高寒草甸典型植被退化小流域土壤容重空间变异特征

Study on Spatial Heterogeneity of Soil Bulk Density of Typical Deteriorated Minor Watershed in Alpine Meadow

以高寒草甸典型植被退化小流域为研究对象,应用GIS技术和地统计学的Kriging空间内插法,研究小流域尺度下景观单元土壤容重空间变异规律。结果表明：0～10 cm土层土壤容重最佳拟合模型为线性模型,10～20 cm,20～30 cm,30～40 cm和40～50 cm 4层土壤容重最佳拟合模型为球状模型;在小流域尺度范围内,40～50 cm土层土壤容重具有强空间变异性,块金系数[C0/（C0＋C）]为15.7%,0～10 cm,10～20 cm,20～30 cm和30～40 cm 4层土壤容重属于中等空间变异,块金系数在27.6%～47.4%之间;分析得出0～10 cm,10～20 cm,20～30 cm,30～40 cm,40～50 cm 5层剖面土壤容重的有效变程分别为1 596 m,1 697 m,1 985 m,1 426 m和1 380 m。通过确定半方差函数、比较变量的空间变异性及空间变异程度,总体上,小流域内土壤容重半方差函数模型拟合效果较好。

Using a typical case of small watershed deterioration in an alpine meadow, this paper studied the spatial heterogeneity of soil bulk density using GIS software and the Kriging interpolation method. The results for soil bulk density modeling are as follows： the optimal model for the soil layer 0-0cm below the surface is linear and the optimal models for soil layers 10-20cm, 20-30 cm,30-40 cm and 40-50 cm below the surface are spherical. The results for spatial heterogeneity are as follows： within the watershed, the soil layer within 40-50cm has the strongest spatial heterogeneity, while the other layers have moderate spatial heterogeneity. Furthermore, the Semi-variance function and Kriging interpolation map of soil bulk density both indicated spatial structure characteristics well. The ranges of the five layers were 1 596m, 1 697m, 1 985 m, 1 426 m and 1 380m, respectively. The soil layer within 20-30cm had the maximum range, and the layer within 40-50cm had the minimum range.