone. Ozone in the

atmosphere can cause cracking of rubber. Oxides of nitrogen can also cause fading of cotton

and rayon fibres.

Control of Air Pollution: - Air pollution can be minimized by the following methods:

1. Siting of industries after proper Environmental Impact Assessment studies.2. Using low sulphur coal in industries3. Removing sulphur from coal (by washing or with the help of bacteria)4. Removing NOx during the combustion process.5. Removing particulate from stack exhaust gases by employing electrostatic

precipitators, bag-house filters, cyclone separators, scrubbers etc.

6. Vehicular pollution can be checked by regular tune-up of engines ; replacementof more polluting old vehicles; installing catalytic converters ; by engine

modification to have fuel efficient (lean) mixtures to reduce CO and


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hydrocarbon emissions; and slow and cooler burning of fuels to reduce NOx

emission (Honda Technology).

7. Using mass transport system, bicycles etc.8. Shifting to less polluting fuels (hydrogen gas).9. Using non-conventional sources of energy.10.Using biological filters and bio-scrubbers.11.Planting more trees

Greenhouse effect:-

The greenhouse effect is an increase in the temperature of a planet as heat energy from

sunlight is trapped by the gaseous atmosphere. Excess carbon dioxide and water vapor

increase this global warming effect. Solar Energy (sunlight) is short-wavelength radiation

which easily penetrates the Earth's atmosphere and warms the Earth; only about one

quarter of incoming sunlight is reflected by the atmosphere. The warmed Earth emits long-

wavelength radiation (infrared waves or heat energy) back into space; these longer waves

are mostly reflected back to Earth by the atmosphere. The size of the atmosphere in the

illustration above is greatly exaggerated in order to show the greenhouse effect. Most of the

Earth's atmosphere is within 10 miles (16 km) of the Earth's surface).

Much of these harmful gases are produced either naturally or by various human

activities; which we should reduce. Brief description and effects of six important

greenhouse gases are given below:

1. Carbon dioxide (CO2) A naturally occurring gas produced by living organisms andfermentation. It is a normal component of the breath we exhale; it is hazardous in

concentrated volumes. Large quantity of carbon dioxide is produced by the

combustion of carbonaceous fuels. Carbon dioxide emissions from fuel burning,

responsible for about 87 percent of global warming, have increased by about 27

percent since the industrial revolution.

2. Nitrogen oxides (NOx) Nitrogen oxides are naturally occurring from microbialaction in soil. NOx is also produced by fuel burning. Scientists say its production is

increased by the use of nitrogen based fertilizers in agriculture, as well as by the use

of catalytic converters in automobiles.

3. Methane (CH4) Methane is a naturally occurring, in-flammable gas. Methane isproduced by geological coal formations and by the decomposition of organic

matters. Leading man-related sources of methane are landfills; livestock digestive

processes and waste, especially ruminants (cud-chewing animals); and wetland rice

cultivation.

4. Hydroflurocarbon gasses (HFCs) Chlorofluorocarbons (CFC), the coolant, cleaning,and propellant gases were blacklisted internationally due to its ozone-eating

characteristics. HFCs do contribute to global warming. Global warming potential of

HFCs is 4,000 to 10,000 times that of CO2.


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5. Perfluorocarbons (PFC), or perflurocompounds Man-made replacement gases forCFCs but result also as a by-product of aluminium smelting. PFCs also used as a

purging agent for semi-conductor manufacture and small amounts are produced

during uranium enrichment processes. Global warming potential of

Perfluorocarbons (PFC), or perflurocompounds is 6,000 to 10,000 that of CO2.

6. Sulfur hexafluoride (SF6) - Very low atmospheric concentration makes it an idealtest gas for gas concentration monitors. Principle uses: insulating material for high-voltage equipment like circuit breakers at utilities. Also used in water leak detection

for cable cooling systems. SF6 is a man-made gas.

Impacts of Enhanced Greenhouse Effect

The enhanced greenhouse effect will not only cause global warming but will also affect

various other climatic and natural processes.

1. Global temperature increase: It is estimated that the earth.s mean temperaturewill rise between 1.5 to 5.5C by 2050 if input of greenhouse gases continues to rise

at the present rate. Even at the lower value, earth would be warmer than it has been

for 10,000 years.

2. Rise in Sea Level: With the increase in global temperature sea water will expand.Heating will melt the polar ice sheets and glaciers resulting in further rise in sea

level. Current models indicate that an increase in the average atmospheric

temperature of 3C would raise the average global sea level by 0.2.1.5 meters over

the next 50.100 years. One meter rise in sea level will inundate low lying areas of

cities like Shanghai, Cairo, Bangkok, Sydney, Hamburg and Venice as well as

agricultural lowlands and deltas in Egypt, Bangladesh, India, China and will affect

rice productivity. This will also disturb many commercially important spawninggrounds, and would probably increase the frequency of storm damage to lagoons,

estuaries and coral reefs. In India, the Lakshadweep Islands with a maximum height

of 4 meters above the level may be vulnerable. Some of the most beautiful cities like

Mumbai may be saved by heavy investment on embankment to prevent inundation.

Life of millions of people will be affected, by the sea level rise who have built homes

in the deltas of the Ganges, the Nile, the Mekong, the Yangtze and the Mississippi

rivers.

3.

