Nitrogen and phosphorus removal performance by three planted floats in eutrophic water bodies in winter

N and P removal performance of planted floats of ryegrass(Lolium multif) ,“Aijiaohuang” and “Suzhouqing” (the latter two are cultivars of Brasica rapa) in natural eutrophic water bodies were investigated.Results show that the removal percentage by ryegrass,“Aijiaohuang”,“Suzhouqing” and the control are 49.75%,45.77%,45.12% and 28.91% in TN respectively;and 67.66%,60.19%,58.28% and 42.56% respectively in TP.The removal efficiency of the planted floats in TN and TP are significantly different(P＜0.05) from those of the control.The three plants are the new and alternative plant resources for the treatment of eutrophic water bodies.Phosphorus bioaccumulation by ryegrass accounts for 89.53% of total removed phosphorus in the system and 34.64% and 42.42% for “Aijiaohuang” and “Suzhouqing”,suggesting that abstraction is the main removal mode of phosphorus.For nitrogen,bioaccumulation accounts for only a small percentage of total removed nitrogen.