Study on the Ratio of Tilapia and Shallot for Fresh Water Aquaponics System

Aquaponics have brought about a new concept for food production since 1970. Aquaponics combined aquaculture and hydroponics, utilizing purified wastewater by nitrification from aquaculture, and use the water for plants. This simplified process can reduce water wasting, and creates a new way of sustainable development for agriculture. However, the nutrients balance between the ecretion from aquatic and the abosorb from the absorption of plants which is the key to the success of running the system need to be determined by experiments. Tilapia and Shallot are the experimental subjects in this study. The total weight of 224g of Tilapia were used for the fish daily ecretion experiment. In order to irrigate the plants with the fixed concentration water, this study conducted the pond sediment soaked experiment to make simlar wastewater. There are five different irrigation types were set up into five different concentration groups by irrigating regularly with deionize or wastewater, represented by 0A,1A,2A,3A and 4A, respectively. After 21 days of irrigation experiment, the soil experiments were conducted before planting and after harvest, determining the nitrogen nutrients absorbed by Shallots. With the nitrogen nutrients data of ecretion and absorption, the ratio between the Tilapia and Shallot could be calculated. With the experimental design of this study, the results shows that irragating Shallots by wastewater with 0.329mg of nitrogen nutrients increased 4.95% of plants growth with adding 1% nitrogen nutrients. The calculation results of fish and plants show that per kg of Tilapia (with size of 45±5.7g) could provide nitrogen nutrients for daily use by Shallot of 93.24g. This study created a new experimental architecture to find out the ratio between the fish and plants, and the results of nitrogen nutrients between fish(Tilapia) excretion and plants(Shallot) uptake could be used in Aquaponics system and help to stabilize the system. This study is the first domestic research of determining the nitrogen nutrients balance for aquaponics system.