岩溶地区坡度与土地石漠化的空间相关性分析

Correlation analysis between rocky desertification and slope degree in karst area of Shaodong county

喀斯特石漠化的本质是水土流失导致土地生产力退化的过程,而坡度大小则影响着水土流失的强度。利用相关调查资料和研究数据,针对邵东县岩溶区石漠化强度变化情况,分析岩溶地区坡度与土地石漠化分布的相关性,构建了石漠化强度分布图和坡度图。在GIS技术的支持下,对石漠化强度分布图和坡度图进行叠加分析,探讨坡度与石漠化分布的空间相关关系。结果表明,邵东县岩溶地区坡度主要集中在16°～25°的斜坡和26°～35°的陡坡之间,陡坡区是不同程度石漠化分布最集中的地区;在坡度<25°的地区,石漠化发生率基本随着坡度的增大而增大,极重度石漠化发生率在坡度>25°的陡坡地区增长迅速。因此坡度增大引起的水土流失加剧是形成石漠化的一个重要原因,所得出的石漠化强度分布与坡度关系规律为地方有关部门进行石漠化治理决策提供了依据。

The nature of rocky desertification in the karst area is a process of the soil erosion leading to the degradation of land productivity, while the magnitude of slope degree fluctuation affects the intensity of soil erosion. For the problem of rocky desertificationin karst area of Shaodong County is quite serious, to further understand the correlation that between slope degree and the distribution of land rocky desertifieation in karst area, two maps of slope degree and rocky desertifieation distribution were constructed by using somerelevant survey information and research data. And they were overlapped and analyzed in order to discuss the correlation between slope degree and rocky desertification, which was supported by GIS technology. The results show that slope degrees of Shaodong Countymainly concentrated between the slope area（16° - 25° ） and steep slope area（26° - 35°）, steep slope area is the most concentrated area where the different level of rocky desertification distribution; The incidence of roeky-desertification increased mainly as the slopeincreased where slope degree is less than 25 ° , but the trend toward the extremely severe rocky desertification is growing rapidly where slope degree is greater than 25 ° , which belongs to steep slope area. Therefore, intensified soil erosion caused by the slope increases isan important reason for the formation of rocky desertification. The findings provide a basis of rocky desertiflcation control and decisionmaking for the local authorities.