崇明三岛土壤有机质和全氮的空间分布特征及影响因素分析

Characteristics of spatial distribution of soil organic matter and total nitrogen as well as the influencing factors in three islands in chongming

采集了崇明三岛土壤表层（0—20cm）土样135个，测试了其中有机质、全氮的含量，在ArcGIS 9．1平台上运用地统计学、叠置分析等方法，研究了土壤有机质和全氮的空间分布特征及其影响因素．结果表明，崇明三岛土壤全氮和有机质含量总体水平偏低，全氮平均值为（0．93±0．47）g·kg^-1，有机质平均值为（18．97±9．27）g·kg^-1，全氮和有机质变异系数分别为0．5096，0．4886，均属中等变异程度．土壤全氯分布的理论模型为球状模型，有机质分布模型为高斯模型，其块金值和基台值之比分别为0．625和0．653，都为中等程度空间相关．崇明土壤全氮和有机质含量总体上呈条带状或斑块状分布，城镇地区呈现以城桥镇和堡镇为2个高值中心向周围逐渐递减的趋势，西沙、东滩和北湖地区含量最低．土壤全氮和有机质含量的空间分布与崇明垦殖和培肥历史表现出较密切的相关性，且表现出一定的城镇效应．

According to the data of soil organic matter（SOM） and total nitrogen（TN） contents in the samples collected from 135 points in topsoil in 2007, the characteristics of spatial distribution and the influencing factors of SOM and TN in three islands in Chongming were analyzed using the software ArcGIS 9. 1 with geostatistics and overlay analysis. The results showed that the contents of SOM （18.97% ±9.27）g ·kg^-1 and TN （0.93 ＋0.47）g ·kg^-1 were relatively low in general. The coefficient of variation （CV） of SOM and TN was 0.509 6 and 0.488 6, respectively. The semivariogram of total soil nitrogen was simulated by the spherical model, and the semivariogram of organic matter, Gaussian. The ratio of nugget to sill of total nitrogen and organic matter was 0. 625 and 0. 653, respectively, indicating that the spatial autocorrelation of SOM and TN was moderately interdependent, respectively. From the areas with higher SOM and TN contents distributing in Chenqiao and Bao town to the vicinity, the values of SOM and TN decreased gradually. Xisha, Dongtan and Beihu were low-value areas. The spatial distributions of SOM and TN were related to the history of reclamation and fertilization, as well as the effect of urbanization.