基于GIS的城乡交错带土壤养分空间特征研究——以洪雅县为例

Analysis of Spatial Distribution of Soil Nutrients in Suburb Region Based on GIS

在ArcGIS9.0平台上运用地统计学方法研究了洪雅县城乡交错带土壤养分的空间变异。结果表明:土壤有机质、全氮、全磷和全钾含量的变异函数最优拟合模型分别为球状、指数、高斯和指数模型。土壤有机质和全氮有相似的空间分布特征,均呈条带状或小团块状分布,由柳街低值中心向北逐渐增加,在高岩村和李家湾达到最高;全磷的空间分布呈明显的带状,北高南低,高值中心在红星村-新村-柳街条带以北,低值中心在阳坪农场;全钾的空间分布与有机质和全氮的空间分布相反,呈条带状或小团块状分布,以柳街为高值中心向北递减。土壤有机质、全氮、全磷和全钾的块金值与基台值之比分别为38.12%、46.97%、87.5%和0,土壤有机质和全氮有中等的空间自相关,全磷空间自相关性弱,而全钾具有恒定的空间自相关性。成土母质、土地利用方式、地形地貌条件和气候等与土壤养分的空间分布均关系密切。

Soil nutrient was of primary importance for maintaining soil productivity, which was an important indicator of soil quality. In this paper, the spatial variability characteristics of suburb region soil nutrient in Hongya were studied by the software ArcGIS 9.0. Results showed that the best theoretical semi-variogram models of soil organic matter （SOM） was spherical model; total nitrogen （TN） and total potassium （TK） were exponential model; and total phosphorus （TP） was Gaussian model. SOM and TN showed a similar pattern in distribution, which appeared as strip belts or gobbets. The lowest value existed in Liu street, and decreased towards the north; the highest value region existed in Gaoyan village and Lijia bay. The spatial distribution of TP appeared as strip belts. The north was high and the south was low, The highest value existed in the north of Hongxing village-Xin village-Liu street, the lowest value region existed in Yangping farm. The spatial distribution of TK, which appeared as strip belts or gobbets, was completely different from that of SOM and TN. The highest value existed in Liu street, and declined towards the north. These values of the ratio of random variance （nugget） to total variance were 38.12% for SOM, 46.97% for TN, 87.5% for TP, 0.00% for TK, respectively. This indicated that SOM and TN had medium spatial autocorrelation; TP had weak spatial autocorrelation; TK had constant spatial autocorrelation. Spatial distribution of soil nutrients had close correlation with soil parent material, climate, land utilization, land management and