福建省变性土特性的研究

STUDY ON CHARACTERISTICS OF VERTISOL IN FUJIAN PROVINCE

在福建沿海低丘、台地玄武岩风化物上发育一种暗色粘质土壤,历史上归属于砖红壤性红壤。本研究证明,它明显区别于砖红壤性红壤,主要表现于:风化-淋溶作用和脱硅富铝化作用较弱,通体暗色,层次分异不明显,粘粒含量高,粘土矿物以蒙脱石占优势,有明显膨胀收缩性,干季出现一定深度的开裂,阳离子交换量大,盐基饱和度和pH值较高。据此,这种土壤有必要从砖红壤性红壤中划分出来。按美国土壤系统分类,本土壤定名为细质、蒙脱石型、高热、典型艳色湿润变性土。可以认为,变性土在我国也应作为一个独立的分类单元。

The dark clay soil developed on the weathering products of the basalt, distributed over hilly land and terraces along Fujian coast has been distinguished into the lateritic red earths Now it is suggested by the authors that this soil is obviously different from the lateritic red earth. As compared with the lateritic red earth, this soil are weaker in leaching-weathering processes and desilicification allitic processes, darker in color of the whole solum, more indistinct in differentiation of the profile, higher in content of the clay within depth of 50 cm, with the clay minerals predominanted by montmorillonite, a larger CEC, the higher base saturation and pH value, more distinct shrinkage-swelling and more cracks in dry season. Moreover, there appear angular blocky structure and slickenside features on the ped faces. According the criteria of the keys to US Soil Taxonomy, this soil is named 'Fine, Montmorillonitic, Hyperthermic. Typic Chromudert'. it is suggested that vertisol should be regarded as an independent classification unit in China. The vertisol exist with the lateritic red earth in the form of catena, its location is lower than that of lateritic red earth. As a result, the bases and clay are often accumulated in vertisol due to their migration from the high lands around it, which offers favorite conditions for development of vertisol. So the development of the vettisol is influenced by topography.