| Popis: |
Urban parks are one of the large infrastructures that enhance quality of life in a metropolis. It is therefore important to maintain a record of soil history, including the development and alteration of land in urban areas. Three historical urban parks were surveyed to obtain information of the land use history. The Institute for Nature Study, designated as a national monument and historical landmark in 1949, is a particularly important site for the study of pedogenesis in urban green spaces. As compared to a reference site, “the Meiji Shrine”, past construction activities, production of artifacts, and land cutting and banking resulted in a disruption of natural soil horizons. Horizon sequences were relatively similar among sites on earthworks but not on terrace surfaces, reflecting the high frequency of change in land use on these areas. Accumulation of total organic carbon decreased with increasing soil depth probably due to forest regeneration. Non-crystalline components increased with increasing soil depth mainly as a result of leaching of non-crystalline components by complexation with soil organic matter under forest vegetation. δ13C values of soil increased with increasing soil depth reflecting vegetation succession. The δ13C values of soil were significantly negatively correlated with a color index of extracted organic matter, indicating that C4 plants have contributed to accumulated carbon, mainly after episodes of fire. Shinjuku-Gyoen site has experienced changes in its land use history during the past four centuries. There were several drastic differences in general soil properties with depth. These soil characteristics reveal signatures of anthropogenic impact such as banking and cutting in the soil profiles. Short and frequent complex anthropogenic alterations were observed in the historical park. High variability of soil properties in the Shinjuku Gyoen site indicates high frequency of land use changes within its history. In the Kitanomaru Garden connected to the East Gardens of the Imperial Palace, three large-scale constructions were performed from the Edo era (1603–1868) to the present. Soils in Kitanomaru Garden are classified as Urbic Technosols, and feature artifacts such as bricks, tiles, concrete, or potteries originating from buildings from the past 400 years. Soils in Kitanomaru Park had a higher soil pH, lower total carbon content and relatively high cation exchange capacity (CEC) compared with natural volcanic ash soils. Moreover, the vertical distribution of soil compactness was characterized by disorders of the compaction layers or having a consolidated layer within 1 m deep. The spatial distribution of the soils having non-intrusive and densely-compacted layers correspondences with the restoration position of a building and land-grading works. |
