丘陵山区土壤阳离子交换量(CEC)的空间分布预测

Spatial Predication of Soil Cation Exchange Capacity (CEC) in Hilly Region

运用GIS的空间分析技术和DEM,在区域范围内可以表征基于地形因子的土壤–景观模型.本研究根据江西省兴国县151个样点数据,分析CEC和地形因子的相关关系,建立回归模型,进行预测.结果表明,表层土壤中CEC含量平均值为8.7cmol/kg.空间分布上,CEC含量在5～8cmol/kg、8～12cmol/kg和12～15cmol/kg的面积分别为1270km2、1500km2和281km2.CEC含量大于12cmol/kg,主要分布在千枚岩和红砂岩发育的土壤中,分布面积分别为242km2和56km2.地形变量中坡向对CEC含量影响最大,CEC含量和有机质、粘粒、海拔、母岩、坡向存在着正相关关系,坡度和CEC含量的相关关系不明显.利用回归分析模型和DEM(30m×30m),预测CEC的空间分布,R2为0.575.

Based on topographic factors, soil-landscape model could be shown using GIS spatial analysis technique and digital elevation model （DEM） in large areas. With the data obtained from 151 sampling sites in Xingguo County, Jiangxi Province, spatial distribution characteristics of cation exchange capacity （CEC） were studied, the correlation between the CEC and topographic factors was analyzed, and regression model was established through linear regression analysis. The result showed that the mean content of CEC was 8.7 cmol/kg in topsoil, and the CEC contents of5-8 cmol/kg, 8-12 cmol/kg and 12-15 cmol/ kg covered an area of 1 270 km^2, 1 500 km^2 and 281 km^2, respectively. The CEC content over 12 cmol/kg was found mainly in the soils derived from phyllite and red sandstone from spatial distribution. Among topographic variables, aspect had an important influence on CEC content. In addition, the CEC content had positively significant correlations with organic matter, clay, parent rocks, elevation and aspect （P〈0.01）. However, there was no significant correlation of the CEC content with slope. The spatial distribution of CEC content could be forecasted by using linear regression model and DEM （30 m×30 m）. R^2 was 0.575. Fig 3, Tab 1, Ref 15