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切沟是黄土高原常见的地貌形态,是流域产沙的主要来源,而植被常被看作抑制切沟发育的关键因子,为探究退耕还林(草)工程以来切沟发育速率的特征,本研究使用吴起研究区间隔6年的2期同时相Quick Bird影像和分辨率为5 m的DEM,应用GIS技术分析研究区内的切沟发育速率及其影响因子。结果表明:2007—2013年研究区内小流域的年均切沟面积变化比例均<0.5%,其中无淤地坝小流域的年均切沟面积变化比例为0.13%,淤地坝小流域的年均切沟面积变化比例为0.12%;相关分析表明:在该研究区内沟间地的植被覆盖度是影响切沟发育的最主要影响因子;通过对30个无淤地坝小流域的年均切沟面积变化比例和植被覆盖度做非线性回归(R2=0.713)可得,当植被覆盖度>0.6时,其抑制切沟发育的效果最明显;方差分析表明:其他影响因子值(植被覆盖度和地貌因子)相近的条件下,有无淤地坝的6组小流域切沟发育速率无显著差异。总之,沟间地植被覆盖度是影响切沟发育的主要影响因子,而淤地坝对发育在沟缘线上的切沟无显著影响,促进植被恢复有利于抑制切沟发育。
Gully is a common topography of the Loess Plateau and is the main source of sediment production in the basin. Vegetation is often seen as a key factor to inhibit the development of the gully. In order to explore the characteristics of the rate of gully development since the project of returning farmland to forestland Using the simultaneous two-phase Quick Bird image and the DEM with a resolution of 5 m in the interval of 6 years in the Wuqi study area, GIS was applied to analyze the developmental rates of the gully and its influencing factors. The results show that the annual average annual gully area change rate is less than 0.5% in the small watershed in the study area from 2007 to 2013, of which the average annual gully area change ratio is 0.13% in the small watershed without siltation dam. The correlation analysis shows that the vegetation coverage in the inter-canal gully is the most important factor affecting the development of cutting gully in the study area. Through the analysis of the years of 30 small siltless dam valleys Non-linear regression (R2 = 0.713) showed that the effect of cutting grove development was the most obvious when vegetation coverage was> 0.6. Variance analysis showed that the values of other influencing factors (vegetation Coverage and geomorphic factors), there was no significant difference in the development rates of the gully between six groups of small watersheds with silt dam. In conclusion, the vegetation coverage in the gully area is the main factor that affects the development of the gully. However, the ditching dams have no significant effect on the gully development in the gully margin, and the promotion of vegetation restoration is conducive to the suppression of the development of the gully.