The world’s population is regularly rising and to meet the increasing demand for food sources, there is a need to produce more food in less space without any effort, that would be environmentally safe and space inconvenient, so that it could maintain the balance between the natural resources and the individual and the community health.
Our mother nature is the best and the most natural food producer. The Symbiosis between the animals and the plants in the oceans and rivers are an example to us as to how they grow together without any effort. It also results in a fantastic and healthy environment that is good for the growth of biodiversity.
The same symbiosis can be seen in Aquaponics where the growing of aquatic animals and plants take place together and this is our today’s topic and we will learn every relatable information about it in this article.
What is Aquaponics Farming?
Aquaponic farming is an integrated technology of producing fish and plants together which essentially comprises two subsystems viz. Aquaculture and Hydroponics, where Aquaculture is the process of raising aquatic animals in a controlled environment like a Greenhouse and Hydroponics is a form of cultivating plants in water. When both these terms combine, they form an Aquaponic system.
The principle behind this farming system is to efficiently utilise the water for producing two crops rather than one and to partition and share the nutrient resources between both the fishes and plants.
This system is commonly used in resource-limited and urban areas where both fish and vegetables can be raised in an integrated system. In general, Green leafy vegetables such as Capsicum, Tomato, Lettuce, Cabbage, Basil, Spinach, Chives, Herbs and Watercress, that have low to medium nutrient requirements are well adapted to the Aquaponic system.
Aquaponics is a great technique of indoor farming and it can be carried out round the year which would provide fresh food, free of pesticides, herbicides and chemical fertilisers.
The initial investment for constructing the Aquaponics system is high but the recurring cost is less and it gives reasonable returns. It has an advantage of using less water, less land, renewal of waste, less labour, etc and the plants and animals derive a symbiotic relationship with each other.
The fish excreta provide nutrients for the plants and in return, the plants clean the water creating a suitable environment for the fishes to grow. Apart from this symbiotic dependence, there is also an opportunity for the microbes that play a very significant role in the nutrition of the plants.
Status & Potential of Aquaponics
Our country is a leading producer of freshwater fish and they achieve impressive yields of about 2 to 10 tonnes per ha per year from traditional methods of fish farming. However, the Aquaponics system has the ability to produce up to five times the quantity of fish in the same area per year, besides growing vegetables as well.
Aquaponics is a relatively new type of practice in our country which has been focused to improve the knowledge base of the fish farmers about the emergence of the future technologies in Aquaculture.
The natural resources such as land and water are regularly shrinking and the growing population, urbanisation and the change in lifestyle has caused a great demand for fresh, hygienic and organic produced fish and vegetables in the cities.
Therefore, Aquaponics has a huge potential for farming the fish and plants in an integrated system in those urban, suburban and the rural environment.
Benefits of an Aquaponics System
The benefits of Aquaponics system mentioned below:
- The yield is 6 times more per square foot than traditional farming.
- It uses 90% less water.
- You can grow any time of the year, in any weather and in any location using the Aquaponics
- Aquaponics recycle the water so the farming can be done in drought prone areas or where less water is available.
- Fewer pests
- No weeding
- Aquaponics provide two streams of income to the commercial growers – from fish and vegetables rather than just one.
- It does not need farmland with fertile soil or even land with soil. It can be constructed on sand, gravel or rocky surfaces.
- Water and nutrients are recycled in a closed-loop manner that conserves water.
- Less energy is consumed and the alternate energy systems like solar, wind and hydroelectrics can also be used to power an Aquaponic
- Fishes are the best ever converter of plant protein to animal protein that is utilised in the Aquaponics
- Fishes have no growth hormones, no Mercury, no Chemicals or pesticides.
- The plants grown in Aquaponics are safe and do not have any kind of chemicals.
- The fish wastes acts as a natural fertiliser for plants, therefore there is no reliance on mined and manufactured fertilisers.
- It is an efficient, sustainable and highly productive system and the products are free of pesticides and herbicides.
- It allows continuous production of food.
- It produces both protein and a vegetable crop.
- It is an integrated system that is sustainable and earth friendly.
- The elimination of soil eliminates soil borne diseases.
