[Purification capacity of ditch wetland to agricultural non-point pollutants].
Ditch wetlands have the capacity to remove and purify non-point pollutants from agricultural drainage by sediment retention, plant absorption and microorganism decomposition. Phragmites communis and Zizania latifolia are two main kinds of plants growing naturally in ditch wetlands in the lower reaches of the Yangtze River. They can absorb N and P efficiently, which is the main mechanism of non-point source pollutants purification by wetlands. The harvest of Phragmites communis and Zizania latifolia will take away 463-515 kg/hm2 of N and 127-149 kg/hm2 of P each year, it equal to N and P discharged from 2.3-3.2 hm2 and 1.3-3.0 hm2 of fields respectively in this area. The absorption and decomposition capacity of Zizania latifolia wetland is higher than Phragmites communis wetland. After harvest of plants, wetlands are uncovered to sunlight and oxygen that speeds the transportation and decomposition of nutrients. The amount of organic matters, TN and TP are higher in sediment of harvested area than in that of control. Therefore, seasonal harvest of plants is an efficient measure for wetlands to purify nutrients and alleviate eutrophication of lakes.
Jiang
Cui-ling
CL
Water Resources and Environment College, Hehai University, Nanjing 210098, China.
Cui
Guang-bo
GB
Fan
Xiao-qiu
XQ
Zhang
Yi-bing
YB
D000042:Absorption; D004785:Environmental Pollutants / Q000378:metabolism*; D004787:Environmental Pollution / Q000517:prevention & control*; D005068:Eutrophication; D019015:Geologic Sediments; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis
D004785:Environmental Pollutants; D010758:Phosphorus; D009584:Nitrogen