This document discusses coastal agriculture and its impacts. It notes that coastal areas provide important environmental services and agriculture can have major positive or negative effects on the coastal environment. Agriculture is a major land use and can impact natural resources, water quality, and habitats through activities like diverting rivers, using pesticides and fertilizers, overcropping, and clearing coastal wetlands. Sustainable policies are needed to minimize agriculture's negative effects on coastal areas.

1. Coastal agriculture
Judith Das
MFSc 2018
Aquatic Environment Management
COASTAL AGRICULTURE

2. • Coastal areas are commonly defined as the interface or transition
areas between land and sea, including large inland lakes.
• Coastal areas are diverse in function and form, dynamic and do not
lend themselves well to definition by strict spatial boundaries.
• Coastal areas are important ecologically, as they provide a number of
environmental goods and services.
• In some coastal areas, and especially in small islands, agricultural
production makes an extremely important contribution to the local
economy or to national agricultural production.

3. There are a number of reasons for giving agriculture particular
attention in integrated coastal resource management planning:
• agriculture has major positive, but also potentially negative effects on
the coastal environment. Sustainable agricultural policies are
therefore needed to minimize the negative impacts of inland
agriculture on coastal areas;
• agriculture is concerned with the production of food, and has
significance for food and livelihood security.
• agriculture may also provide raw materials to industry located in
coastal areas and may therefore economic significance.

4. • the main user of land and, agricultural can have impact on natural
resources ,quality and flows of water and on natural habitats;
• where tourism or other capital-intensive activities are developed in
coastal areas, smallholders may be highly tempted to sell productive
agricultural land for non-agricultural purposes
• agriculture may play a key role in the local economy through the
production of food or by providing raw materials to industry.

5. Impacts of coastal agriculture
Area of impact/subsector Use or activity Environmental or social change Impact of social/economic
concern
Estuary, harbour and inshore
water quality impacts
Agriculture Diversion of rivers for
irrigation
Reduced water flow in rivers, increased
estuary salinity, decreased estuary
circulation
Decreased fish yields
Agriculture High use of pesticides Toxic pollution of estuaries and inshore
waters
Decreased fish yields
Agriculture High use of fertilizers Increased amount of nutrients entering the
water leading to eutrophication of rivers,
estuaries and inshore waters
Decreased fish yields
Agriculture Excessive cropping or
grazing on watersheds
Watershed erosion, river turbidity,
sedimentation of fish habitat in estuaries
and inshore waters, floodplain deposition
and beaches covered with sediment
Decreased fish yields,
silting of navigation
channels, increased flood
hazard, and decreased
tourism attraction

6. Groundwater
quality/quantity
Agriculture/Coastal
aquaculture
Withdrawal of
groundwater at a
greater rate than
natural recharge
Salt-water intrusion of aquifer leading
to increased salinity, contamination of
groundwater
Reduction in the water
available for use, risk to
human health
Mangrove and other
coastal wetland impacts
Agriculture/Coastal
aquaculture
Reclamation of
mangrove for rice
paddy
Destruction of mangrove, filling and
canalization
Reduced fish yields,
reduced filtration
capability, increased
risk of shore erosion,
increased risk from
flooding, increased risk
of storm damage

7. Agriculture Draining of salt
marsh and coastal
wetlands (in
temperate countries)
for grazing and
cropping
Lowering of land surface and
accelerated rise in sea level
Increased frequency
and extent of flooding,
increased beach
erosion, increased
salinity in coastal soils
and in upstream
`wedges', increased
need for `hard' coastal
defences
Coral reef and atoll impacts
Agriculture/Forestry Irresponsible
agricultural and/or
forestry practices in
coastal watersheds
Watershed erosion, turbidity and
siltation of coral reefs
Decreased fish yields,
decreased tourism and
recreational value

