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Home , Hydroponics

duets BY PETER KONJOIAN AND TODD GUERDAT

Aquaculture + =

has triggered the birth of a new animal at the same rates as conventional industry — . hydroponic growers. So far, we’ve done The growth of global aquaculture that with head at a pilot scale. coupled with growing demand has We’re now scaling up and getting our created concern over food security and processes ironed out at a -scale quality for U.S. seafood consumption. At in our research site here the same time, aquaculture growth in the at UNH. U.S. has been stifled by siting challenges (location) and operating costs resulting Peter: The difference in using terrestrial in low profit margins and high risk. animal waste versus aquaculture waste in production appears to be the Peter Konjoian is president of Konjoian’s Peter: OK Todd, this sounds familiar crux of the challenge. With integration Education Services Inc. His career spans four decades as a to what’s happening on the crop side of aquaculture and hydroponic systems commercial grower, researcher and consultant. Todd Guerdat is of agriculture. The locally grown food in mind and given that early DIY systems assistant professor of at the University movement’s mission is improving food are not yielding the profitability needed of New Hampshire. Konjoian can be reached at peterkfes@ security and quality using systems to solve the global seafood challenge, comcast.net. located close to consumption centers. what aspects of system integration are oining me this month is Todd The headline of our article is Aquaculture + you studying to solve the problem? Guerdat, assistant professor of Hydroponics = Aquaponics. As simple as Jagricultural engineering at the the equation looks, help us understand Todd: Aquaponic systems capitalize University of New Hampshire. Todd the potential benefits of marrying on the benefits of integration in a variety received his undergraduate degree and plants as well as the challenges of of ways, especially when we focus on a from the University of North Carolina- combining them. treatment approach for developing Wilmington in 1999. He then managed . How can we treat the North Carolina State University Todd: One big limitation in aquaculture the fish waste stream to convert it Fish Barn, Cooperative Extension’s is the management of fish wastes. into quality nutrition? Most of commercial-scale demonstration, Traditionally, wastes are captured, the needed for hydroponic research, and training recirculating treated and discharged from aquaculture production are present in the water, but aquaculture facility. While at N.C. State, facilities. This represents a large cost aquaculture waste nutrients are not he earned his Master’s and Ph.D. degrees for the operation and lost opportunity perfectly suited to hydroponic systems in Biological and Agricultural Engineering in terms of nutrient utilization. The without conditioning. The biggest with emphasis on agricultural water and essence of integration is the utilization of nutrient concern for hydroponic systems wastewater treatment. Todd’s research a waste from one system as a resource is organic carbon. The next concern is at UNH focuses integrating agricultural for another. But aquaculture wastes the relative proportions, stoichiometry, of processes to optimize system efficiency don’t integrate easily with terrestrial nutrients available to the plants. Is there and profitability. agriculture which is why we are looking at more than a crop needs, too hydroponic cropping systems to receive little , too much or not enough Peter: Most of our readers are these nutrients. of any minor element? plantsmen so a good place to begin Simply plugging one plumbing system We’ve demonstrated good stoichiometric is describing the global challenges into another and calling it integrated analyses in the water in which the fish commercial fisheries are facing. Why is farming isn’t how it works, yet this is how are cultured and we are working now this topic relevant to growers, first as many are approaching aquaponics in on ways to condition the solid waste consumers and second as horticulturists? the DIY communities. Current research to develop a clarified nutrient . is looking at this from two perspectives; However, each nutrient source (liquid or Todd: Peter, an excellent question. water treatment to accommodate the solid waste stream) has more organic Here are several facts that many find plant’s physiological requirements and carbon than conventional hydroponic shocking. Over half of the seafood overall system economics. We want to solutions. The inevitable result is consumed worldwide is produced facilitate the treatment of the aquaculture microbial accumulation, biofilm, from aquaculture. Eighty percent of wastes such that we meet the nutritional in the system on the plant , grow the seafood consumed in the U.S. is needs of the plants. bed surfaces, clogged emitters, etc. imported, by itself responsible for a Our goal is to balance the stoichiometry nearly $11 billion domestic trade deficit. of the nutrients in our fish generated Peter: Microbial contamination and Global increase in seafood demand “” solutions so we can grow biofilm are issues greenhouse growers

16 OCTOBER 2018 GPNMAG.COM DUETS

Todd: Predicting where we go with integration clear nutrient solutions or even dried and pre- requires a lot of patience. You and I have mixed salts). discussed a number of scenarios in which the Hydroponic operations would benefit from a nutrients from aquaculture supply the needs nutrient source that is naturally derived for the for hydroponic cropping systems. The devil of sake of gaining organic (or similar) certification implementation is really in the details of the without the problems of organic carbon in the economic research. But the concept of a fish nutrient source. This means that instead of also being a plant farmer, and vice versa, coupling our systems (the traditional model is a tough sell given the complexity of either of where fish and plants use the same treated the systems individually. water), we enable an avenue for nutrients to flow While a dairy farmer grows and cows, from one facility to the other without the burdens the waste from a dairy operation is captured of dual system management. Decoupling the and stored for a period of time before being hydroponic and aquaculture systems means each applied to the fields. In aquaponic systems, the system thrives and can manage their needs much

