A Preliminary Study On The Production Effects And Nutrients Distribution In Aquaponics

An aquaponics was designed to explore the production performance and nutrients distribution in the system.At the same time,the effects of adding macro elements and middle elements in aquatic water on the yield and quality of tilapias and vegetables and the nutrients distribution in tilapia,vegetables,water and growth media in the Alternanthera bettzickiana-Tilapia nilotica system and the Nasturtium Officinale-Tilapia nilotica system was observed.Moreover,the effects on the yield,quality and the efficiency of nutrients and water of lettuces cultured in wastewater were also reaserched.The main results were as follows:(1)Several vegetables and tilapias could be normally grown in different trials and the treatment of adding nutrients could promote the growth of vegetables.In the Alternanthera bettzickiana-Tilapia nilotica system,the treatment of adding nutrients could significantly increase the yield of edible part of the vegetable at the first harvest and increase production by 59.2%.At the same time,it also significantly enhanced the vitamin C content of the vegetable in different harvest periods.In the Nasturtium Officinale-Tilapia nilotica system,treatment of adding nutrients could also increase the yield of the edible part of the vegetable.Especially,it could significantly increase the content of vitamin C at the first harvest.The content was about up to 29.8%.(2)Compared to the treatment that didn?t be complemented with nutrients,the treatment with appropriate addition of nutrients improved the total water use efficiency(WUE)of fishes and vegetables.The WUE of treatment 1 nutrient was complemented in aquaculture increased of 8.7% compared to the the treatment with no nutrients addition.The WUE of treatment 2 that complemented with nutrients increase to 133.3% compared the the treatment with no nutrients addition.(3)After adding macro elements and middle elements,the water in the system was in a eutrophic environment.As a result,the utilization of nutrients by tilapia and vegetables was cut down and the nutrient distribution ratios in plants and tilapias were reduced.Nitrogen,phosphate and calcium are mainly distributed in tilapia.Vegetables could absorb and reuse some nitrogen,phosphorus and potassium that not be used by tilapia.(4)Wastewater from aquaponics could be well need for the production of lettuce.Compared with Formula A for leaf vegetable by SCAU,the treatments of aquaculture wastewater complemented with nutrients and added nutrient aquaculture wastewater promoted the plant growth and significantly increased the biomass of lettuce about 31.1% and 18.7%.Respectively,the water in these treatments was used efficiently and consumed more than 91.5%.At the same time,there was very high level of the several nutrients utilization in these treatments.Removal rates of nitrogen and phosphorus of wastewater by means of planting lettuce were more than 96.0%.