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基于特征变量与支持向量机回归克里格(SVRK)法的湿地土壤有机质空间变异特征分析
陈思明1, 王 宁2, 秦艳芳1, 张红月1
1.闽江学院海洋学院;2.福建农林大学林学院
摘要:
选取有效变量与适宜方法有助于揭示河口湿地土壤有机质的空间分异特征,对维护湿地生态平衡和全球碳循环具有重要作用。以福州市闽江河口湿地为研究区,采用逐步回归分析(SLR)与主成分分析(PCA)法筛选显著的特征变量,运用支持向量机回归克里格(SVRK)法分析了湿地土壤有机质的空间异质性,并与神经网络克里格法(BPNNK)、回归克里格(RK)法进行了比较。结果表明:通过SLR和PCA分析发现,归一化植被指数(NDVI)、比值植被指数(RVI)、土壤水分指数(PDI)、汇流累积量(FA)及沉积物移动指数(STI)与土壤有机质含量关系密切,其判定系数R2为0.446,显著性概率值P<0.000 1,可转换为3个独立的特征变量用于模型的预测。研究区土壤有机质的空间变异主要受结构性因素影响,呈现出“北低南高”的空间格局,采用SVRK模型的预测精度更高,能较好地体现河口湿地土壤有机质的空间异质特征。该研究可为同类区域的土壤有机质空间特征研究提供方法支撑。
关键词:  河口湿地  土壤有机质  逐步回归分析法  支持向量机回归克里格法
DOI:10.13758/j.cnki.tr.2020.06.026
分类号:S156.8
基金项目:福建省科技计划项目(2020J01831)和福建省教育厅中青年教师教育科研项目(JT180407)资助。
Study on Spatial Variability of SOM in Estuary Wetland, Southeast China Based on Characteristic Variables and SVRK
CHEN Siming1, WANG Ning2, QIN Yanfang1, ZHANG Hongyue1
1.Ocean College, Minjiang University;2.College of Forestry, Fujian Agriculture and Forestry University
Abstract:
Choosing suitable auxiliary and effective method is the prerequisite to accurately predict the spatial distribution of soil organic matter (SOM) in estuarine wetland. In order to achieve this purpose, a case study was conducted in the Minjiang Estuary Wetland of Fuzhou, southeast China. A total of 23 environmental factors were extracted by ArcGIS geostatistical analyst and remote sensing image analysis technique. Then, stepwise regression model and principal component analysis were used to screen the characteristic variables. At last a hybrid model of the support vector regression Kriging (SVRK) was proposed to analyze the spatial variability of SOM, and compared with BP neural network Kriging (BPNNK) and regression Kriging (RK). The results showed that normalized vegetation index (NDVI), ratio vegetation index (RVI), perpendicular drought index (PDI), flow accumulation (FA) and sediment movement index (SMI) were significantly correlated with SOM, which had the higher coefficient of determination (R2 = 0.446) and the significant probability value (P<0.000 1). Three principal components, explained at least 94% of the total variance, were extracted from these environmental factors by principal component analysis and used as characteristic variables. The spatial variability of SOM was affected by structural factors, showing a trend of "lower in the north and higher in the south". Compared with RK and BPNNK, SVRK had the highest prediction accuracy, and more accurately reflected the spatial variability of SOM, can provide a methodological support for the study of spatial variability of SOM in the same or similar region.
Key words:  Estuary wetland  Soil organic matter  Stepwise regression  Support bector regressior kriging

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