8. OPPORTUNITIES AND CONSTRAINTS FOR
AGRICULTURE IN COASTAL AREAS
Opportunities
• The following three particular types of opportunity are identified being
potentially important in the development of agriculture in a coastal area:
• Opportunities dependent on natural resources: coastal areas offer favourable
environmental conditions for agriculture , consist of alluvial accumulation plains.
relatively flat, fertile soils and substantial supply of water, from surface and/or
subsurface sources.
• Most coastal areas also have a milder and more humid climate than the interior
as a result of the moderating influence of the sea
• In contrast to fisheries and forestry activities, coastal agriculture does not involve
harvesting of coastal resources; its relationship is usually more competitive (the
expansion of agriculture into mangrove forests) and antagonistic (the
modification of coastal ecosystems) than exploitative.

9. Opportunities arising from location.
• Land and sea communications can also have implications for coastal
agriculture.
• Coastal roads may give access to markets for agricultural products, and also
facilitate input supplies. Improved roads may allow new areas of land to be
brought into cultivation, and new water sources may also become
accessible. However, roads in relatively isolated coastal areas are often
poor, denying farmers market access or leading to produce reaching
consumers in poor condition.
• Even in the absence of good roads, produce can be shipped to markets by
river as far as the coast and by boat along the coast. This may be the most
significant locational advantage of coastal areas

10. Derived or secondary opportunities
• Coastal industries and development arising may also lead to increased
demand for agricultural raw materials.
• Tourism may also encourage demand for higher-value, perishable
agricultural products.
• The impact of both types of increased demand and development also
increases the land values.

11. Constraints
Proximity of the sea.
• Low-lying agricultural land is subject to severe drainage and soil salinity problems
caused by high, more or less saline, water-tables, stagnation of rain and runoff
water and flooding from rivers or periodic storm surges.
• physical damage from wind storms or tidal waves, and sensitivity to airborne salt
deposition. Low-lying agricultural lands may also be susceptible to shoreline
retreat and flooding as a result of coastal erosion, subsidence or a rise in sea
levels which could result from global climatic change.
• Higher air humidity in coastal areas is favourable to the occurrence and
propagation of certain plant diseases and pests that constrain crop growth.
• occurrence of tides that induce the penetration of sea water far inland during
high tides causes periodic increases in river water salinity that complicate its safe
use for irrigation

12. Upstream effects
• Upstream dams and irrigation schemes can deprive coastal areas of water
for irrigation and, by removing silt and regulating floods, may affect the
fertility of coastal alluvial agricultural land.
• inland encroachment of agriculture to forested land, slash and burn
practices, overgrazing and inappropriate cultivation methods may increase
runoff and erosion in catchment areas, with coastal land affected by
increased sediment in rivers, lower dry season river flows and increased
flooding.
• The quality of surface water available to coastal agriculture may also be
affected by upstream discharges of industrial and urban effluents and by
drainage of chemicals and salts from agricultural land into rivers.

13. Space and resource constraints
• Opportunities for expansion or relocation of agricultural activities are limited.
Agricultural development and population growth lead to pressures on resources such as
water and land.
• Space constraints and competition for land and water become more intense with
urbanization. Many forms of agriculture require extensive amounts of land to produce
relatively low-value outputs. As competition for land intensifies smallholders, unable to
invest and intensify tend to lose their land and migrate to the coastal towns.
• irrigation uses high volumes of water inefficiently, to produce relatively low-value
outputs. Increasing water scarcity divert water away from agriculture to residential and
industrial uses, and to other types of agriculture.
• increasing pressure on land lead to overexploitation, with inappropriate land use
through the extension of agricultural activities into areas that may not be suitable for
agriculture.

