1. Environmental Science – Food and Land
Department of Chemistry
Kongu Engineering College
2. UNIT - I - Environmental Studies and Natural Resources
Introduction to Environmental Science – uses, over-exploitation and
conservation of forest, water, mineral, food, energy and land
resources – case studies
3. Introduction to Environmental Science
The term environment is derived from a French word
‘environner’ which means ‘surrounding’. It refers to
an aggregate of all conditions that affect the existence,
growth, and welfare of an organism or a group of
Definition: It can be defined as a sum total of all the living (biotic) and non-living
(Abiotic) elements and their effects that influence human life.
While all living or biotic elements are animals, plants, forests, fisheries, and birds, non-
living or abiotic elements include water, land, sunlight, rocks, and air.
4. Environmental Science:
“The systematic & scientific study of our environment and our role in it. This branch
includes the knowledge of Pure Science & to some extent Social Sciences”.
“The branch of Study concerned with environmental issues. It has a broader coverage
than environmental science and includes the social aspects of the environment”.
Environmental education is a process that allows individuals to explore environmental
issues, engage them in problem solving, and take action to improve the environment.
As a result, individuals develop a deeper understanding of environmental issues and
have the skills to make knowledgeable and responsible decisions.
6. Objectives of Environmental Education
Awareness: To help individuals and social groups to acquire basic awareness of and
sensitivity towards the environment & its related problem.
Knowledge: To help individuals and social groups to acquire basic understanding of
the environment, its associated problems and their responsible role towards the
betterment of the environment.
Attitude: To help individuals and social groups to acquire social values, strong feeling
of concern for the environment and the motivation for actively participating in its
protection and improvement.
Skills: To help individuals and social groups to acquire the skills for solving
7. Evaluation ability: To help individuals and social groups to evaluate environmental
measures and education program in terms of ecological, political, economical, social,
aesthetic and education factors.
Participation: To help individuals and social groups to develop a sense of
responsibility and urgency regarding environmental problems to ensure appropriate
action to solve those problems.
9. Importance of Environmental Studies
Environmental Studies is useful in checking environmental pollution and related
It helps in maintaining ecological balance.
It helps to gain skills to assess the environmental impact of human activities.
Environmental study will help to protect biodiversity.
It gives us basic knowledge of environment and associated problems.
It helps to achieve sustainable development .
It helps to educate people regarding their duties towards the protection of
The knowledge of environmental science will be applied to the study of agriculture..
10. International Efforts for Environment
Environmental issues received international attention
about 35 years back in Stockholm Conference, held on
5th June, 1972.
Since then we celebrate World Environment Day on
At the United Nations Conference on Environment
and Development held at Rio de Jeneiro, in 1992,
known popularly as Earth Summit.
Ten years later, the World Summit on Sustainable
Development, held at Johannesberg in 2002,
highlighted the key issues of global environmental
Later, Conference on Climate Change was held at
Copen Hagen in the year 2009 and is known as Copen
11. Need for Public Awareness
Earth’s resources are dwindling and our environment is being increasingly degraded
by human activities and hence something needs to be done.
Government alone cannot perform all the clean-up functions.
Individual/group efforts in their own every possible way has to be made to protect
Mass public awareness: newspapers, radio, television strongly influences public
opinion on conserving our environment.
Methods for Public Awareness
Through mass & media
Through organizing seminars & conferences
Involvement of youth
Through print, broadcast and internet
13. Natural Resources
Life on this planet earth depends upon a variety of goods and services provided by the
nature, which are known as Natural Resources.
Natural resources are resources that exist without any actions of human kind.
Any stock or reserve that can be drawn from nature is a natural resource.
water, air, soil, minerals, coal, forests, crops and wildlife
Classification of Natural Resources:
The natural resources are of two kinds
1. Renewable Resources
2. Non-Renewable Resources
14. 1. Renewable Resources
The resources which cannot be exhausted even after continuous utilization are termed
as renewable resources.
Examples: Sun, Wind, and Tidal energy etc.
2. Non-Renewable Resources
The resources which cannot be immediately replaced once they are depleted are called
Examples: Fossil fuels, such as coal, petroleum and natural gas etc.
15. Here we are going to discuss the following six Natural Resources
16. FOOD RESOURCES
Food is an essential requirement for the human survival. Each person
has minimum food requirement. The main components of food are
carbohydrates, fats, proteins, minerals and vitamins.
