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    基于LUCC的冀北土石山区东北沟流域土壤侵蚀时空变化分析

    Temporal and spatial variability of soil erosion in Dongbeigou Watershed in northern mountainous area, Hebei Province, based on Land Use/Cover Change(LUCC)

    • 摘要: 在GIS技术的支持下,利用气候、土壤、植被盖度、DEM、土地利用现状调查和影像等数据,揭示东北沟流域土地利用和土壤侵蚀变化特点,明确土地利用类型与土壤侵蚀的关系。结果表明:1)近20年来流域土地利用变化剧烈,林地增加,草地、耕地和难利用土地减少,林地和草地之间及其内部转化较为明显;2)土壤侵蚀模数由1990年的5136.13t/(km2·a)减小到2009年的1823.30t/(km2·a),土壤侵蚀强度明显减弱,土壤侵蚀由轻度侵蚀(32.78%)和中度侵蚀(28.49%)为主减弱到以微度侵蚀(42.16%)和轻度侵蚀(33.25%)为主;3)不同土地利用类型的平均土壤侵蚀模数均有大幅度的下降,其差异也比较明显,林地、居住建筑用地的侵蚀强度较小,难利用土地土壤侵蚀强度较大。难利用土地是今后水土流失治理的重点区域。

       

      Abstract: Land-use has a direct effect on the change of soil erosion intensity through changing vegetation cover, soil property and runoff velocity. The Dongbeigou Watershed with an area of 19.34km2 was chosen as the study area. Based on climate, vegetation coverage, soil, land-use survey and Quickbird image data in 1990 and 2009, the change characteristics of land-use and soil erosion were revealed by means of the shift matrix of land-use and Revised Universal Soil Loss Equation (RUSLE) supported by GIS. The results showed: the forestland increased from 38.56% in 1990 to 55.83% in 2009 compared to the decrease of grassland, cropland and barren land. The main conversion happened between forestland and grassland. The annual average soil erosion modulus decreased from 5136.13t/(km2·a) in 1990 to 1823.30t/(km2·a) in 2009. The soil erosion intensity decreased significantly. The area where the slight soil erosion (200-2500t/(km2·a)) happened constituted 32.78%, and the area where the moderate soil erosion (2500-5000t/(km2·a)) happened constituted 28.49% in 1990, whereas, in 2009 the area where slight soil erosion happened constituted 33.25%, and where little slight erosion soil erosion (<200t/(km2·a)) happened constituted 28.49%. The average soil erosion modulus of different land use types declined greatly, but there were great differences among the soil erosion modulus of different land use types. The soil loss rate happening in forestland and residential land was low, but the soil loss rate happening in barren land was high. The barren land is the key area of soil and water conservation in future.

       

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