商丹盆地黄土母质发育土壤的微形态特征及其诊断意义  

MICROMORPHOLOGICAL FEATURES OF SOILS DERIVED FROM LOESS IN SHANGDAN BASIN AND THEIR SIGNIFICANCE IN SOIL DIAGNOSIS

作　　者：庞奖励[1] 黄春长[1] 查小春[1] 周亚利[1] 高鹏坤 王蕾彬 

机构地区：[1]陕西师范大学旅游与环境学院,西安710062

出　　处：《土壤学报》2015年第2期272-280,共9页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(41271108;41030637;41371029);国家社科基金项目(14BZS070);中央高校基本科研费(GK201301003)资助

摘　　要：阐明商丹盆地黄土母质发育土壤的微形态特征及其诊断意义。以茶房村土壤剖面为研究对象，在Lical 偏光显微镜下对土壤形成物、粗颗粒、孔隙等微形态单元的类型、空间分布及变化进行了研究。结果表明，与上部淋溶层和下部母质层相比，Bt 层（110~230 cm）黏土大量聚集且淀积黏土含量/残积黏土含量的比值（Ki/r）很高、但黏土胶膜不发育，粗颗粒数量减少、粒径降低孔隙个体增大，边沿更加平滑；矿物成分趋于单一。这些微形态特征证实了 Bt 属于典型的“黏化层”，结合成土因素检索，此土壤可归为简育湿润淋溶土。Investigations were done of micromorphological features of the soils derived from loess, with a view to revealing diagnostic significance of these features and providing reliable micromorphological basis so as to define positions of these soils in the Chinese Soil Taxonomy. A soil profile at Chafangcun, Shaanxi Province, China was selected as object of the study. Soil samples were collected from the profile for analysis of relevant soil physical and chemical properties （ inclu- ding chroma, magnetic susceptibility, particle-size composition, total iron and free iron content, etc. ） in laboratory. The soil was prepared into thin slices, which were put under a Leica-DMRX petrographic microscope for observation of soil micromorphology and the images were processes with the Nis-Elments BR 3.2 image analysis software for extraction of micromorphologic unit images and quantitative measurement of relevant parameters. Results show that the Chafangcun soil profile has an A-AB-Bt-BC-C profile structure, with a large volume of secondary illuvial clay accumulated in Bt Horizon （110 -230 cm in depth ） , reaching to 15 %- 30% in content and making the illuvial clay/residual clay ratio （Ki/r） var- ying between 4 and 9. The illuvial clay minerals exist mainly in the form of irregular lumps, and then in the form of clay cutan, mostly 〈 0. 15mm in thickness. Compared with Bt Horizon, the upper eluvial horizon is apparently lower in sec- ondary clay mineral （ 〈 5% ） , dominated with residual clay mostly in the form of concentrate; and the lower parent mate- rial layer is much lower in secondary clay （ generally 〉 3% ） , mostly in the form of very thin clay cutan, sparsely present on edges of the pores. In the upper eluvial horizon coarse particles （ 〉 10 μm） are generally in the form of subangularsubround lumps, 30.0 μm in average particle size, moderate in content （ 10.4% ） , and unevenly distributed in the hori- zon,. In the parent material layer, coarse particles are in the form of apparent

关 键 词：微形态 黏化层 简育湿润淋溶土 商丹盆地 黄土母质 

分 类 号：P904[天文地球—自然地理学]