14. Potential harmful effects of agriculture on the
coastal environmentActivity Environmental change Impact of social concern
Estuary flood control, impoundment or
diversion of coastal rivers
Increased estuarine salinity, reduced
circulation, sediment trapping, decreased
supply of beach material to shoreline,
shoreline erosion
Reduced crop yields, reduced
fish yields, increased water-
borne diseases
Agricultural pesticides Toxic pollution of estuaries and inshore
waters
Killing of fish, reduced fish
yields, potential human
consumption of toxic fish, coral
pollution and loss
Fertilizer use Increased amount of nutrients,
eutrophication and pollution of estuaries
Killing of fish, reduced fish
yield, coral pollution and loss
Overcropping or grazing in coastal
watershed
Watershed erosion, estuary sedimentation
and increased turbidity, increased
deposition in flood plains
Corals and beaches covered
with sediment, coral death,
decline in fish yields,
decreased recreation and
tourism attraction, obstruction
of navigation channels with

15. Competition for land: Agriculture is the major occupier of land for
cultivation and grazing. Associated settlement, buildings, roads and irrigation
and drainage works take up still more land.
• In many coastal areas, significant clearing and drainage of coastal wetlands
(swamps and mangrove forests) is taking place for cultivation. Such action
results in habitat loss and loss of biological diversity.
• Soils of these wetlands are difficult to manage, yields often decline after a
few years and land has to be abandoned, creating pressure for further
clearance, drainage and destruction of coastal wetlands.
• Coastal wetlands and dunes also used for grazing. This may not necessarily
result in direct destruction, but it may do if steady degradation continues
over several years

16. Competition for water: Dams and irrigation schemes, inland or near the
coast, may reduce surface flows, with effects on the timing as well as the
overall volume of river flows. Irrigation and cropping activities in coastal
areas may lower the water-table.
• Where irrigation systems extract groundwater from coastal aquifers
become exhausted or increasingly saline as salt water intrudes into them.
• Reduced or erratic surface and groundwater supplies in coastal areas can
pose serious problems to coastal ecosystems, to aquaculture and to
industrial and domestic water supply systems.
• Overexploitation of groundwater can also lead to subsidence and greater
susceptibility to flooding.

17. • Antagonistic effects: The antagonistic effects of agricultural activities tend to be
related to water flows.
• Intensive agricultural activities may result in water pollution through runoff of
agricultural chemicals.
• Soil erosion, which has many causes, increases sediment in watercourses which
can silt up ports and cover coral reefs.
• Poorly managed irrigation can lead to saline runoff, or the release of toxic
substances that find their way to the coast.
• Changes in water quality may have far-reaching effects. Increased sediments in
water, for example, are damaging to coral reefs which require clear and clean
water.
• Toxic chemicals and organic wastes in surface water damage, and may destroy,
sensitive coastal ecosystems.

18. POLICY ISSUES IN COASTAL AGRICULTURAL
PLANNING
• In agricultural planning in coastal areas, broader objectives should be
defined with reference to national policies on economic, regional and
agricultural development.
• Coastal ecosystems are often fragile and can be irreversibly damaged. In
application of the precautionary principle, measures to avoid possible
detrimental effects of agricultural development on coastal ecosystems
should feature strongly in coastal area agricultural development plans.
• Agricultural plans must include objectives on efficient use of land and
water, selection of new land for agriculture, and the maintenance (or
restoration) of the water flows and stocks and water quality necessary to
support coastal ecosystems etc.

19. • It is important that objectives be maintained and made operational
throughout plan monitoring and implementation.
• Changes in the external effects of agriculture can be achieved by a
change in agricultural activities or by a change in practices (or
technology) for existing activities.
• Voluntary, regulatory and incentive approaches may be used to
encourage desired changes in activities or practices. These
approaches may involve subsidies, the provision of services, taxation,
regulation and institutional development.

20. POKKALI
• Pokkali rice cultivation are centuries old organic system. This system
utilizes the symbolic relationship between rice and prawns.
• This is a natural system of cultivation which relies upon monsoons
and sea tides. Rice resides form feed for prawns and prawn
excrement forms fertilizer for rice, which makes it ecologically stable
and also reduces the input.
• The present social and economic system makes it very difficult for
maintaining the system in its original form. Even with government
efforts to promote the organic system, the Pokkali fields are
diminishing at an alarming rate.

