基于Moran＇s I和地统计学的浙江森林土壤有机碳空间分布研究

Using Moran's I and geostatistics to analyze the spatial distribution of organic carbon in forest soil of Zhejiang province

以浙江省森林土壤有机碳为研究对象,在省域林地范围内利用网格布点采样,共布设840个土壤剖面样点,通过对数转化对土壤有机碳进行正态分布性检验。采用Moran's I与地统计学结合的GIS技术对森林土壤有机碳的空间变异性及分布格局进行了系统研究。全局Moran's I表明森林土壤有机碳具有极显著的空间自相关性,局部Moran's I揭示千岛湖周边地区、丽水西部等地是森林土壤有机碳高值集聚区,而浙江中部地区是低值集聚区。应用地统计学分析方法进行实验变异函数计算和最适合模型的拟合,得出森林土壤最好的理论模型为指数模型,随后用普通克里格估值方法绘制了森林土壤有机碳的空间分布图,测算表明土地经营管理方式改变、人为改变土地类型、局域性种植经济林等非区域性因素对森林土壤有机碳的空间变异影响显著。

In ordor to study the distribution of forest soil organic carbon（ SOC）,a total of 840 soil sampling sites were laid based on a grid of 4 km × 6 km,using portable GPS. Normality test was applied for log-transformed data of forest SOC data. Moran＇s I,geostatistics and GIS techniques were used to study the spatial variation and spatial patterns of SOC. Extremely significant spatial auto-correlation of forest SOC was found based on the global Moran＇s I value. Local Moran＇s I index revealed that high SOC values were located around the area of Qiandao Lake,the west part of Lishui city,while low SOC values were located in the middle part of Zhejiang province. The experimental variogram of SOC was calculated and fitted by exponential model. Further ordinary Kriging was applied to interpolate the SOC in forests of Zhejiang province. The spatial patterns of SOC were strongly related to human being activity such as planting economic forest,changing soil management and so on.