INTRODUCTION TO ENVIRONMENTAL STUDIES AND NATURAL RESOURCES

1.1 INTRODUCTION

Environment is a French word
Environ (Surroundings)

1.2 DEFINITIONS

 Environment is derived from the French word Environ which means to encircle or surround.
 Environment is sum total of water, air, and land, inter-relationships among themselves and also with the human beings, other living organisms and property. The above definition given in Environment Act, 1986 clearly indicates that
environment includes all the physical and biological surroundings and their interactions.

1.3 SCOPE

Scope of environmental science is broad. Some of the aspects of scope of environmental science are:
 Studying the interrelationships among biotic and abiotic components for sustainable human ecosystem,
 Carrying out impact analysis and environmental auditing for the further catastrophic activities,
 Developing and curbing the pollution from existing and new industries,
 Stopping the use of biological and nuclear weapons for destruction of human race,
 Managing the unpredictable disasters and so on.
There are some major issues like global warming, depletion of ozone layer, dwindling forests and energy resources, loss of global biodiversity etc., that are going to affect the mankind as a whole and for that we have to think globally.

1.4 NEED FOR PUBLIC AWARENESS

 Public awareness very essential to help understand pros and cons of environmental problems.
 The United Nations Conference on Environment and Development held in Rio de Janerio in 1992 and popularly known as Earth summit followed by the world summit on sustainable Development in 2002, have highlighted key issues of global environmental concern.
 Environmental pollution cannot be removed by laws alone.
 The proper implementation and especially public participation are important aspects.
 Public participation is possible only when the public is aware about the ecological and environmental issues.
 A drive by the government to ban the littering of polythene cannot be successful until the public understands the environmental implications of the same.
 The public has to be educated about the fact that if we are degrading our environment we are actually harming ourselves.

1.5 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.

1.5.1 FOREST RESOURCES

1.5.1.1Commercial uses

 Man depends heavily on a larger number of plant and animal products from
forests for his daily needs.
 The chief product that forests supply is wood, which is used as fuel, raw material
for various industries as pulp, paper, newsprint, board, timber for furniture items,
other uses as in packing articles, matches, sports goods etc.
 Indian forests also supply minor products like gums, resins, dyes, tannins, fibers,
etc.
 Many of the plants are utilized in preparing medicines and drugs; Total worth of
which is estimated to be more than $300 billion per year.
 Many forests lands are used for mining, agriculture, grazing, and recreation and
for development of dams.
Depending upon the climate conditions, forest may be classified as:
 Tropical Rain Forests: They are evergreen broadleaf forests found near the
equator. They are characterized by high temperature, high humidity and high
rainfall, all of which favor the growth of trees.
 Tropical deciduous forests: They are found a little away from the equator and
are characterized by a warm climate the year round. Rain occurs only during
monsoon.
 Tropical scrub forests: They are found in areas where the day season is even
longer.
 Temperate rain forests: They are found in temperate areas with adequate
rainfall. These are dominated by trees like pines, firs, redwoods etc.
 Temperate deciduous forests: They are found in areas with moderate
temperatures.
 Evergreen coniferous forests (Boreal Forests): They are found just south of
arctic tundra. Here winters are long, cold and dry. Sunlight is available for a few
hours only.

1.5.1.2 Ecological uses

The ecological services provided by our forests may be summed up as follows:
 Production of Oxygen: The main green house gas carbon dioxide is absorbed by
the forests as a raw material for photo synthesis. Thus forest canopy acts as a sink
for carbon dioxide thereby reducing the problem of global warming caused by
green house gas CO2
 Wild life habitat: Forests are the homes of millions of wild animals and plants.
About 7 million species are found in the tropical forests alone.
 Regulation of hydrological Cycle: Forested watersheds act like giant sponges,
absorbing the rainfall, slowing down the runoff. They control climate through
transpiration of water and seed clouding.
 Soil Conservation: Forests bind the soil particles tightly in their roots and
prevent soil erosion. They also act as wind breakers.
 Pollution moderators: Forests can absorb many toxic gases and can help in
keeping the air pure and in preventing noise pollution.