Types of Food Supply:
1. Croplands mostly produce grains and provide about 76% of the
Example: Rice, wheat, maize, barley, sugarcane, potato.
2. Rangelands produce meat, mostly from grazing livestock and
Example: Meat, milk, fruits etc
3. Oceanic fisheries supply about 7% of the world’s food.
Example: Fish, prawn, crab, etc.
17. World Food Problems
The food supplied from the existence of less percentage of the
land is not enough to feed all the people.
The problem of population explosion has made it worse.
The world population increases and cultivable land area
decreases. Therefore the world food problem arises.
Environmental degradation like soil erosion, water logging, water
pollution, salinity affect agricultural lands
Urbanization in developing countries deteriorates the agricultural
The food grains like rice, wheat, corn and the vegetable like potato
are the major food for the people all over the world, the food
Human activity which degrade most of the earth’s net primary
productivity which supports all life.
18. World Scenario :
During the last 50 years world grain production has increased
almost three times. But, at the same time, population growth
increased at such a rate in LDCs [Less Developed Countries].
Every year 40 million people [50% of children (1-5year)] 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.
In countries like North America and Europe the daily average
calorie intake is about 3500 cals, which is nearly one – third more
than that required for healthy living.
In Ethiopia, Sudan and Somalia the food production is very low
due to drought, war and governmental mismanagement.
These startling statistical figures more than emphasize the need to
increase our food production, equitably distribute it and also to
control population growth.
19. Indian Scenario:
Although India is the third largest producer of stable crops, an
estimated 300 million Indians are still undernourished. India has
only half as much land as USA, but it has nearly three times
population to feed. Our food problems are directly related to
The world Food Summit, 1996 has set the target to reduce the
number of undernourished to just half by 2015, which still means
410 million undernourished people on the earth.
UNDER NUTRITION AND MALNUTRITION
Macronutrients: Carbohydrates, Proteins, Fats.
Micronutrients: Vitamins A,C,E, Minerals such as iron, calcium and
The food and Agriculture Organization (FAO) of United Nations
estimated that on an average the minimum caloric intake on a
global scale is 2,500 calories/day. People receiving less than 90%
these minimum dietary calories are called undernourished and if
it is less than 80% they are said to be seriously undernourished.
20. Besides the minimum calorific intake we also need proteins, minerals etc. Deficiency or
lack of nutrition often lead to malnutrition resulting in several diseases as shown in the
21. Overgrazing and Agriculture
It is a process of eating away the forest vegetation without giving it
a chance to regenerator.
Impacts of overgrazing:
Overgrazing removes the cover of vegetation over the soil and the
exposed soil gets compacted.
So the roots of the plant cannot go much deep into the soil and the
adequate soil moisture is not available.
Thus overgrazing leads to organically poor, dry, compacted soil
which cannot be used for further cultivation.
Due to overgrazing by livestock, the cover of vegetation gets
removed from the soil. The roots of the grass are very good
binders of the soil.
When the grasses are removed, the soil becomes loose and gets
eroded by the action of wind and rainfall.
22. Loss of useful species:
Overgrazing affects the soil composition of plant
population and their generation capacity.
The grassland consists of grasses and forbs with high
When the livestock grazes the grasses heavily, the root
stocks which carry the food reserve get destroyed. The
other secondary species will appear in their places which
are less nutritive in nature. Some livestock keep on
overgrazing these species also.
It reduces grass cover, which will have impact on
Finally it causes deforestation
Agriculture is an art, science and industry of managing the growth of
plants and animals for human use.
Agriculture society slowly took shape during the “Neolithic period”
(i.e., new stone age) about 10,000 B.C. the early agriculturists’
practiced “Slash and burn cultivation” or “shifting cultivation” or
“Swidden”. This starts with the clearing of small plots in tropical
forests by cutting and burning the vegetation.
Agriculture includes cultivation of the soil, growing and harvesting
crops, breeding and raising livestock, dairying and forestry.
Types of Agriculture
The two major types of agricultural systems are
1. Traditional agriculture,
2. Modern agriculture (or) Industrialized agriculture
24. 1. Traditional agriculture:
It involves a small plot, simple tools, surface water, organic fertilizers
and a mix of crops. They produce enough food to feed their families
and to sell it for their income.
