Clay minerals in some upland soils from Thailand

Abstract

Abstract The clay mineral composition of upland soils sampled from 15 sites belonging to various great soil groups in Thailand was studied. Mica clay mineral was the dominant mineral in addition to kaolinite in Alluvial Soil formed on the river levee of Kanchanaburi, Noncalcic Brown Soil of U-Thong Agric. Exp. Stn., Suphanburi and Red Brown Earth of Chatturat, Chaiyaphum. These soils had relatively high total potassium contents. Smectite was positively demonstrated in Grumusol of Phattanikom, Lopburi and Rendzina of Chai Badan, Lopburi, in both cases being derived from calcareous bed rocks. The materials were characterized by very high CEC values. Kaolinite was the principal detectable mineral in the clay fraction of the following soils: Low Humic Gley Soil of Maejo Agric. Exp. Stn., Chiangmai; Gray Podzolic Soil of Huaypon Agric. Exp. Stn., Rayong; Red Yellow Podzolic Soils of Nan Agric. Exp. Stn., Nan, Kangadai, Prachuabkirikan and Dochanipee, Chiang Saen; Reddish Brown Lateritic Soil of the Corn and So...