渝东南岩溶区典型土壤的系统分类研究

Soil Taxonomy of Typical Soils in Karst Area of Southeast Chongqing

为明确渝东南岩溶区典型土壤在中国土壤系统分类中的归属,以该区域石灰岩发育的典型土壤个体为研究对象,挖掘8个典型剖面,通过野外观测、分层取样与分析,依据《中国土壤系统分类检索(第三版)》进行分类检索,并与发生分类进行参比。结果表明,8个供试剖面分别被划归为3个土纲(淋溶土、雏形土和新成土)、5个亚纲、7个土类和7个亚类等系统分类高级单元;在系统分类基层单元归属上,8个剖面分别被划归为8个土族和8个土系。黄棕壤参比到简育常湿雏形土和酸性常湿雏形土,黄壤参比到简育湿润淋溶土,石灰(岩)土参比到钙质常湿(湿润)淋溶土、钙质湿润雏形土和湿润正常新成土。结合成土环境分析可知,在渝东南岩溶区海拔<1 000 m的地区,海拔越高,其水分状况越好,越容易形成黏化层;若海拔大致相同,坡度是影响土壤形成黏化层的首要因素;地形和海拔也与渝东南岩溶区的土壤水分状况、雏形层的形成等密切相关,是影响渝东南土壤系统分类归属划分的重要因素。

Eight soil profiles developed from calcareous rock were selected in karst area of southeast Chongqing as study objects, their attributions were identified in Chinese Soil Taxonomy(CST) according to the information of field observation and laboratory measurement, and their references to soil genetic classification(SGC) were also identified. The results showed that the tested soil profiles were identified as Argosols, Cambosols and Primosols Orders, 5 Suborders, 7 Groups and 7 Subgroups, and were sorted into 8 soil families and soil series in CST. The yellow-brown soil groups in SGC were sorted into Hapli-Perudic Cambosols and Acidi-Perudic Cambosols in CST. The yellow soil groups in SGC were sorted into Hapli-Udic Argosols in CST.The limestone soil groups in GSCC were sorted into Carbonati-Perudic Argosols, Carbonati-Udic Argosols, Carbonati-Udic Cambosols and Udi-Orthic Primosols in CST. According to soil-forming environment, the higher the elevation is, the better the water condition is, and the more easily formed for Argic horizon. Slope is the primary factor for the formation of Argic horizon under the similar elevation, terrain and elevation are closely related to soil moisture and the formation of Cambic horizon in the karst area of southeast Chongqing, which are important factors for soil identification in CST in southeast Chongqing.