OdyssEYExplorers: Aquaponics: A Sustainability Project

Operation Lettuce Fish to End World Hunger: An Aquaponics Project at Odyssey Community School.

In the fall of 2011, The Odyssey Community School in Asheville installed two 50-gallon Aquaponic systems in their greenhouse in order to teach the community about this promising new sustainable approach to conserving soil. The 4th and 5th grade class was put in charge of maintaining the two dozen Tilapia fish and Lettuce beds. Their goal is to bring awareness to the problem of degraded soil around the world and to help spread Aquaponic technology to parts of the world that need it most.

According to the USDA, over 70% of soil (or 3.6 billion hectares) in dry regions of the world is considered to be degraded and therefore difficult or impossible for growing crops (Dregne and Chou, 1994). On a global scale, the annual loss of 75 billion tons of soil, costs the world about $400 billion per year, or approximately $70 per person per year (H. Eswaran, R. Lal and P. F. Reich, 2001). Soil compaction, a major type of soil degradation, has reduced crop yields in West African countries by 40 to 90% (Charreau, 1972; Kayombo and Lal, 1994). Aquaponics is a viable way for people who have no access to productive soil to get the greens and protein needed for a healthy diet without shipping it in from a distant location.

Aquaponics is a combination of two commonly used forms of agriculture Aquaculture and Hydroponics. Aquaculture is the growing of fish in a contained area for commercial use and Hydroponics is the growing of plants without using soil. An Aquaponic system can be as small as a bucket or as large as an acre field. This system was first used by the Chinese and Aztec cultures over 2,000 years ago that recognized the nutritional value that fish waste, specifically nitrogen, gives to plants.

The Odyssey School is growing a species of fish called Tilapia because of the fish’s ability to grow quickly, withstand temperature or system fluctuations, and its desirable taste. The Tilapia are fed a combination of fish food pellets from the store and duckweed that is grown in buckets in the greenhouse. On top of the two fish tanks are beds filled will pebbles in which a variety lettuce grows. The class chose to grow lettuce because it is a winter crop that is nutritious and liked by all. The fish waste is pumped from the tanks onto the beds above where bacteria convert the ammonia into Nitrates and then Nitrogen so that the plants can use it for nutrients. Water is then filtered back into the tank to conserve water and the cycle begins again. Odyssey students plan on a getting some of the electricity needed to power the system from a Solar panel that was made for a previous research project by a different Odyssey School student. This will help to make the system more sustainable, and therefore, more realistic as a solution to fight hunger in third world countries who may not have access to consistent electricity.

Odyssey students help maintain the Aquaponic System by feeding the fish, checking the temperature, pH, and Ammonia levels and make adjustments necessary to keep the system balanced and productive. They also plant, maintain, harvest, and sell the lettuce they grow to members of the Odyssey community. With the money they make, students plan to buy a sustainable Aquaponic system for a school in another country that is suffering from famine or malnutrition due to soil depletion.

References

DREGNE, H.E. and CHOU, N.T. 1994. Global desertification dimensions and costs. In: Degradation and Restoration of Arid Lands, ed. H.E. Dregne. Lubbock: Texas Technical University.

KAYOMBO, B. and LAL, R. 1994. Response of tropical crops to soil compaction. In: Soil Compaction in Crop Production,eds. B.D. Sloane and C. Van Ouwerkkerk, 287–315. Amsterdam: Elsevier.

CHARREAU, C. 1972. Problemes poses par l’utilization agricole des sols tropicaux par des cultures annuelles. Agronomie Tropicale, 27, 905–929.

Eswaran, H., R. Lal and P.F. Reich. 2001. Land degradation: an overview. In: Bridges, E.M., I.D. Hannam, L.R. Oldeman, F.W.T. Pening de Vries, S.J. Scherr, and S. Sompatpanit (eds.). Responses to Land Degradation. Proc. 2nd. International Conference on Land Degradation and Desertification, Khon Kaen, Thailand. Oxford Press, New Delhi, India.