27
Climate smart aquaculture and fisheries
Plants
MR. NGOEPE TK
0730265668
INTRODUCTION
2
Aquaponics is basically a
combination of aquaculture and
hydroponics.
It is characterized by three main
components, namely, fish,
bacteria and plants
Hence, this presentation will
focus on the plants in
aquaponics system.
Main Differences Between Aquaponics and Traditional Crop
Production
• There are many similarities between
aquaponics and traditional production,
while the basic plant biology is always the
same (Figures 1 and 2)
• Importance of elaborate major differences:
To bridge the gap between traditional and
aquaponics practices.
3
Figure 1
Figure 2
Main Differences Between Aquaponics and Traditional Crop
Production Cont.…..
4
Generally, the differences are between:
Use of fertilizer;
Consumption of water;
The ability to use non-arable land;
and
Overall productivity.
Labour intensity
Monoculture support
Traditional
farming
Main Differences Between Aquaponics and Traditional Crop
Production Cont.…..
Fertilizer use
Aquaponics Traditional
Aquaponics gets its nutrients from the water source, the by-products of the fish system.Aquaponics mimics a natural ecosystem, it produces many nutrients that plants need without chemicals.
Traditional agriculture and gardening often use mined or manufactured chemical and synthetic fertilizers, pesticides and herbicides.
5
Water useAquaponics and hydroponics
do not typically discharge or
exchange water under normal
operation, but instead,
recirculate and reuse water very
effectively.
Aquaponics uses
approximately 10 percent of the
water that the traditional irrigated
farm requires for the same
vegetable production
Thus, aquaponis cultivation
allow production where water is
scarce or expensive
Main Differences Between Soil And Soil-less Crop Production
Cont.…..
6
Aquaponics Traditional
More efficient Less efficient
Higher yield Lower yield
No competition with weeds
Requires weeding.
Land use
Efficiency and yield
Main Differences Between Soil And Soil-less Crop Production
Cont.…..
Reduced labour and improved working
conditions
Aquaponics: Less work, and work
involved is of a high quality
usually use raised beds and do not need
weeding
Harvesting is also a basic methodology
compared with traditional farming, and
products do not require extensive cleaning
to remove soil contamination
Suitable for any gender and many age
classes and capacity levels of individuals.
Sustainable monoculture
7
Aquaponics Traditional
Possible to
grow the
same crops in
monoculture,
year after year
More
challenging
because the
soil becomes
“tired”, lose
fertility, and
pests and
infections
increment
Main Differences Between Soil And Soil-less Crop Production
Cont.…..
• High initial investment and
increased complication
Aquaponics: intense labour for initial
set-up and installation coupled with
high cost.
Aquaponics: fairly expensive system
compared to hydroponics,
Because plant production units need
to be supported by the aquaculture
installations.
If any one part of the system fails, the
entire system can collapse.
Aquaponics requires reliable power
supply
Generally, aquaponics is far more
complicated than traditional
agricultural.
8
Photosynthesis
Photosynthesis
It is vital to locate an aquaponics unit in a place where each plant will have access to
sunlight,
To ensure adequate energy for photosynthesis.
9
Process of photosynthesis
Nutrient requirements
Nutrients are required for the enzymes that facilitate photosynthesis, for growth and
reproduction
Nutrients are sourced from the soil.
However, in the absence of soil, these nutrients need to be supplied another way. In
aquaponics, all of these essential nutrients come from the fish waste.
Two categories of nutrients: macronutrients and micronutrients
10
macronutrients micronutrients
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Sulphur (S)
Iron (Fe)
Manganese (Mg)
Boron (B)
Zinc (Zn)
Copper (Cu)
Molybdenum (Mo)
Sources of nutrients in aquaponics
Fish waste
Teleosts mostly excrete nitrogen (N) in the form of ammonia (NH4) through their gills
while their faeces contain organic N, phosphorus (P), and carbon (C).
The solid fish waste is broken down by heterotrophic bacteria; this action releases the
essential nutrients into the water.
Maintain the optimum water pH
(6–7) –to ensure plant do not suffer from deficiency
K, Ca or Fe need to be supplemented for proper plant development.
Fish and plants require different amounts of iron, potassium and calcium=Potential
deficiency may occur.
11
Sources of nutrients in aquaponics
Water Quality for Plants
Water characteristics must be carefully measured and maintained within proper ranges to
assure optimized performance of the organisms and to secure success.
• pH
pH outside optimum range-plants
experience nutrient lockout.
Temperature and season
High water temps=heat stress for the
plants.
• Dissolved oxygen
Without oxygen, the plants can
experience root-rot
• Ammonia, nitrite and nitrate
Ammonia and nitrite are very toxic to fish and
Should always be maintained below 1 mg/litre.
12
Selection Of Plant Species
13
Leafy green plants Fruiting vegetables Root crops
• Do extremely well in aquaponics along with some of the most popular fruiting vegetables, including tomatoes, cucumbers and peppers.
• Have higher nutrient demands and are more appropriate for established systems with adequate fish stocks.
• Require special attention, and they can only be grown successfully in deep media beds.
Selection Of Plant Species
14
Low nutrient
demand plants
High nutrient demand plants
Selection Of Plant Species
High-nutrient demand plants, include the
• Botanical fruits:
Cucumbers, tomatoes, strawberries, peppers, and eggplants.
• Other plants with medium nutrient demands are:
Cabbages, such as kale, cauliflower, broccoli and kohlrab.
