澎湖紅棕壤之化育的研究

Abstract

1. 本研究選取花嶼系代表剖面──花嶼粘土從新分為五層，進行粘土礦物成分及數項理化性質之補充分析，以為該系土壤化育之研究。 2. 粘粒部份（<2μ）分析結果，用以鑑別及定量粘土礦物者計有：X-Ray照片分析，示熱差分析，熱重量分析，陽離子交換能量，游離鐵及氧化鉀之含量等。 3. 分析結果發見花嶼系粘土全土體各層之主要粘土礦物成分為Kaolinite 約60%，次要成分為Muscovite19－25%，Fe2O3為9－11.4％，其第一、二層並含有約3％左右之Gibbsite。 4. 花嶼粘土之剖面形態及礦物成分與夏威夷之低腐殖紅壤有別，由該粘土所含之Kaolinite在60%左右，表層且有Gibbsite之存在，其紅壤化非屬初期，如與臺灣其他紅棕壤相比，則紅壤化作用尤有過之。 5. 應用 Barshad氏研究土壤化育區分土層方法，根據物理性之補充分析結果及礦物成分，至易將該花嶼粘土剖面分別其第一、二層為積聚層，第三、四層為分解層，第五層為母質層，並可排列其全剖面層次順序為 B2，B1，A12，A11及C層，證之Harrassowitz氏研究標準磚紅土之分層理論至為符合，故花嶼粘土應屬於化育相當良好之紅棕壤。 1. This is a clay mineral study of Hwayu clay (representative soil series) by sampling 5 lazers of the original undisturbed soil monolith, and to analysis several supplemental items of their physical and chemical properties in order to study its soil development. 2. Data from X-Ray photographies, differential thermal analysis, thermal gravimetric analysis, cation exchange capacity, free iron oxide and potash were used to characterize quantitatively the minerals in the clay fractions (<2μ) of Hwayu clay profile. 3. Kaolinite was identified in substantial amounts about 60% of all lazers, other minerals include muscovite 19-25%, Fe2O3 9-11.5% and about 3% of gibbsite in the first or second lazer of the profile. 4. The Hwayu clay is different from the soils of Low Humic Latosols is Hawaii base on the analytical results of their morphology and clay minerals. The soils of Hwayu clay is not in the young stage of Laterization according to the content of Kaolinite and Gibbsite and is stronger than that of the other Reddish Brown Lateritic Soils in Taiwan, if we cOmpare their Laterization. 5. It is easily to stratified the first and second lazers as accumulated horizon, the third and forth lazers as decomposed horizon, and the fifth lazer as C horizon by using Barshad’s soil development study method base on the results of the supplemontal physical analysis and conform with clay mineral analysis. So it may be arrange the five lazers in order as B2, B1, A12, A11 and C also. It conforms Harrassowitze’s theory which distinguishes the strata of typical Laterite. Therefore, the Hwayu clay should be classified as a rather good developed Reddish Brown Lateritic Soils.