Soil Database of 1:1,000,000 Digital Soil Survey and Reference System of the Chinese Genetic Soil Classification System

Soils maps of China have been generated at different scales from ground surveys and laboratory analyses. A comprehensive effort coordinated by the Office for the Second National Soil Survey of China resulted in a series of soil maps covering the extent of the country at a scale of 1:1,000,000. The map series is now being converted from its current paper form to a digital format. The 1:1,000,000 digital soil map of China will consist of three parts: soil mapping unit boundaries, soil attributes, and the “reference system for Chinese soils.”The spatial data is based on the soil genetic classification of China, consisting of 12 orders, 61 great groups, 235 subgroups, and 909 families. The 1:1,000,000 soil maps are delineated based on the soil family definitions. The sampled soil attributes included physical, chemical, and fertility properties measured for 2473 soil species (series) (known as TuZhong in Chinese). The reference system for Chinese soils will use the attribute data for each soil species (series) to cross reference soil names in three classification systems, namely, Soil Genetic Classification of China, U.S. soil taxonomy, and the FAO World Reference Base for Soil Resources (WRB). The cross‐reference system will be constructed in a relational database so that any Chinese or international scientists can access equivalent names for a soil in any of the three systems.