Comparison of the growth characteristics and the optimize configuration modes of the nitrogen and phosphorus uptake capacity of three kinds of plant cultivated on the floating-bed

In order to improve purification efficiency of the floating bed, Canna indica, Thalia dealbata and Lythrum salicaria were chose as research objects and constructed a eutrophication prevention project in Lake Dianshan. The survival rates of the three plants were higher than 70%.The reaping biomass of Canna indica and Thalia dealbata were significantly greater than their respective initial biomasses. The reaping biomasses of Canna indica and Thalia dealbata were 3.65kg and 2.40kg respectively; The nitrogen and phosphorus uptake ability of the three kinds of plant were significantly different from each other. The phosphorus uptake ability of Canna indica was greatest, followed by Thalia dealbata and subsequently, Lythrum salicaria. The nitrogen uptake ability of Thalia dealbata was greatest, followed by Canna indica. and subsequently, Lythrum salicaria. Canna indica and Thalia dealbata cultivated acreage proportion were optimized When the proportion of the cultivated acreage of Canna indica and Thalia dealbata equals to 4/3, the mixed cultivated floating-bed could uptake 85.42g/m² more nitrogen than the floating-bed cultivated with Canna indica only. Similarly the phosphorus removal capacity of the mixed cultivated floating-bed was 7.72 g/m² lower than the floating-bed cultivated with Canna indica only; When the proportion of the cultivated acreage of Canna indica and Thalia dealbata equals to 3/4, the mixed cultivated floating-bed could generate a high level of phosphorus removal capacity. In addition, the phosphorus removal capacity of the mixed cultivated floating-bed was greater than the floating-bed cultivated with Thalia dealbata only. The results showed that Canna indica and Thalia dealbata could be used as floating-bed cultivated plants in Lake Dianshan and the surrounding areas. To perform a comprehensive treatment of eutrophication, the optimize configuration mode should be considered.