广西凤山县林地石漠化指数研究

Study on rocky desertification index for Fengshan county of Guangxi province

为了准确评定林地石漠化等级,以广西凤山县林地为案例,提出了林地石漠化指数这一定量新指标来量化评价林地石漠化的程度。根据林地的基岩裸露率、植被综合覆盖度、坡度、土层厚度4个指标对林地石漠化评价的重要程度,釆用专家打分得到重要性比较结果,釆用层次分析法计算得出各个指标的权重值。结果表明:基岩裸露率、植被综合覆盖度、坡度、土层厚度4个指标的权重值分别为0.553 4、0.284 1、0.062 9、0.099 6,表明林地石漠化指数各指标重要性最大的是基岩裸露率,其次是植被综合覆盖度,然后是土层厚度、坡度;无石漠化、潜在、轻度、中度、强度、极强度各等级的石漠化指数区间分别为[0,0.161]、(0.161,0.352]、(0.352,0.418]、(0.418,0.720]、(0.720,0.868]、(0.868,1]。利用该指数能够实现对广西凤山县林地的石漠化程度等级的量化评定。

In order to accurately assess the rocky forestland desertiifcation grade, by taking the forestland in Fengshan county of Guangxi province as a studied object, a new quantitative indicator index of rocky desertiifcation wasproposed to quantify the rocky forestland evaluation. According to the importance degrees of four indexes （bedrock exposed rate, comprehensive vegetation coverage rate, slope, soil thickness） to evaluation of rocky desertiifcation, the comparison results of importance was obtained by using expert scoring method, and the weight values of each index were calculated by using analytic hierarchy process method. The results show that the weight values of bedrock exposed rate, comprehensive vegetation coverage rate, slope, soil thickness were 0.5534, 0.2841, 0.0629, 0.0996 respectively, indicating the importance of indicator of all indicators was the bedrock exposed rate, followed by comprehensive vegetation coverage rate, soil thickness, slope; And the index intervals of rocky desertiifcation index of no rocky, potentially, mild, moderate, strength and extreme strength rocky grade were [0,0.161], （0.161,0.352], （0.352,0.418], （0.418,0.720], （0.720,0.868], （0.868,1] respectively. The rocky desertiifcation forestland grade indicator index system can quantitatively evaluated the forestland rocky desertiifcation status quo in Fengshan County of Guangxi Province.