Author : Buree Boonsompoppunth

Summary : Four soil profiles in each toposequence of Amphoe Muang and Amphoe Dan Khun Thot, Nakhon Ratchasima province, were studied to determine their physical, chemical and mineralogical characteristics and to gain understanding of the nature of their genesis in relation to the topography. the mineral contents of the silt fraction were determined by x-ray diffraction technique. The clay was characterized by x-ray diffraction and differential thermal analysis (DTA). The mineralogy of the light and heavy minerals in fine sand and very fine sand fractions was determined by grain count using petrographic microscope. The micromorphology study was performed on thin sections from selected horizons in each profile. In Amphoe Muang Toposequence Profile SR-4 which occurred in the low terrace contained more clay than the other three profiles that occurred on the higher terrace or elevation. Likewise, in Amphoe Dan Khun Thot Toposequence, Profile SR-8 which occurred in the same physiographic position as Profile SR-4 contained more available water than the rest of the profiles.