Effects on Human Health: The global warming will lead to changes in the rainfallpattern in many areas, thereby affecting the distribution of vector-borne diseases

like malaria, filariasis, elephantiasis etc. Areas which are presently free from

diseases like malaria, schistosomiasis etc. may become the breeding grounds for the

vectors of such diseases. The areas likely to be affected in this manner are Ethiopia,

Kenya and Indonesia. Warmer temperature and more water stagnation would

favour the breeding of mosquitoes, snails and some insects, which are the vectors of


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such diseases. Higher temperature and humidity will increase/aggravate

respiratory and skin diseases.

4. Effects on Agriculture: There are different views regarding the effect of globalwarming on agriculture. It may show positive or negative effects on various types of

crops in different regions of the world. Tropical and subtropical regions will be

more affected since the average temperature in these regions is already on the

higher side. Even a rise of 2C may be quite harmful to crops. Soil moisture will

decrease and evapo-transpiration will increase, which may drastically affect wheat

and maize production. Increase in temperature and humidity will increase pest

growth like the growth of vectors for various diseases. Pests will adapt to such

changes better than the crops. To cope up with the changing situation drought

resistant, heat resistant and pest resistant varieties of crops have to be developed.

Measures to Check Global Warming To slow down enhanced global warming the

following steps will be important:

1. Cut down the current rate of use of CFCs and fossil fuel.2. Use energy more efficiently.3. Shift to renewable energy resources.4. Increase Nuclear Power Plants for electricity production.5. Shift from coal to natural gas.6. Trap and use methane as a fuel.7. Reduce beef production8. Adopt sustainable agriculture.9. Stabilize population growth.10.Efficiently remove CO2 from smoke stacks.11.Plant more trees.12.Remove atmospheric CO2 by utilizing photosynthetic algae.

GLOBAL WARMING:-

Global Warming or Climate Change, measurable increases in the average temperature of

Earths atmosphere, oceans, and landmasses. Scientists believe Earth is currently facing a

period of rapid warming brought on by rising levels of heat-trapping gases, known as

greenhouse gases, in the atmosphere. Greenhouse gases retain the radiant energy (heat)

provided to Earth by the Sun in a process known as the greenhouse effect.

Greenhouse gases retain the radiant energy (heat) provided to Earth by the Sun in a

process known as the greenhouse effect. Greenhouse gases occur naturally, and without

them the planet would be too cold to sustain life as we know it. Since the beginning of the

Industrial Revolution in the mid-1700s, however, human activities have added more and


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more of these gases into the atmosphere. For example, levels of carbon dioxide, a powerful

greenhouse gas, have risen by 35 percent since 1750, largely from the burning of fossil

fuels such as coal, oil, and natural gas. With more greenhouse gases in the mix, the

atmosphere acts like a thickening blanket and traps more heat.

What is Global Warming?

Global Warming is the increase of Earth's average surface temperature due to effect ofgreenhouse gases, such as carbon dioxide emissions from burning fossil fuels or from

deforestation, which trap heat that would otherwise escape from Earth. This is a type

ofgreenhouse effect.

Global Warming Impacts

Many of the following "harbingers" and "fingerprints" are now well under way:

1. Rising Seas--- inundation of fresh water marshlands (the everglades), low-lyingcities, and islands with seawater.

2. Changes in rainfall patterns --- droughts and fires in some areas, flooding in otherareas. See the section above on the recent droughts, for example!

3. Increased likelihood of extreme events--- such as flooding, hurricanes, etc.4. Melting of the ice caps --- loss of habitat near the poles. Polar bears are now

thought to be greatly endangered by the shortening of their feeding season due to

dwindling ice packs.

5. Melting glaciers - significant melting of old glaciers is already observed.6. Widespread vanishing of animal populations --- following widespread habitat

loss.

7. Spread of disease --- migration of diseases such as malaria to new, now warmer,regions.

8. Bleaching of Coral Reefs due to warming seas and acidification due to carbonicacid formation --- One thirdof coral reefs now appear to have been severely

damaged by warming seas.

9. Loss of Plankton due to warming seas --- The enormous (900 mile long) Aleutionisland ecosystems of orcas (killer whales), sea lions, sea otters, sea urchins, kelp

beds, and fish populations, appears to have collapsed due to loss of plankton,

leading to loss of sea lions, leading orcas to eat too many sea otters, leading to

urchin explosions, leading to loss of kelp beds and their associated fish populations.


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What is the Ozone Layer?

The ozone layer is the Shield in the Sky. All life on earth depends on the existence of this

layer of gas called the ozone layer. The ozone molecule is composed of three atoms of

oxygen and is an extremely rare component of the earths atmosphere: in every 10 000 000

air molecules, about three are ozone. More than 90% of ozone is found in the upper

atmosphere (stratosphere). The ozone layer, as a shield, absorbs all but a small fraction of

the harmful and damaging UV-B radiation coming from the sun. This layer is therefore, veryimportant in protecting human, plant and animal lives from UV-B which, in high doses, can

be particularly damaging to natural life as we know it today.

What is depleting the ozone layer?

Chlorofluorocarbons (CFCs) account for approximately 80% of stratospheric ozone

depletion. Other compounds that contribute to ozone depletion include: halons, carbon

tetrachloride, methyl chloroform, hydrochlorofluorocarbons (HCFCs), and methyl bromide.

These are known as industrial halocarbons.

These compounds are used in refrigerators, furniture foam, fire extinguishers, etc. Human

activities also contribute to the gradual disappearance of the ozone layer such as,

deforestation, fertilizer use, and fossil fuel combustion. There are a couple of reasons why

industrial halocarbons are very effective at ozone depletion.

