北京市平谷区农用地土壤有机质空间变异特征

    Spatial variability characteristics of farmland soil organic matter in Pinggu District, Beijing, China

    • 摘要: 采用传统统计、地统计及地理信息系统(GIS)相结合的方法,初步研究了北京市平谷区农田土壤有机质(SOM)含量的空间分布规律及其影响因素。传统统计分析结果表明,研究区土壤样本呈对数正态分布,平均值为15.36 g×kg-1,变异系数为0.32,属中等变异程度。方差分析表明,高程和土地利用类型均对研究区SOM含量的分布有显著影响。地统计分析表明,研究区SOM含量空间变异具有一阶趋势和各向异性特征;由空间自相关部分和随机部分引起的空间变异性程度大体相当,具有中等的空间相关性。结合普通Kriging插值方法,获得了研究区SOM含量的空间分布图,比较分析表明研究区农用地SOM含量的空间分布是自然和人为利用因素共同作用的结果。

       

      Abstract: Based on the analysis of 989 topsoil sampling points in Pinggu District , Beijing, the county scale spatial characteristics of farmland soil organic matter (SOM) content were studied employing traditional statistics, geostatistics and geographic information system (GIS). The results of traditional statistics show that SOM content follows a lognormal distribution, with a arithmetic mean of 15.36 g?kg-1. SOM content was moderately variable in the area, with a coefficient of variation (C.V.) of 0.32. Based on the results of ANOVA, elevation and land use type both affect significantly the distribution of SOM content in study area. The geostatistical characteristics of SOM content were analyzed under GIS platform. The distribution of SOM content in the study area exhibit a one–order (linear) trend and anisotropy, the spatial autocorrelation distances (ranges) are large (17.0 km on the long axle and 12.6 km on the short axle) and the degree of spatial autocorrelation is moderate. A contour map of SOM content was obtained using ordinary Kriging interpolation, and the spatial distribution pattern was analyzed further. The SOM spatial pattern was approximately consistent with the spatial structure of topography and land use type.

       

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