System management ofLemna minorin aquaponics

Abstract

In farming, sustainability together with food safety is one of the main objectives to be achieved. Aquaponics is a technique that combines aquatic animals, such as fish, with the hydroponic production of plants that function as biological filters. The proper functioning of the system is based on the dynamic balance of the elements that make it up. Several studies confer aquatic macrophytes such as L. minor, great attributes, highlighting their use for feeding different species. Unfortunately, there is very little information on the system management of macrophytes in aquaponics. To determine the appropriate management parameters for the cultivation of L. minor integrated into the production of Oreochromis niloticus, in aquaponics, three experiments were carried out to evaluate the effect of the hydraulic retention time (HRT), the planting density, plant dissemination and the balance of nutrients in the systems. The results show that the highest biomass production and plant growth are achieved with high flow rates and short HRTs. Planting density has a direct effect on the behaviour of the plant. Regarding the balanced budget, between 7% and 8% of the nutrients (input in dry matter, N and P) are retained by L. minor, keeping the water quality within adequate limits for tilapia production.

Productivity and Elemental/Chlorophyll Composition of Collard Greens in an Aquaponic System at Different Combinations of Media and Black Soldier Fly (Hermetia illucens) Larvae Frass Supplementations

“…Even visually, it was clear that collard greens grown in media were far more robust compared to those in the foating raft, which is consistent with other reports on leafy green growth in aquaponic systems [15,18]; Knaus et al 2020 [5,18]. It is known that fow rates can greatly infuence plant growth in an aquaponic system [22], but the fow rates between the two plant beds were similar in this study. Te better growth might be related to minerals being more accessible as a result of organic debris accumulation in the media-flled bed and subsequent bacterial mineralization, but this requires more investigation.…”