土地利用与地形因子关系研究——以砖窑沟流域为例

Relationship between topographic factor and land use——A case study of Zhuanyaogou watershed

以黄土丘陵沟壑区的砖窑沟流域为例,依据2003年和2008年两期土地利用现状图,采用地理信息系统(GIS)软件和统计分析(SPSS)软件,进行了基于10m×10m栅格单元的土地利用与地形因子关系的研究,探讨了土地利用格局的演变及其驱动力。结果表明:基于栅格的土地利用类型与坡度、坡向和海拔关系的综合分析是从数量上准确剖析土地利用空间分布特征及其演化规律的有效方法;砖窑沟流域的海拔、坡度、坡向的平均值分别为1069m、19.24°和279°(西坡);采用各种土地利用类型的sin(坡向)和cos(坡向)平均值绘制坡向分布图,可直观地显示各种土地利用类型坡向分布特征。分析表明,农田和宜林荒山共占流域总面积的80%左右,二者的分布和变化控制着整个流域土地利用的地形分布格局。农田主要以坡地和梯田的形式分布于坡上、峁顶和梁顶,坡度较低,而海拔较高,与坡度呈显著负相关,与海拔呈显著正相关;而宜林荒山往往分布于坡度较大而海拔较低的位置,与坡度呈显著正相关,而与海拔呈显著负相关。研究结果反映了黄土丘陵沟壑区土地利用的地形地貌特征。生态建设项目的实施可在短时间使土地利用的空间分布发生较大变化。

GIS and SPSS were used to quantitatively analyze the relationships between land use type and topographic factors for 2003 and 2008.The succession pattern and driving factors of land use were also explored on 10 m×10 m grid-base for Zhuanyaogou watershed in the hilly region of the Loess Plateau of China.The study shows that land elevation,slope gradient and aspect significantly influence the spatial distribution of land use.The average elevation,slope gradient and aspect of the watershed are respectively 1 069 m,19.24° and 279° （west）.Aspect-distribution map from average sin（aspect） and cos（aspect） of different land use types clearly shows the distribution characteristics of land use.Farmlands and barren-hills form about 80% of the study area,and their distribution change controls the topographic pattern of land use distribution in the watershed.Farmlands are mainly located in the upper slope and tops of the loess mountain ridges with low slope gradients and high elevations.While farmland area is significantly negative correlated with slope gradient,it is significantly positive correlated with elevation.Barren hills exhibit the opposite trend.The results fully reflect the topographic characteristics of land use in the study area.Implementation of eco-construction projects could induce significant changes in the spatial distribution of land use in the short-run.