Graduate students Anna Devitto and Sean Fogarty integration of the aquaculture and hydroponic more efficiently, ideally. are working with lettuce (foreground), systems creates a constant nutrient production (background) and Tilapia (fish tank) in a newly and uptake balance that is year-round, day in Peter: From my horticultural perspective constructed greenhouse range at a University of and out. Both types of production, aquaponics there’s another issue in a coupled system that New Hampshire research farm. and dairy, are doing the same thing — utilizing shares the same water between the fish and wastes as resources — however, the way in plants: pH management. Generally, fish require deal with every day. An integrated system that which the nutrient management plan gets a higher pH than the types of plants we grow shares water creates a whole new challenge; implemented is drastically different. on the hydroponic side of the system. If one sanitation products used to treat crop Ultimately, the goal is to allow everyone to assumes that the higher level organism, the water and delivery systems are probably not specialize and thrive. What I mean by this is animal, should receive its optimal environment good for the fish. Let’s introduce the topic of we are working on a way to allow each type of regarding pH then the plant side of the coupled coupled versus decoupled integrated aquaponic system to focus on its strengths. Fish system is going to be forced to tolerate a sub- systems. I’m not a fan of zero sum propositions need to supply the much-needed seafood optimal growing environment. and believe as our research advances we may domestically but need a way to reduce the huge Growers are keenly aware of the effect drifting find applications for both system philosophies. costs of waste treatment by creating a market pH has on crop nutrient availability. From my What’s your vision of this part of the challenge? for the treated nutrient solutions (think clean, plant-centric perspective a decoupled system

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www.mastertag.com 1-800-253-0439 18 OCTOBER 2018 GPNMAG.COM Providing practical and affordable solutions for growers, retailers, and consumers! DUETS approach makes a lot of sense. economic constraints and build aquaponic and aquaculture of your collaborators. I’m also Remove the fish waste, treat it to an economic strategy around producers with an engineering confident that your growing group remove organic carbon, adjust the integrating these two different and biological focus covering the of graduate students is up to the pH, and use it on the hydroponic systems (scale vs scope). gamut of topics of integration. challenge. Seeing that UNH is my side. If a little tweaking to the We’re also planning on undergraduate alma mater I get to stoichiometry is needed inject creating hands-on workshops Peter: This is an exciting project, close with a “Go Wildcats!”. additional nutrients to deliver a annually for hydroponic, Todd, and I am pleased to be one perfect nutrient solution. Can this approach work?

Todd: Yes, but, aquaponic systems (coupled) are much more efficient in the utilization of nutrients than each of the systems operated separately. By integrating hydroponic cropping systems with recirculating aquaculture, the wasted nutrients (think nitrogen) are directly assimilated by the crops. This represents a cost savings as well as a reduction in what we discharge (water and nutrients), which means we spend money on growing a saleable product instead of treating wastes and simply discharging. The result is an improved production model because we’re potentially impacting the economics for both systems by monetizing HYBRID IMPATIENS FOR SUN & SHADE! aquaculture waste treatment and capitalizing on consumers being New sub-series structure for laser-matched vigor groups more conscious of where their food Apollo has highest vigor • Helios has mid-range vigor comes from, all tied up in a push Aurora sub-series features unique bi-color patterns for produce with an "organic" or similar certification. The crux to naturally and organically produced crops is the nutrient source; it almost always comes from animal agriculture … .

Peter: You just schooled me on why this challenge requires agricultural engineering, a tip of my cap. You did state earlier that overall SUNSTANDING SUNSTANDING system economics are holding back HELIOS MAGENTA ORANGE AURORA the initial DIY systems, thanks for reinforcing that fact. How about a final comment on this complex research topic?

Todd: Our research objectives are to develop a complete understanding of the nutrients produced from the aquaculture facility (nutrient mass balance), develop good agricultural INCREDIBLE PROFIT POTENTIAL practices (GAPs) for food safety, Finish packs & quarts in 5-7 weeks and evaluate different integrated SUNSTANDING when you direct-stick with innovative pest management (IPM) strategies APOLLO PURPLE Quick Turn™ Cuttings for microbes and insects. We will design integrated systems optimized under different production and/or Discover bold & bright blooms at SunStandingAnywhere.com Book cuttings with your preferred broker today!