Hydroponics and aquaponics are agricultural systems without soil that produce high yields with minimal inputs. By eliminating soil as a growing medium and avoiding water wastage, these intensive methods support sustainable and profitable localized food production, even in water and land scarce environments.
Hydroponics
Hydroponics, a well-established technique, is widely utilized in greenhouses to cultivate tomatoes and lettuce. These plants are directly grown in a water-based solution that contains all the necessary nutrients they require. In some instances, inert media such as pebbles or clay pellets are employed to provide support for the plants. By eliminating soil, hydroponics completely eradicates harmful soil organisms and weeds. As a result, the need for labor and herbicides is significantly reduced. Moreover, the controlled environment shields the crops from most airborne pests. Any occasional infestations or fungal infections can be effectively managed by using targeted pesticides and fungicides.
Hydroponics usually utilizes only 20 percent of the water needed for conventional farming. The primary recurring cost involves periodically replacing the water that has depleted nutrients. Every day, the electrical conductivity of the solution is checked to ensure the optimal nutrient levels are maintained. When an imbalance in chemicals is detected, the solution must be replaced. Every 4 to 6 hours, energy is required for aerating and pumping the solution. Although hydroponic cultivation can be carried out indoors with artificial lighting, it increases the energy expense while enabling year-round food production.
Aquaponics
Both aquaponics and vermicomposting are systems used to fertilize and cultivate plants, with the main difference being the use of fish in aquaponics and worms in vermicomposting.
Aquaponics is an innovative technique that promotes the harmonious collaboration between fish and plants in cultivations. This exceptional approach to food production is relatively recent and warrants some recognition.
The necessary equipment you will require.
If you want to try aquaponics, there are specific equipment requirements. You will require a planting bed that can contain 8-10″ of water and accommodate surface planting for the plants. As the roots mature, they will hang freely in the water, getting ample access to water. It is essential to note that certain plants thrive without soil more effectively than others.
In order to complete the system, you will require a fish tank. Goldfish or tilapia are commonly chosen by most individuals for this purpose. The fish tank serves as the place where you will provide food for the fish. When the fish produce waste, it gathers at the bottom of the tank. A pump is responsible for transferring the waste water out of the tank and into the planting beds. This assists in maintaining cleanliness in the fish tanks by removing waste. The nutrients in the wastewater are consumed by the planting beds, resulting in its purification. The water is then circulated from the planting beds back to the fish tanks, initiating the cycle once again.
To complete the process, do not forget to obtain fish food. The welfare of your fish has a direct impact on your plants. Similarly, the well-being of your plants greatly influences your fish. Maintaining a balanced aquaponics system is of utmost importance.
What should be done with the waste?
Aquaponics possesses the advantage of converting raw fish waste into usable fertilizer for food production, rather than allowing it to be released into the environment. It is noteworthy to mention that modern salmon farms, on average, release an amount of raw manure equivalent to that of a town with a population of 65,000, without making any effort to mitigate its impact. Aquaponics provides an effective solution for utilizing this raw fish sewage and deriving significant benefits from it.
What is the status of the fish?
Aquaponics can be described as a method not only focused on plant production, but also as a means to raise fish in a healthy manner. Unlike tilapia fish farms that utilize genetic or hormonal manipulation, aquaponics avoids such practices and ensures that fish are not exposed to harmful metals. The organic approach to raising fish in aquaponics results in delicious fish. If you have ever considered integrating fish production into your organic home garden, this could be a suitable option to pursue.
Hydroponics vs. Aquaponics
Despite being high-yielding systems that maximize space utilization and significantly reduce water dependency, each method has its own set of advantages and disadvantages.
- Energy requirement. Power is required to run the aerators and pumps that keep both the hydroponic and aquaponic systems running. Daily power expenditure is higher in aquaponics with its frequent water circulation. However, it is easily offset by the higher returns from both the fish and the plant crops.
- Waste disposal. Periodic replacement of the hydroponic solution results in large amounts of wastewater. Disposal of this fertilizer-rich water into natural water bodies is an environmental risk. It can promote algal growth and be a threat to aquatic ecosystems. In aquaponics, solid waste generated by the fish in excess of what gets broken down by the worms and bacteria is the only waste. Since it is organic in nature, it can be disposed of into the common drain or used for composting.
- Monoculture and the risk of diseases. In hydroponics, the liquid medium for each crop is specifically formulated to meet its specific nutritional requirements; hence, monoculture is preferred for the maximum utilization of the fertilizer input. Disease risk, especially from fungal infections, is higher in hydroponics; and an outbreak can spoil the entire batch. Hence, special measures are taken to protect the crops from contamination. Fish waste is a general organic fertilizer, and a variety of plants can be grown together in aquaponics. In a well-established system, the different components such as fish, worms, plants, and various bacteria form a natural ecosystem that resists diseases.
- The necessity of solid growing media. Solid media can be completely eliminated in hydroponics; its only function is to provide an anchor for the plants. When pebbles or clay balls are used, 6-inch deep beds are the norm. Aquaponics also does away with soil, but other coarse media like clay pellets or rock pieces are used to provide a home for the beneficial bacteria similar to the ones that exist in the soil. Waste-eating germs also thrive among the solid media. To sustain these organisms, 12” deep beds are recommended.
- Time delay for the maturing of the system: Hydroponic units can be set up quickly and start running without any gestation period. Yield is determined solely by the normal growth period of the given crop. The complex setup of the aquaponic system requires a maturation period to become functional. The establishment of bacterial colonies for the effective breakdown of fish waste is an indispensable part of aquaponics. It can take 3-6 months.
- Risk of loss in case of mechanical failure: No mechanical system is fail-proof. Electrical failure, mechanical faults, blockages in the plumbing, and malfunctioning of monitoring devices, can affect the system adversely. In hydroponics, most problems can be resolved immediately without causing lasting damage, as it has a 5-6 hour flood-drain cycle. Aquaponics has very short recirculation cycles, once every 30 to 45 minutes, so the cost of even temporary failure can be particularly high, often resulting in the loss of the entire fish stock due to toxic chemical build-up in the aquaculture tank. The solid waste produced by the fish makes the system comparatively more prone to blockages too.
- Chemical control of pests and addition of nutrients. An outbreak of pests or infections in hydroponically grown crops can be quickly controlled by spraying the crops with appropriate pesticides or fungicides. Any nutritional deficiencies spotted in a crop can be rectified by adding the required fertilizer to the growing media. Any addition of chemicals to an aquaponic system entails careful consideration, as it can upset anyone of the different components such as fish, bacteria, and worms. Iron deficiency can be usually tackled by supplementation, but pests have to be controlled mechanically.
