Kan kamnoet khong din chakkan phuphang yukapthi khong hin granite nai phaknua khong prathet Thai.
1985
Sarakam Kawtasi
An investigation into genesis of soils from weathering of granite was conducted in Northern Thailand. The emphasis was given on field morphology, physical and chemical properties, mineralogical characteristics and micromorphology of the weathering profiles. Result revealed that important genetic processes of these soils were directly related to the weathering of mineral components of granite. Rocks and minerals successively lose their structure and release their compositional elements into soil solution. Subsequently, the remaining materials combine and form new minerals in soils. Feldspar transforms to smectite, kaolinite and gibbsite whereas biotite changes to smectite, illite, kaolinite and oxides of iron. Quartz undergoes physico-chemical change to attain smaller grain sizes successively. Important pedological processes include eluviation and illuviation of clay. Other soil processes comprise littering and decomposition of organic materials on surface soil making the soil layer high to very high organic matter content. The soil developed were deep to very deep, well-drained and moderately permeable. Their available phosphorus, total exchangeable bases and base saturation percentages were low. Their cation exchange capacities were moderately low to medium except in the surface soils where the high cation exchange capacity values were related directly with the high values of organic matter content. All soils had high available potassium. Quartz was the dominant mineral species in the soil silt fraction. Feldspars, micas and kaolinite, however, could also be found but in medium to small amounts.
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