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Impacts of agriculture, aquaculture on environment
Written By: Saad Arif Sair
The term “Agriculture” may be defined as: the art and
science of growing plants and other crops and the
raising of animals for food, other human needs, or
It is the science, art, or occupation concerned with
cultivating land, raising crops, and feeding, breeding, and
raising livestock; farming.
Agriculture & Environment
Often, when speaking of the agricultural impact on
the environment, one restricts any consideration to
processes of pollution of surface and ground waters
from chemicals added to the soil during agricultural
No doubt, such processes exist and may have even a
prominent importance. They are caused either by
water infiltration in soil, with the consequent
possibility of nutrient and pesticide leaching.
Impact of Environment on Agriculture
Environment effect the agriculture due to:
Agricultural & Environmental Implications
Developing measures that will encourage flexibility in
land use. Crop management in relation to climate
change is a key topic of global concern.
Increasing water management efficiency in order to
sustain agricultural production under changing
Integrating agricultural, environmental and cultural
policies to preserve the heritage of rural environments.
Environmental Impacts of Agriculture
When farming operations are sustainably managed,
they can help preserve and restore critical habitats,
protect watersheds, and improve soil health and water
But when practiced without care, farming presents the
greatest threat to species and ecosystems.
Negative environmental impacts from unsustainable
farming practices include:
Land conversion & habitat loss
Wasteful water consumption
Soil erosion and degradation
Land conversion & habitat loss
A major and growing land use:
Agriculture is a major land use. Farmland covers 38% of
the world's land area. This area is still expanding to
meet demand for food.
Natural habitats converted to monocultures:
Rising demand for food and other agricultural products
has seen large-scale clearing of natural habitats to make
room for intensive monocultures.
Land conversion & habitat loss
Freshwater is also affected:
Waste water of Fields also effect to the fresh water of
river ,oceans Etc.
Land lost to desertification:
On top of habitat loss due to clearing, unsustainable
agricultural practices are seeing 12 million hectares of
land lost each year to desertification.
Wasteful Water Consumption
Agriculture, the greatest user of water:
Globally, the agricultural sector consumes about 70% of
the planet's accessible freshwater more than twice that
of industry (23%), and dwarfing municipal use (8%).
Wasteful and unsustainable:
The main causes of wasteful water use are:
1. leaky irrigation systems
2. wasteful field application methods
3. cultivation of thirsty crops not suited to the
Soil Erosion and Degradation
Erosion caused by deforestation can also lead to
Arable land destroyed:
It is estimated that since 1960, one-third of the world’s
arable land has been lost through erosion and other
Waterways clogged & polluted:
Soil carried off in rain or irrigation water can lead to
sedimentation of rivers, lakes and coastal areas.
The use of pesticides, fertilizers and other agrochemicals
has increased hugely since the 1950s.
Pesticides often don't just kill the target pest. Pesticides
can also kill soil microorganisms.
Fertilizers are not directly toxic. However, their presence
in freshwater and marine areas alters the nutrient
Agricultural practices are responsible for around
14% of global greenhouse gas emissions
Wetland rice cultivation
Burning of savanna
Agricultural residues, and plugging
Lost genetic diversity:
The widespread use of genetically uniform modern
crop varieties has caused agricultural crops to lose
about 75% of their genetic diversity in the last century.
This lost genetic diversity reduces the potential for
modern crops to adapt to, or be breed for, changing
conditions and so directly threatens long-term food
Aquaculture is the farming of aquatic organisms such
as fish, shellfish and even plants. The term
aquaculture refers to the cultivation of both marine
and freshwater species and can range from land-based
to open-ocean production.
AQUACULTURAL SYSTEMS, PRACTICES AND PROBLEMS
HAVING POTENTIAL IMPACT ON THE ENVIRONMENT
Destruction of Habitat for Aquacultural activities:
The creation of ponds for marine shrimp aquaculture
has led to the destruction of thousands of hectares of
mangroves and coastal wetlands.
Mangroves provide nursery grounds for many species,
including commercially important fish, and their
destruction may lead to substantial losses for
Collecting wild Juveniles as Stock
Aquaculture of some species relies on juvenile fish or
shellfish being caught from the wild to supply stock,
rather than using hatcheries to rear them. Shrimp
farms in many areas rely on wild caught juveniles. This
has led to over exploitation and shortages of wild
The main environmental impact of crab culture is the
procurement of larvae from wild brood stock, and the
on-growing of wild crablets.
Depletion and Salinization of Water/land
Pumping of groundwater to supply freshwater to
marine shrimp farms has resulted in depletion and,
sometimes, Salinization of local water supplies,
causing water shortages for coastal communities.
There have also been many reports of crop losses after
agricultural land has become salinized by effluent
water pumped out from shrimp farms onto land.
Poor research in fish diseases and abuse of medicines
Novel fish diseases cannot be treated, and diagnosis of
aquatic diseases in the third world involves
undeveloped instruments and weak technical power.
Hence inability to distinguish bacterial and nutritional
diseases, which directly influence correct medication.
Once the disease comes on, the abuse of medicines is
Weak environment protection consciousness
Though various high-yielding aquaculture methods
such as industrial fish farming, cage fish culture, and
raceway culture are developed to some extent.
Fishing and environment protection consciousness are
still deficient, and the random discharge of
aquaculture waste waters without any treatment has
deteriorated the whole aquaculture environment, and
blocked the sustainable development of this industry.
Residual feeds and excrements (fish waste)
Feeds are the basic material of aquaculture, and the
source of main nutritional matters.
Most feeds of aquaculture are outside source foods and
given to aquatic animals directly. Large amount of
residual feeds and the excrements of aquatic animals
all impact the water environment.