The first is the fact that they survive long enough to reach the stratosphere and second they

help natural reactions that destroy ozone. Once in the stratosphere, UV-C radiation breaks

up compounds releasing chlorine and bromine.

Effects of Ozone Depletion

Ozone depletion in the stratosphere will result in more UV radiation reaching theearth especially UV-B (290-320 nm). The UV-B radiations affect DNA and the

photosynthetic chemicals. Any change in DNA can result in mutation and cancer.


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Cases of skin cancer (basal and squamous cell carcinoma) which do not cause death

but cause disfigurement will increase.

Easy absorption of UV rays by the lens and cornea of eye will result in increase inincidents of cataract.

Melanin producing cells of the epidermis (important for human immune system)will be destroyed by UV-rays resulting in immuno-suppression. Fair people (can.t

produce enough melanin) will be at a greater risk of UV exposure.

Phytoplanktons are sensitive to UV exposure. Ozone depletion will result indecrease in their population thereby affecting the population of zooplankton, fish,

marine animals, in fact the whole aquatic food chain.

Yield of vital crops like corn, rice, soybean, cotton, bean, pea, sorghum and wheatwill decrease.

Degradation of paints, plastics and other polymer material will result in economicloss due to effects of UV radiation resulting from ozone depletion.

ROLE OF INDIVIDUALS IN POLLUTION PREVENTION

Prevention is better than cure Similarly it is better to control the air pollutants at its

source itself. The following are the steps to be taken to control the air pollution.

1. The exhaust gases from automobiles and vehicles should be minimized by the use ofcatalyst.

2. Chimneys may be used to reduce the concentration of pollutants at the ground level.3. Smoke may be removed by cottrell's electrostatic precipitator.4.

Dust Particles can be removed by the use of bag filters and dust separators.

5. Plants take carbon dioxide during photosynthesis and release oxygen to environment.Hence more trees should be planted.

6. Non polluting fuels can be used for energy production.


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What is Soil Pollution?

In a general sense, soil pollution definition is the presence of toxic chemicals (pollutants or

contaminants) in soil in high enough concentrations to be of risk to human health and/or

ecosystem. Additionally, even when the levels of contaminants in soil are not of risk, soil

pollution may occur simply due to the fact that the levels of the contaminants in soil exceed

the levels that are naturally present in soil (in the case of contaminants which occur

naturally in soil). Soil pollutants include a large variety of contaminants or chemicals(organic and inorganic), which could be both naturally-occurring in soil and man-made. In

both cases, the main soil pollution causes are the human activities (i.e., the accumulation of

those chemicals in soil at levels of health risk is due to human activities such as accidental

leaks and spills, dumping, manufacturing processes, etc.). Accumulation due to natural

processes is also possible, but it has only been recorded in few cases (such as the

accumulation of higher levels of perchlorate in soil from Atacama Desert in Chile which is

purely due to natural processes in arid environments). Natural processes, however, may

have an influence of the human released toxic chemicals (pollutants) in the soil, overall

decreasing or increasing the pollutant toxicity and/or the level of contaminated soil. This is

possible due to the complex soil environment involving the presence of other chemicals

and natural conditions which may interact with the released pollutants.

What Causes Soil Pollution?

Soil pollution is a result of many activities and experiments done by mankind which end up

contaminating the soil. Here are some of the leading soil pollution causes:

Industrial wastes such as harmful gases and chemicals, agricultural pesticides,fertilizers and insecticides are the most common causes of soil pollution.

Ignorance towards soil management and related systems. Unfavorable and harmful irrigation practices. Improper septic system and management and maintenance of the same. Leakages from sanitary sewage. Acid rains, when fumes released from industries get mixed with rains. Fuel leakages from automobiles, that get washed away due to rain and seep into the

nearby soil.

Unhealthy waste management techniques, which are characterized by release ofsewage into the large dumping grounds and nearby streams or rivers.

What are the Effects of Soil Pollution?

The effects of pollution on soil are quite alarming and can cause huge disturbances in the

ecological balance and health of living creatures on earth. Some of the most serioussoil

pollutioneffects are:
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Decrease in soil fertility and therefore decrease in the soil yield. How can one expectcontaminated soil to produce healthy crops?

Loss of soil and natural nutrients present in it. Plants also would not thrive in suchsoil, which would further result in soil erosion.

Disturbance in the balance of flora and fauna residing in the soil. Increase in salinity of the soil, which therefore makes it unfit for vegetation, thus

making it useless and barren.

Generally crops cannot grow and flourish in polluted soil. Yet, if some crops manageto grow, they would be poisonous enough to cause serious health problems in

people consuming them.

Creation of toxic dust is another potential effect of soil pollution. Foul smell due to industrial chemicals and gases might result in headaches, fatigue,

nausea, etc., in many people.

Soil pollutants would bring in alteration in the soil structure, which would lead todeath of many essential organisms in it. This would also affect the larger predators

and compel them to move to other places, once they lose their food supply.

Control Soil Pollution

Toxic chemical compounds, salts, radioactive agents, toxins and other waste contribute to

soil pollution. These have adverse effect on plant and animal health. Soil contains both

organic as well as inorganic material. The organic material is formed due to decaying of

plant and animal matter. This often makes up the upper most layer of soil. The organic soil

such as rocks, has taken over thousands of years to be formed. The top layer is made up of

organic soil, while the layers below are inorganic soil. Pollution has gradually reached the

inorganic layers as well. There are different types of soil pollution, namely agricultural soil

pollution, industrial waste causing soil pollution, urbanization causing soil pollution. Thesedifferent types of pollution cause the fertility of the soil to reduce and mineral content in

the soil to be destroyed. Therefore, measures have to be taken for preventing soil pollution.

