Research On Digital Soil Mapping Based On Taxonomic Distance

Conventional map of soil investigation which is based on the " double crisp model " is not an accurate expression of the soil's double continuity in properties and geographical space, however, with the rapid development of precision agriculture, the content and accuracy of the output information of soil map have been higher demand, meanwhile, a large number of supply about various observations data and information technology, which make the digital mapping become a hot research field of soil science quickly.In this thesis, K-means clustering method was tried to apply to continuous soil classification through regional case studies, then the gradual transition characteristics of soil types in the study area was analyzed and revealed, and the visual expression of the geographical space was achieved by the form of a continuous mapping. On the one hand, the intuitive judgments of "affinity distance" relationship of the local soil in the embryology was achieved; on the other hand, data support for the quantitative fit of quantitative covariates of soil environment was provided. The main results are summarized as follows:1) According to the soil characteristics of Fengqiu and physical analysis data of 40 collected soil profile, texture (silt, sand, clay content), organic matter, conductivity, pH, soil color and the depth of soil occurrence were selected as the classification index by use of K-means clustering analysis, then the classified distance between the five center soil profiles and the profile were calculated, the soil types were divided into five categories, and named according to Chinese soil taxonomic classification.2) The classification map of single soil was obtained by applying interpolation methods in statistics to interpolation prediction of regional soil for distance of profile category, and the continuous classification map of Fengqiu was achieved. Based on the theory that the smaller classified distance, the more similar property, the soil map of Fengqiu was obtained by analyzing five maps of a single type of the classified distance. 3) The conclusion was gained that soil map derived IDW interpolation prediction was more in line with principles of soil genesis by analyzing comparatively the soil map which was calculated by interpolation prediction methods of ordinary kriging and IDW,then its rationality was further validated by referring landforms map of Fengqiu.2) The classification map of single soil was obtained by applying interpolation methods in statistics to interpolation prediction of regional soil for distance of profile category, and the continuous classification map of Fengqiu was achieved. Based on the theory that the smaller classified distance, the more similar property, the soil map of Fengqiu was obtained by analyzing five maps of a single type of the classified distance.