Effects of planting density and harvest of Ipomoea aquatic on the purification efficiency of eutrophic pond water

We use two kinds of treatments(different density and harvest) to study the characteristics and effects of eutrophic water purification by Ipomoea aquatica in water bucket.The results show,after 12 days outdoor culture,the removal rate of NO-2、NO-3、PO3-4、TN、TP and Chla in high density group(10 g/L) are 90.88%、93.98%、98.96%、82.36%、88.89% and 89.33%,respectively.It means that the high density group is significantly higher than the control group(0 g/L).Otherwise,harvest will accelerate the tiller,promote absorption of nitrogen and phosphorus,and improve the DO in water.The phosphorus and nitrogen concentration of plant tissue change,it shows positive correlation with the growth of the water body of the phosphorus and nitrogen.It also shows a positive correlation between the nitrogen removal rate and the density of plant,the high density group(10 g/L) of Ipomoea aquatica removed the 52.05% of TN and 40.41% of nitrogen,respectively.