Nutrient supply of plants in aquaponic systems

TLDR

Protocols for applying nutrient amendments in aquaponic systems remain undeveloped. The study presents data on plant nutrient concentrations in aquaponic systems, compares them to standard hydroponic solutions, and examines the potential of organic supplementation for nutrient‑deficient plants. The authors measured plant nutrient concentrations in aquaponic systems and compared them to standard hydroponic solutions. Fish‑derived nutrient levels in aquaponic systems are lower than in hydroponic solutions, yet plants—especially leafy greens—still thrive, indicating that continuous monitoring of water chemistry and ammonium levels is essential to maintain adequate nutrient concentrations and ratios.

Abstract

In this preliminary article we present data on plant nutrient concentrations in aquaponic systems, and compare them to nutrient concentrations in “standard” hydroponic solutions. Our data shows that the nutrient concentrations supplied by the fish in aquaponic system are significantly lower for most nutrients, compared to hydroponic systems. Nevertheless, plants do thrive in solutions that have lower nutrient levels than “standard” hydroponic solutions. This is especially true for green leafy vegetables that rarely need additional nutritional supplementation. It is concluded that in the highly complex system of aquaponics, special care has to be taken, via continuous monitoring of the chemical composition of the circulating water, to provide adequate concentrations and ratios of nutrients, and special attention has to be paid to the potentially toxic component, ammonium. If certain plants require nutrient supplementation, we consider that one based on organic substances would be most beneficial. However, protocols for the application of such nutrient amendments still need to be developed.