Study On The Growth Characteristics And Water Purification Efficiency Of Floating Bed Plants In Winter

At present,increasingly freshwater aquaculture waste water directly emission without treatment,which it made the receiving water body eutrophication and biodiversity reduce.Artificial floating bed technology is a surface soilless planting technology of modern agronomic and ecological engineering measures integrated comprehensively,which is convenient,cost-effective and feasible.Focused on aquaculture waste water pollution in Changfeng animal husbandry Group Co.Ltd.in Yichang,taking Apium graveolens(Ag),Chrysanthemum coronarium(Cc),Allium sativun(As),Brassica juncea(Bj),Lactuca sativa var longifoliaf(Ls),Spinacia oleracea(So)as floating bed cultivated plants in this experiment which began on December 10 in 2015 with the transplant of plants to the water surface,finished on MarchlO in 2016.The winter growth of the hydroponic plants,the nitrogen and phosphorus absorbing capacity,the food safety of plants are analyzed in this paper.Research and the main conclusions are as follows:(1)Growth characteristics of the floating bed plantAfter about 90 days of acclimation,6 species of tested plants showed different growth characteristics.The survival rate of Ag,Cc and As are more than 87%,the survival rate of Bj is 84.48%,the survival rate of Ls is 41.95%,So all died in February.Ag,Cc and Potherb Bj has been taking a new leaf and root variable length,we have new roots grow,and Ls growth,poor adaptability.The biomass of Ls was decreased by 43.60%compared with the beginning of the experiment.The other 4 kinds of economic plants of the fresh weight of biomass relative to the amount of growth is Cc(651.91%)>Ag(197.69%)>Bj(160.04%)>As(129.87%).The water on the part of net biomass more than 60%plants with Ag,Cc,As and Bj,and there was a significant linear relationship between the biomass of the 4 plants and the amount of water in the water.(2)Plant uptake of nitrogen and phosphorusThe 5 part is on the nitrogen content in the plant body part and under water in 31.31?56.13 g kg-1 and 3.69?55.89 g·kg-1.The content of phosphorus in water and water was between 1.11?1.83 g kg-1 and 1.19?1.73 g·kg-1.The distribution of nitrogen and phosphorus in the lower part of the plant water was different.Ag,Cc in the nitrogen and phosphorus content showed on water>underwater parts distribution,N and P elements were transported to the upper part of the water;The content of N and P in As was underwater part>water part of the distribution;Bj and Ls in total nitrogen content showed water>water under part of the distribution,N is transported to shoot,and total phosphorus content under water>water are mainly enriched in the roots.The accumulation amount of N and P in 5 plants were between 1.15?5.18 g·m-2 and 0.04?0.21g·m-2.Size ordering:As>Ag>Bj>Cc>Ls and Ag>As>Bj=Cc>Ls.The correlation of 5 kinds of plant nitrogen and phosphorus accumulation and biomass,biomass nitrogen and phosphorus accumulation in response,to calculate the content of nitrogen and phosphorus absorption by plant harvesting and weighing.(3)The purified effect of cultivated plants floating bedAfter estimation the net water of 5 kinds of plants,The TN is about 0.326?0.682 m3 ·(m-2 floating bed),As,Ag,Bj has better absorption effect on N,can be used as the preferred plant for nitrogen removal;The net water content of TP is 0.046?0.210 m3-(m-2 floating bed),Show Ag>As>Bj>Cc>Ls,The phosphorus removal efficiency of celery is better,it can be the first choice for phosphorus removal.(4)5 kinds of economic plants,the aquaculture waste water floating bed cultivation(Ag,Cc,As,Bj,Ls),the amount of heavy metals indicators have not exceeded the Chinese national standard of food safety and green vegetable standard.