Promote Bio Fertilizers: To increase agricultural yield, most farmers took to using

chemical fertilizers. No doubt that the yield did indeed increase, but at the cost of the soil

losing its fertility. To restore the fertility of the soil to what it was, will take a very long

time, however, one has to start at some point of time. Drastic measures are required for the

same. Farmers should be encouraged to start using bio fertilizers. The microorganisms in

these fertilizers will help in increasing the fertility of the soil.

Promote Use of Bio Pesticides and Fungicides: To avoid soil pollution, it is important,

that along with fertilizers, farmers should shift to bio pesticides and fungicides, also known

as herbicides. These products will take a little longer to react, but they do not have adverse

effect on the soil. It is best to use manure both as a fertilizer as well as pesticide, as it has

far less side effects as opposed to its chemical counterpart.


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Reduce Toxic Waste: If one has to look at the soil pollution facts, it will be seen that toxic

waste has a big role to play in soil pollution. Hence, industrial toxic waste should be treated

to reduce its toxicity before it is disposed off. At the same time, responsible methods should

be used for disposing off the waste. The best, however, is to avoid the use of harmful

chemicals unless they are of extreme importance.

Recycle Waste: Although a lot of propaganda has been carried out about recycling waste,

not many measures have been taken about the same. If each family has to take it uponthemselves to recycle waste, the land pollution caused due to landfills will be reduced

considerably. The land so saved can be used constructively for a number of better tasks.

Reuse: After plastic was invented, people thought it was convenient to opt for plastic

containers, bags, etc., which could be disposed off after use. However, plastic is one of the

main cause of soil pollution, as it takes a very long time to disintegrate. Therefore, people

should consider shifting to reusable containers like glass, cotton bags, etc. Although paper

does disintegrate faster, a lot of trees are cut for producing paper bags. Therefore, it is best

to opt for cloth bags. Similarly, instead of using tissue papers in the kitchen, etc., one should

opt using cloth napkins, handkerchief, etc. This will go a long way in reducing landfills.

Opt for Organic Products: There is no doubt that the organic products are costly as

opposed to the chemically grown products. But choosing the organic products will

encourage more organic production. This will help in preventing soil pollution.

Deforestation: To prevent soil pollution, deforestation measures have to be undertaken at

rapid pace. Soil erosion is caused, when there are no trees to prevent the top layer of the

soil from being transported by different agents of nature like water and air. At the same

time, measures should be taken to avoid over cropping and over grazing, as it leads to flood

and soil erosion and further deterioration of the soil layer.

What is Forest?

the forest is a complex ecosystem consisting mainly of trees that buffer the earth and

support a myriad of life forms. The trees help create a special environment which, in turn,

affects the kinds of animals and plants that can exist in the forest. Trees are an important

component of the environment. They clean the air, cool it on hot days, conserve heat at

night, and act as excellent sound absorbers. Plants provide a protective canopy that lessens

the impact of raindrops on the soil, thereby reducing soil erosion. The layer of leaves that

fall around the tree prevents runoff and allows the water to percolate into the soil. Rootshelp to hold the soil in place. Dead plants decompose to form humus, organic matter that

holds the water and provides nutrients to the soil. Plants provide habitat to different types

of organisms. Birds build their nests on the branches of trees, animals and birds live in the

hollows, insects and other organisms live in various parts of the plant. They produce large

quantities of oxygen and take in carbon dioxide. Transpiration from the forests affects the

relative humidity and precipitation in a place.


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What are the different types of forest?

Forests are classified by biomes so that each forest type corresponds to a climatic region.

Within the main three forest biomes (tropical, temperate or boreal) one can find multiple

forest types. More

1. Tropical forests (rainforests but also others) occur near the equator and are themost ecologically rich of all forest types. They regenerate very rapidly but they arethe most threatened forests, primarily by logging (reforestation is rare but it has

been successfully achieved in some places) and clearance for agriculture (which is

often permanent and leads to soil erosion). They are characterized by 25-35 m tall

trees with a multi-layered and continuous canopy, a highly diverse flora, and a fauna

including numerous birds, bats, small mammals, and insects. More There are four

tropical forest types: evergreen rainforest, seasonal rainforest, semi-evergreen

forestand moist/dry deciduous forest. More

2. Temperate forests occur in eastern North America, northeastern Asia, and westernand central Europe. Regeneration is slower because the growing season is short.

Their total area has not changed much in recent years but plantations have steadily

replaced old-growth forests. More Temperatures vary from 30C to 30C and

precipitation (75-150cm) is evenly distributed throughout the year. The soil is

fertile and the canopy moderately dense. There are some 3-4 species of flora per

square kilometer and fauna is represented by squirrels, rabbits, birds and deer

among others. More There are five temperate forest types: moist conifer forest,

dry conifer forest, Mediterranean forest, temperate coniferous and temperate

broad-leaved rainforest. More

3. Boreal forests, or taiga, represent the largest terrestrial biome. They are found inareas with shorter, warm summers and long winters. Hence the growing season isvery short, and regeneration occurs slowly. There are boreal forests in Europe, Asia,

Siberia, and North America. Because of the cold climates, plant life in the boreal

forest is sturdy, consisting mainly of evergreens and other resilient vegetation. The

forest canopy is so dense that little light reaches the forest floor. More

Temperatures are very low and annual precipitations (mostly snow) range from 40

to 100 cm. The soil is nutrient-poor and acidic. Flora is mostly cold-tolerant

evergreen conifer and fauna includes woodpeckers, bear, lynx, fox and wolf among

others.

