Aquaponic vers. Hydroponic

Is crop production in aquaponics more sustainable than in conventional hydroponic cultivation systems?

The aquaculture research group of the Marine Bioeconomy Section at the Alfred Wegener Institute is currently investigating this question in a new project as part of a BSc thesis. Katrin Weiss (BSc student at the University of Bremerhaven) is analysing and comparing nutrient balances of a conventional hydroponic production with nutrient balances of an aquaponic system for this thesis in the coming weeks. The indoor farming start-up Greenhub (University of Leipzig - SEPT Competence Centre) has provided two identical systems for the research. In one system, the plants - lettuce, basil and pak choi - are fertilised with a conventional mineral mix. In comparison, the nutrients in the second system come largely from metabolic products of tilapia. How sustainable this combined approach is depends not only on the plant growth generated but also, of course, on how much nutrient can be recycled by this method. In the coming weeks, Katrin Weiss will collect this data and eventually be able to assess the potential savings in nitrogen and other components. The work is mentored by Kai Lorkowski (Technical Director of the Centre for Aquaculture Research) and Dr Stephan Ende (Research Associate of the Marine Bioeconomy Section).

The newly developed aquaponics and hydroponics prototypes by the start-up Greenhub offer a high degree of flexibility for answering numerous scientific questions due to their compact and modular design. Especially the high degree of automation through intelligent, sensor-based control technology and the user-friendly app facilitate the daily management for the researchers. As a result, the systems provide an environment that reduces human involvement to a minimum. Thus, in addition to lighting cycles, many other parameters such as fertiliser dosing can be monitored and controlled from the office via the app. Much of the automatically generated data is stored and can be accessed by the scientists at any time.

Greenhub is currently in the product development phase and is funded by the PTJ and BMWI as part of an EXIST start-up grant. In the joint prototype phase, the systems will be tested for functionality from mid-January 2022 to mid-May 2022 at the Centre for Aquaculture Research (ZAF). With the knowledge gained, the prototypes will then be transferred into a marketable product.