Components of an Aquaponics System
Aquaponics system comprises of the following components:
- Water quality – The quality of water is very important and the optimum range of certain parameters are required for a successful fish culture that is structured below:
|S.No.||Water Parameters||Optimum Range|
|1||Temperature||26°C – 30 °C|
|2||Dissolved Oxygen||4 – 6 ppm|
|3||pH||7 – 8|
|4||Alkalinity||120 – 150 ppm|
|5||Ammonia||< 0.05 ppm|
|6||Nitrite||< 0.5 ppm|
|7||Nitrate||< 5 ppm|
- Targeted Fish Species – The species for the Aquaponic system are those who can tolerate high density stocking. Some of the fish species include Monosex Tilapia (Oreochromis niloticus), Pangasius (Pangasiandon hypophthalmus).
- Model Unit – The model units for a small-scale Aquaponics unit is as follows:
- Fish pond/tank – The area required for constructing a fish pond is 80 m² with a diameter of 7.2 m and volume of 60 m³ or 60,000 litres. It should have an effective water depth of 1.68 m and a maximum depth of 2.13 m in the centre of the pond. The system should be so designed that it could handle more than 50 fish per m³, that is a total of 3000 fish.
- Plant Grow Beds – The number of grow beds in FRP tanks should be 10, with the dimension of 6×2×1 ft or 1.83 × 0.61 × 0.3 m for each bed. The solid media used to grow plants through which water from fish tanks would pass, should be gravel or expanded clay pebbles (hydrotons) or lightweight expanded clay aggregate (LECA).
- Moving Bed Biofilm Reactor & Filtration – A moving bed biofilm reactor (MBBR) and a filtration unit is installed in the Aquaponics system for the water treatment.
- Stocking & Yield – The stocking densities inside the tank is determined by the species requirements and their operational considerations. It can be understood better by the following table (indicative).
|A (Fish Culture)|
|1||Fish tank volume||60 m³|
|2||MBBR & Filtration unit||1 set|
|3||Targeted species||GIFT Tilapia and Pangasius|
|4||Fingerling stocking (50/m³)||3000 nos.|
|5||Fish Culture period||5-6 months|
|6||Survival||90% (2700 nos.)|
|7||Average body weight||750 gram|
|8||Expected Yield/Unit/Cycle||2700 fish × 750 gm = 2025 kg|
|9||Total Production/Unit/Year||2025 kg × 2 cycles = 4050 kg per year|
|B (Vegetable Cultivation)|
|1||No. of Plant Grow beds||10 nos.|
|2||Plant varieties||Tomato, Mint, Chilly, Lettuce, Basil|
|3||Planting Density||15 – 20 saplings/bed|
|4||Total no. of Plant||150 – 200 plants|
|5||Plant Cultivation period||Throughout the year|
|6||Harvest type||Partial harvest|
|7||Expected yield/bed/year||5-10 kg/bed/year|
In the Aquaponic farming system, you need to divide it into two sections- Aquaculture where the animals would live and the Hydroponic section where you will grow your plants because you cannot simply place vegetables and fish inside the water tank and expect the result. After this division you need to add the following components:
- Setting basin to grab food waste, biofilms and the settled fine particles.
- Biofilter to create a good environment for the bacterias. You can use gravel or sand as a supporting medium for plants if you want to save yourself from putting so much money on an expensive biofilter.
- Rearing tank for the fishes to live and eat.
- Hydroponic subsystem for the plants to grow and absorb the nitrates that are created by the bacteria.
- Sump where the toxicity free water would run from the Hydroponics system to the Rearing tank.
There are three living components that you need to make the Aquaponics work. They are – animals, plants and bacteria.
- Animals – Animals have the ability to tolerate crowding and variable water conditions, so you can use freshwater fish like Tilapia for this kind of environment. Other than this, you can also go for Barramundi, Eel-tailed catfish, Murray cod, Silver perch, Jade perch and Crayfish or Prawns as well.
- Plants – You can use many types of plants depending upon the type and quantity of the animals you have but some plants that will work efficiently are Cucumber, Tomato , Shallots, Lettuce, Snow peas, Chiles, Red salad onions, Basil, Spinach and Chinese cabbage.
