• Agriculture has been considered as a way of life.
Ever increasing population places greater
demands on agriculture to increase the
production, to match the increasing demands for
• With agricultural development though food
production has successfully increased nearly
everywhere but it has failed to match with the
growing population in many areas - specially
developing countries of Africa, Asia and Latin
Over the period of time, the development of
agriculture was achieved in terms of:
• Expansion and /or conversion of agricultural
• Increased agricultural productivity
• Multiple-cropping pattern
• Conversion of single-cropping system to two
tier / or three tier cultivation
• Expansion of natural limits.
In due course of time, agricultural development
became possible due to
• Development of modern scientific techniques
• Advanced technology
• Expansion of irrigational facilities
• Use of chemical fertilizers
• Use of pesticides and insecticides
• Development and use of high yielding varieties of
• Changed agricultural practices
• Mechanization of agriculture
• Varying crop sequences and
• Land ownership and the land tenure.
Expansion and Conversion of
• Conversion and expansion of agricultural land
and forest areas changes in their natural
limits. Thousands of millions of tons of soil is
lost annually due to large-scale deforestation
and/ or poor land management records chain
reaction in the broad areas.
Application of Chemical
Fertilizers, Pesticides and Insecticides
• Fertilizer application in South Asia including
India has multiplied with widespread
introduction of the Green Revolution. Not only
the number of fertilizer plants has gone up but
also the production has multiplied, resulting in
many a disorder.
The High Yielding Varieties
• The introduction of high yielding varieties has
changed the agricultural environment by
creating a variety of pest problems. Many of
these either were unknown or were of minor
importance in the early sixties.
• The increased irrigational facilities, higher use
of fertilizers and the high yielding varieties led
to the resurgence of pests.
Development of Irrigational Facilities
• The multiple cropping and intensive uses of
chemical fertilizers and heavy watering of the
agricultural land result in the rise of the water
level. As a result, such areas have developed
the problem of water logging, ultimately
damaging the standing crops, microorganisms,
animals and even the human population.
Intensive and Extensive Cultivation
• The introduction of intensive cultivation to get
the maximum production and the variety of
crops through multiple cropping, crop-
rotations, changing crop-combination from
the same unit of land has resulted in the
decline of the productivity and total
production due to critical limit of the soil.
• The use of tractors, combined with harvesters
increased with suitable machinery to work on
difficult soils became practicable and has
brought such lands under plough. Increasing
use of machinery arid tractors with the
development of two-tier and/or three-tier
cultivation system has pulverized the land.
• Substances which are added to the soil to
increase its fertility are called Fertilizers.
• Many natural substance like leaves, cow
dung, bone meal compost etc are used to
make up the deficiency of nitrogen
, phosphorus and potassium in soils. These
substance are known as natural fertilizers.
Important phosphatic fertilizers are
1) Super phosphate of lime ( Calcium super
2) Triple super phosphate
3) Ammonium superphosphate
• A fertilizer which contains more than one plant
nutrients is called mixed fertilizer.
• Mixed fertilizer Containing
nitrogenous, phosphatic and potash
fertilizers in definite proportions.
• Such fertilizers are called NPK fertilizers
Impact of excessive use of fertilizers on
• The increased use of fertilizers to expand food
supplies have come at a large cost to our
• Modern agricultural techniques are typically
wasteful in their use of fertilizers.
• Often, many farmers add large amounts of
fertilizer or manure at the time of sewing in
order to cover and protect the young plants.
• This technique is inefficient, since the young
plants are unable to absorb most of the
• Therefore, much of the nitrogen is lost to the
environment in a number of ways.
Biofertilizers are ready to use live
formulates of such beneficial
microorganisms which on application to
seed, root or soil mobilize the availability of
nutrients by their biological activity in
particular, and help build up the micro-
flora and in turn the soil health in general.
Benefits from using biofertilizers
•Increase crop yield by 20-30%.
•Replace chemical nitrogen and phosphorus by 25%
•Stimulate plant growth.
•Activate the soil biologically.
•Restore natural soil fertility.
•Provide protection against drought and some soil
Advantages of bio-fertilizers
2.Suppliment to fertilizers.
3.Eco-friendly (Friendly with nature).
4.Reduces the costs towards fertilizers use, especially
regarding nitrogen and phosphorus.
•Pesticides are chemical substances used to kill
insects, fungi, rodents,weeds or other living
things which are harmful to plants, animals or
•Pesticides function as poisons for the important
biological process of insects, fungi etc which
lead to the death of these organisms.
Classification of pesticides
• Depending upon the purpose for which the
pesticides are used, they are classified as
• i) insecticides v) algaecide
• ii) herbicide vi) molluscicides
• iii) fungicides vii) miticides
• iv) rodenticides viii) nematocides.
•Chemicals used to kill the insects are called
insecticides. Insecticides are further classified
into Stomach poisons, contact poison and
• Herbicides are used to destroy weeds (destroy
the growth of plants).
eg: 2,4 D (2,4 dichloro phenoxy acetic acid)
•Fungicides are are chemicals which are
used to prevent the growth of fungi or
eradicate fungal diseases of plants.
Eg: Lime, sulphur, formalin etc
•These are chemicals used to kill rats and
mice which destroy crops and spread
Eg: Sodium fluoroacetate, Zinc phosphide
•These are chemicals added to water to destroy
Eg: copper sulphate
•These are chemicals used to destroy mollusks
like snails , slugs etc
eg: Copper sulphate, metaldehyde etc
•Chemicals used to destroy mites are called
eg: organo phosphates.
•These are chemicals used for the distruction of
nematodes like round worms, thread worms etc
The excessive use of pesticides have created tremendous adverse
effects on environment
1) Environmental pollution:-
Pesticides drained to water bodies causes water
pollution . hence water in river, lakes and seas gets
polluted which becomes hazardous to aquatic
animals like fishes.
Pesticides may also washed down to ground water
which pollute drinking water. During the spraying of
pesticides it may reach in to atmosphere and pollute
• Certain pesticides such as DDT, BHC etc
persisted in the environment accumulated in
blood,milk and fat of animals.Beyond certain
permitted levels, they are very dangerous to
human beings and animals
• Pesticides may kill the friendly insecticides
along with the inimical insects during its action
• Different herbicides used for destroying weeds
can destroy the vegetation in the neighboring
• Repeated use of pesticides may produce
immunity or resistance in insects. Resistance has
been observed in houseflies, mosquitoes etc.
• Effect on human health ;- Pesticides cause
several harmful effects in human body.
Pesticides are proved to be lethal if their intake
exceed a maximum limit.