Afforestation: is the establishment of a forest or stand of trees in an area where there

was no forest. Reforestation is the reestablishment of forest cover, either naturally (by

natural seeding, coppice, or root suckers) or artificially (by direct seeding or planting).

Many governments and non-governmental organizations directly engage in programs of

afforestation to create forests, increase carbon capture and sequestration, and help to


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anthropogenically improve biodiversity. (In the UK, afforestation may mean converting the

legal status of some land to "royal forest".) Special tools, e.g. tree planting bar, are used to

make planting of trees easier and faster.

In areas of degraded soil: In some places, forests need help to reestablish themselves

because of environmental factors. For example, in arid zones, once forest cover is

destroyed, the land may dry and become inhospitable to new tree growth. Other factors

include overgrazing by livestock, especially animals such as goats, cows, and over-harvesting of forest resources. Together these may lead to desertification and the loss of

topsoil; without soil, forests cannot grow until the long process of soil creation has been

completed - if erosion allows this. In some tropical areas, forest cover removal may result

in a duricrust or duripan that effectively seal off the soil to water penetration and root

growth. In many areas, reforestation is impossible because people are using the land. In

other areas, mechanical breaking up of duripans or duricrusts is necessary, careful and

continued watering may be essential, and special protection, such as fencing, may be

needed.

A plantation: is a long artificially established forest, farm or estate, where crops aregrown for sale, often in distant markets rather than for local on-site consumption. The term

plantation is informal and not precisely defined. Crops grown on plantations include fast-

growing trees (often conifers), cotton, coffee, tobacco, sugar cane, sisal, some oil seeds

(notably oil palms) and rubber trees. Farms that produce alfalfa, Lespedeza, clover, and

other forage crops are usually not called plantations. The term "plantation" has usually not

included large orchards (except for banana plantations), but does include the planting of

trees for lumber. A plantation is always a monoculture over a large area and does not

include extensive naturally occurring stands of plants that have economic value. Because of

its large size, a plantation takes advantage of economies of scale. Protectionist policies andnatural comparative advantage have contributed to determining where plantations have

been located.

Among the earliest examples of plantations were the latifundia of the Roman Empire,

which produced large quantities of wine and olive oil for export. Plantation agriculture

grew rapidly with the increase in international trade and the development of a worldwide

economy that followed the expansion of European colonial empires. Like every economic

activity, it has changed over time. Earlier forms of plantation agriculture were associated

with large disparities of wealth and income, foreign ownership and political influence, and

exploitative social systems such as indentured labor and slavery.

Pollution due Agricultural Patterns:

A wide range of contaminants can reach the river either via groundwater or through

drainage ditches, including artificial fertilizer residues, insecticides, herbicides, pesticides


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and farmyard waste, all of which are potentially very harmful. Accidental milk spillage from

dairies is a serious contaminant.

Undiluted animal manure (slurry) is one hundred times more concentrated than domestic

sewage, and can carry a parasite, Cryptosporidium, which is difficult to detect. Silage liquor

(from fermented wet grass) is even stronger than slurry, with a low pH and very high BOD

(Biological Oxygen Demand). With a low pH, silage liquor can be highly corrosive; it can

attack synthetic materials, causing damage to storage equipment, and leading to accidentalspillage.

Milk spillage, silage liquor, cattle and pig slurry; these are all examples of point source

pollution. Diffuse source pollution from agricultural fertilizers is more difficult to trace,

monitor and control. High nitrate concentrations are found in groundwater and may reach

50mg/litre (the EU Directive limit). In ditches and river courses, nutrient pollution from

fertilizers causes eutrophication. This is worse in winter, after autumn ploughing has

released a surge of nitrates; winter rainfall is heavier increasing runoff and leaching, and

there is lower plant uptake. Phytoplankton and algae thrive in the nutrient-rich water.

Normally, blue-green algae are very important in the river ecosystem, photosynthesisingsunlight energy, and liberating oxygen into the water. In large numbers, however, algae can

become excessive, discolouring the water, giving an unpleasant smell and robbing the

water of valuable oxygen as bacteria work overtime feeding on dead algae remains. Blue-

green algae can also produce toxins, which kill wildlife, cause skin rashes, and cause pains

and stomach upsets.

Eutrophication is thus depriving the river of oxygen (called "oxygen debt"). As algae

dominate and turn the water green, the growth of other water plants is suppressed; these

die first, disrupting the food chain. Death of invertebrates and fish follow on, and their dead

remains in turn lead to excess bacterial activity during decomposition, reducing oxygen

levels still further. Water with high BOD figures are badly polluted, lower figures are better.

Pesticide and fertilizer:-

Despite land degradation, agricultural yields continue to increase, in part thanks to

synthetic fertilizers and pesticides that temporarily boost soil productivity. Fertilizer

consumption has increased exponentially since the 1950s, so much so that 50% of all

commercial fertilizer ever produced has been applied since 1984.

