Cross-Reference System for Translating Between Genetic Soil Classification of China and Soil Taxonomy

Soil classification systems are not consistent among countries or organizations thereby hindering the communication and organizational functions they are intended to promote. The development of translations between systems will be critical for overcoming the gap in understanding that has resulted from the lack of a single internationally accepted classification system. This paper describes the application of a process that resulted in the translation of the Genetic Soil Classification of China (GSCC) to Soil Taxonomy (ST). A brief history of soil classification in China is also provided to familiarize readers with GSCC and its origins. Genetic Soil Classification of China is the attribute base for the recently assembled digital form of the 1:1 000 000 soil map of The People’s Republic of China. The translation between GSCC and ST was based on profile, chemical, and physical descriptions of 2540 soil series. First, the 2540 soil series were classified to their equivalent soil order, suborder, great group, and subgroup according to ST and GSCC subgroup descriptors. Order names for both classification systems were then linked to corresponding map units in the 1:1 000 000 digital soil map of China using a geographic information system (GIS). Differences in classification criteria and in the number of orders of the two systems (there are more GSCC orders than ST orders) meant that each GSCC order could possibly be assigned to more than one ST order. To resolve the differences, the percent correspondence in area between orders was determined and used as the criterion for assigning GSCC orders to ST orders. Some percentages of correspondence were low so additional processing was used to improve the assignment process. The GSCC suborders were then matched with ST orders. When the area for each order was summarized, the percentage of correspondence increased except for two subgroups in the Ferrasols order. CLASSIFICATION is a fundamental part of the rational study and management of soil resources, serving as an organizational framework and descriptor of soil properties. Systematic soil classification is also a vehicle for communicating research results and extending the benefits of new knowledge to other locations. Classification in conjunction with soil mapping provides a method for planning agricultural output, makes possible the application of new management techniques, and supports the use of environmentally sound land use practices. To date there is no universally accepted soil classification system. Internationally, only Soil Taxonomy (ST) (Soil Survey Staff, 1994) and World Reference Base for Soil Resources (WRB) (FAO/ISRIC/ISSS, 1998) are used extensively. ‘‘Soil Classification–A Global Desk Reference’’ edited by noted soil taxonomists, was published recently, to stimulate formation of an international soil classification system (Eswaran et al., 2003). Even given the development of an internationally recognized system, a great deal of time will have to be dedicated to translating existing systems into the new global standard. Soil classification in China provides an interesting example of how systems can be cross-referenced to improve the understanding of soil properties. Soil classification in China has undergone several important transformations, resulting in the creation of two soil classification systems based on different academic philosophies, namely GSCC and Chinese Soil Taxonomy (CST). Currently the two systems are used together. Nevertheless, the large volumes of soil data and information gathered and accumulated since the initiation of the study of soil science in the early 1930s, including soil maps and soil survey reports, have mostly been prepared and sorted on the basis of GSCC. For example, the second national soil survey (1979–1994) was documented using GSCC, as were all the soil maps and soil survey reports at all administrative levels (township, county, city, province, and country). Genetic Soil Classification of China, however, differs sharply from ST, which is used extensively throughout the world. Since non-Chinese scientists and other users of soil data outside of China do not know much about GSCC, it is extremely difficult for Chinese soil scientists to exchange information, cooperate with foreign colleagues, and publish papers in international journals. Further, it is difficult for soil scientists from countries outside of China to acquire a working knowledge of GSCC terminology and criteria, because the source materials are published in Chinese, which is not a familiar second language for many soil researchers. To overcome these obstacles, Chinese scientists know and are compelled to translate all soils information on the basis of ST. However, such translations are performed on an individual basis without guidance on how to conduct them, increasing the possibility for inconsistencies when relating soils from one system to another. So that while Chinese soil scientists are familiar with ST, there is no national standard for translating between the two systems. The solution was to establish a reference system between GSCC and ST. To that end, Chinese soil scientists have been devoting untiring efforts (Shi and Gong, 1996, 2004b; Gong et al., 1999, 2000). Some initial studies have been done to get an idea of how the two systems might X.Z. Shi, D.S. Yu, W.X. Sun, and Z.T. Gong, State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China; E.D. Warner, G.W. Petersen, and H. Lin, Office for Remote Sensing of Earth Resources, The Pennsylvania State University, University Park, Pennsylvania, USA. Received 29 Sept. 2004. *Corresponding author ([email protected]). Published in Soil Sci. Soc. Am. J. 70:78–83 (2006).