陕北黄土区小流域不同植被恢复模式下切沟形态参数差异分析

Analysis on the Difference of Gully Morphological Parameters Under Different Vegetation Restoration Modes in Small Watershed of Loess Region of Northern Shaanxi

本文以陕北黄土丘陵沟壑区吴起县合沟小流域(自然恢复)及柴沟小流域(退耕还林)为研究对象,基于GeoEye-1高分立体像对数据(0.5 m)选取39条切沟,在ArcGIS中采用目视解译法提取沟缘线,计算切沟参数,进一步利用方差分析,对比分析两种植被恢复模式下切沟形态参数差异.结果表明,两种植被恢复模式下切沟的形态特征参数并无明显差异,侵蚀沟的特征皆为横向侵蚀速率大于纵向;两个小流域中约有50%的断面形状是先U型后V型,U型断面比例差异显著,自然恢复模式下U型断面较多;合沟与柴沟小流域中切沟的沟长、面积、体积并无明显差异,断面的顶宽、底宽和沟深的差异性在两种植被恢复模式下也并不显著,但切沟断面的宽深比以及底宽顶宽比差异显著.

In this paper,the Hegou small watershed(natural restoration)and Chaigou small watershed(conversion of cropland to forest)in Wuqi County of northern Shaanxi loess hilly and gully region were taken as the research objects,and 39 gullies are selected based on GeoEye⁃1 high score stereoscopic image pair data(0.5m).In ArcGIS,the manual visual interpretation method is used to extract the gully line and calculate the gully parameters,and then the variance analysis is used to compare and analyze the difference of the gully mor⁃phological parameters under the two vegetation restoration modes.The results showed that there is no obvious difference in the morphological characteristic parameters of the gullies under the two vegetation restoration modes,and the characteristic of the gullies is that the lateral erosion rate is greater than the longitudinal rate;A⁃bout 50%of the cross⁃sections in the two small watersheds are U⁃shaped and then V⁃shaped.There is a signifi⁃cant difference in the proportion of U⁃shaped cross⁃sections,under the natural restoration mode,there are more U⁃shaped cross⁃sections;Between the small watersheds of Hegou and Chaigou,there is no significant difference in the length,area and volume of the gully erosion.The difference in the top width,bottom width and depth of the section is not significant under the two vegetation restoration modes,however,there are significant differences in the ratio of width to depth and the ratio of bottom to top of the gully section.