摘要
为克服传统地形分类方法中仅依据单一指标(如高程)的缺点,以钟祥市土壤有机质空间分布为例,综合由30 m精度数字高程模型生成的地形因子,依据其在不同地形条件下的层次组合规律构建地形分类规则,精确地划分为13种典型地形单元,并运用普通克里金法对不同地形单元内的土壤样本插值,获得相应区域的土壤有机质空间分布。通过组合各地形范围下的结果,以获取蕴含地形因素影响的有机质空间分布。研究发现,地形起伏较大的地形单元的预测精度与全局预测结果精度相似度达0.75,而地势平缓区域内的预测精度大幅度提升,比全局预测结果精度提升了16.39%,因此基于地形单元的空间预测可以精确有效地获取土壤有机质空间特征。利用地形分区获取较高精度的有机质空间分布,进一步探讨了有机质地统计学研究中地形的协同影响。
The spatial distribution of soil organic matter （SOM） has intimate connection with topography, but the synergy effect of topography for SOM spatial redistribution was frequently ignored in the study of SOM by traditional geostatistics. In order to investigate the influence of different topography on the spatial distribution of SOM, the method of SOM spatial interpolation based on topographic unit was proposed. Firstly, the terrain factors such as slope, aspect, topographic wetness index and topographic position index were calculated from the digital elevation data （30 m × 30 m）. Secondly, the topographic units were precisely divided into 13 different classical types more subtly by integrating the terrain factors, which effectively avoided the traditional terrain classification method that only based on elevation data. The regions were divided, which was based on terrain classification rules formed by the distribution of terrain factors in different landforms. Thirdly, soil samples were collected in different topographic types, and the distribution of SOM for each sample set in different topographic units was generated by ordinary Kriging. Then, the corresponding results of interpolation for each sample set were segmented based on topographic unit region, and combining the result in each region, the spatial distribution of SOM based on topographic unit was obtained. Finally, verification and comparison with the accuracy of each SOM distributions were performed, which were obtained by using topography based geostatistics and traditional global geostatistics, respectively. The results of experiment for researching the SOM distribution in Zhongxiang City showed that higher accurate and efficacious spatial layout of SOM can be acquired by geostatistics based on topographic units, especially in the gently topography region, the precision was increased by 16.39%. The SOM prediction accuracy in the rest of the terrain unit was similar to the global prediction accuracy with Pearson correlation coefficient of 0.75. Using geomorphic zoning to obtainhigher accuracy for spatial distribution of SOM, and the influence of＂ topography was considered in the study of SOM geostatistics.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2015年第4期161-167,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金资助项目(41171174)
国家高技术研究发展计划(863计划)资助项目(2013AA102401)
关键词
地形单元
土壤有机质
地统计
空间变异
Topographic unit Soil organic matter Geostatisties Spatial variability