Effects or impacts of traditional agriculture
Deforestation: Cutting and burning of trees in forests to clear the land
for cultivation results in loss of forest cover.
Soil erosion: Clearing of forest cover exposes the soil to wind, rain
and storms, thereby resulting in loss of top fertile layer soil.
Loss of nutrients: During cutting and burning of trees, the organic
matter in the soil gets destroyed and most of the nutrients are taken
up by the crops within a short period. Thus the soil becomes poor in
nutrient, which makes the farmers shift to another area.
2. Modern agriculture:
It makes use of hybrid seeds of single crop variety, high-tech
equipments, lot of fertilizers, pesticides and water to produce large
amount of single crops.
25. 1. Problems in using Fertilizer
(a) Micronutrient imbalance:
Most of the chemical fertilizers used in modern agriculture contain nitrogen, phosphorous
and potassium (N, P, and K) which are macronutrients. When excess of the fertilizer are
used in the fields, it causes micronutrient imbalance.
Example: Excess use of the fertilizer in Punjab and Haryana has caused deficiency of the
micronutrient zinc in the soil, which affects the productivity of the soil.
(b) Blue baby syndrome (nitrate pollution):
When the nitrogenous fertilizers are applied in the fields, they leach deep into the soil and
contaminate the ground water. The nitrate concentration in the water gets increased.
When the nitrate concentration exceeds 25 mg/L, they cause serious health problem
called “Blue baby syndrome”. This disease affects infants and lead to death.
A large proportion of N and P fertilizers used in crop fields is washed off by the runoff
water and reaches the water bodies causing over nourishment of the lakes. This process
is known as Eutrophication.
Due to eutrophication lakes get attacked by algal blooms. These algal species use up
the nutrients rapidly and grow very fast. Since the life time of the algal species are less
they die quickly and pollute the water, which inturn affect the aquatic life
26. 2. Problems in using pesticides
In order to improve the crop yield, lot of pesticides used in the agriculture.
First generation pesticides:
Sulphur, arsenic, lead and Mercury are used to kill the pests.
Second generation pesticides:
DDT (Dichloro diphenyl trichloromethane) is used to kill pests.
Although these pesticides protect our crops from huge losses due to pests, they produce
number of side-effects.
1. Death of non-target organisms:
Many insecticides not only kill the target species, but also kill the several non-target
species which are useful to us.
2. Producing new pests:
Some pest species usually survive even after the pesticide spray which generates
highly resistant generations. They are immune to all types of pesticides and are
Many of the pesticides are non-biodegradable and keep on concentrating in the food
chain. This process is called bio-magnification. These pesticides in a bio-magnified
form are harmful to the human beings.
Risk of cancer:
Pesticides enhance the risks of cancer in two ways
1. It directly acts as carcinogens.
2. It indirectly suppresses the immune system.
Desired qualities of an ideal pesticide
An ideal pesticide must kill only the target species
It must be a biodegradable
It should not produce new pests
It should not produce any toxic pesticide vapour.
Excessive synthetic pesticide should not be used.
Chlorinated pesticides and organophosphate pesticides are hazardous, so they
should not be used.
28. 3. Water logging
Water logging is the land where water stand for most of the year
Problems in water logging:
During water-logged conditions, pore-voids in the soil get filled
with water and the soil-air gets depleted. In such a condition the
roots of the plants do not get adequate air for respiration. So,
mechanical strength of the soil decreases and crop yield falls.
Excessive water supply to the croplands.
Preventing excessive irrigation, sub-surface drainage technology
and bio-drainage by trees like Eucalyptus tree are some method
of preventing water-logging
29. 4. Salinity
The water, not absorbed by the soil, undergoes evaporation leaving
behind a thin layer of dissolved salts in the topsoil. The process of
accumulation of salts is called salinity. The saline soils are
characterized by the accumulation of soluble salts like sodium
chloride, calcium chloride, magnesium chloride, sodium sulphate,
sodium bicarbonate and sodium carbonate. The pH of the water
exceeds 8.0 (alkalinity)
Problems in salinity:
Most of the water, used for irrigation comes only from canal or ground,
which contain dissolved salts. Under dry climates, the water gets
evaporated leaving behind the salt in the upper portion of the soil. Due
to salinity the soil becomes alkaline and crop yield decreases.
