湿地植物对外源氮、磷输入的响应研究

通过人工控制试验,研究了氮、磷输入对沼泽湿地植物地上生物量,相对密度以及植物对氮、磷吸收量的影响.结果表明:营养物质氮、磷的长时间累积,导致湿地植物地上生物量和相对密度均呈逐渐下降的年际变化趋势,地上生物量和相对密度之间表现为微弱的单峰变化关系.在氮输入下,随着氮施用量的升高,氮的吸收率从62.3%下降到5.5%;在磷输入下,随着磷施用量的升高,磷的吸收率从3.1%下降到0.8%.氮、磷的施用量愈高,植物对氮、磷的吸收率愈小.氮、磷输入有可能改变湿地生态系统的物种组成和结构及湿地生态系统的稳定和保护,应当考虑湿地中营养物质的长期作用.

Response of Wetland Plants to Nitrogen and Phosphorus Inputs

Effects of nitrogen and phosphorus on the marsh wetland plant aboveground biomass, relative density, as well as N and P uptake were studied through manual control experiments, The resuh showed that plant biomass and relative density gradually decreased annually due to N and P accumulation in wetland, There was a weak unimodal relationship between aboveground biomass and relative density. Absorption rate of nitrogen descended from 62.3 % to 5.5 % with increasing application of nitrogen, and absorption rate of phosphorus descended from 3.1% to 0,8% with increasing application of phosphorus. The amount of nitrogen and phosphorus removed by plant harvesting decreased with increasing input of nitrogen and phosphorus. Input of nitrogen and phosphorus might cause the alteration of wetland plant community structure and composition. The effects of nutrient accumulation should be considered to protect the stabilized wetland ecosystem.