- Bacterias – For efficient nitrification, you need two types of bacterias – One is Nitrosomonas which transforms Ammonia into Nitrates and another is Nitrobacter that transforms Nitrites into Nitrates. However, Nitrates are harmful to fish, so you need to have a spaced area such that the concentration does not get so high that it would create health concerns for the other living components.
Different Techniques used in Aquaponics Farming System
The different type of techniques used in an Aquaponics System are:
- Media beds – The media bed technique of Aquaponics uses containers that are packed with rock media like gravel or expanded clay for supporting the roots of the plants. The bed is flooded and drained of nutrient-rich water so that it could provide nutrients and oxygen to the plants they need. The growing media that is used for supporting these plants plays the role of both mechanical and biofilter to confine and break down waste. It is an inexpensive, simple and productive technique for small scale business. The media supports plants like soil, so you will be able to produce large root mass plants such as fruits, flowering plants, vegetables and root vegetables. It is not space efficient but requires more inputs of labour so it is hard to scale in commercial use.
- Deep Water Culture (DWC) – This system uses floating rafts for suspending the plant roots into the nutrient rich aerated water. The developing plant roots are directly suspended into the pool of water which is 1 foot in depth. There is no media to retain and process the solid wastes so filtration techniques must be incorporated into the system. Deep water culture requires more advanced Aquaculture techniques and system requirements so the upfront costs are higher. It is suitable for commercial Aquaponics production because it is one of the most stable technique for Aquaponics system and it has more water in the system so drastic nutrient and temperature fluctuations would occur very less and it is ideal for warmer climates because it would be hard to resist the daily temperature swings in colder climates. Also, the larger root zone plants can be grown here and removing the plants is also easier as compared to the media beds.
- Nutrient Film Technique (NFT) – This design is the most popular in the commercial industry because of its space efficiency and lower labour costs. The crops can be grown in a vertical plane which are easily reachable and harvestable. This method is best suited for leafy greens but it is not suited for large fruiting plants because the root masses can clog the channel and their weight may not be supported.
Fishes are the chief components of an Aquaponic system and it is the source of natural fertiliser for plants so it is important to plan which type of plant you want to grow and then pair them with the right type of fish species.
Before selecting the type of fish, consider these factors:
- Temperature Requirement
- The available fish in your location
- Which fish is legal in your location
- The type of fish and their maintenance
- Size and space requirements
- Filtration capacity
- Fish diet
- Breeding habits
Suitable Fishes for the Aquaponic System
You can use a variety of fishes but these are the most suitable:
- Ornamental fish
Suitable Vegetables for Aquaponics System
In most cases, the plants that grow best in Hydroponics are also compatible in the Aquaponics system. Leafy green vegetables and Herbs are most commonly grown in the Aquaponics. Cucumber and Tomato are often grown but it is a bit too advanced for a beginner.
Before selecting the plants consider these factors:
- What type of system you are going to use
- The requirements of your plants
The most commonly grown plants are:
- Swiss chard
- Bok Choy (Pak Choi)
- Radish sprouts
Suitable Plants to grow in an Aquaponics System
Different plants have different nutrient requirements and the system should be well established so that it could maintain the plants with higher nutrient demands and a well-established system consists of all the beneficial bacteria as well. Aquaponics system should be so arranged that it should have been running for at least six months and could last up to 3 years. The plants that require higher nutrients can be grown with experience in Aquaponic farming.
Some of the plants that could grow well in Aquaponics system are:
Aquaponics are hailed as the future of food production because they utilise only 2 to 10% of the water that is required in traditional vegetable or crop production and they also have the potential to produce 10 times the output without using any type of harmful chemicals, pesticides or herbicides.
The most significant aspect of Aquaponics is that they use minimum land that is being dubbed as Urban Aquaponics or Urban Agriculture or Terrace gardening or Vertical gardening or Indoor farming etc.
It is a highly efficient farming system that utilises the natural resources in a very limited quantity resulting in the conservation of the precious natural resources like water, land and environment.