福建红壤和砖红壤性红壤的发生和分类的探讨

本文研究了发育于福建中亚热带和南亚热带13个土壤剖面的理化性质、微形态性质和粘粒矿物性质,讨论了这些土壤的富铝化程度、红壤和砖红壤性红壤土类划分指标的选择及分类问题,结果表明,供试土壤均处于中度脱硅富铝化阶段,但在程度上有差别。以B层粘粒高岭石的平均含量为主要指标,平均硅铝率为辅助指标,将供试土壤分为两个土类:第一类是砖红壤性红壤,其B层粘粒高岭石平均含量大于70%,或介于60—70%之间,但硅铝率小于2.10;第二类为红壤,其B层粘粒高岭石平均含量小于60%,或介于60—70%之间,但硅铝率大于2.10,这里红壤和砖红壤性红壤的概念不完全等同于地带性土壤的概念。

STUDY ON THE GENESIS AND CLASSIFICATION OF RED EARTH AND LATERITIC RED EARTH IN FUJIAN PROVINCE

This paper deals with the physical, chemical, micromorphological, and mineralogical properties of thirteen profiles of soils developed in the southern subtropical region and the central subtropical region in Fujian. The dcgree of allitic weathering, selection of indices for dividing soil groups, and classification of these soils are discussed. These soils are all in the moderate allitic stage, but with more or less different degrees of development. As for the allitic soils which have not yet deeply weathered, kaolinization can reflect the soil development degree to a great extent. Thus, the average kaolinite contents of clays in B horizons have been chosen as the main index for dividing soil groups, and the average silica-alumina ratios of clays in these horizons as the accessory index. All the soils have been divided into two groups. The first is the group of lateritic red earths, of which the average kaolinite contents of clays in B horizons are more than 70%, or the average silica-alumina ratios of clays in B horizons are less than 2.10 when the kaolinite contents are between 60% and 70%. The second is the group of red earths, of which the average kaolinite contents of clays in B horizons are less than 60%, or the average silica-alumina ratios of clays in B horizons are more than 2.10 when the kaolinite contents are between 60% and 70%. The distribution of the two groups soils does nor entirely conform with the zonality.