|Budget Amount *help
¥3,300,000 (Direct Cost : ¥3,300,000)
Fiscal Year 2004 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 2003 : ¥2,700,000 (Direct Cost : ¥2,700,000)
Yakushima (shima=island) belongs to the semitropical climate zone, but we can see the cool temperate climatic zone and vegetation at the top of Miyanoura-dake (dake=peak,1935 m).
There are many studies about the nature of Yakushima (Hayashi, 1952 ; Tagawa and Hotta, 1996. Kimura et al.,1996), and there are several studies about soils (Yagi et al., 1979 ; Yambe,1979).
In Yakushima, however, pedogenesis was not studied well. Therefore, in order to investigate soil formation and distribution, we have surveyed soil morphology. In this report, we report morphological characteristics of soils.
Soil profiles are described according to the Handbook of Soil Survey (Japanese Society of Pedology,1997), and the soil classification follows those by the Unified Classification (1986), and the Forest Soil Division (1976).
The Nakama had the B horizon, with reddish brown color indicating accumulation of clay. Therefore, the Unified Classification, as Red soil by the Forest Soil Division, classified Nakama as Typic Red-Yellow soil. The Anbo-gawa and the Yakusugi Land were classified as Typic Yellow-Brown soil by the Unified Classification, or as Yellowish Brown Forest soil by the Forest Soil Division, because of color of the B horizon. The Hanayama-hodo and the Yodogo-koya were classified as Acid Brown Forest soil by the Unified Classification, or as Brown Forest soil by the Forest Soil Division because of color of the B horizon. Since the Miyanoura-dake had the characteristic of a profile under the grassland, with thick A horizon showing brownish brown to dark brown, it was classified as Humic Brown Forest soil by the Unified Classification, or Black soil by the Forest Soil Division. These results suggest that soils indicate the vertical zonality, that is, Red/Yellow Brown soil Brown Forest soil Black soil, in Yakushima.