He Y.,Hohai University |
Peng S.,Hohai University |
Xu J.,Hohai University |
Zhang J.,Kunshan Promotional Station of Water Conservancy Technique in Jiangsu Province |
And 2 more authors.
Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering | Year: 2012
The change in nitrogen concentration and distribution feature of carbon-to-nitrogen ratio in the agricultural ditch and wetland system were analyzed based on the observed data in fields to investigate the nitrogen removal effect from drainage water in the system under a controlled irrigation and drainage condition. Results showed that TN, NH 4 +-N and NO 3 --N concentrations in drainage were peaking after fertilization and then were significantly reduced after agricultural ditches were made to store water, causing 63.9% 67.8% and 83.2% nitrogen removal efficiencies in TN, NH 4 +-N and NO 3 --N, respectively. The nitrogen concentration was reduced further after the drainage water was purified in wetlands, resulting in 47.7%, 44.3% and 82.0% average removal efficiencies for TN, NH 4 +-N and NO 3 --N. Since the influence of organic matters on water quality is little under the controlled irrigation and drainage condition, a low carbon-to-nitrogen ratio was maintained in general. The agricultural ditch and wetland system are effective in removing nitrogen in paddy field drainage water. However, the influence of low carbon-to-nitrogen ratio on the Nitrogen removal efficiency is little under a controlled irrigation and drainage condition.