广西涠洲岛沉凝灰岩土壤微形态研究

Micromorphological Study on Soils Derived from Sedimentary Tuff on Weizhou Island of Guangxi

关键词:  沉凝灰岩土壤  微形态  土壤分类  涠洲岛

Key words:  soil derived from sedimentary tuff  micromorphology  soil classification  Weizhou Island

摘要:

用常规方法分析广西涠洲岛1号剖面(离火山口水平距离约200m)和2号剖面(离火山口水平距离约1600m)沉凝灰岩母质发育的土壤的理化性状,用不饱和聚醛树脂-丙酮混合液浸渍固化原状土样,切片后在偏光显微镜下观察土壤微形态特征。结果表明,两个剖面土壤的微形态特征明显不同,而且与同地带的砖红壤的微形态特征也有很大差异。据此及土壤的其他性状,我们认为将涠洲岛陆岛上的土壤全部划归为砖红壤是不合适的,建议将1号剖面的土壤归类于初育土纲、石质初育土亚纲中的薄层土类,将2号剖面的土壤归类于铁硅铝土纲、湿润铁硅铝土亚纲中的棕红壤土类。

Abstract:

The routine analysis methods were used to analyse the physical and chemical properties of the soils of profile 1 (about 200 m away from the volcanic mouth) and profile 2 (about 1600 m away from the vocanic mouth) derived from sedimentary tuff on Weizhou Island in Guangxi. The micromorphology of the soils was observed under polarizing microscope after having soaked and solidified in the mixed solution of unsaturated aldehyde resin and acetone and then sliced. The results show that the micromorphology of soils of the two profiles is obviously different and very different from the micro-morphology of laterite in the same zone. Based on the micromorphology and other properties of the soils, we think that it is unsuitable to classify all the terrestrial soils of Weizhou Island into laterite group. We proposed to classify the soil of profile 1 into the group of Leptisols which belongs to the suborder of Lithic primarosols under the order of Primarosols and to classify the soil of profile 2 into the group of Brown-red soils which belongs to the suborder of Udic Fersiallisols under he order of Fersiallisols.