砂姜黑土形态特征的观察

对我国不同地区不同类型的原砂姜黑土进行了野外剖面和室内微形态观察。结果表明,我国大部分原砂姜黑土具有明显变性特征,表现在旱季土体开裂,土体中具有大量滑擦面和楔形体,显微薄片上可看到大量纤维状光性定向粘粒。粘粒含量、粘粒矿物学组成和线胀系数等都符合变性土的特征。拟将具有变性特征的原砂姜黑土划归为变性土;而将那些不具变性特征的变异和过渡类型的原砂姜黑土仍列入砂姜黑土土类。

MORPHOLOCGICAL FEATURES OF SHAJIANG BLACK SOILS IN CHINA

The profile morphological character and micromorphological features of six shajiang black soils distributed in different regions over China were studied. The results indicated that most shajiang black soils have obvious vertic features, which are showed out in such aspects as abundant crackings at dry season, numerous slicken sides and wedge structural aggregates in solums and plenty of optically oriented clay of fibrous form observable from the thin sections of soil. Furthermore, clay content, mineralogy and COLE index also met the need of vertic characters. As a result, these shajiang black soils wee tutatively classified into vertisols. But some other shajiang black soils without (or without evident) vertic features were still classified into shajiang black soil.