Speaker: Dr. Emmanuel Ayipio, Postgraduate Fellow, Auburn University Description: Aquaponics combines recirculating aquaculture systems (RAS) with soilless horticulture. A successful aquaponics system is hinged on nutrient cycling. Therefore, managing nutrients levels becomes essential for a successful aquaponics operation. Low nutrient concentrations can be a limiting factor to achieving potential yields in aquaponics. Unlike conventional hydroponics systems where nutrient recipes exist, plant production in aquaponics depends on the RAS component. Nutrient loadings differ among RAS due to differences in fish species, feeding rates, density and are mostly outside the control of the soilless Horticulturist. Also, aside low nutrient concentration, there is daily variability in nutrient concentration which makes nutrient management a challenge. In this webinar, I will share the experiences I gained from our pilot-scale commercial aquaponics operation at Auburn University. I will highlight some of the successes and failures of our system. The talk will mostly focus on pH management, substrate choice, hydroponics system type, irrigation scheduling and their effect on productivity of selected crops. Some of the key observations were that 1. pH had no significant effect on nutrient uptake, 2. pinebark substrate can substitute for perlite but depends on number of plants per container, 3. the deep-water culture is preferred over NFT (nutrient film technique) and substrate culture in aquaponics, and 4. in the NFT system, hydraulic retention time affects nutrient availability.
