Abstract: By using slag and gravel as substrates, and with no plant as the control, three carbon levels (C1, C2, and C3) and three nitrogen levels (N1, N2, and N3) were set to study the removal efficiency of COD, TN, and TP in subsurface Acorus calamus constructed wetland with different C/N ratios. A significantly higher removal efficiency of COD and TN was found in the wetlands with plants, compared with the control. A. calamus increased the removal efficiency of COD and TN by 10.53% and 6.73%, respectively, but had no significant effect in the removal of TP. With the changes of N and P concentrations and C/N ratios in the influent, the removal efficiency of COD, TN and TP in planted wetlands were 67.57%-75.85%, 20.91%-56.82%, and 7.15%-17.78%, respectively. The N and Paccumulations in aboveground part of A. calamus were 4.44-14.79 and 1.11-3.37 g·m^-2, occupying 6.91% and 10.67% of the total N and P removal, while those in belowground part of A. calamus were 2.35-5.20 and 0.74-1.41 g·m^-2, occupying 2.69% and 6.02% of the total N and P removal, respectively, which implied that it would be helpful to remove the N and P in wetland system through harvesting the aboveground part of plants.

Key words: Ephemeral plants, Distribution, Soil moisture, Gurbantonggut desert