The data were obtained from the Harmonized World Soil Database version 1.2 (HWSD) constructed by the Food and Agriculture Organization of the United Nations (FAO) and the International Institute for Applied Systems (IIASA), Vienna. The data source in China is the 1:1 million soil data provided by the Nanjing Soil Survey of the Second National Land Survey. The soil classification system used is mainly FAO-90.

  Unique validation identifier for the core soil regime unit:

  MU_GLOBAL-HWSD database soil mapping unit identifier with connected GIS layers.

  MU_SOURCE1 and MU_SOURCE2- Source database mapping unit identifiers.

  SEQ-Soil unit sequence in soil mapping unit composition.

  The soil classification system utilizes the FAO-7 classification system or the FAO-90 classification system (SU_SYM74 resp. SU_SYM90) or FAO-85 (SU_SYM85).

  The main fields of the Soil Properties table include:

  ID (database ID);

  MU_GLOBAL (soil unit identifier) (global);

  SU_SYMBOL Soil Mapping Unit;

  SU_SYM74 (FAO74 classification);

  SU_SYM85 (FAO85 classification);

  SU_SYM90 (soil name in FAO90 soil classification system);

  SU_CODE Soil mapping unit code;

  SU_CODE74 Soil unit name;

  SU_CODE85 Soil unit name;

  SU_CODE90 Soil unit name;

  REF_DEPTH (soil reference depth);

  AWC_CLASS(19.5)；

  AWC_CLASS (effective soil water content);

  PHASE1: Real (soil phase);

  PHASE2: String (soil phase);

  ROOTS: String (depth classification to the bottom of the soil where barriers exist);

  SWR: String (soil water content characteristic);

  ADD_PROP: Real (specific soil type in the soil unit related to agricultural use);

  T_TEXTURE (top soil texture);

  T_GRAVEL: Real (top gravel volume percentage);

  T_SAND: Real (top sand content);

  T_SILT: Real (surface silt content);

  T_CLAY: Real (top clay content);

  T_USDA_TEX: Real (top-level USDA soil texture classification);

  T_REF_BULK: Real (top soil capacity);

  T_OC: Real (top organic carbon content);

  T_PH_H2O: Real (top level pH);

  T_CEC_CLAY: Real (cation exchange capacity of the top clay layer soil);

  T_CEC_SOIL: Real (cation exchange capacity of top soil);

  T_BS: Real (Top Basic Saturation);

  T_TEB: Real (top exchangeable salt base);

  T_CACO3: Real (top carbonate or lime content);

  T_CASO4: Real (top sulfate content);

  T_ESP: Real (top exchangeable sodium salt);

  T_ECE: Real (top conductivity);

  S_GRAVEL: Real (Subgrade Gravel Volume Percentage);

  S_SAND: Real (bottom sand content);

  S_SILT: Real (bottom silt content);

  S_CLAY: Real (subsoil clay content);

  S_USDA_TEX: Real (underlying USDA soil texture classification);

  S_REF_BULK: Real (subsoil capacity);

  S_OC: Real (Substrate Organic Carbon Content);

  S_PH_H2O: Real (Substrate pH);

  S_CEC_CLAY: Real (cation exchange capacity of the underlying clay layer soil);

  S_CEC_SOIL: Real (cation exchange capacity of the subsoil);

  S_BS: Real (Substrate Basic Saturation);

  S_TEB: Real (bottom exchangeable salt base);

  S_CACO3: Real (underlying carbonate or lime content);

  S_CASO4: Real (bottom sulfate content);

  S_ESP: Real (Substrate Exchangeable Sodium Salt);

  S_ECE: Real (Substrate Conductivity);

  This database is divided into two layers, where the top layer (T) soil thickness is (0-30cm) and the bottom layer (S) soil thickness is (30-100cm).