坡地土壤溶质迁移参数的空间变异特性

以氯离子为示踪离子,以41m×5m径流小区为研究区域,采用原状土柱法,通过拟合穿透曲线估计了氯离子在坡地土壤中的迁移参数,并利用经典统计学和地统计学理论分析了溶质迁移参数在坡面的空间变异特征.结果表明,平均孔隙流速从坡上到坡下有逐渐增加的趋势,属于中等程度变异,在坡面的变异具有漂移特征;弥散系数在距坡顶0～20 m范围内变化不大,20 m以下呈逐渐上升趋势,属于中等程度变异,具有空间自相关特征,其自相关特征长度为21 m;弥散度从坡上到坡下有逐渐增加的趋势,属于中等程度变异,具有空间自相关特征,其自相关特征长度为10 m.

Spatial variability of slope land soil solute transport parameters

In this paper, the transport parameters of chlorine in a slope land soil were determined in situ by fitting breaking-though curve, and the spatial variability of the parameters in a 41 m x 5 m runoff plot was analyzed by using traditional and geo-statistics. The results showed that the average pore-water velocity increased gradually from the top to the bottom of the slope, and the diffusive-dispersive coefficient (D) had no remarkable variation within 20m away from the top but gradually increased with the distance beyond 20m. The dispersivity (alpha) had the same characteristics as D. The pore-water velocity (v) had a floating feature on the slope, while parameters D and alpha showed obvious spatial correlation characteristics, the range of the spatial correlation being 21m and 10m, respectively.