1.5.2 over Exploitation of Forests

 Man depends heavily on forests for food, medicine, shelter, wood and fuel.
 With growing civilization the demands for raw material like timber, pulp,
minerals, fuel wood etc. shot up resulting in large scale logging, mining, roadbuilding
and clearing of forests.
 Our forests contribute substantially to the national economy.
 The international timber trade alone is worth over US $ 40 billion per year.
 The devasting effects of deforestation in India include soil, water and wind
erosion, estimated to cost over 16,400 cores every year.

1.5.3 Deforestation

 Deforestation means destruction of forests.
 The total forests area of the world in 1900 was estimated to be 7,000 million
hectares which was reduced to 2890 million ha in 1975 fell down to just 2,300
million ha by 2000.
 Deforestation rate is relatively less in temperature countries, but it is very
alarming in tropical countries.
 Deforestation is a continuous process in India where about 1.3 hectares of forest
land has been lost.
 The per capita availability of forest in India is 0.08 hectares per person which is
much lower than the world average of 0.8 hectares.
 The presence of waste land is a sign of deforestation in India.

1.5.3.1 Causes of Deforestation

Major causes of deforestation are listed below:
 Development projects
 Shifting cultivation
 Fuel requirements cutting and burning
 Construction of dams
 Growing food needs.

1.5.3.2 Consequences of deforestation

Some of the effects of deforestation are listed below:
a) Effect on climate
Global warming
Less rainfall
Hot climate.
b) Effect on biodiversity
Loss of medicinal plants.
Loss of timber, fuel wood.
c) Effect on resources
Loss of land resource
Loss of soil fertility
Soil erosion
Drastic changes in biogeochemical cycles
d) Effect on economy
Increase in medicinal values
Demand of industrial products.
e) Effect on food
Loss of fruit production
Loss of root based foods.

1.5.4 Case Studies

Desertification in hilly regions of the Himalayas:
 Desertification in Himalayas, involving clearance of natural forests and plantation
of monocultures like Pinus roxburghi, Eucalyptus camadulensis etc., have upset
the ecosystem by changing various soil and biological properties.
 The area is invaded by exotic weeds. These areas are not able to recover and are
losing their fertility.

1.5.4.1 Disappearing Tea gardens in Chhota Nagpur

Following the destruction of forest rain fall declined in Chhota Nagpur to such an
extent that tea-gardens also disappeared from the region.

1.5.4.2 Waning rain fall in Udhagamandalam

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.

1.6 TIMBER EXTRACTION

 Logging for valuable timber such as teak and mahogany not only involves a few
large trees per hectare but about a dozen more trees since they are strongly
interlocked with each other by vines etc.
 Also road construction for making approach to the trees causes further damage to
the forests.
 In India, firewood demand would continue to rise in future mostly consumed in
rural areas, where alternative sources of energy, are yet to reach.

1.7 MINING

 Mining is the process of removing deposits of ores from substantially very well
below the ground level.
 Mining is carried out to remove several minerals including coal.
 These mineral deposits invariably found in the forest region, and any operation of
mining will naturally affect the forests.
 Mining from shallow deposits is done by surface mining while that from deep
deposits is done by sub-surface mining.
 More than 80,000 ha of land of the country are presently under the stress of
mining activities.

1.7.1 Effects of mining resources

 Mining operation require removal of vegetation along with underlying soil mantle
and overlying rock masses. This results in destruction of landscape in the area.
 Large scale of deforestation has been reported in Mussorie and Dehradun valley
due to mining of various areas.
 Indiscriminate mining in Goa since 1961 has destroyed more than 50,000 ha of
forest land.
 Mining of radioactive mineral in Kerala, Tamilnadu and Karnataka are posing
similar threats of deforestation.

1.8 DAMS AND THEIR EFFECTS ON FORESTS AND TRIBAL

PEOPLE
 Big dams and river valley projects have multi-purpose uses and have been
referred to as "Temples of modern India”.
 India has more than 1550 large dams, the maximum being in the state of
Maharashtra (more than 600) followed by Gujarat (more than 250) and Madhya
Pradesh (130).
 The highest one is Tehri dam, on river Bhagirathi in Uttaranchal and the largest in
terms of capacity is Bhakra dam on river Sutlej.

1.8.1 Effects on Tribal people

 The greatest social cost of big dam is the widespread displacement of local
people.
 It is estimated that the number of people affected directly or indirectly by all big
irrigation projects in India over the past 50 years can be as high as 20 millions.
 The Hirakud dam, one of the largest dams executed in fifties, has displaced more
than 20,000 people residing in 250 villages.

