基于GIS的耕地土壤有机质空间插值模型比较及空间分异分析——以贵州省望谟县乐元镇为例

Spatial interpolation model comparison and spatial differentiation analysis of farmland soil organic matter based on GIS——A case study at Leyuan town, Wangmo county, Guizhou province

探究贵州省望谟县乐元镇耕层土壤有机质空间分异规律,为土壤肥力评价和管理工作,耕地资源的可持续利用提供指导.以望谟县土地利用现状图、土壤图及耕地地力评价数据库为材料,利用ArcGIS1O.0地统计分析模块中的克里格法,分析望谟县乐元镇耕层土壤有机质的空间变异性,对比选择最优的克里格插值模型.结果显示：望谟县乐元镇耕层土壤有机质拟合的最优理论模型是二次有理式模型,搜索方向为8 Sectors,搜索点数为2～12是较好的选择,R2为0.926; C0/sill值为0.76,表明耕层土壤有机质在人类活动的影响下空间相关性减弱,并逐渐趋于均一化;通过绘制有机质的克里格插值分布预测图,为研究区有机肥的施用提供参考.

Taking advantage of organic topsoil data of Leyuan town in Wangmo county, we can explore the spatial variability of tillage-layers oil organic matter content, and guide the evaluation and management of soil fertility, so as to achieve the sustainable use of land resource. Based on the status of land use maps, soil maps, evaluation of farmland database of Wangmo,this paper applied Kriging method of ArcGIS10.0 to analyze the spatial differentiation of cultivated soil organic matter of Leyuan town in Wangmo county, and elected the optimal Kriging interpolation model. The optimal Kriging interpolation model of tillage-layer soil organic matter on Leyuan town in Wangmo county was the Rational Quadratic model. When the search direction was 8 sectors, search points was 2-12, model interpolation was better, and R2 was 0.926. The value of Co/sill was 0.76, this showed that the spatial correlation of tillage-layer soil organic matter was very weak and was affected by human activities, like tillage ,the application of fertilizers and cropping system. These factors made the spatial correlation of tillage-layer soil organic matter weaken, and gradually became homogenization. The range of variation of topsoil organic matter content was wide, but less affected by outliers, and the various data were provided with highly spatial correlation. At the same time, the Kriging interpolation distribution forecast figure could move forward a single step to conduct fertilizer.