2007 Volume 51 Issue 2 Pages 56-67
Because the content of insoluble residue is a little in limestone, it is a problem for many years what is the parent materials of dark red soils distributed on limestone. In this paper, it was investigated that properties and uniformity of parent materials in the dark red soils developed over Kinshousan, Ohgaki city, and Maesato, Ishigaki island. The outline of the results are summarized as follows: The indissoluble residue after the treatment with 1 mol L^<-1> acetic acid was 6 and 318g kg^<-1> in the limestones in the Kinshousan soil and the Maesato soil, respectively. It suggested that main materials of Kinsyousan soil is besides limestone. On the other side, it was estimated that limestone was an important parent material in the Maesato soil. The ESR-signal intensity associated with the oxygen vacancies in silt-sized quartz showed that fine quartz in both soils was derived from eolian dust. However, the limestone also affected the physical and chemical properties, and clay mineralogical composition. Moreover, the clay mineralogical composition showed a characteristic of pedogenesis under the climate in which each soil had formed. Furthermore, the influence of the Akahoya tephra was confirmed in the Kinshousan soil, too. Therefore, the Kinsyousan soil is a dark red soil that is derived from not only eolian dust but limestone and Akahoya tephra influenced of pedogenesis under the warm temperate climate. The Maesato soil is a dark red soil that is derived from limestone and eolian dust infuluenced of pedogenesis under the humid sub-tropical maritime climate.
