Removal Effect of Ditch Pond Wetlands on Non-Point Source Pollutants from Agricultural Drainage

Abstract

Ditch pond wetland systems have the capacity to remove and purify non-point pollutants of nitrogen and phosphorus from agricultural drainage. This paper measured the changes of nitrogen and phosphorus content in ditches, ponds of runoff water, aquatic plants and sediment. The results show that ditch, pond has the very good intercept and removing effect for nitrogen and phosphorus. The total removal rate of TN and TP were 61.13% and 63.08% in ditch pond wetlands. Phragmites communis, Zizania latifolia, reed nitrogen absorption per unit area respectively were 2.468 g/m2, 1.795 g/m2, 2.174 g/m2. Phragmites communis, Zizania latifolia, reed absorb phosphorus amount per unit area respectively were 0.643 g/m2, 0.351 g/m2, 0.338 g/m2. The TN content and TP content of sediment is increase from ditches1to ditches3. TN content of sediment at pond import is higher than at pond export. TP content changed little in the pond sediment.