Recognition of characteristics and pedogenic units of urban park soils in western Tokyo, Japan
2006
Takeda, M.(Tokyo Inst. of Technology, Yokohama (Japan)) | Watanabe, M. | Tachibana, N.
Natural soils in urban areas have been disturbed and transformed to artificial soil as a result of surface filling or mixing of construction waste and garbage. Urban soils with lithological discontinuities are generally classified into Man-made soils, under which two subgroups, Landfill soils and Reformed soils, are placed according to grading method. This study aims to discuss the methodology for classifying urban soils developed under park use. The land creating history, use, management and soil physical-chemical properties were investigated for seven urban parks in western Tokyo. A total of 196 samples collected from the surface layer (0-5cm) and the second layer (5-15cm) at 98 sampling sites were applied for soil analyses by taking into consideration of the properties of Andosols (Kuroboku soils), the widely distributed soil in the western Tokyo region. Soil profile, soil compactness, water content, pH (H20) and pH (NaF), total carbon content, C/N ratio, and Melanic Index were examined to obtain soil characteristics. The physical-chemical feature of the second layer was regulated by the stress of miscellaneous urban fill depending on specific land creating history of each park. While that of the surface layer was regulated by the use and management of the parks. A diagnostic surface layer was extracted for each use division in the park; preservation forest, grassland, bare land, and wood chip sections. The results suggested a two-dimension coordination system composed of grading method and use, which may help subdividing urban park soils into soil units. Modification of the criteria on soil properties is required to construct a useful system for regional urban planning.
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