黄土高原北部坡面尺度土壤饱和导水率分布与模拟

Distribution and simulation of saturated soil hydraulic conductivity at a slope of northern Loess Plateau

为探明黄土高原北部坡面土壤饱和导水率(Ks)空间分布特征,为土壤水文过程模拟与预测提供理论依据,采用经典统计学和地统计学的空间变异分析方法,分析了坡面尺度土壤Ks的空间变异特征,并用一阶自回归状态空间模型对Ks的空间分布进行了模拟。研究区坡面尺度Ks的变异为中等程度变异,具有中等程度空间依赖性,变程为42 m。Ks与容重、砂粒、粉粒和黏粒含量在不同滞后距离下均具有自相关关系和交互相关关系。容重和土壤颗粒是影响坡面Ks空间分布的主要因素。状态空间模拟结果表明,基于容重和土壤颗粒的状态空间方程可以很好地解释坡面Ks的变异状况(R2>0.9)。一阶自回归状态空间模型可用于田间条件下坡面尺度Ks分布特征的预测。

To provide a theoretical basis for simulating soil hydraulic processes, classical statistics and geo-statistics were used to characterize the spatial distribution of saturated soil hydraulic conductivity （Ks） at a slope scale in the northern Loess Plateau. Furthermore, the first order autoregressive state-space model was applied to simulate the distribution of K. The magnitude of K variability was moderate according to the coefficient of variation. The degree of spatial dependence was moderate with range of 42 m. Bulk density, sand content, silt content, and clay content were auto-correlated. Cross-correlation existed between Ks and other factors at different lag distance. Bulk density and soil particles were the key factors to affect the spatial distribution of Ks on the sloping land. A combination of bulk density and soil particles was the best to explain the spatial variation of Ks（R^2〉0.9）. The first order autoregressive state-space model is suitable for simulating the K distribution at a slope scale.