黄土高原不同生物气候区土壤侵蚀动态变化研究

基于地理信息系统(GIS)和遥感(RS)技术,利用修正的通用土壤流失方程(RUSLE)模型,结合遥感影像、数字高程数据(DEM)、土壤类型数据及相关统计资料确定了模型参数因子,在重点分析我国黄土高原不同生物气候区降雨侵蚀力因子和植被覆盖因子时空变化特征的基础上,计算出各区2000~2012年土壤侵蚀模数,分析了土壤侵蚀强度的时空动态变化特征。结果表明:区域多年平均土壤侵蚀量为1.35×109t,土壤侵蚀模数为2 264 t/(km2·a)。土壤侵蚀强度以微度侵蚀和轻度侵蚀为主,侵蚀面积比例为74.31%;近13 a来,黄土高原的土壤侵蚀强度呈显著降低的变化趋势(P=0.03),平均每年减少54.22 t/(km2·a)。土壤侵蚀正在向微度、轻度土壤侵蚀转变,土壤侵蚀模数减少的区域占整个侵蚀区域的69.05%,增加的区域占30.95%。研究结果对黄土高原区域生态恢复和生态建设具有一定的指导意义。

Spatial -temporal changes of soil erosion of different bioclimatic zones in the Loess Plateau

With the geographic information system (GIS)and remote sensing (RS)technology,and based on remote sensing image data,digital elevation model (DEM)data,soil type data and relevant statistical data,by the modified revised universal soil loss equation (RUSLE),we first analyzed the spatial and temporal dynamic changes of rainfall erosion factor and vegetation cover factor of different bioclimatic zones,then calculated the soil erosion modulus of these zones in the Loess Plateau from 2000 to 2012 and explored the spatial and temporal dynamic changes of soil erosion intensity in this region.The result showed that the average annual amount of soil erosion was 1 .35 billion tons and the average soil erosion modulus was 2 264 t·km -2 ·a -1 ;soil erosion type were mainly slight erosion and light erosion,accounting for 74.31 % of the total area of soil erosion.;the soil erosion of the Loess Plateau presents a decreasing trend from 2000 to 2012 (P =0.03),with a rate of 54.22 t·km -2 ·a -1 ;soil erosion intensity transforms into slight and light erosion.About 69.05% of the region showed decreasing trend while the rest showed in-creasing trend (30.95%).This study is of great significance to the ecological restoration and construction of the Loess Plateau.