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采用经典统计学和地统计学相结合的方法探讨了黄土丘陵沟壑区小流域土壤水分(0~300 cm)水平和垂直方向的空间变异特征,以及土地利用和地形因子对其影响规律。结果表明:(1)土壤水分的垂直变化表现为先降低后增加;变异系数为11.22%~21.05%,具有中等程度变异,土壤水分平均值与变异系数之间呈显著负相关。(2)梯田的层状分布和微地形的存在削弱了土壤水分在水平方向上的空间相关性;水平方向变程范围在19~102m,增加采样密度能增加土壤水分的空间结构信息;(3)土壤水分在垂直方向上存在强烈或中等程度的空间自相关;垂直方向的变程的范围为0.67~2.64 m;(4)不同环境因子基台值的变化格局与平均土壤含水量相反,水分的增加对基台值有一定的平滑效应;不同土地利用类型对土壤水分垂直变异影响程度依次为荒草地>林地>退耕地>耕地,而坡位则表现为梁>沟谷。
Using the combination of classical statistics and geo-statistics, the spatial variability of soil water (0-300 cm) and vertical direction in the small watershed of the hilly-gully region of the Loess Plateau was studied, and the influence of land use and topographical factors on it was also discussed. The results showed that: (1) The vertical variation of soil moisture decreased first and then increased; the coefficient of variation was 11.22% ~ 21.05%, with a moderate degree of variation. The average value of soil moisture was significantly negatively correlated with the coefficient of variation. (2) The terrace distribution and the micro-topography weaken the spatial correlation of soil moisture in the horizontal direction. The range of horizontal variation ranges from 19 m to 102 m. Increasing the sampling density can increase the spatial structure of soil moisture. ) There is a strong or moderate degree of spatial autocorrelation of soil moisture in the vertical direction; the range of vertical variation ranged from 0.67 to 2.64 m; (4) The change pattern of base station values of different environmental factors was opposite to the average soil water content, The effects of different land use types on the vertical variation of soil moisture were as follows: grassland> forest land> abandoned farmland> cultivated land, while slope position showed as beam> gully.