1.8.2 Effects on forests

Thousands of hectares of forests have been cleared for executing river valley
projects which breaks the natural ecological balance of the region. Floods, landslides
become more prevalent in such areas.
Eg:
The Narmada sagar project alone has submerged 3.5 lakh hectares of best forest
comprising of rich teak and bamboo forests.
The Tehri dam submerged 1000 hectares of forest affecting about 430 species of
plants according to the survey carried out by the botanical survey of India.

1.9 WATER RESOURCES

Water is an important component of all living beings. Nearly 80% of
earth’s surface is covered by water.

1.9.1 Uses of Water

 Due to its unique properties, water is of multiple uses for all living organisms.
 Water is absolutely essential for life.
 Most of the life processes take place in water contained in the body.
 Uptake of nutrients, their distribution in the body, regulation of temperature, and
removal of wastes are all mediated through water.
 Human beings depend on water for almost every developmental activity.
 Water is used for drinking, irrigation, and transportation, washing and waste
disposal for industries and used as a coolant for thermal power plants.
 Water shaped the earth's surface and regulates our climate.

1.9.2 Hydrological cycle

1. Evaporation
2. Precipitation
3. Transpiration

Evaporation

The transformation of water from liquid to gas phases as it moves from the
ground or bodies of water into the overlying atmosphere. The source of energy for
evaporation is primarily solar radiation. Evaporation often implicitly includes
transpiration from plants, though together they are specifically referred to as
evapotranspiration. Total annual evaporation amounts to approximately 505,000 km3
(121,000 cu mi) of water, 434,000 km3
(104,000 cu mi) of which evaporates from the
oceans.

Precipitation

Condensed water vapor that falls to the Earth's surface .Most precipitation occurs
as rain, but also includes snow, hail, fog drip, graupel, and sleet. Approximately 505,000 km3
(121,000 cu mi) of water falls as precipitation each year, 398,000 km3
(95,000cu mi) of it over the oceans.

Condensation

The transformation of water vapor to liquid water droplets in the air, creating
clouds and fog.

Transpiration

The release of water vapor from plants and soil into the air. Water vapor is a gas
that cannot be seen.

Snowmelt

The runoff produced by melting snow.

Runoff

The variety of ways by which water moves across the land. This includes both
surface runoff and channel runoff. As it flows, the water may seep into the ground,
evaporate into the air, become stored in lakes or reservoirs, or be extracted for
agricultural or other human uses.

Infiltration

The flow of water from the ground surface into the ground. Once infiltrated, the
water becomes soil moisture or groundwater.

Subsurface Flow

The flow of water underground, in the vadose zone and aquifers. Subsurface
water may return to the surface (e.g. as a spring or by being pumped) or eventually seep
into the oceans. Water returns to the land surface at lower elevation than where it
infiltrated, under the force of gravity or gravity induced pressures. Groundwater tends to
move slowly, and is replenished slowly, so it can remain in aquifers for thousands of
years.

Sublimation

The state change directly from solid water (snow or ice) to water vapor.

1.10 OVER UTILIZATION OF SURFACE AND GROUND WATER

 With increasing human population and rapid development, the world water
withdrawal demands have increased many folds and a large proportion of the
water withdrawn is polluted due to anthropogenic activities.
 Out of the total water reserves of the world, about 97% is salty water and only 3%
is fresh water.
 Even this small fraction of fresh water is not available to us as most of it is locked
up in polar ice caps and just 0.003% is readily available to us in the form of
ground water and surface water.

1.10.1 Effects of over exploitation of water

 Subsidence: When ground water withdrawal is more than its recharge rate, the
sediments in the aquifer (a layer of rock that is highly permeable and contains
water) get compacted, a phenomenon knows as ground subsidence. It results in
sinking of overlying land surface. Due to this structural damage in buildings,
fracture in pipes etc., occurs.
 Lowering of water table: Mining of groundwater is done extensively for
irrigating crop fields. However, excessive mining would cause lowering of water
table.
 Water logging: When excessive irrigation is done with brackish water it raises
the water table gradually leading to water-logging and salinity problems.

