东北漫岗黑土区切沟侵蚀发育特征

随着人们对土壤侵蚀空间尺度认识的加深, 发育在更大空间尺度上的切沟愈来愈受到重视。切沟是土壤侵蚀的重要组成部分, 但现有的土壤侵蚀模型尚未包括切沟侵蚀部分。本研究利用高精度差分GPS, 在对东北典型漫岗黑土区切沟监测的基础上, 借助GIS 平台生成DEM, 通过DEM 的叠加分析, 探讨了沟内蚀积变化特征。并在此基础上, 提出了东北切沟侵蚀的概念模型, 认为冬春季冻融侵蚀产生沟内堆积-雨季径流产生侵蚀的过程可能是该区切沟发育的一种重要模式。

The Growth Characteristics of Gully Erosion over Rolling Hilly Black Soil Area of Northeast China

In this study, short-term gully retreat was monitored from the active gullies selected in representative black soil area, using differential GPS. With the support of GIS, multitemporal digital elevation models (DEM) were constructed in light of the data collected by GPS and used for further analysis. Based on the analysis of multi-temporal DEM, we discussed the erosion-deposition characteristics of a gully and a developing model for black soi l gully area of Northeast China was proposed. The results are: (1) The analysis of the monitored gully data in 2004 indicated that the retreat of gully head reached more than 10 m, gully area extended 170-400 m², gully net eroded volume 220-320 m3 and gully erosion modulus 2200-4800 t·km^-2·a^-1. (2) Compared with the mature gully the initial gully grows rapidly, and its erosion parameters are relatively large. The erosion parameters have not only to do with flow energy, but also with growth phase. (3) There are significant seasonal differences in gully erosion parameters. The extension of gully area and width dominates in winter and spring without marked net erosion while changes mainly occur in gully head expansion and net erosion in rainy seasons. (4) It is remarkable for freeze-thaw erosion in the black soil area of NE China. The gully wall of SG2 extended 0.45 m under freeze-thaw effect in 2004, and the distance of gully head retreated maximally 6.4 m. (5) Due to freeze-thaw action and snowmelt, gully is primarily in the interior adjustment process in winter and early spring. There are much more depositions compared with that in autumn, which can almost happen throughout the gully, while erosion mostly occurs near head, esp. for gullies having a relatively long history of development.