| dc.description.abstract | In aquaponic systems, nitrate production and uptake rates must be tailored to one another to prevent costly imbalances. Consequently, the objective of this research was to provide additional management guidance for floating raft aquaponic production systems growing Italian large-leaf basil (Ocimum basilicum var. 'Rutgers Obsession DMR').
Experiment 1 focused on establishing ammonia excretion rates based on protein intake of tilapia (Oreochromis spp.), koi (Cyprinus carpio haematopterus), and hybrid striped bass (Morone chrysops x M. saxatilis). Data collected during the experiment showed respective ammonia excretion rates for tilapia, koi, and hybrid striped bass of 50.9, 64.5, and 79.0 mg TAN per gram of protein ingested, though feed digestibility potentially affected some of the measurements.
Experiment 2 attempted to identify nitrate uptake rates for individual Italian large-leaf basil plants grown hydroponically with an observed yield of 85.6 grams of fresh shoot mass for every 342.9 mg of available (NO3-)-N. Calculations using a maximum ammonia excretion rate of 92.2 mg TAN per gram of protein, and an ideal nitrification rate of 0.976 grams of nitrate (NO3-) per gram ammonia, indicated a protein input requirement of 44.4 mg per each gram of shoot material. The use of ammonia excretion measurements from Experiment 1 resulted in estimated protein input requirements of 80.6, 63.6, and 52.0 mg of protein for tilapia, koi, and hybrid striped, respectively.
Experiment 3 evaluated dissolved nitrogen availability for marketable basil culture in floating raft aquaponic systems using recommended feeding and fish stocking rates. While the feed input to the aquaponic systems ended up being even less than recommended, a surplus of nitrogen at the conclusion of the experiment indicated that feed input requirements for herb and leafy green production in aquaponic systems is much lower than recommendations. Additionally, feed input calculations using projected nitrogen production and uptake rates were even lower, with a requirement of only 16.5 grams of 32% protein feed per day to produce 3338.8 grams of fresh shoot material over 28 days. Subsequently, actual protein input requirements for basil were estimated to be between 44.4 and 67.5 mg protein per each gram of shoot mass to be produced. | |
