Table 1.
Set of environmental covariates used for spatial predictions of soil properties worldwide
| Factor | Predictor name | Resolution (m) | Source | Reference |
|---|---|---|---|---|
| Soil, parent material, age, and organisms | soil-vegetation image (six Landsat bands) | 30a | GEOS3 | Demattê et al.29 |
| Climate | annual temperature | 1,000a | CHELSAb | Karger et al.39 |
| annual precipitation | 1,000a | |||
| Relief | elevation | 90 | MERITc | Safanelli et al.40 |
| slope | 90 | Theobald et al.41 | ||
| multiscale topographic position Index | 90 | Yamazaki et al.42 | ||
| Spatial position | Euclidean distance to rivers | 90 | Behrens et al.43 |
a
The native resolution was resampled to 90 m.
b
Database: CHELSA (Climatologies at High Resolution for the Earth’s Land Surface Areas, https://chelsa-climate.org/)
c
Database: MERIT DEM (Multi-Error-Removed Improved-Terrain Digital Elevation Model, http://hydro.iis.u-tokyo.ac.jp/∼yamadai/MERIT_DEM/)