贵州省后寨河小流域地形因子、人为干扰与石漠化定量研究

为定量研究喀斯特区域地形因子、人为干扰和石漠化之间的关系。基于网格法和实地观测,建立后寨河流域石漠化信息数据库并分析。结果表明:后寨河流域石漠化面积为14.43 km~2,不同利用类型石漠化面积呈以下规律:荒地坡耕地乔木林地耕地灌木林地灌草地草地弃耕地园地乔灌木林地水田经果林地;流域内岩石裸露率和土壤厚度主要受到坡度、坡位和人为干扰的制约,而人为干扰具有主观性,主要在岩石裸露率低、土壤较厚和坡度较缓的区域进行农业生产活动。荒地和弃耕地占据了石漠化面积的32.64%,且存在较大潜在石漠化的风险。回归模型发现人为干扰程度对岩石裸露率(负效应-0.286)和土壤厚度(正效应0.264)的直接效应最大,坡向对岩石裸露率(正效应0.067)和土壤厚度(负效应-0.054)的直接效应最小。认清地形因子、人为干扰和石漠化之间的耦合关系有利于喀斯特小流域石漠化治理。

Quantitative relationships among topography anthropogenic disturbance, and rocky desertification in the Houzhai River Basin, Guizhou Province, China

The relationship among topographic factors, human disturbance, and rocky desertification in karst areas was quantitatively assessed. A rocky desertification information database was established for the Houzhai River Basin and analyzed using grid-sampling and field observation. Rocky desertification affected a total of 14.43 km², and affected multiple land use types, including uncultivated lands, sloping croplands, arbor forestlands, arable land, shrub lands, shrub grass-lands, grasslands, abandoned lands, garden lands, arbor-shrub mixed forestlands, paddy lands, and artificial fruit forestlands. The rock exposure rate and soil thickness were mainly restricted by slope gradient, slope position, and human disturbance. Otherwise, human disturbance is subjective, mainly in areas with low rock exposure, thick soil, and gentle slope gradient. Uncultivated lands and abandoned lands accounted for 32.64% of the rocky desertification area, and there was a greater risk rocky desertification under these types of land use. A regression model revealed that the degree of human disturbance directly affects both rock exposure rate (negative effect:-0.286) and soil thickness (positive effect:0.264). However, only insignificant effects were observed for slope direction on either rock bareness (positive effect:0.067) or soil thickness (negative effect:-0.054). According to these findings, rocky desertification in karst mountainous basin can be easily remedied by, understanding its relationships with topography and human disturbance.