山东暗色粘性土的特性及发生学研究

本文对山东省主要暗色粘性土进行了形态学、粘土矿物学、物理化学特性以及发生学的研究。结果表明,大部分粘质砂姜黑土和暗色粘质湿潮土具有明显的变性特征,表现为干时开裂、湿时膨胀,剖面上部土体中有大量的滑擦面和明显的土壤翻转现象。土壤微形态以具有因强烈胀缩而产生的光性定向粘粒和裂纹裂隙为主要特征,并有较多铁锰和碳酸盐的浓聚物。土壤粘粒的硅铁铝率较高,粘土矿物以蒙脱石为主,蒙脱石的发生与其所处的地球化学环境密切相关。耕层之下的黑土层粘粒含量最高,且以蒙脱石占绝对优势,因此胀缩性最强,是具有变性特征最明显的层次。土壤的强烈胀缩性是这些暗色粘性土形态发生的内在原因,干湿交替的土壤水分状况则是其形态发生的必要条件。

CHARACTERISTICS AND GENESIS OF DARK CLAY SOILS IN SHANDONG

The morphogenetic,clay mineralogical,physico-chemical properties of main dark clay soils in Shandong were studied.The majority of clay shajiang black soils and dark clay chao soils have denaturation features with cracking upon drying and swelling when rewetted. The micromorphology of these soils is characterized by optically oriented clay grains and cracks resulted from frequently shrinking and swelling,and there are many concentrates of iron-manganese and carbonate in the soil.Silica-sesquioxide ratio is relatively high in clay particles,in which smectitic clay is major.The dark-colored horizon has the strongest shrink-swell potential and the most obvious denaturation features because it contains the most clay particles dominated by smectitic clays.The swell-shrink characteristic of soil is the internal cause and soil water regime of alternative drying-rewetting is the essential con- dition for morphogenesis.