TANAKA Ueru Kyoto Univ.Fac.Agri., Instructor, 農学部, 助手 (10231408)
HIRAI Hideaki Utsunomiya Univ.Fac.Agri., Associate Professor, 農学部, 助教授 (20208804)
OKAGAWA Nagao Kyoto Univ.Foreign Student Center, Professor, 留学生センター, 教授 (00093211)
ARAKI Shigeru Kyoto Univ, Center for African studies, Associate Professor, アフリカ地域研究センター, 助教授 (00158734)
KYUMA Kazutake Kyoto Univ.Fac.Agri., Professor, 農学部, 教授 (80027581)
Soil samples were collected from arable land in Asia (Thailand, Malaysia, India, Cambodia, Sri Lanka, Bangladesh, Philippines, Indonesia, Vietnam, Burma and East Malaysia), South America (Parguay, Brazil and Columbia) and Africa (Nigeria, Ivory Coast, Sierra Leone, Liberia, Zaire and Rwanda) and analyzed for mineralogical and physico-chemical characterization.
Multivariate statistical analysis (principal component analysis) was applied to the above mentioned soils data and three factors controlling soil fertility, i.e.inherent potentiality, organic matter status and available phosphorus status were extracted, each of these enabling quantitative soil evaluation. The same procedure was applied to those samples and two factors, i.e.Iithology and weathering status, were identified and proved to be useful for characterizing the nature of soil materials. All such factors were closely related to the type of predominating clay minerals of each soil.