2013 Volume 39 Issue 3 Pages 412-421
The purpose of this paper is to elucidate the correspondence of the physical characteristics of urban park soils with anthropogenic land use, such as history of previous building, reclamation methods and current park management. We measured the vertical soil hardness at 134 points in the Kitanomaru Garden (Chiyoda city, Tokyo) using a cone penetrometer and carried out spatial analysis using a GIS software. The non-intrusive layer, defined as penetration depth of less than 50 cm, was counted up to 34 (25.3%) among the entire 134 points. The dense-compacted layer reached 90 (67.1%) points out of 134. Formation of the non-intrusive layer was depended on degrees of human impacts. Appearing of the first dense-compacted layer appeared in 0-25 cm irrespective of forest and planting or not. The total thickness of the dense-compacted layer was higher in 25-50 cm. At the points of cutting and lawn area, the total thickness of the dense-compacted layer was particularly higher in more than 50 cm. In the study area, the dense-compacted layer was formed from 0-25 cm depth, and appeared 1-2 times in the soil profile. In addition, the total thickness of the dense-compacted layer occupied nearly half of soil profile. From our obtained results, the formation of non-intrusive layer and dense-compacted layer of soils revealed a strong correlation with land use history and land grading. The characteristics of urban soils are difficult to estimate from current landscapes, such as topography and vegetation. We suggest the measurement of vertical soil hardness as a useful method to evaluate the process of soil formation under intensive anthropogenic land use and land creation in urban area.
