摘要：国内外文献中有关土壤黏化作用可分为淀积黏化、残积黏化和次生黏化等3种，但淋溶土鉴定的诊断层——黏化层的形成只涉及淀积黏化作用和次生黏化作用2种。中国南方山地丘陵地区土壤脱硅富铁铝化明显、土壤铝饱和度高、黏粒矿物中有较多的1：1型矿物，多数情况下难以发生淀积黏化作用。而次生黏化作用一般发生在温带地区，其气候条件主要为半干润。因此，除一些石灰性母质发育的土壤外，南方山地丘陵地区一般不具备淋溶土形成的成土环境。而该区某些土壤上下层质地的差异常常是漫长历史时期表蚀的结果，把这类上下质地差异的土壤划归为淋溶土不符合土壤发生分类原则。建议在《中国土壤系统分类检索》的黏化层定义中参照美国土壤分类系统中黏化层的定义，把盐基饱和（即盐基饱和度大于50%）作为鉴定黏化层的一个指标，避免在土壤调查中夸大南方山地丘陵地区淋溶土的出现范围，以解决南方山地淋溶土与雏形土鉴定上的不确定性问题。

关键词：淋溶土;黏化作用;黏化层;南方丘陵山地土壤

中图分类号：S151;S155文献标志码：A论文编号：cjas20191100257

Soil Clayization and Argic Horizon Identification in Mountain and Hilly Areas of Southern China

ZHANG Mingkui

（College of Environmental and Resource Sciences，Zhejiang University，Hangzhou 310058，Zhejiang，China）

Abstract：Soil clayization discussed in the domestic and foreign literatures can be divided into three types：argillification，residual clayization and secondary clayification，but the formation of argic horizon，as a diagnostic horizon identified by luvisols，only involves argillification and secondary clayization. In mountainous and hilly areas of southern China，because of obvious soil desilication and aluminization，high soil Al³⁺saturation，and high proportion of 1：1 type in clay minerals，it is difficult to have argillification in most cases. Secondary clayization generally occurs in the temperate regions with climatic conditions of semi-dry. Therefore，except for some soils derived from calcareous parent materials，there is no soil-forming environment of luvisols in mountainous and hilly areas of southern China. However，the difference of soil texture between surface and lower horizons in those areas is often the result of surface erosion in a long historical period. It is inconsistent with the principle of soil genesis and classification to classify those soils as luvisols. In order to avoid exaggerating distribution of luvisols in hilly and mountainous soils in southern China，and solve the uncertainties in the identification of both luvisols and cambosols，it is suggested that the definition of argic horizon in Keys to Chinese Soil Toxonomy should refer to the definition of argic horizon in USA Soil Taxonomy for taking base saturation （i.e. base saturation greater than 50%）as an index to identify argic horizon.

Keywords：Luvisols;Clayization;Argic Horizon;Hilly and Mountainous Soils in Southern China

0引言

淋溶土是地球表面分布最為广泛的土壤类型，许多土壤分类系统中都设有淋溶土纲，如美国土壤系统分类中的淋溶土纲（Alfisols）[1]，FAO分类系统中的高活性淋溶土（Luvisols）、低活性淋溶土（Lixisols）、灰化淋溶士（Podzoluvisols）、黏磐土（Planosols）[2]。不同分类制中淋溶土的定义或鉴定标准不尽相同，但多数土壤分类制中都以黏化层作为淋溶土的主要鉴定依据[1-3]。……