Nutrient mitigation capacity of agricultural drainage ditches in Tai lake basin

Eutrophication in agricultural drainage ditches by over-fertilization with nitrogen and phosphorus is a serious environmental concern. Various management practices have been proposed to help to alleviate nutrient quantity transported to Tai lake. The current study was carried out to compare the nutrient mitigation capacity of a constructed ecological ditch (C) and a traditional soil ditch (T) of the similar size and landform in Taihu basin. Results show that there was a very slight difference existed in nitrate nitrogen (C: 7.7%; T: 6.2%) percent reductions between the two ditches, but significant differences existed for ammonium nitrogen (C: 31%; T: 7.6%), total nitrogen (C: 27%; T: 5%), and total phosphorus (C: 26%; T: 9.2%) after the ditches run under stable conditions. However, both of the agricultural drainage ditches were able to mitigate nutrients and reduce the quantity reaching to downstream aquatic receiving systems. In order to provide a higher and more stable pollutants degradation effect, further studies are needed to optimize the ditch structure design and examine ecosystem dynamics.