21. • Pokkali cultivation can be considered as man’s ingenuity in harnessing
natural events for farming. It is a system of integrated farming, which
does not affect the natural ecological processes. This system does not
require any external inputs.
• The farmers use a native variety for rice cultivation known as Pokkali
having duration of 120 days. This variety is effectively resistant to
flood and salinity. The plant grows to a height to 1.5 m. Other
varieties which are being used include Chettivirippu, Vyttila 1, and
Vyttila 2

22. • The preparation of Pokkali system of rice cultivation starts in the
month of May. Initial work starts with raising bunds followed by
making mounds of 1 m2 base and 50 cm height
• The mounds are allowed to dry by preventing the entry of water into
the fields. With the south west monsoons down pouring, salts and
toxic elements are washed off from the mounds and drained off. On
these mounds, sprouted Pokkali seeds are sown
• The seeds are sprouted by tightly packing them in baskets of coconut
leaves with an inside lining of banana or teak leaves and soaking in
fresh water for 12 to 15 hours

23. • After a month period, the mounds are leveled off. The seedlings on
the mounds are spread uniformly in the field. The seedlings grow
quickly and get established in the field and withstand floods that
follow
• The crop will be ready for harvest within 4 months and harvesting is
mainly down using boats
• The prawn farming is generally done during November to April

24. • After the monsoon period, the canals and backwaters of the region become
saline and large quantities of juvenile prawns and fingerlings of other fishes enter
these canals.
• The juvenile prawns are guided into fields by means of water channels having a
head at its gate (known as sluice gates) and the gates prevent them from moving
out. This is known as prawn culture filtration, and locally known as
“chemmeenkettu” in pokkali fields.
• The prawns and fish grow in the field providing additional income to farmers.
The left over residues of rice cultivation act as natural food for fish farming.
• The prawns feeding on the stubbles of rice cultivation helps to keep the disease
incidence in the following crop of rice to a minimum as well as the prawn
execreta is a good natural fertilizer for the rice crop.

26. • The sluice gates are maintained in such a way as to provide maximum
entry of saline water into the fields and preventing the escape of fish from
the field while maintaining maximum water exchange.
• Harvesting normally at the time of low tides. The prawns and fish are
caught in the sluice nets locally known as “thoombuvala”
• White prawns (Naran) and tiger prawns (Kara) are the major cultivated
prawns
• The best utilization of ecological cycle takes place in Pokkali fields making it
environmental friendly.
• Absence of the use of chemical fertilizers and pesticides makes it an
organic rice production system with less expenditure compared with
normal rice cultivation.

27. • The major environmental concerns of loss of biodiversity, over
exploitation of natural resources and coastal degradation are not
present in this system. This system is an ecofriendly cultivation
practice
• The present day concerns in Pokkali cultivation is lack of farm labor
and economic inviability.
• Since the rice-fish cultivation depends on the proper combination of
rain and tides, due to the present climatic changes, there is concern
about the unpredictability of the system.

28. • Planning and construction of spillways for more rice production in
Kuttanad area was not done in a planned manner resulting in
environmental problems and socio-economic disasters The total area
under Pokkali cultivation of 25,000 ha has reduced to 5,500 ha in the
last few decades
• The real estate boom has resulted in reclamation and drainage of
most of the Pokkali lands for the construction of houses and multi
storied residential flats

29. REFERENCE
• Pokkali rice cultivation in Kerala. Agric. Update, 11(3): 329333, DOI :
10.15740/HAS/AU/11.3/329-333,Roshni vijayan
• FAO ,1998.Integrated coastal area management and agriculture
• Agriculture in coastal areas :environmental issues and
impacts,2012,Francoise Vernier

30. THANK YOU