While fertilizer application can increase short term crop yields or keep the grass on yourlawn green through November, it comes with its share of detrimental environmental and

health effects. Many of the problems stem from the inability of the soil to retain all of the

fertilizer applied. In fact, it is estimated that about one half of every metric ton of fertilizer

applied to fields never even makes it into plant tissue, but instead ends up evaporating or

being washed into local waterways.


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Nitrogen (N), phosphorus (P), and potassium (K) are the primary major nutrients required

for plant growth and are the main components of most fertilizers. These chemicals are

energy intensive to produce, create vast amounts of waste, and contribute to greenhouse

gas emissions. Producing one unit of N requires 1.4 units of carbon and 3 units of carbon

are required to manufacture, transport and apply 1 unit of P as P2O5 fertilizer. For every

ton of phosphoric acid produced, five tons of phosphogypsum are generated. Over the past

50 years, more than 700 million metric tons of phosphogypsum have accumulated in

Florida alone, huge stacks at times covering more than 300 hectares at more than 60

meters high with settling ponds that threaten local water sources. The production of nitric

acid, the primary feedstock for synthetic commercial fertilizer, is also a source of nitrous

oxide, a greenhouse gas 310 times more potent than carbon dioxide, and accounted for

15.9 Tg CO2E in 2005, the equivalent emissions of 2.9 million vehicles. According to the

World Health Organization, some 3 million people a year suffer from severe pesticide

poisoning. Pesticide exposure can lead to cancer, birth defects and damage to the nervous

system. Drinking water contaminated by pesticide runoff is a main source of exposure.

Excess fertilizer use and runoff causes eutrophication in waterways which threatens

animal and plant health. The surplus nutrients stimulate excessive plant growth, such as

algal blooms, which consume nearly all the available oxygen in the water and cause other

plants and animals to suffocate. Surplus nitrogen and phosphorus from fertilizer runoff,

animal manure, soil erosion and sewage have created a dead zone of more than 7000

square miles in the Gulf of Mexico near the mouth of the Mississippi River. These huge algal

blooms are starving out shellfish and threatening commercial fisheries and area

economies-the U.N. reported nearly 150 dead zones throughout the worlds oceans in 2007.

Runoff

Transfer of land water to the oceans Runoff is the movement of landwater to the oceans,

chiefly in the form of rivers, lakes, and streams. Runoff consists of precipitation that neither

evaporates, transpires nor penetrates the surface to become groundwater. Even the

smallest streams are connected to larger rivers that carry billions of gallons of water into

oceans worldwide. Excess runoff can lead to flooding, which occurs when there is too much

precipitation. Two recent ev ents in the United States have caused major flooding.

What Is Desertification?

Desertification is a process in which more of our land is becoming desert. It is not becoming

a major problem because the land is hot and dry, but it is becoming a problem because the


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soil is useless for growing crops. Desertification is most likely to occur in areas where

rainfall is scarce.

What Causes Desertification?

Overgrazing:- Overgrazing was not as large of a problem long ago because animals would

move in response to rainfall. People would move with the animals so it prevented

overgrazing in such areas. Now, humans have a steady food supply so they do not have tomove about. Therefore, people use fences to keep their animals in one place which causes

overgrazing.

Farming of Average Land:- Farming of average land is causing desertification worldwide.

Farmers are clearing average land, and using it which takes away the richness in the soil.

People should let the average land replenish itself before farming. (Desertification, 2005)

Destruction of Plants in Dry Regions;- Destruction of plants in dry regions is causing

desertification to occur. People are cutting down tress to use them as a source of fuel. Once

all these trees are cut down there is nothing to protect the soil. Therefore, it turns to dust

and is blown away by the wind. (Desertification, 2005)

Incorrect Irrigation in Arid Regions Causes a Build Up of Salt in the Soil:- Incorrect

irrigation is commonly used in poorer areas. Farmers are using canal irrigation and other

poor techniques because of the lack of water. This type of irrigation causes a build up of salt

in the soil. (Desertification, 2005)

The Effects of Desertification:-

Soil becomes less usable:- The soil can be blown away by wind or washed away rain.

Nutrients in the soil can be removed by wind or water. Salt can build up in the soil whichmakes it harder for plant growth.

Vegetation is Lacked or Damaged :- Loosened soil may bury plants or leave their roots

exposed. Also, when overgrazing occurs, plant species may be lost.

Causes Famine Places that have war and poverty are most likely to have famine occur.

Drought and poor land management contribute to famine.

Food Loss The soil is not suited for growing food; therefore the amount of food being made

will decline. If the population is growing, this will cause economic problems and starvation.

People near Affected Areas Desertification can cause flooding, poor water quality, dust

storms, and pollution. All of these effects can hurt people living near an affected region.


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Waste land Management:-

Introduction

Soils are the most precious natural wealth of any nation as it takes almost 1000 years to

produce an inch of soil and they are vital to our existence. It is therefore imperative that we

manage and conserve it to meet our growing needs for food, fibre, fuel and other things.

It has been estimated that out of the 329 m.ha. of the total geographic area of India, some

167 m.ha have been suffering from various kinds of degradations, such as water-erosion

(90 m.ha), wind erosion (50 m.ha), salinity and alkalinity (7 m.ha) and flooding (20 m.ha).

Another 20 m.ha. in the canal irrigation areas as under risk of becoming degraded.

On an average it is estimated that every year 2.1 m. ha land is degraded either by

deforestation or other misuses. While to feed our increasing population we should bring

about 8 m. ha. land under cultivation every year. So these facts lead us to the development

of wasteland to make it in a proper use, either for ecological balance or for crop production.

