摘要
沟渠湿地可通过底泥截留吸附、植物吸收和微生物降解净化农田排水汇集的非点源污染物 ,芦苇 (Phragmitescommu nis)和茭草 (Zizanialatifolia)是长江下游地区沟渠中自然生长的 2种主要挺水植物 ,能有效吸收N、P营养成分 ,是湿地净化非点源污染物的主要机制 .芦苇和茭草收割以后 ,每年可带走 4 6 3～ 5 15kg/hm2 的N和 12 7～ 14 9kg/hm2 的P ,相当于当地2 3～ 3 2hm2 农田流失的氮肥、1 3～ 3 0hm2 农田流失的磷肥 .茭草的吸收和分解能力明显高于芦苇 .收割除带走植株体中的营养成分外 ,也改善了湿地光照和曝气条件 ,促进营养物质的分解转化 ,芦苇收割区底泥和水体中的有机质、TN、TP明显低于未收割区 .因此 ,定期收割是保证自然湿地净化功能 。
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/hm 2 of N and 127～149 kg/hm 2 of P each year, it equal to N and P discharged from 2 3～3 2 hm 2 and 1 3～3 0 hm 2 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.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2004年第2期125-128,共4页
Environmental Science
基金
国家自然科学基金资助项目 (5 0 10 90 0 1)
国家自然科学基金重点项目 (5 0 2 3 90 3 0 )
关键词
沟渠湿地
非点源污染
富营养化
净化能力
ditch wetlands
non point pollution
eutrophication
purification