15
Seed Starting Techniques
16
WAYS OF STARTING SEEDS IN
AQUAPONICS
1. Direct sowing
3. Cutting and cloning
2.Starter plugs
1
2
3
Plant Health, Pest And Disease Control
• Plant health is the overall status of well-being that allows a plant to achieve its
full productive potential.
• Plant health, including disease prevention and pest deterrence and removal, is
an extremely important aspect of aquaponics food production (Figure 6.8).
17
FIGURE 6.8. Common diseases of plants include mildew caused by a fungus (a); canker/blight
caused by bacteria (b); and leaf spots caused by bacteria or fungus (c)
Plant Health, Pest And Disease Control
Prevent pest using:
18
Integrated production and
pest management
(IPPM) techniques
Trapping
physical barriers
Crop rotation
Companion planting
If pests remain a problem
Apply mechanical
removal techniques
before considering
sprays
Only use aquaponics-safe
remedies
E.g. Plant extracts,
repellents, biological
insecticides, soft soaps, ash, plant
oils.
Plant Health, Pest And Disease Control
Physical barriers
A ring of copper flashing can prevent snails and slugs from climbing up the legs,
and a coating of petroleum jelly can prevent ants. Placing the bottom of the legs
in a container of water can also prevent ants.
Hand inspection and removal
The removal, either by hand or using a high-pressured stream of water, of heavily
infested leaves or plants helps to avoid and/or to delay the spread of insects to
surrounding plants
19
Plant Health, Pest And Disease Control
Trapping
Sticky traps positioned slightly above the canopy of plants are effective in
protected environments (e.g. net houses, greenhouses). Blue sticky cards trap
adult stages of thrips while yellow sticky cards trap whiteflies and
microlepidoptera (Figure 6.11). Sticky traps are less effective in outdoor
conditions as new insects can easily come from the surrounding areas.
20
FIGURE 6.11. Yellow sticky trap (a) installed in a greenhouse (b)
Plant Health, Pest And Disease Control
Treatment – inorganic or chemical
As aquaponics is an integrated system containing fish, plants and beneficial
micro-organisms, it is not possible to use the standard disease treatments of
conventional agriculture (i.e., chemical fungicides) as they are toxic to fish.
However, common practices used for organic agriculture are possible, provided
that they do not harm fish and/or the bacteria.
Treatment – biological
Biological control agents that can be used for aquaponics such as Thricoderma
spp., Ampelomices spp. and Bacillus subtilis, which are cultured micro-organisms
used to fight against specific diseases. These biological agents can be applied
either on leaves or at the root zone. They provide protection against the most
common soil-borne diseases including downy mildew, powdery mildew and some
bacteria.
21
Planting design
• The design of the grow beds helps to maximize plant production in the
available space.
• Before planting, choose wisely which plants will be grown.
• Important considerations are:
Plant diversity
companion plants
nutrient demands
market demands and ease of access
22
Planting design
• Staggered planting
It is important to stagger planting.
In this way there can be constant
harvest and replanting, which helps
to maintain a balanced level of
nutrients in the unit.
At the same time, it provides a
steady supply of plants to the table
or market.
Keep in mind that some plants
produce fruit or leaves that can be
harvested continually throughout a
season.
23
Financial benefits
• Aquaponics is capable of generating and increasing both income and revenue that
making a major GDP contribution for South Africa from commercial scale productions.
• The farmers could generate significant revenue by supplying the local markets and
feeding schemes (hospitals, schools and prisons) with relatively cheap, good quality
animal protein and fresh vegetables.
• Vegetables can be produced every four months and three production cycles can be
achieved every year, while fish can be harvested every 6 months and two production
cycles are achieved every year, bringing consistent cash flow within a short period.
• Which in return makes farmers less vulnerable and not relying generally on
government aid more especially the disaster relief aid caused by climate change.
• Aquaponics products can be further extended to include other vegetables as per a
manufacturing schedule.
• Currently ARC is conducting a study on how to maximize profitability of vegetables
based on market price trend analysis that will be coupled with farmers growing
schedules
24
SUMMARY
• The main advantages of aquaponics over soil-based agriculture refer to no
wasted fertilizer; lower water use; higher productivity/quality; ability to utilize
non-arable land; and offset of tillage, weeding and other traditional agricultural
tasks. Basically, plants require sunlight, air, water and nutrients to grow.
• The essential macronutrients consist of nitrogen, phosphorus, potassium,
calcium, magnesium and sulphur; whereby micronutrients include iron, zinc,
boron, copper, manganese and molybdenum. Any deficiencies of these
nutrients need to be addressed by supplying the limiting nutrients with
supplemental fertilizer or increasing mineralization.
• Of the water quality parameters, pH is the most significant owing to the fact
that it affects the availability of essential nutrients.
25
SUMMARY
• The appropriate temperature range for most vegetables is 18–26 °C, although
many vegetables are seasonal. Winter vegetables require temperatures of 8–
20 °C, and summer vegetables require temperatures of 17–30 °C.
• Leafy green herbs and vegetables do extremely well in aquaponics. Large
fruiting vegetables are also applicable, including tomatoes, peppers, eggplant,
and cucumbers, peas and beans. Root crops and tubers are less commonly
grown and require special attention.
• Integrated production and pest/disease management uses physical,
mechanical and cultural practices to minimize pests/pathogens, and then uses
fish-safe chemical and biological treatment in targeted applications, when
necessary.
• Intelligent planting design can maximize space, encourage beneficial insects
and improve production. Staggered planting provides continual harvest as well
as a constant nutrient uptake and more consistent water quality.
26
Thank
you
