Dynamic Of Biomass Of Phragmites Communis And The Discussion Of Harvest Time At Taihu Wetland

As one of the dominant species at Taihu wetland in Suzhou, Phragmites communis was observed during a whole growing season, the dynamic of Phragmites communis such as the biomass,TN,TP,heavy metals,cellulose content and fiber length and width were researched and analyzed to discuss the best harvest time and provide the basis for protecting and restoring Taihu wetland ecosystem in Suzhou. The results as follows:1. The aboveground and undergrond biomass of Phragmites communis increased first and decreased later during the period from April in 2009 to January in 2010, and reached the maximum value in the end of October ; Descending order of biomass in different components of Phragmites communis is:stem>leaf>ear; Descending order of biomass in different local habitats is: SFF>FF>UF,descending order of root-shoot ratio is: UF>SFF>FF;2. The content of TN and TP in different components of Phragmites communis received the maximum value in the late days of October; Descending order of TN in different components of Phragmites communis is: leaf>ear>stem; Descending order of TP in different components of Phragmites communis is:ear>leaf>stem; Descending order of TN and TP in different local habitats is: FF>SFF> UF;3. The content of heavy metals in different components of Phragmites communis got the maximum value in the early December,while riched the miximum vulue in July,2009; Descending order of different heavy metals in Phragmites communis is: Fe>Mn>Zn>Pb>Cu>Cr; Descending order of heavy metals in different local habitats is: FF>SFF>UF; Descending order of Zn in different components of Phragmites communis is:stem>root> ear>leaf,while the other kinds of heavy metals in different components of Phragmites communis is:root>ear>leaf>stem;4. The content of cellulose in the stem of Phragmites communis riched the maximum value in the late of October; Descending order of cellulose in the stem of Phragmites communis in different local habitats is:UF>FF>SFF;The content of cellulose in different levels of the stem is:lower>middile>upper;5. The best time for Phragmites communis to remove the most nutrients is from the end of October to the early of November at Taihu wetland in Suzhou.