Escaping Salmon and their threat to Wild Fish
Farmed Atlantic salmons have escaped in vast
numbers and are successfully breeding with their wild
Farmed salmon have a lower genetic variability than
wild salmon. Experiment show that the offspring are
less fit than wild salmon and a high proportion die.
Interbreeding of farmed with wild salmon could
therefore drive already vulnerable populations of wild
salmon towards extinction.
Environmental impacts of Aquaculture
Influence on physiochemical parameters
The main influence of aquaculture on water
quality is to increase the suspended
substances and the nutritional salts in waters.
Cages used in aquaculture can also reduce the
dissolved oxygen in the water. The wastes of
cage aquaculture increased the total
concentration of water nutrient and increased
the turbidity of the waters.
Influence on substrate of aquaculture facilities
On the bottom of facilities used in aquaculture, the
contents of C, N and P are higher than the contents
those used for other purpose, and the oxygen
consumption is also higher.
When the organic matters accumulated on the mud
bottom are too much, the physiochemical index of the
bottom will be changed, and the decomposing function
of microorganisms results into bloom, and the
dissolved oxygen in the bottom is depleted, as a result of
numerous sulfates in the water, hydrogen- sulphide
(H2S) build up in the environment.
Influence on planktons and bottom dwellers
The input of outside-source materials and organic
matters can increase the productivity of the planktons.
Feeds make the nutrient matters in waters to gradually
increase, and the phytoplankton propagated largely at
the beginning, but as time goes on and the continual
expansion of aquaculture is still on a large scale, the
nutrient matters input increases to a point the water
quality deteriorates, so the amount of phytoplankton
will begin to reduce.
Escaped domestic fish and ecosystem health
Another influence of aquaculture on aquatic biology is
that the escaping fishes would impact their wild
neighbours in biology.
Escapees from small-scale scenarios and unreported
escape cases seem to make up a large proportion of the
escaped farmed fish. The escaping fishes in the
aquaculture may spread diseases and change the
inheritance composition of genes of wild swarm, and
infect local epidemics to wild swarms.
The influence on the ecological environment
In the recent years, because of the development of
aquaculture, the seductive profit of aquaculture has
raised a aquatic tide in the world, most lakes, rivers,
swamps, coastal lowlands and mudflats are changed
into shrimp culture ponds and fish culture ponds.
These lowlands were mangroves, saline soils and
agricultural lands, and some of them were inhabiting,
spawning and refuge places for many fishes and
shellfishes. Unreasonable development will destroy
the ecological environment of shells, and the natural
Reduced functionality of wetlands
Natural wetland functions support a wide array of
environmental goods and services that sustain
economic activities and societal systems. However,
aquaculture development can damage the functional
integrity of wetlands, disrupting the supply of
environmental good and services.
Loss of the mangrove root system could decrease
sediment stability, leading to erosion, which could
increase saline intrusion and the risk of flooding
Wastewater from land-based aquaculture is routinely
discharged to streams and rivers supplying other
aquaculture operations downstream, whilst waste
discharged from pen and cage farms may be conveyed
to other farms by currents and tides.
Moreover, for pen and cage aquaculture facilities there
is a danger that discharged wastes that may
contaminate water intended to supply the farm.
High potential strategies for low impact aquaculture
Community-based management usually centers on
common pool resources ‘non-exclusive resources to
which the rights of use are distributed among a
number of co-owners, generally identified by their
membership to some group such as a village or
Include: community pastures, grazing lands and
forests, wastelands, dumping grounds and threshing
areas, village ponds, rivers and other common pool
Horizontally integrated production
Horizontally integrated production has been defined
as ‘the use of unexploited resources derived from
primary aquaculture activities to facilitate the
integration of secondary aquaculture practices.
Horizontal integration has the potential to perform
several important functions, the most valuable being
the assimilation of wastes, reducing discharges to the
Reducing waste discharges through horizontal
integration will contribute to environmental
protection and reduce the risk of negative feedback
Resource efficient production
The poor resource-base of small-scale farms in developing
countries means that unexploited nutrient sources e.g. crop
by-products, terrestrial weeds; aquatic plants and manure
represent important production enhancing inputs to
Alternative strategies that have evolved to integrate the
production of livestock and aquaculture; manure from
cattle, buffalo, sheep, and poultry has been employed
to enhance production in aquaculture systems.
Sustainable seeds supplies
Sustainable access to fry and fingerlings can constitute
a significant constraint to aquaculture development.
Several traditional aquaculture practices evolved based
on the collection of gravid females or seed from the
wild, however, harvest of wild seed was often
unsustainable and unable to support higher
RECOMMENDATIONS AND CONCLUSION
Most aquatic wastes come from feeds, to reduce these
wastes, limit the percentage of un-consumed feed in
the culture facility.
To reduce nutrient wastes, Aquaculture effluents
should be monitored and managed, to avoid or reduce
any negative environmental impacts.
In feeding of fishes, the proper feed quantity should be
confirmed, this will reduce the amount of feeds
scattered and loss during feeding.
Using fishery chemicals correctly The chemical
dosage must the strictly controlled, and the
performance and method of fishery chemical
administration must be correctly known.
Enhancing management level of aquaculture
Implementing rules about aquaculture resource
development, and comprehensively utilizing the
regulations of fishery resource management.
Based on the above discussion it may be concluded
that a number of promising technical, social and
institutional approaches with potential to contribute
to low impact aquaculture have been identified and to
some degree tested, however, strategies are required
that promote and support their uptake and where
necessary adaptation. Awareness of promising
approaches to low impact of agriculture and
aquaculture should be promoted amongst target
institutions including national and local government
authorities, extension agents, development
practitioners, educational establishments and
communities that stand to benefits.