东北漫岗黑土区地形因子对浅沟侵蚀的影响分析

Effect of Topography on Ephemeral Gully Erosion in Northeast China with Black Soils

浅沟侵蚀是坡耕地上重要的产沙方式之一,地形是控制其发生及发展的关键因素。通过对东北漫岗黑土区两个小流域的地形因子和浅沟侵蚀进行相关分析发现,浅沟长度、侵蚀体积与坡面长度呈显著相关,与汇水面积也有较好的相关。根据地形临界理论,确定了研究区浅沟和切沟侵蚀发生的地形临界(S-A)关系:SEG=0.052A-E 0G.148和SG=0.072 A-G 0.141,可以用来预测小流域内可能发生浅沟侵蚀以及浅沟向切沟侵蚀转变的部位。在地形分析的基础上,建立了预测浅沟长度的回归模型,交叉验证表明模型对单条浅沟长度的预测误差较大,平均误差37%;而预测浅沟总长度效果较好,预测浅沟总侵蚀量与实测值的误差也只有6%。

Ephemeral gully erosion in cultivated land is an important source of sediment. Topography has significant impacts on its development. The correlation between catchment topography and ephemeral gully erosion in northeastern China with black soils was discussed. The results show that ephemeral gully length and eroded volumes are significantly correlated with watershed length. A critical slope-upslope area relationship （S = αA^h） for ephemeral and classical gullies was established for the study area by means of log10-1inear regression to analyze the evolution from ephemeral to classical gully. The resulting relationships are SEG = 0. 052A^-0.148 EG and Sc = 0. 072AG^-0.141, respectively, for ephemeral and classical gullies. Furthermore, a linear regression model for the prediction of total gully length at the catchment level was established using field data, and although it didnot successfully predict the length of individual gullies, it explained better the variation in total gully length in the catchment.