If you didn’t get a chance to read the previous article comparing the different urban farming concepts, I’d suggest catching up. Let’s pick up where we left off to see how we can gain more and use less through aquaponics #gainmoreuseless.
Understanding Different Farming Terms and Methods
Aquaponics is different from Hydroponics. Hydroponics is a style of soilless farming that involves purchasing liquid or dry fertilizers. Hobbyists or small farms typically use liquid forms. Commercial farms prefer combining dry powers to get the right macro and micronutrients or NPK (Nitrogen, Phosphorous, and Potassium) to supply their crops. Aquaponics relies on the same soilless farming techniques seen in Hydroponics like deep water culture (DWC) but instead source their nutrients from the waste excreted by fish.
There are several hydroponic techniques used in aquaponics. Deep-water culture (DWC) or float systems are the most widely used method in aquaponics. This method uses floating rafts to submerge plant roots in nutrient-rich oxygenated water in a pond or reservoir 8 to 12 inches deep. Submersible air pumps and air stones provide oxygen to the water. Without oxygen, the plant roots would not absorb the nutrient-rich water, eventually causing the plant to suffocate and die.
The Role of Fish in Aquaponics
The general rule of thumb for fish stocking density is one pound of fish per 5-7 gallons of tank water. The fish you choose for aquaponics is solely a matter of opinion, dependent on your region. Some studies explore saltwater aquaponics, but freshwater systems come highly recommended if farms don't want to worry about an added layer of water filtration or battle corrosion. In warmer climates, Tilapia, the bottom feeders, are the industry standard. They require little maintenance, fed just about anything, are disease resistant, and can withstand near extreme water temperatures and temperature fluctuations. If you think Tilapia is a poor choice as a nutrient source, there are alternatives. But if an aquaponic farm wants to introduce another business segment, like selling fish. They must obtain proper fish licenses for production and distribution varying by state regulations. The fish selection should be considered, based on the advantages previously mentioned about Tilapia. And, the only other alternative worth consideration for most climates is Bass.
There is an opportunity to be made with aquaponics. The world wild fish catch rate is 170 billion pounds. And the British Department of Health diet recommends the global consumption of fish to be 230 billion pounds, or two servings of fish per week (1-oily fish and 1-white fish). To ensure our global stocks remain unchanged, as monitored by the United Nations Food and Agriculture (FAO), we need to farm an added 60 billion pounds of fish a year. If the global wild fish stocks become depleted by overfishing, it will disrupt global ecosystems. One disturbance being the imbalance of microscopic marine algae, Phytoplankton, the base of many aquatic food webs. Overfishing can result in long-term algae blooms affecting zooplankton, fish, birds, and other animals, including animal and human exposure to poisons or toxins. Aquaponics can satisfy both the global food demand for fish and produce. And, these points position aquaponics in a uniquely strong position in the world of sustainable agriculture.
The fish you choose for aquaponics is solely a matter of opinion, dependent on your region. Some studies explore saltwater aquaponics, but freshwater systems come highly recommended if farms don't want to worry about an added layer of water filtration or battle corrosion. In warmer climates, Tilapia, the bottom feeders of the sea, are the industry standard. They require little maintenance, fed just about anything, are disease resistant, and can withstand near extreme water temperatures and temperature fluctuations. If you think Tilapia is a poor choice as a nutrient source, there are alternatives. But if an aquaponic farm wants to introduce another business segment, like selling fish. They must obtain proper fish licenses for production and distribution varying by state regulations. The fish selection should be considered, based on the advantages previously mentioned about Tilapia. And, the only other alternative worth consideration in warmer climates is Bass.
Why is Aquaponics be considered in Urban Farming?
The benefit of aquaponics is it's a self-regulating system. No other farming practice can recreate a natural ecosystem like aquaponics. The outputs, like fish waste, can be reused as a plant fertilizer or, in the case of a vegetarian fish like Tilapia, can be used as fish food. When algae bloom, this too can be collected as fish food for vegetarian fish as well.
Many, if not all, aquaponic farms are built in climate-enclosed environments or greenhouses. They can harness the energy from the Sun to engage photosynthesis without obstruction and added lighting, and if so desired, utilize supplemental lighting on overcast days.
Supplemental light usage means the crops grown in the greenhouse are not reliant on grow lights to produce crops. With some clever ingenuity, an aquaponic farm can maximize its square footage. Using vertical farming practices without restricting natural or supplemental light sources. Since aquaponics recirculates water, water loss includes:
the water consumption from plants
evaporation (liquid into vapor),
and transpiration (evaporation from a plant's stem, leaves, and flowers).
Conclusion
It comes down to a singular point of emphasis. We must gain more than we lose #GainMoreLoseLess. We will always gain more if we are:
capturing natural sunlight to engage photosynthesis,
use wind or pollinators to cross-fertilize crops,
and utilize water or water vapor in the form of dew, humidity, or rainfall.
Aquaponics is a unique method of farming. Essentially, your farming fish and food like fruits, vegetables, and herbs. If incorporating water and energy capture technologies, you can now farm water and energy. And, if dedicated to creating a negative feedback loop system, there are many forms of waste you can reuse. Fish waste converts itself into plant feed naturally with aquaponics. It's also a great source of food for vegetarian fish. When algae bloom due to a chemical imbalance in the summer months, this too can be used as vegetarian fish food condensed into pellets. Algae can also process into biomass or biofuels for textiles and renewable energy. The opportunities in aquaponics are seemingly endless, and it might be time to consider it as a staple for sustainable agriculture and urban farming practice.
Conclusion
Aquaponics is a unique method of farming. Essentially, your farming fish and food like fruits, vegetables, and herbs. If incorporating water and energy capture technologies, you can now farm water and energy. And, if dedicated to creating a negative feedback loop system, there are many forms of waste you can reuse. Fish waste converts itself into plant feed naturally with aquaponics. It's also a great source of food for vegetarian fish. When algae bloom due to a chemical imbalance in the summer months, this too can be used as vegetarian fish food condensed into pellets. Algae can also process into biomass or biofuels for textiles and renewable energy. The opportunities in aquaponics are seemingly endless, and it might be time to consider it as a staple for sustainable agriculture and urban farming practice.
"In nature, nothing exists alone."
Rachel Carlson
Located 45-minutes outside Houston, Texas, in a town called Hockley, a climate-enclosed aquaponic farm captures the rays from our Sun to produce living lettuce and other vegetables and herbs. The farm delivers food to its plants by converting fish waste into nutrients. Constantly finding new methods to harvest food, water, waste, and energy, Sustainable Harvesters is pushing forward on its mission to contribute to the movement of sustainable agriculture. If you're in the area, stop by to try their hallmark living lettuce and other living vegetables known to last 3-4 weeks in your fridge. Otherwise, find them at one of your local farmer's markets or restaurants. Want to learn more about aquaponics, sustainable agriculture, and future projects? Sign up for a Saturday farm tour to learn more!
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