The principle of aquaponics clearly defined – Eurasia Review
This is one of the great topics of sustainable food production: aquaponics – the combination of fish farming in aquaculture and growing plants in hydroponics. That’s the short definition. What convinces consumers is the resource-efficient approach that saves water, energy and artificial fertilizers. This is the theory. Missing or vague definitions and standards make it difficult to properly plan and assess factories. Researchers led by the Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB) have now tightened definitions and created a computational model for resource use. They argue that the coupling of internal flows, for example water, nutrients and energy, needs to be evaluated. After all, it’s the idea of the cycle that ultimately makes aquaponics sustainable.
The coupling of fish farming and fish farming is not new. In southern China, farmers have been raising fish in their paddy fields for around 1,200 years. In the past, as today, the principle of fertilizing plants with nutrients from fish excretions and using water for both has been used. Over the past 20 years, the combined cultivation of fish and vegetables has become popular around the world under the term aquaponics due to its resource-efficient circulation principle. Professor Werner Kloas’ research team at the Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB) has also developed an aquaponics system, the “tomato fish”.
Aquaponics and trans-aquaponics: the tomato fish is not a rice carp
IGB researchers have just published an article on the principle of aquaponics in the journal Reviews in Aquaculture. Their objective: to precisely define the coupling of the systems. “Aquaponics has great potential for environmentally friendly food production. However, its implementation also presents challenges. The system is only sustainable when fish farming and market gardening are effectively coupled. This framework is intended to help further develop the systems and test them, ”explained Werner Kloas.
The authors distinguish the term “aquaponics” from “trans-aquaponics”. Thus, aquaponics is the exclusive combination of fish farming in a recirculation system – that is to say in basins in which the water is treated by filtration systems – and the culture of plants in hydroponics. Hydroponics is the soilless cultivation of plants in which the roots of a plant grow in a nutrient solution, a mixture of water and nutrients dissolved in it. This principle is used, for example, in the aquaponics system of the IGB.
Trans-aquaponics extends the term to the cultivation of fish and plants using other methods. “An example of trans-aquaponics would be carp farms in rice fields in China,” said IGB researcher Gösta Baganz, the study’s lead author.
It’s all about the coupling
The researchers are also introducing a new measure of water use: the plant’s product water usage is the amount of water that a plant needs per year to produce one kilogram of fresh product. . Indeed, saving water can be the great advantage of an aquaponics system, but is not necessarily implemented in a consistent manner. With the new parameter, this aspect can now be objectively evaluated.
In order to quantify all the nutrient, water and energy flows, the researchers also developed a computational model. The formation of carbon dioxide emissions as well as waste and sewage can also be determined with the model. “We also want to increase transparency for consumers. After all, many consciously opt for the higher price tag for aquaponics products because they assume they were produced in an environmentally friendly way. The first step in an objective assessment procedure has now been taken, ”summarized Gösta Baganz.