博尔塔拉河流域土壤有机碳的空间结构分析

Spatial Structure Analysis of Soil Organic Carbon in Bortala River Basin

利用描述性统计分析和地统计分析,对博尔塔拉河流域0—20cm深度土壤有机碳的空间分布特征进行了研究。结果表明:博尔塔拉河流域土壤有机碳符合正态分布;半方差函数分析表明,博河上部和下部有机碳较好地符合高斯模型分布,中部有机碳符合线型模型分布。块金值与基台值的比值表明博河上部土壤有机碳含量的空间相关性很弱,说明随机性因素(如施肥、耕作措施、种植制度等各种人为活动)引起的空间变异起主要作用;中部和下部土壤有机碳含量表现为中等空间相关性,表明结构性(如气候、母质、地形、土壤类型、自然因素等)因素和随机因素共同起作用。Kriging插值表明:(1)博尔塔拉河流域土壤有机碳的空间分布特征主要以斑块状为主,基本与耕地分布相吻合;(2)全流域最大值出现在下游,可能与耕作模式以及河流从上游携带大量营养物质,通过灌溉在下游土壤沉淀累积有关;(3)博乐市周边土壤有机碳含量最低,这可能主要与博乐市周围为城市和工业用地有关。

Using statistical analysis and geostatistical analysis,spatial distribution of soil organic carbon in depth of 0—20cm in the Bortala River Basin was investigated.The results showed that the semivariance analysis indicated that soil organic carbon change process had obvious size difference.Organic carbon distribution in the upper and lower reaches of Boratala River Basin can be well described by Gaussian model,and the organic carbon distribtution in the middle reaches can be fitted by the linear model.The ratio of nugget value and base value indicates that the spatial correlation of soil organic carbon content in the Bo River upper is very weak,the random factors（such as fertilization,tillage,cropping systems and other human activities cause spatial variability）play the major role;soil organic carbon contents in the middle and lower reaches exhibited moderate spatial correlation,indicating that structural factors（such as climate,parent material,topography,soil type,natural factors）and random factors play the roles.The Kriging interpolation showed that：（1）the spatial distribution characteristics of soil organic carbon present as the plaque in Bortala River Valley,which is consistent with the distribution of cultivated land;（2）the maximum value of the whole basin appeared in the downstream because of the cultivation mode and large amounts of nutrients moved from the upstream of river,soil deposition in the lower reaches due to irrigation;（3）soil organic carbon content around Bole City is the minimum,which may be related to the city and industry land around Bole.