三江平原湿地沟渠侵扰带土壤DOC分布特征

Distribution characteristics of dissolved organic carbon in soil of drain intrusive belt in Wetlands of Sanjiang Plain

在三江平原选择排水沟渠位于湿地低处的某一特定沟渠,平行于沟渠方向按照1.2m×1.2m的网格布点法分层采集土壤,共设计25个采样点,100个土壤样品,测定土壤可溶有机碳(DOC)含量,研究湿地沟渠侵扰带土壤DOC分布特征。结果显示,随着距沟渠距离减小,土壤DOC含量及其水平和垂直分布变异性有增加的趋势,并且到沟渠边缘达到最大。原因是沟渠对湿地土壤的影响是双重的。它为湿地地下水流创造了一个排泄点。沟渠侧向径流将湿地上坡方向的土壤DOC带到沟渠边缘,引起临近沟渠湿地土壤DOC的累积。沟渠水迅速流走,沟渠边缘土壤产生更大频率的水位波动。另外,排水沟渠对湿地沟渠侵扰带土壤DOC分布的影响大小与土壤本身的剖面过程密切相关。

The study was focused on a certain ditcti in the lower part of the wetland in Sanjiang Plain. Soil samples were collected along the drainage ditch and the DOC content of the soil was analyzed in order to study the influence of the drainage ditch on the distribution characteristics of DOC in the soil of drain intrusive belt in Wetlands. The results indicate： the DOC content and DOC horizontal and vertical distribution variability of drain intrusive belt increase as the distance from the ditch decreases, and reaches the maximum on the margin of the ditch. Because the effect of the ditch on soils in the wetland is two-fold. First, it creates a discharge point for groundwater in the wetland. The lateral flow moves toward the ditch and bring a lot of soil DOC into the margin of the ditch. Second, the ditch drains water quickly from the soils on the margin of the ditch producing a greater frequency of water table fluctuation. In addition, the distribution of DOC in the soil of drain intrusive belt in wetlands also depends on the entire soil profile and the processes in the soil profile.