属性数据与空间数据连接对土壤有机碳储量估算的影响

土壤有机碳(Soil Organic Carbon, SOC) 库在陆地生态系统中具有重要作用。在基于GIS利用土壤类型法估算SOC储量时，由于土壤图比例尺的限制，属性数据与空间数据的连接会导致对SOC储量的估算结果产生很大不确定性。利用中国滇黔桂地区（云南省、贵州省和广西壮族自治区）798个土壤剖面及1∶[KG-*2]50万土壤图在不同的制图单元水平上，分别采用算术平均值法、中值法和面积加权平均值法（以土种志中的面积为权重）估算了该地区1 m深度SOC储量，并与基于土壤学专业知识连接方法（Pedological Knowledge Based Method, PKB）的估算结果进行了比较。结果表明：面积加权平均值法比中值法和算术平均值法的估算结果更为准确，而且在土类、亚类和土属水平上应用面积加权平均值法对SOC储量的估算结果差异不大。在采用较大比例尺、较为详细的土壤图时，PKB法较理想；反之，则面积加权平均值法较好。

Effects of the Linkage between Spatial Data and Attribute Data on Estimates of Soil Organic Carbon

Soil organic carbon (SOC) pool plays a key role in the terrestrial eco systems. Limited by the map scale of soil maps, the linkage between attribute and spatial data can cause large uncertainties in estimating SOC storage with the soil type method. In this study, with a total of 798 SOC density data and the 1:500 000 soil maps, the SOC storage in Yunnan Guizhou Guangxi Region of China (including Yunnan province, Guizhou province and Guangxi Zhuang Autonomous Region) was estimated using the soil type method with the linkage of arithmetic mean method, median method, and area weighted mean method (based on the area recorded in the Soil Series) based on different map units and the results were compared with that of the linkage of PKB method (Pedological Professional Knowledge Based Method). The results show that the linkage of area weighted mean method is better than arithmetic mean method and median method. The differences of the estimates with area weighted mean method based on different map unites are the smallest. The PKB method can do better when the detailed soil maps with large map scales are utilized, or else the area weighted mean method should be adopted