湘东地区花岗岩红壤在中国土壤系统分类中的归属

为了研究湖南省东部花岗岩红壤在中国土壤系统分类中的归属,选取湘东地区8个由花岗岩母质发育的典型土壤剖面,在对其成土环境、剖面形态特征及其理化性质进行研究的基础上,按照中国土壤系统分类方案,检索出了其诊断层和诊断特性,据此确定了其在中国系统分类中的归属。结果表明,供试的8个土壤剖面包含了淡薄表层、暗瘠表层、低活性富铁层、黏化层等9个诊断层和诊断特性,其在中国系统分类体系中的位置分别为:淋溶土、富铁土和雏形土3个土纲;湿润淋溶土、湿润富铁土和湿润雏形土3个亚纲;简育湿润富铁土、铝质湿润淋溶土、酸性湿润淋溶土和铝质湿润雏形土4个土类;普通铝质湿润雏形土、普通简育湿润富铁土、普通铝质湿润淋溶土、普通酸性湿润淋溶土4个亚类;按照土族和土系划分标准,建立了黏壤质硅质混合型酸性热性-普通铝质湿润雏形土等6个土族和脱甲系(43-CS18)等8个土系。实践表明,目前的土族土系划分标准适用于供试土壤基层分类单元划分。与土壤发生学分类结果相比,土壤系统分类结果更能定量反映出湘东花岗岩母质发育土壤性状的差异,进而客观反映出土壤发育阶段和土壤类型的差异。

Taxonomy of Granite-derived Red Soils in Eastern Hunan

In this paper, 8 typical granite-derived soil profiles in eastern Hunan Province were selected, the information of soil-forming environment and profile morphological characteristics were observed in fields, the physico-chemical properties of soils were measured in lab, the diagnostic horizons and diagnostic characteristics of the soil profiles were determined, the senior units and basic units of taxonomy were identified and established according the definition and standards on Chinese Soil Taxonomy, The results show that there are 9 diagnostic horizons and characteristics such as Ochric epipedon, Umbric epipedon, LAC-ferric horizon and Argic horizon in the 8 soil profiles. These soil profiles belong to Argosols, Ferrosols and Cambosols in soil order and to four soil subgroups of Typic Ali-udic Cambosols, Typic Hapli-udic Ferrosols, Typic Ali-udic Argosols and Typic Acidi-udic Argosols. According to the classification standards of soil family and soil series, 6 soil families and 8 soil series are identified and established finally. This study proved that the current classification standards of soil family and soil series are applicable in determining the basic units of soil taxonomy, and compared with soil genetic classification, and soil taxonomy can better reflect the differences in granite-derived soil characteristics in eastern Hunan and disclose more accurately the differences in soil developmental stage and in soil types.