1.11 FLOODS AND DROUGHT

 Heavy rainfall often causes floods in the low-lying coastal areas.
 Prolonged downpour can also cause the over-flowing of lakes and rivers resulting
into floods.
 When annual rainfall is below normal and less than evaporation, drought
conditions are created.

1.11.1 Causes of flood and drought

 Deforestation, overgrazing, mining, rapid industrialization, global warming etc.,
have contributed largely to a sharp rise in the incidence of floods.
 Deforestation leads to desertification and drought too. When the trees are cut, the
soil is subject to erosion by heavy rains, winds and sun.
 The removal of thin top layer of soil takes away the nutrients and the soil
becomes useless.
 The eroded soils exhibit droughty tendency.

1.11.2 Preventive measures

 Clear knowledge in control of drought and desertification can be very useful for
dealing with the problem.
 Carefully selected mixed cropping helps to optimize production and minimize the
risks of crop failures.
 Social forestry and Wasteland development can prove quite effective to fight the
problem, but it should be based on proper understanding of ecological
requirement and natural process.

1.12 CONFLICTS OVER WATER

Indispensability of water and its unequal distribution has often led to inter-state or
international disputes. Issues related to sharing of river water have been largely
affecting our farmers and also shaking our governments. Many countries are
engaged in bitter rivalries over this precious resource.
For instance,
Argentina and Brazil, dispute each other's claims to the La Plata river,
India and Pakistan fight over the rights to water from the Indus,
Mexico and USA have come in conflict over the Colorado river,
India and Bangladesh are fighting for Bhrahmaputra river, and
Iran and Iraq contest for the water from Shatt-Al- Arab River.

Within India, water conflicts are still being continues between the states.
For Eg.,
 Sharing of Krishna water between Karnataka and Andhra Pradesh,
 Sharing of Siruvani water between Tamilnadu and Kerala, and others.
 Sharing of Cauvery between Karnataka and Tamilnadu
 On June 2,1990, the Cauvery Water dispute Tribunal was set up which through an
interim award directed Karnataka to ensure that 205 TMCF of water was made
available in Tamil Nadu's Mettur dam every year, till a settlement was reached.
 In 1991-1992 due to good monsoon, there was no dispute. In 1995, the situation
turned into a crisis due to delayed rains and an expert Committee was set up to
look into the matter which found that there was a complex cropping pattern in
Cauvery basin.
 Samba paddy in winter, Kuravai paddy in summer and some cash crops
demanded intensive water; thus aggravating the water crisis.
 Proper selection of crop varieties, optimum use of water, better rationing are
suggested as some measures to solve the problem

1.13 BIG-DAMS –BENEFITS AND PROBLEMS

Dams are built across the river in order to store water for drinking, agricultural,
industrial purpose. Now days they are mainly used for the hydropower production.

1.13.1 Benefits

 River valley projects with big dams play a key role in the development process
due to their multiple uses.
 These dams aim at providing employment for tribal people and raising the
standard and quality of life.
 Dams can help in checking floods and generate electricity and reduce water and
power shortage, provide irrigation water to lower areas, provide drinking water in
remote areas and promote navigation, fishery.

1.13.2 Problems

 The impacts of big dams can be upstream as well as downstream levels. The
upstream problems include the following:
 Displacement of tribal people
 Loss of forests, flora and fauna
 Changes in fisheries
 Saltation and sedimentation of reservoirs
 Loss of non-forest land
 Stagnation and water logging near reservoir
 Breeding vectors and spread of vector –borne diseases
 Reservoir induces seismicity causing earthquakes
 Microclimatic changes
 Growth of aquatic weeds

1.13.3 Downstream problems include the following

 Water logging and salinity due to over irrigation
 Microclimatic changes
 Reduced water flow and slit deposition in river
 Flash foods
 Salt water intrusion at river mouth
 Loss of land fertility
 Outbreak of vector-borne diseases like malaria.

1.14 MINERAL RESOURCES

Minerals are naturally occurring substances with definite chemical and physical
properties.

