黄土区微地形降雨侵蚀量分形特征研究

摘要

In order to determine the micro topography fractal characteristics of rainfall erosion on sloping lands of the loess area, this paper used the slope surface soil of gullied rolling loess area as a sample, set up four kinds of farming pattern, five grade levels and observed the erosion of the tiny terrain data by indoor artificial rainfall tests. R/S analysis method of rainfall erosion of tiny terrain was analyzed and the Hurst index was determined. The results show that under the conditions of different cultivation patterns and slope of tiny terrain, the rainfall erosion fitting parameters H are greater than 0.5 (dimension D<1.5), which indicates that rainfall erosion exists sustainable state and the rainfall erosion of the next time period has the same trend of changes as the past.%为了确定黄土区坡地微地形降雨侵蚀量分形特征，采用黄土丘陵沟壑区坡地表层土为供试土样，设置4种耕作方式、5个坡度等级，进行室内人工降雨试验，得到了微地形的侵蚀量观测数据。应用R／S分析法对微地形的降雨侵蚀量进行分析，确定了Hurst指数。结果显示：不同耕作模式和坡度条件下微地形降雨侵蚀量拟合参数H都大于0．5（维数D＜1．5），说明降雨侵蚀量存在着状态可持续性，下一时段的降雨侵蚀量与过去时段的变化趋势相同。