高寒草甸区典型景观单元土壤养分空间变异性研究

Study of the Spatial Heterogeneity of Soil Nutrients of Typical Landscape in Alpine Meadow Regions

应用GIS技术和地统计学空间内插法,对黄河源区达日县跨热洼尔玛流域高寒草甸小流域典型景观单元土壤有机质、全氮和全磷的空间分布特征进行了研究.结果表明:高寒草甸土壤养分(全氮、有机质、全磷)最佳拟合模型为球状模型;在小流域尺度范围内,土壤养分空间变异性依次为:全氮>有机质>全磷;其中高寒草甸土壤全氮含量具有强空间变异,块金系数(C0/(C0+C))为23.5%,有机质和全磷属于中等空间变异,其块金系数(C0/(C0+C))分别为35.9%、41.7%;全氮、有机质和全磷的有效变程分别为2 133 m、1 412 m和1 239 m.区域土壤养分影响因素分析显示:不同植被覆盖下土壤有机质和养分的积累和平衡状况存在差异,其空间变异主要受海拔、地形、坡度、植被、根系分布状况等因素影响.

The spatial heterogeneity of soil nutri ents including organic matter（OM）, total nitrogen （TN） and total phosphorus（TP）in a typical minor watershed of alpine meadow was studied using GIS technical and Kriging interpolation method. Fifty four samples in ten paths were collected and analyzed. The best simulation model of these soil nutrients is spherical model. The soil spatial heterogeneity in typical valley was graded as TN〉OM〉TP; soil TN has the strongest spatial heterogeneity with the nugget coefficient （C0/（C0 ＋C）） of 23.5%; spatial heterogeneity of OM and TP has moderate variability with the nugget coefficient （C0/（C0＋C））of 35.9% and 41.7%. And the spatial scale of soil OM, TN and TP were around 2133 m, 1412 m and 1 239 m, respectively. The Kriging interpolation map and semi-variance function could express the spatial variability and its level. In this study the model which can describe soil nutrients distribution best is semi-variance model. Variability of soil nutrients is mainly influenced by altitude, landform, gradient, vegetation, root distribution and etc.