1.14.1 Uses of minerals

Mineral is an element or inorganic compound that occurs naturally. The main uses of
minerals are as follows:
 Development of industrial plants and machinery
 Generation of energy e.g. coal, lignite, uranium
 Construction, housing, settlements
 Defense equipments- weapons, settlement
 Transportation
 Communication-telephone wires, cables, electronic devices
 Medical system- particularly in Ayurvedic System
 Formation of alloys for various purposes
 Agriculture- as fertilizers, seed dressings and fungicides
 Jewellery- e.g. Gold, silver, platinum, diamond

1.14.2 Environmental impacts of mineral extraction

Major mines which are known for causing severe problems are given below:
 Jaduguda Uranium Mine, Jharkhand- exposing local people to radioactive
hazards.
 Jharia coal mines, Jharkhand- underground fire leading to land subsidence and
forced displacement of people.
 Sukinda chromite mines, Orissa- Seeping of hexavalent chromium into river
posing serious health hazard, Cr6+
being highly toxic and carcinogenic.
 Kudremukh iron ore mine, Karnataka- causing river pollution and threat to
biodiversity.
 East coast Bauxite mine, Orissa-Land encroachment and issue of rehabilitation
unsettled.
 North-Eastern Coal Fields, Assam-Very high sulphur contamination of
groundwater

1.14.3 Impacts of mining: Mining is done to extract minerals from deep deposits in

soil.
Environmental damages caused by mining activities are as follows:
 Devegetation and defacing of lands: Mining requires removal of vegetation
along with underlying soil mantle and overlying rock masses. This results in
destruction of landscape in the area.
 Subsidence of land: Subsidence of mining areas results in tilting of buildings,
cracks in houses, buckling of roads, bending of rail tracks and leaking of gas from
cracked pipe lines leading to serious disasters.
 Groundwater contamination: Mining pollutes the groundwater. Sulphur,
usually present as an impurity in many ores is known to get converted into
sulphuric acid through microbial action, thereby making the water acidic.
 Surface water pollution: The acid mine drainage often contaminates the nearby
streams and lakes. The acidic water, radioactive substances like uranium, heavy
metals also contaminate the water bodies and kill aquatic animals.
 Air pollution: In order to separate and purify the metal from other impurities in
the ore, smelting is done which emits enormous quantities of air pollutants.
Oxides of sulphur, arsenic, cadmium and lead etc. shoot up in the atmosphere near
the smelters and the public suffers from several health problems.
 Occupational Health Hazards: Miners working in different type of mines suffer
from asbestosis, silicosis, black lung disease.

1.14.4 Remedial measures

 Adopting eco-friendly mining technology
 Utilization of low grade ores by using microbial – leaching technique. In this
method, the ores are inoculated with the desired strains of bacteria like
Thiobacillus ferroxidans, which remove the impurities and leave the pure mineral.
 Re-vegetating mined areas with appropriate plants
 Gradual restoration of flora
 Prevention of toxic drainage discharge

1.14.5 Case studies

1. Mining and quarrying in Udaipur
    Soap stones, building stone, and dolomite mines spread over 15,000 hectares in
   Udaipur have caused many adverse impacts on environment.
    About 150 tons of explosives are used per month in blasting.
    The Maton mines have badly polluted the Ahar river.
    The hills around the mines are suffering from acute soil erosion.
    The waste water flows towards a big tank of “Bag Dara".
    Due to scarcity of water people are compelled to use this effluent for irrigation
   purpose.
    The animals like tiger, lion, deer, and birds have disappeared from the mining
   area.
2. Mining in Sariska and Tiger Reserve in Aravallis
    The Aravalli range is spread over about 692 Km in the North-west India covering
   Gujrat, Rajasthan, Haryana, and Delhi.
    The hill is rich in mineral resources.
    Mining operations within and around the Sariska Tiger reserve has left many
   areas permanently infertile and barren.
    The precious wild life is under serious threat.

1.15 FOOD RESOURCES

1.15.1 World Food Problems

 During the last 50 years world grain production has increased almost three times.
 The per capita production is increased by about 50%.
 At the same time population growth increased at such a rate in less developed
countries.
 Every 40 million people die of undernourishment and malnutrition.
 This means that every year our food problem is killing as many people as were
killed by the atomic bomb dropped on Hiroshima during World War II.
 This statistics emphasize the need to increase our food production, and also to
control population growth.
 It is estimated that 300 millions are still undernourished.

