Abstract:

To research the ability of absorbing  nitrogen and phosphorus, experiments on rice and swamp cabbage(Ipomoea aquatica) were carried out. Rice and swamp cabbage were transplanted on floating beds on the surface of eutrophic water bodies of different N/P ratios (8∶1, 25∶1, and 55∶1) in 25L plastic buckets. Results show that rice and swamp cabbage can both absorb the nitrogen and phosphorus from water bodies, and are recommended as floating-bed plants to control eutrophication. Among the three water bodies of different N/P ratios, the amount of  TP removed by rice was higher than that by swamp cabbage, while TN and NH₃-N removed by rice were smaller than those by swamp cabbage. Different plants should be chosen depending on the characteristics of water bodies. In water body of low N/P ratio (8∶1), TN, NH₃-N, and TP were best removed by rice and swamp cabbage, with the net removal rate of 19.0%, 91.4%, 95.0% by  rice, and 28.2% , 99.2%, and 87.2% by swamp cabbage respectively.   

Key words:  floating bed, plants, nitrogen, phosphorus, N/P ratio, uptake ability