Productivity and economic feasibility of stacked aquaponics

• Main Author: Neoh, Seong Lee
• Format: Thesis
• Language: English; English
• Published: 2012
• Subjects: SB126.5-126.57 Hydroponics. Soilless agriculture
• Online Access: https://eprints.ums.edu.my/id/eprint/41623/1/24%20PAGES.pdf; https://eprints.ums.edu.my/id/eprint/41623/2/FULLTEXT.pdf; https://eprints.ums.edu.my/id/eprint/41623/

Aquaponics sometimes suffer from unreliable production due to nutrient fluctuations and unprofitability due to the high cost involved. To address these issues, this thesis evaluates the conventional nutrient management of aquaponics by, firstly, comparing plant growth in inorganic fertilizer solution and fish effluent, and secondly, evaluating the nutrient remediating property of Ipomea aquatica. A new Stacked Planting Unit (SPU) which utilizes the vertical space and has a high planting density was proposed as a way of increasing aquaponics' economic profitability. The SPU was evaluated economically and biologically (plant yield). Portulaca spp. was planted in three different solutions: distilled water, aquaculture effluent, and inorganic fertilizer water solution. After 40 days the plants in the inorganic fertilizer solution recorded 145% more biomass gain compared to plants in aquaculture effluent. Physiological development of plant was observed to be markedly superior in the inorganic fertilizer compared to the other treatments.In another experiment, Ipomea aquatica with well developed roots had their roots submerged in aquaculture effluent for seven days and it was found that nitrate and phosphorus were reduced by 59% and 65%, respectively. The two experiments suggested that although phytoremediation is relatively reliable, a different approach in aquaponics recirculation strategy had to be adopted as the growth performance of plants is unsatisfactory. Sweet Basil (Omicum basilicum) and Pak Choy (Brassica rapa) were grown in the SPU and their biomass gain was recorded for each row. Basil represented a medium sized plant and Pak Choy represented a short plant. It was found their biomass were reduce by 33% ± 1% respectively. Even so, SPU accommodated 108% more plant in an area of land when compared with the conventional planting unit and the increased plant number per area in the SPU compensated for the non-ideal biomass gain. Pak Choy yielded 2.77 kg/m² and Basil 1.51 kg/m² more than the conventional planting unit. It was also found that the RAS system used in this research would make a loss of RM6675 per year, but if it is joined to the SPUs, forming stacked aquaponics, the system as a whole, would reverse economically and return a profit.