Salinity impacts on aquaponic Kale Winterbor (Brassica oleracea): Production, water quality, and sensory properties

Aquaponics describes recirculating aquaculture systems that include plants to remove excess nutrients. In inland brackish water aquaculture, salt is a major cost; therefore, water reuse is crucial for sustainability. Utilizing aquaponics may allow producers to limit brackish water discharge while producing a marketable crop, but information on suitable plant species and marketability is limited. Kale is a well-known leafy green that has shown some degree of salt tolerance. However, the performance of kale in brackish aquaponic production conditions and the impacts on consumer perceptions are unknown. This study’s aims were to evaluate kale’s tolerance to artificial seawater, determine effects of kale on water quality, and quantify consumer perceptions of the resulting product. Kale was grown at 0, 5, 10, 15 and 20 salinities during a 23-day experiment. Kale removed nitrogen and reduced phosphorus within two weeks, although concentrations of N, P, Ca and K in leaf tissue decreased as salinity increased. Kale survival was 100 % in all treatments; however, growth was significantly reduced as salinity increased. A consumer taste test (n = 112) reported saltiness ratings increased in a dose-respondent manner that corresponded with higher concentrations of Na in plant tissues. The 5 salinity sample was liked significantly more than the 0 (control) salinity, and no samples were liked less than the control. Informing consumers about the production method improved willingness to pay by 38 %. This study reveals the potential of kale to help manage nutrient build up in brackish water aquaculture while producing a marketable crop. • Kale grew slower as salinity increased up to 20. • Survival was 100 % and all plants appeared healthy. • Kale takes up ammonia and has a variety of effects on dissolved elements. • Salinity improved or had no impact on consumer sensory liking. • Consumers were willing to pay more for aquaponic-grown kale.