Distribution and development of sclerotium grains as influenced by aluminum status in volcanic ash soils |
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| Authors: | Makiko Watanabe Takashi Kado Hiroyuki Ohta Nobuhide Fujitake |
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| Institution: | 1. Tokyo Institute of Technology , Interdisciplinary Gradate School of Science and Engineering , Yokohama, 226-8502, Japan;2. School of Agriculture , Ibaraki University , Ami-cho, Inashiki-gun, Ibaraki, 300-0393, Japan;3. Faculty of Agriculture , Kobe University , Kobe, 657-8501, Japan |
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| Abstract: | Granulometric and clay mineralogical analyses were performed on soil types differing in their genesis which had been formed on the raised coral limestone terraces and plateaux under the perhumid subtropical maritime climate of the Ryukyu Islands. The amount of clay fraction in Rendzina-like soil on the lower terrace was relatively small (8-34%) and decreased with depth, while those in Terra fusca-like soils on the middle terraces and in Terra rossa-like soil on the plateau were very large (45–78%) suggesting the occurrence of clay migration. Rendzina-like soil mainly contained illite and metahalloysite with a moderate amount of mixed layered mineral consisting of illite and vermiculite, and a small amount of vermiculite, Al-vermiculite, goethite, and quartz. Clay mineral composition of Terra fusca-like and Mottled Terra fusca-like soils was similar to that of Rendzina-like soil except that the content of illite was lower in these soils. Terra rossa-like soil, on the other hand, mainly contained Al-vermiculite, metahalloysite, and gibbsite, indicating a highly advanced stage of hydroxyaluminium interlayering. Differences in clay mineral composition from that of Rendzina, Terra fusca, and Terra rossa soils in the European countries were recognized, in that mont-morillonite was absent and hydroxyaluminium interlayering actively proceeded in the soils studied here. This finding is considered to reflect the rapid alteration and intense hydroxyaluminium interlayering of clay minerals under the perhumid subtropical conditions. |
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| Keywords: | aluminum Andosols distribution density sclerotium grains |
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