by Sylvia Bernstein
This article was originally published in 2013 by Garden Culture Magazine, US Issue 1.
Sylvia is the author of “Aquaponic Gardening: A Step by Step Guide to Growing Fish and Vegetables Together,” and the President and Founder of The Aquaponic Source, the leading U.S. based company focused entirely on the home aquaponic gardener. She runs the Aquaponic Gardening Community, the largest online community site dedicated to aquaponic gardening in North America, and is the Vice Chairman of the Aquaponics Association. She also writes the Aquaponic Gardening Blog and teaches and speaks extensively about aquaponics and its exciting potential.
“Can we feed the more than 9 billion people anticipated to live on this planet in 2050 without destroying Earth’s life support systems?” This captivating conundrum was the title of a cover article for Nature Magazine’s edition titled “Solutions for a Cultivated Planet.” The article details the findings of an international group of scientists and researchers who gathered at the University of Minnesota tasked with nothing less than figuring out how to sustainably secure the world’s future food supply.
Nothing in the Nature Magazine report was surprising for anyone engaged in the worldwide ‘future of food’ dialogue. However, what was striking was that aquaponics (growing fish and plants together in a recirculating, soilless system) was not included among the set of proposed solutions. Aquaponics is a food growing approach that addresses the harmful practices cited in the study and simultaneously realizes the potential for increased food production envisioned by the researchers. Widespread adaptation of aquaponics could both alleviate all of the environmental destruction cited by the researchers and provide the vehicle for increased sustainability and productivity. First, the environmental problems with current agricultural practices were outlined in the report as follows.
1. “Farm and ranch lands cover nearly 40 percent of Earth’s land area”
While aquaponic techniques can’t address this shocking statistic per se, they can certainly mitigate the impact. Because aquaponics is a soil-less growing technique, plants and fish can be grown anywhere, including on land that is considered unfertile (too sandy, too rocky, too toxic) and even in old warehouse buildings and unused parking lots.
2. “Agriculture consumes nearly three-quarters of the earth’s available water”
Because aquaponics is a recirculating system, the only water “lost” is either held in the plants, transpires through their leaves, or evaporates from the top of the fish tank. Aquaponics is generally thought to use less than a tenth of the water of traditional agriculture for the same crop output.
3. “Agricultural activities such as clearing land, growing rice, raising cattle and overusing fertilizers make up 35 % of the single largest contributor of greenhouse gases to the atmosphere”
None of these practices have any place in aquaponic growing.
4. “About 40% of all crops the planet produces are used to feed animals.”
Fish are the single most efficient converter of feed to flesh of any edible animal. One and a half pounds of feed will bring to harvest one pound of edible, omnivorous fish fillets. It takes eight pounds of feed to produce the same single pound of beef fillets.
5. While not mentioned in the article, we should also add “consuming petroleum” to this list.
Between oil-based fertilizers, oil-fueled farming machinery, and long distances between farm and table, modern food is “dripping” with oil. Aquaponic systems on the other hand, have no oil-based inputs and are run entirely on a small amount of electricity. This electricity can be created through currently available renewable energy methods.
The researchers then recommended five changes to current practices that they believe will not only help to solve the issues stated above but will also extend our ability to feed the burgeoning world’s population. All but one can be implemented through aquaponic growing techniques.
“Halt farmland expansion.”
As explained above, because aquaponics is a soilless growing system that can be set up anywhere, it is perfectly suited to address this goal.
“Close yield gaps. Many parts of Africa, Latin America and Eastern Europe have substantial “yield gaps”- where farmland is not living up to its potential for producing crops. Closing these gaps through improved use of existing crop varieties, better management and improved genetics could increase current food production nearly 60 percent.”
Because of the consistent and ideal mix of water, oxygen and fertilizer that an aquaponics system provides, plants grow significantly faster in an aquaponics system than they do in soil. In addition, plants can be placed closer together in aquaponics systems because they are not competing for those resources in their root zone. This is an answer to the search for “better management” techniques that the researchers are seeking.
“Use inputs more strategically. Current use of water, nutrients and agriculture chemicals suffer from what the research team calls “Goldilocks’ Problem”: too much in some places, too little in others, rarely just right. Strategic reallocation could substantially boost the benefit we get from precious inputs.”
Since aquaponic systems use comparatively so little water, inherently produce their own nutrients, and use no agricultural chemicals, the problem of redistribution becomes a non-issue.
“Shift diets. Growing animal feed or biofuels on top croplands, no matter how efficiently, is a drain on human food supply. Dedicating croplands to direct human food production could boost calories produced per person by nearly 50 percent.”
Fish protein is not only heart-healthy but, as mentioned above; it is the most efficient converter of plant protein to animal protein known to man.
“Reduce waste. One-third of the food farms produce ends up discarded, spoiled or eaten by pests. Eliminating waste in the path from farm to mouth could boost food available for consumption another 50 percent.”
Because aquaponics systems are raised off the ground they tend to have fewer pest issues than traditional agriculture. And because aquaponic farms can be set up anywhere, producing food directly within densely populated communities can be implemented right now, with no new technologies needed. The path from farm to table can be made as short as down the block or even from backyard-to-table. Thus, aquaponics is an attractive way to localize food production and to cut out the waste inherent in the long paths we have from farm to market to home – paths that could be reduced to near zero with widespread aquaponics.
Aquaponics is not the answer to all of our future food supply and environmental issues. Grains and root crops, for example, will probably always be most efficiently grown in the soil. But for above ground, vegetative crops and fish protein, there simply isn’t a better growing technique on, and for, the planet.
How Does It Work?
Aquaponics is, at its most basic level, the marriage of aquaculture (raising fish) and hydroponics (growing plants in water and without soil) together in one integrated system. The fish waste provides organic food for the growing plants and the plants naturally filter the water in which the fish live. The third and fourth critical, yet invisible actors in the play are the beneficial bacteria and composting red worms. Think of them as the Conversion Team. The beneficial bacteria exist on every moist surface of an aquaponic system. They convert the ammonia from the fish waste that is toxic to the fish and useless to the plants, first into nitrites and then into nitrates. The nitrates are relatively harmless to the fish and most importantly, they make terrific plant food. At the same time, the worms convert the solid waste and decaying plant matter in your aquaponic system into vermicompost.