Aquaculture effluent is shown to be low in dissolved plant nutrients thus affecting plant growth and productivity. In addition, daily nutrient variability makes it difficult to predict crop yields and negatively affect production planning in aquaponics . Empirical growth models in which growth functions are fitted to experimental data can efficiently predict yield and quality of product. Also, understanding resource use efficiency by assessing physiological responses can assist in pro per management schemes. The objective of the current study was to analyze the growth of cherry tomato fertigated with biofloc tilapia effluent using known growth models and evaluate the photosystem efficiency under such conditions. The study was conducted in an experimental natural-lit greenhouse, without supplemental light, at the Auburn University Aquaponics Facility. Cherry tomato (Solanum Lycopersicon L. “Favorita”) was raised in 72-cell Styrofoam trays filled with 50% perlite, 50% peat (v/v) mix. Uniformly aged and sized seedlings were transplanted into 11-L rectangular Dutch buckets filled with 100% horticultural grade coarse perlite. The a quaculture effluent was drawn from a biofloc tilapia system using a 1 hp pump. A timer-clock, connected to the pump, was set to come on every 30 minutes and fertigate for 1 minute and was connected to solenoid valves which open when the clock is on. A drip system was used to deliver the fertigation solution to each pot. Single plants per pot were grown with intra-row spacing of 0.46 m (18”) with a total population of 204 plants. Destructive sampling for dry matter growth, and partitioning commenced two weeks after transplanting and proceeded on a weekly basis. Plant tissue nutrient content for macro and micronutrients are being assessed every two weeks. The dry matter progression so far is being fairly described with a logistic growth curve. At week 4 after transplanting, a diurnal assessment of stomata response and chlorophyl fluorescence was done using LI-600 porometer/fluorometer. The trends showed that although stomata conductance showed a bell shape response with the hour of the day and peaked between 10 am and 1 pm, photosystem II efficiency had the opposite response due to higher leaf transpiration. Which indicates that the higher stomata conductance was more correlated with transpiration but not light use due to high mid-day temperatures. It is anticipated that this information would provide insight into establishing a useful predictive model for cherry tomato growth in aquaponics. The results will be used as decision support tool to facilitate effective planning for cherry tomato production in aquaponics.
Keywords : Aquaponics, yield prediction , aquaponics tomato, biofloc effluent.