The salt deposit is removed by flushing them out by applying more
good quality water to such soils.
Using sub-surface drainage system the salt water is flushed out
30. CASE STUDY
1. Water logging and salinity in Haryana and Rajasthan
Introduction of canal irrigation in Haryana state resulted in rise in water-table followed
by water-logging and salinity in many agricultural lands causing huge economic losses as a
result of decrease in crop productivity. Similarly Rajasthan has also suffered badly due to the
biggest irrigation project, “Indira Gandhi Canal Project” which converts a big area into water
soaked waste land.
2. Pesticides in Delhi
It has been reported in Delhi, that the high accumulation of pesticides and DDT in the
body of mothers causes premature deliveries or low birth weight or death of many children’s.
3. Pesticide in Pepsi and Coca-Cola
Food centre for Science and Environment (CSE) India has reported that Pepsi and
Coca-cola companies are selling soft drinks with pesticide content 30-40 times higher than
EU guidelines permit. It also said that the total average pesticide content in all Pepsi
products were 0.0180 mg/L, while in coco-cola products 0.0150 mg/L, which are 30-40
times higher than European Union limits. This damages the nervous system. The centre
said the reason for high pesticide content in India is due to the use of ground water in soft
drinks and bottled water industries.
31. LAND RESOURCES
Land as a resource
Land is the most important and valuable resources for mankind as it provides food
fiber, wood, medicine and other biological materials needed for food.
Soil is the mixture of inorganic materials (rocks and minerals) and organic minerals
(dead animals and plants)
Top soil is classified as a renewable resource, because it is continuously regenerated
by natural process at a very slow rate.
But if the rate of erosion is faster than the rate of renewal, then the soil becomes a non-
Land provides food, wood, minerals, etc., for us.
Land nurtures the plants and animals that provide our food and shelter.
Land is used as watershed or reservoir.
Land acts as a dust bin for most of the wastes created by the modern society.
Land is used for construction of buildings, industries etc.
32. Land degradation
Land degradation is the process of deterioration of soil or loss of fertility of the soil
The soil texture and soil structure are deteriorated.
Loss of soil fertility, due to loss of invaluable nutrients.
Increase in water logging, salinity, alkalinity and acidity problems.
Loss of economic social and biodiversity.
Fertilizers and pesticides
Damage of top soil
Water logging, soil erosion, salination and contamination of the soil with industrial wastes
all cause land degradation.
33. Soil Erosion
It is a process of removal of superficial layer of the soil from one place to another.
Types of soil
Caused by gradual removal of
top soil by the natural process
Rate of erosion is
Caused by man-made activities
Rate of erosion is
Soil fertility is lost
The soil loss its ability to hold water and sediments
Sediment runoff can pollute water and kill aquatic life
The soil erosion is affected by water in the form of rain, run-off, rapid flow, wave action.
Wind carry away the fine particles of soil and creates soil erosion
Overgrazing, mining and deforestation cause soil erosion. About 35% of the world soil
erosion is due to overgrazing and 30% of the world soil erosion is due to the
Landslides cause soil erosion.
Construction of dams, buildings, roads removes the protective vegetal cover and leads
to soil erosion.
35. Control of soil erosion (or) soil conservation practices
Conservational till farming:
In tradition method, the land is ploughed and soil is broken up
and leveled to make a planting surface. This disturbs the soil and
makes it susceptible to erosion. However, no-till-farming
machines make slits in the unploughed soil and inject seeds,
fertilizers and water in the slit. So the seed germinates and the
It involves planting crops in rows across the contour of gently
sloped land. Each row acts as a small dam to hold soil and to
slow water run-off.
It involves conservation of steep slopes into a series of broad
terraces which run across the contour. This retains water for
crops and reduces soil erosion by controlling run off.
36. Alley cropping (or) Agro forestry:
It involves planting crops in strips or alleys between rows of trees of
shrubs that can provide fruits and fuel wood. Even when the crop is
harvested, the soil will not be eroded because trees and shrubs still
remain on the soil and hold the soil particles.
Wind breaks or shelter belts:
The trees are planted in long rows along the boundary of cultivated
lands which block the wind and reduce the soil erosion. Wind breaks
help in retaining soil moisture, supply of some wood for fuel and
provide habitat for birds.