Dynamics of biomass, nitrogen and phosphorus storage of Phragmites australis in Baiyangdian Lake
白洋淀湿地芦苇生物量及氮、磷储量动态特征

As the special habitat formed by the interaction between terra and water area, wetlands play important roles in biogeochemical cycling process of nitrogen and phosphorus. To understand the growth dynamics and characteristics of Phragmites australis (Cav.) Trin. Ex Steudel in Baiyangdian Lake, a typical wetland ecosystem, field investigation and laboratory measurements were conducted to identify its biomass, nitrogen and phosphorus content and storage. Results showed that with the growth of P.australis, biomass of leaf and root increased firstly and reached the maximum value in June and August respectively, then decreased. In comparison, biomass of stem, sheath and shoot increased during the whole growth season, and reached the maximum value in October. It also showed that nitrogen and phosphorus content of each aboveground component was the highest at April, during the early period of growth. Nitrogen and phosphorus content of root reached the maximum value in August and April respectively, and the time that nitrogen and phosphorus content of each component reached the minimum value was different. There were significant relationships between nitrogen and phosphorus storage, and biomass with the maximum nitrogen and phosphorus storage of shoot were (18.91±2.12) g·m-2 and (1.17±0.13) g·m-2, respectively, occurring both in June.