The FAO provides distinct definitions for aquaculture and hydroponics. Aquaculture refers to the farming of aquatic organisms in both coastal and inland regions, involving manipulation of the breeding process to enhance output. On the other hand, hydroponics is a type of agricultural production that doesn’t involve soil, with nutrients being delivered to the crops in a liquid solution.
Both methods of farming, in their various forms, have been effectively employed for several decades in the commercial sector.
Aquaponics is the merging of aquaculture, a process of raising aquatic animals, and hydroponics, a method of cultivating plants in water without soil. This integration has given rise to a novel agricultural concept known as integrated agro-aquaculture (IAA) systems, which is gaining popularity as its potential is being realized.
The systems that are bound to shape the future of aquaponics are recirculating systems, be it in aquaculture or hydroponics, which are presently not operational. These systems provide remarkable advantages.
How aquaponics operates
In the tank, the fish eat and release nitrogenous waste into the water. The water, as well as any leftover food, is pumped to the biofilter unit. There, bacteria and fungi decompose the waste and food into more basic nutrients.
After its nutrients are extracted by the biofilter, healthy water is transferred to the hydroponic unit where plants utilize them during their growth. As a result, the plants contribute to purifying the water, which is later collected in a reservoir and reintroduced to the fish-growing system via a pump.
Included in the fish that were raised are;
- Striped bass
- Tilapia
- Trout
- Catfish
- Goldfish
- Koi
The hydroponic unit incorporates a variety of plants.
- Leafy vegetables like Chinese lettuce, cauliflower, basil, microgreens, kale,
- Small plants like strawberries and cherry tomatoes
- Herbs
It should be emphasized that aquaponic plants have low nutrient needs.
Components of an aquaponics system
- Fish tanks
Fish are raised and reside in this location. The tanks can either be rectangular or circular and are typically constructed of plastic. Optimal water conditions required for the fish’s development, such as pH, oxygen levels, and temperature, are always upheld. An air stone is introduced into the water to maintain adequate levels of oxygen and feeding is conducted at set intervals.
- Biofilter
The nitrifying bacteria (nitrosomonous and azotobactor) and fungi disintegrate nitrous waste and leftover food in the fish tank water into simpler substances and extract any surplus solids before the water is directed to the hydroponic unit via a pump.
- The water pump
This is employed to transport water throughout the system and disperse it to the various parts.
- Hydroponic unit
Aquaponics utilize various hydroponic systems as their core method of growing plants in a certain location.
- Deep water raft system
Most commercial aquaponics farms utilize this system as it is highly favored. The plants are situated within a foam raft structure in a large container, with their roots exposed to the nutrient-rich water from the bottom biofilter. Mesh pots provide support for the plants’ roots.
- Nutrient film technology
The plant roots absorb nutrients as the nutrient water from the biofilter flows down a sloping channel.
The plants are positioned uniformly in a line, with the top portion above and the roots resting in a channel. Occasionally, mesh pots are employed to provide support for the plants, and in certain cases, the roots are sustained by media such as gravel. Leafy vegetables are grown using the NFT method in indoor vertical farming for commercial purposes.
- Media-filled beds
Porous stones or clay pellets are placed in the containers to aid in the growth of plants, which are subsequently nourished with nutrients from the biofilter through a pumping mechanism.
- Vertical aquaponics
Plants are grown in rows on top of one another using tower systems, vertical deep water culture units, and PVC NFT pipe channels.
How aquaponic farms work
In general, aquaponic farms operate in a straightforward manner. They typically have one or more tanks that house fish, with the water from these tanks being directed to mechanical filters. After this point, the water is subjected to a bio-filtering process before finally being delivered to hydroponic cultivation channels. By following this process, the metabolic waste produced by the fish can be transformed into nutrients that are beneficial for growing plants.
Aquaponics offers more than just a dependable source of premium food; it also presents a chance to advance people’s socioeconomic status, ultimately enhancing food security and autonomy.
Aquaponics has evolved from basic small-scale cultivation to the establishment of 120 deep-water cultivation greenhouses in Ethiopia, as well as urban aquaponics projects (Urban Farmers) in The Hague, demonstrating its effectiveness in producing eco-friendly food worldwide.
Advantages of aquaponics
- There is double output; fish from the tanks and a regular supply of fresh vegetables.
- The system is easy to maintain and manage.
- Aquaponics saves water and facilitates water recycling since it’s reused compared to normal farming methods.
- Aquaponics can be carried out anywhere in the world even in arid no arable land places.
- The output from the system is entirely organic without pesticides, herbicides or chemical fertilizers.
- It is easy to control pests and diseases.
- There are no weeds
- The system is environmentally friendly.
Disadvantages of aquaponics
- It requires daily maintenance to manage; feeding the fish, cleaning the tanks, and maintaining adequate water conditions for the fish like temperature, carbon dioxide, PH, solids concentrations, and PH.
- Initial startup costs can be high for some people.
Bottom line
Aquaponics allows for the dual cultivation of plants and vegetables, providing numerous advantages, and can be implemented on a small scale or in backyard settings through DIY units for hydroponics enthusiasts and farmers alike.
