Wasabi 2.0 at the Afaup forum
Organized by Afaup (French Association for Urban Agriculture) on October 28 and 29, 2025, the "Technical Forum for Food-Producing Cities" brought together field workers, researchers, and local authorities to discuss the technical and social challenges of urban agriculture. The event aimed to move beyond preconceived ideas, particularly that of food self-sufficiency in cities, to reposition urban agriculture as a lever for agroecological, social, and territorial transition. The conclusions have just been published at this link.
The introductory lectures remind us that urban agriculture does not feed the city through volume, but through the diversity of its functions: soil regeneration via bio-waste, climate adaptation, creation of cool islands, biodiversity, social innovation, and strengthening the link between city dwellers and food. As part of an agroecological approach, it is based on respect for living organisms, adaptation to local contexts, and a long-term vision.
The research presented shows a scientific rise in the principle, which is now structured and recognized. It confirms the health feasibility of urban production, its partial but real potential to feed people, and the value of innovative systems (micro-farms, alternative substrates, circular management of urban flows). Cooperation between researchers and practitioners appears essential to produce useful and operational knowledge.
Our leader, Haïssam Jijakli, contributes to the chapter "Technical and economic models in aquaponics." In his presentation, he offers a snapshot of the technical and economic models of urban agriculture, with a particular focus on aquaponics. After a presentation of the Wasabi platform platform (reminder: Walloon Platform for Innovative Systems in Agriculture and Urban Biodiversity) and based on a study conducted for the FAO (Food and Agriculture Organization of the United Nations), he identifies six major economic models, ranging from domestic or educational projects to commercial farms of various sizes, in urban, peri-urban, or above-ground contexts.
The presentation by the professor from Gembloux Agro-Bio Tech emphasizes that aquaponics is based on a circular logic: water recycling, use of fish effluents as fertilizers, optimization of space, and reduction of inputs. The research results presented show that agronomic performance (yields, commercial quality, pest pressure) is broadly comparable to that of hydroponics for most crops, although some long-term production remains more technically demanding.
On the economic front, he emphasizes the diversity of business models and the fact that profitability depends not only on yields, but also on scale, cost control, market opportunities, and the local context. Aquaponics can be economically competitive, and in some cases even more profitable than hydroponics, provided that it is rigorously designed and risks are anticipated.
Finally, Haïssam Jijakli highlights future research needs: performance optimization, detailed technical and economic analyses, decision-making tools, and experimental devices. Aquaponics thus appears to be a promising but demanding field in the process of structuring, requiring a strong link between research and field practices. Our leader continues the discussion in a short interview:
Your work shows agronomic performance similar to hydroponics, but with certain limitations on long or very demanding crops. What are the reasons for these limitations?
The performance limitations on crops such as tomatoes can be attributed to a lower concentration of nutrients essential for flowering and fruiting (phosphate, potassium). To overcome these limitations, it is possible to supplement the plants' water with nutrients that are not sufficiently concentrated, provided that this does not negatively affect the growth and health of the fish. If this were the case, it would be possible to decouple the system, i.e., the water would flow from the fish to the plants but no longer from the plants to the fish.
Intra-urban aquaponics remains marginal despite its advantages in terms of circularity and space savings. In your opinion, what are the main obstacles to its deployment in cities today?
All agricultural activity in cities is limited by the amount of space available and the cost of that space. Aquaponics is no exception to these limitations. Some aquaponics projects face additional technical and financial challenges when, for example, they want to set up on rooftops. It is advisable to develop simple systems and, if possible, on land. Finally, the economic model and the real needs of consumers are not always taken into account. It is important to know the profile of consumers in the neighborhood where you want to set up in order to meet their expectations.