Concept and Definition:- The term wasteland designates various types of unutilized

land. It was used to indicate small pieces of common land usually on less fertile tract, which

failed to yield a return to the medieval farmers. A lay man may define the wasteland which

is lying uninhibited, uncultivated, land left after some use or land which is no longer

serving any purpose. Partially or fully degraded land through some usages may be called

"waste land" rather than wasteland. The most widely accepted definition of wasteland is

the land presently lying unutilized due to any reason. it may be degraded or not degraded.

Classification:-

The wastelands in general may be put under two categories: cultivable wasteland and

uncultivable wasteland.

Culturable Wasteland: The land which is capable or has potential for the development of

vegetative cover and not being used due to different constraints of varying degrees such as

erosion, water-logging and salt effects etc.

Unculturable Land: The land can not be developed for vegetative cover for instance

barren rockey areas, deserts and snow-covered glacial areas. Table 1 enumerates the

various causes for the degradation of utilizable land.


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Table 1: Casual agents for wastelands

Sr.

No

Kinds of

wastelands

Causing agents

Water Wind Man Others

1Utilizable waste

land

1. Sheet Erosion1. Sand

dunes1. Shifting ciltivation

1. Shall

soil

2. Rill erosion 2. Sand bar 2. Mine spoils2. La

slides

3. Gullied land3. Coastal

land3. Industrial waste land

4. Ravinous land4. Land affected by

roads, kilns

5. Water logging 5. Strip land

6. Salinity

Sodicity

7. Diara land

8. Marshy land

9. Bouldery land

2Unutilisable

waste land

1. Bare rockey

land

2. Glacier land

3. Deserts

Effects And Control Measures Of Urban And Industrial Waste:

A number of variations in climate, altitude, geological formation and landscape pattern may

be observed in any wasteland. Great variability in land use and vegetation pattern and cultural

practices is also evident The introduction of irrigation on a large scale and injudicious water

management practices have added new dimensions to the problem of land degradation. The kind

and intensity of the problem of the degraded land depend on the variations in land and climatic

conditions and their management. Keeping these in view, approaches to development planning of

the various categories of wastelands are briefly discussed.

A. Erosion by water

It is well recognized that a large area in the country is degraded due to soil erosion by

water. The causes of this erosion are mainly lack of vegetative cover, slope, nature of soil, rainfall,

and its intensity, cropping system and land management. Depending upon intensity and degree of

soil erosion it may be categorised into (i) sheet erosion (ii) Gully erosion and (iii) ravines.


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Appropriate measures based on these categories may be suggested to check runoff and soil loss.

The measures include interalia cultural practices, bunding, terracing grassed water ways etc.

Cultural practices used for checking runoff and soil loss include planting erosion-resistant

crops, like legumes and grasses, adopting suitable cropping system, management and use of

mulches

B. Landslide ControlThe problem of landslides and landslips is common especially in the hilly areas posing

threat to agricultural lands, highways and village habitants. The main causes for land-slides are

weak geological formations, seismic disturbances, improper land use, deforestation, mining and

glaciers. The Central Soil and Water Conservation Research and Training Institute, Dehradun has

successfully demonstrated the control measures which include fencing to check biotic interference,

diversion of water flow, construction of gabion wells and check dams, gully plugging and

maintaining vegetation cover for stabilization and checking erosion.

C. Erosion by Wind

The Indian desert situated in the north-west states of Rajasthan, Gujarat, Haryana andPunjab. Nearly 70% of the desert region is covered by wind-worked sandy-soils, sands, loamy sand

and sand dunes. The problems encountered in the area are wind erosion, deposition and movement

of sand- dunes, low soil moisture storage, instability of soil structure and poor soil fertility etc. The

following may be the suggested measures to overcome the problem.

1. Afforestation, plantation of windbreaks and shelter belts. The suitable plant species for this

purpose are Prosopis chilensis (syn. P. juliflora),Azadirachta indica andAlbizia libback. Soil removal

in sheltered areas was only 3 tonnes/ha as against 72 tonnes/ha in unsheltered areas.

2. Grassland development. Grasses like Cenchrus ciliaris (Anjan grass and Lasiurus sindicus (wild

peas) were found effective in arresting drifting of soil in April-June as suggesting that degradedlands in wind erosion prone areas may be kept under grasses.

3. Strip Cropping: The field strip cropping of grain legumes or cereals in grass strips developed at

the Central Arid Zone Research Institute (CAZRI) is very effective tool for controlling wind erosion.

4. Mulching: Mulching is found very effective in reducing the wind erosion.

5. Fixing of Sand dunes.

D. Riverine Land, Coastal and High altitude slopy lands

The rivers carrying heavy sediment cause mendering action and bank erosion. The riversoriginating from Himalayas causes greater effect. Depending on the velocity of flow, the fertile areas

are eroded and large quantities of sediments are .deposited along the banks. Such riverine lands are

called Khader in north India, diara in eastern Uttar Pradesh and Char in West Bengal.


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In hilly areas, during rainy season many seasonal streams (chos) carry sediment load

causing sever soil erosion. They diverge in different directions from the foot of the hills forming a

net work of innumerable chos, some of them taking the shape of big rivers. With slowing of runoff,

the transported sediment of sand and silt are deposited converting fertile land into sandy and

bouldery degraded land.