1.15.2 Impacts of overgrazing and agriculture

1.15.2.1 Overgrazing

Overgrazing can limit livestock production. Over grazing occurs when too many animals
graze for too long and exceed the carrying capacity of a grass land area.
Impact of overgrazing
 Land degradation: Overgrazing removes the grass cover. The humus content of
the soil is decreased and it leads to poor, dry, compacted soil.
 Soil erosion: The soil 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.
 Loss of useful species: Due to overgrazing the nutritious species like cenchrus,
panicum etc. are replaced by thorny plants like Parthenium, Xanthium etc. These
species do not have a good capacity of binding the soil particles and, therefore,
the soil becomes more prone to soil erosion.

1.15.2.2 Agriculture

Traditional Agriculture and its impacts
 Usually involves a small plot
 Simple tools
 Naturally available water
 Organic fertilizer and a mix of crops

1.15.2.3 Main impacts

 Deforestation
 Soil erosion
 Depletion of nutrients

1.15.2.4 Modern Agriculture and its impacts

 It makes use of hybrid seeds of selected and single crop variety.
 High-tech equipments, lots of energy subsidies in the form of fertilizers and,
pesticides
 Irrigation water

1.15.2.5 Main impacts

 Impacts related to high yielding verities (HYV): The uses of HYVs encourage
monoculture i.e. the same genotype is grown over vast areas. In case of an attack
by some pathogen, there is total devastation of the crop by the disease due to
exactly uniform conditions, which help in rapid spread of the disease.

1.15.3 Fertilizer related problems

 Micronutrient imbalance: Chemical fertilizers have nitrogen, phosphorus and
potassium (N, P and K) which are essential macronutrients. Excessive use of
fertilizers cause micronutrient imbalance. For example, excessive fertilizer use in
Punjab and Haryana has caused deficiency of the micronutrient Zinc in the soils,
which is affecting productivity of the soil.
 Nitrate Pollution: Nitrogenous fertilizers applied in the fields often leach deep
into the soil and ultimately contaminate the ground water. The nitrates get
concentrated in the water and when their concentration exceeds 25 mg/L, they
become the cause of a serious health hazard called "Blue Baby Syndrome" or
methaemoglobinemia. This disease affects the infants to the maximum extent
causing even death.
 Eutrophication: A large proportion of nitrogen and phosphorus used in crop
fields is washed off along with runoff water and reach the water bodies causing
over nourishment of the lakes, a process known as Eutrophication. (Eu=more,
tropic=nutrition). Due to Eutrophication the lakes get invaded by algal blooms.
These algal species grow very fast by rapidly using up the nutrients. The algal
species quickly complete their life cycle and die thereby adding a lot of dead
matter. The fishes are also killed and there is lot of dead matter that starts getting
decomposed. Oxygen is consumed in the process of deco
 Pesticide related problems: Thousands of types of pesticides are used in
agriculture. The first generation pesticides include chemicals like sulphur, arsenic,
lead or mercury to kill the pests. They have number of side effects as discussed
below:
 Creating resistance in pests and producing new pests: About 20 species of
pests are now known which have become immune to all types of pesticides and
are known as "Super pests".
 Death of non-target organisms: Many insecticides not only kill the target
species but also several non-target species that are useful to us.
 Biological magnification: Many of the pesticides are non-biodegradable and
keep on accumulating in the food chain, a process called biological magnification.
This is very harmful.
 Water Logging: Over irrigation of croplands by farmers for good growth of their
crop usually leads to water logging. Inadequate drainage caused excess water to
accumulate underground and gradually forms a continuous column with the water
table. Under water-logged conditions, pore-spaces in the soil get fully drenched
with water and the soil- air gets depleted. The water table rises while the roots of
plants do not get adequate air for respiration, Mechanical strength of the soil
declines, the crop plants get lodged and crop yield falls. In Punjab and Haryana,
extensive areas have become water-logged due to adequate canal water supply or
tube-well water. 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 Problem: At present one third of the total cultivable land area of the
world is affected by salts. Saline soils are characterized by the accumulation of
soluble salts like sodium chloride, sodium sulphate, calcium chloride, magnesium
chloride etc. in the soil profile. Their electrical conductivity is more than 4 ds/m.
So dic soils have carbonates and bicarbonates of sodium, the pH usually exceed
8.0 and the exchangeable sodium percentage (ESP) is more than 15%.