三江平原小叶章模拟实验对氮磷的净化

模拟研究三江平原小叶章湿地生态系统对N、P的净化规律。结果表明,在小叶章生长期和成熟期,模拟系统对N、P的去除率随时间变化呈负指数型增长,最高去除率在实验初期分别达到93.26%、98.98%;在净化过程中,P的加入会促进模拟系统对N的吸收,并减缓其对N净化能力的衰退幅度,而模拟系统对P的净化不受N输入的影响。基于小叶章生态系统中N、P营养元素的分配和循环,小叶章对N元素的净化效应大于P元素,土壤子系统对P元素的净化起主导作用,整个模拟系统对N、P元素的净化效果很显著,总净化率分别可达53.11%、58.95%。该结果为东北地区湿地净化功能的研究和非点源污染的治理提供理论根据。

Study on purification of nitrogen and phosphorous in Deyeuxia angustifolia simulated experiment in Sanjiang Plain,China

It is important to better understand the nutrient distribution and circulation of the Deyeuxia angustifolia wetland in Sanjiang Plain, as this ecosystem plays a unique role in the ecological service functions of the region. However, little attention has been paid to the purification function of the wetlands in the Sanjiang Plain. Due to the agricultural exploitation since 1950's, over-fertilization has resulted severe in non-point pollution in the region. A potted plant experiment was conducted in Sanjiang Plain in 2004 to investigate the process and regulation of N and P purification of Deyeuxia angustifolia. Six levels of N and P input concentrations were set up, each for three repetitions. The water, soil, and plants were re-sampled, and TN and TP concentration in them were determined and analyzed.Results showed that the removal rate of N and P presents negative exponential increasing with time in a simulated ecosystem of Deyeuxia angustifolia. The highest removal rate of N and P was 93.26% and 98.98% in the early period of experiment, respectively. One reason is that Deyeuxia angustifolia grows quickly, and absorbs significant N and P. The other reason is that N and P content in soil is originally lower, and significant N and P can be absorbed through some routes. During the purification process, the purification role of N was promoted, while the purification decay extent was decreased through input of P. However, the purification role of P was not affected by input of N. Based on the distribution and circulation of N and P in the simulated ecosystem of Deyeuxia angustifolia, the vegetable sub-system was vital to the purification role of N, while soil sub-system played an important role in the purification of P. The purification effect of N and P was made apparent across the whole simulated ecosystem, where the purifying rate was 53.11% and 58.95%, respectively. This study can provide the scientific basis for understanding the purification function in the wetlands of the Northeastern region and in planning for the effective control of the non-point pollution.