区域LUCC的土壤侵蚀响应研究——以榆林市为例

Study on the Response of Soil Conservation under Regional LUCC——A Case Study in the Yulin Region

借助3S技术,采用美国通用的水土流失方程(USLE),对榆林市1987,1999年和2002年的土壤水力侵蚀、生态系统土壤保持情况进行测算,在此基础上,基于G IS平台按不同区域对测算结果进行汇总。研究表明:单位面积各类生态系统保土功能排序是园地>林地>灌木林地>草地。降雨的年际变化和地形的空间差异是单位面积生态系统土壤保持量年际变化和空间差异的主导因素。1987,1999,2002年全市各类生态系统土壤保持总量分别是2.22×108t,1.96×108t和2.07×108t。研究期间(1987-2002年),全市生态系统土壤保持效率不断提高,但存在空间差异:1987,1999年南6县生态系统土壤保持总量、保持效率显著高于北6县,而2002年北6县略高于南6县;且整个研究期间北6县生态系统土壤保持效率提高显著,而南6县变化小且2002年略有下降;相对于北6县而言,南6县实际对进一步提高土壤保持效率的制约较大。

Based on the technologies of 3S （RS, GPS and GIS） and universal soil loss equation （USLE）, in this paper the values of soil erosion and soil conservation perunit area in different ecosystems in the Yunlin region in 1987, 1999 and 2002 are estimated and was integrated. The results show that the soil conservation per unit area of all the ecosystems was in an order of garden plots 〉 woodlands 〉 shrubberies 〉 grasslands. The interannual difference of precipitation and the spatial difference of landforms were the dominant factors resulting in the interannual change and spatial difference of soil conservation per unit area in all the ecosystems. The total quantities of soil conservation per unit area in all the ecosystems in the Yulin region in 1987, 1999 and 2002 were 2.22 × 10^8 t, 1.96 × 10^8 t and 2.07 × 10^8 t respectively. During the whole study period from 1987 to 2002, the ratio of soil conservation per unit area in all the ecosystems in the Yulin region was continuously increased, but there was some spatial difference, that means the total quantities and efficiencies of soil conservation of all the ecosystems in 6 counties in the south in 1987 and 1999 were significantly higher than that in 6 counties in the north, but they were slightly higher in 6 counties in the north than that in 6 counties in the south in 2002. During the whole study period, the efficiencies of soil conservation in all the ecosystems in 6 counties in the north were significantly increased, But not in 6 counties in the south and even slightly decreased in 2002. Comparatively, there was more natural restriction in making further soil conservation efficiency in 6 counties in the south than that in 6 counties in the north.