县域尺度土壤有机质与土地利用动态耦合关系定位对比研究——以渭北旱塬区长武县为例

以陕西省长武县为研究区域,根据大规模采样数据,结合1983年和2008年土地利用空间数据,运用定位对比监测方法,分析了25年来不同土地利用变化的幅度、空间分布特征和方向,并对这种变化影响下的土壤有机质含量演化特征进行了研究。结果表明:该区土地利用方式在这一时期变化显著,旱地、草地、非农用地面积大幅减少,林地、果园面积大幅增加。土地利用方式的转变已经成为土壤有机质含量变化的驱动因素,其中,旱地转变为林地和果园,土壤有机质含量变化明显,分别增加了6.6 g/kg和5.11 g/kg,而林地转变为旱地和草地则无明显增量。土壤有机质含量的变化不仅改变了土壤结构,有效地控制了水土流失的发生,而且为该区域的土地利用方式朝着健康的方向发展,提供了参考价值。

Localization Comparison on Dynamic Coupling Relationship Between Land Use Change and Soil Organic Matter at County Scale——A Case of Changwu County in Weihe Arid Plateau Region

Taking Changwu County in Shanxi Province as the study area,based on the land use spatial data between 1983 to 2008,the land use change range,transfer direction and spatial distribution characteristics which led to the evolution regularity of soil organic matter content were analyzed by using GIS spatial analytical method.The results showed that land use dynamic change in this period was remarkable,the areas of dry land,grass land and waste land decreased largely,but the areas of forest land and orchard increased greatly.Meanwhile,the transformation of land use change which resulted in the increase of soil organic matter at different degrees had become the driving force of soil organic matter content variation.Soil organic matter content increased respectively 6.6g/kg and 5.11g/kg after conversion from dry land to forest land and orchard,but the increment did not vary obviously after forest land was converted to dry land and grass land.The variation of soil organic matter content not only improved soil structure but also controlled the loss of water and soil,which provided the valuable information to guide land use change toward a proper direction