India has a long sea-coast in the states of Gujarat, Maharashtra, Kerala, Karnataka, Tamil

Nadu, Andhra Pradesh and West Bengal, Goa, Andaman & Nicobar. In total we have 5600 km long

coast sea line. During the monsoon and cyclonic periods, there is blowing and shifting of sand

causing damage to the standing crops in the neighbouring areas. Hence, plantation of Casurina on

the sandy foreshore backed by plantation of other suitable tree species further inland can minimize

this problem.

Keeping in view the environmental and ecological conditions in the region, land use

planning requires proper choice of crop-forest pasture as suited to land and soil conditions. Grass-

legume rotation is the best cropping system for soil conservation and providing nutritious fodder

for the livestock. The over grazing pasture lands have to be restored and systematic and scientific

grazing should be emphasized.

E. Salt-affected Soils

Salt affected soils may be classified into two categories : (i) saline soils (ii) alkaline soils. In

table 2, some particulars of these kinds of soils are given in table 2.

Table 2: Grouping of salt affected soils

Sl.No Type of soil Type of salt

present

pH

value

Environment Main

adverse

effect

Method of

reclamation

1 Saline soils Sodiumchloride &

sulphate

< 7.0 Arid & semi-arid

Highosmotic

pressure/

toxic effect

Removal ofexcess salts/

leaching

2 Alkali soils Sodium ions

capable of

alkaline

hydrolysis

> 7.0 Semi-arid,

semi-humid

and humid

Effect

physical

properties

of soil

Lowering pH

by chemical

amendments

1. Saline Soils

Irrigation and high rainfall without provision of. drainage leads to salinization. The main

factors of salinization are high salt content in the profile or salt layer, saline ground water, high

water table, and seepage from canals and ingress of sea. The reclamation measure largely includes

leaching with good quality .water and provision of drainage. So that the salts are kept well below


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the root zone. Leaching requirement for each area has to be worked out and provided accordingly

so that the salt do not rise above the normal root zone level of the commonly cultivated crops.

The sodic or alkali soil occur in the Indo-Gangetic plain and parts of M.P. As these soils are

saturated with sodium ions capable of alkaline hydrolysis (sodium-carbonate type salts), it will be

necessary to replace the excess sodium in the exchange complex with calcium, gypsum, being

relatively in expensive and abundanly available is the most commonly used amendment in the

reclamation of sodic soils. Washing down with good quality of water is also necessary to leach

down or remove the excess salt at the surface and the sodium released from the exchange complex.Drainage has to be provided to keep the salt well below the root zone.

Once the soils are reclaimed, it may be preferable to take a green manure crop initially to

improve the soil tilth.

2. Acidic soils

The suggested process of reclamation for highly acidic soils which having pH < 5.5 and are

totally unproductive. The measures are (i) use of lime rich industrial wastes like basic slog, paper-

mill sludge and cement factory waste to reduce the cost, (ii) annual application of 3 to 5 qt/ha in

rows for legumes rather than 2 to 2.4 tonnes, for a crop cycle of 5 years and (iii) application of rock

phoshate of proper quality as a source of phosphorus supplemented by lime for amelioration and

Ca nutrition of plants.

F. Water logged Areas

It is estimated that India is having approximately 6 m. ha water logged area. Water logging

result in restriction of the normal circulation of air. The depth of water-table which is considered

harmful depend upon crop, type of soil and quality of water. The remedial measures used are

1. Drainage either surface or sub surface or both to remove surplus water

2. Lining of canals to prevent seepage and rise of water table.

3. Sinking tubewell and utilizing water for irrigation thereby 0lowering water table.

4. Waterlogged lands contiguous to the sea coast may be ameliorated for crop cultivation or used

for fish culture.

G. Shifting Cultivation

Shifting cultivation or jhuming is a primitive form of cultivation practised in north-eastern

states of India or in regions where land is not a limiting factor. The dense forest and other

vegetation on the slopping or other land is cleared .and crops raised without any management. As

yields decreases, new forest is cleared for the purpose, leaving the old area to vagaries of nature

causing erosion of soil and rendering soils shallow, unstable and degraded.

For management of jhumed land the suitable land for intensive cultivation have to be

identified. Depending upon the climatic factors, soil characteristics and associated features

intensive system of land use and cropping pattern will have to be evolved for each specific site

without being detrimental to environment. Careful soil and water conservation practices have to be


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formulated. Training of the farmers in the scientific farming systems and management of resources

is necessary

H. Intercropping systems involving plantation crops

Most of the plantations crops are obtained from small holdings, where it is customary to

integrate crops and animal production with perennial crops. Most of such intensive land use

systems consist of some form of crop combination, although there are other possibilities for

intimate plant associations leading to more efficient use of land and other available resources. Someof the prominent examples of integrated plantation crop system include

* Cocoa food crops like wheat & paddy

* Multi-storey plantations like Coconut + papaya

* Tea interplanted withAlbizzia moluccana

* Banana + Sugarcane + cucurbits

I. Developing wasteland with animal Husbandry

It is considered that animals are a big nuisance causing serious degradation to vegetation onthe one hand and man himself by over harvesting of wood for ever increasing need of fuel and

industry on the other hand. The problem of soil degradation by animals may be overcome by the

proper management of increasing demand of fodder by developing silvi-pastoral system and

growing fodder crops on wasteland and developing pastures on marginal and degraded land. On

pastures the grazing should be systematic.

Since most of the wasteland is owned by small and marginal farmers so animal husbandry is

the best source of alternative income for them.

unit vi air pollution

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