Data for project: Interpretable prediction of topsoil organic carbon content based on machine learning, deep learning and its hybrid geostatistical algorithms

Numerical soil variables were obtained from SoilGrids 2.0 (soilgrids.org/). Soil taxonomic suborder and parent-material kind were obtained from USDA-NRCS gSSURGO (nrcs.app.box.com/v/soils/folder/243464012908), and land-cover classes were obtained from the 2011 National Land Cover Database through the MRLC viewer (mrlc.gov/viewer/). The definitions of the variables are as follows: Site_ID: Unique soil sampling-site identifier; Longitude/Latitude: Geographic coordinates in decimal degrees; SOC_0_30_Weighted_gkg: Depth-weighted SOC content for the 0–30 cm layer (g/kg); SR_B1–SR_B7: Landsat 7 surface-reflectance bands; LST: Land surface temperature (°C); NDVI/EVI/SAVI/MSAVI/RVI/DVI/GNDVI: Vegetation indices; BSI: Bare Soil Index; NDWI/MNDWI: Moisture- and water-related spectral indices; TCB/TCG/TCW: Tasseled Cap brightness, greenness, and wetness; NIR_Contrast/NIR_Variance/NIR_Entropy: Near-infrared texture metrics; Elevation: Elevation above sea level (m); Slope/Aspect: Terrain slope and aspect; Northness/Eastness: Cosine- and sine-transformed aspect; TPI/mTPI: Local and multi-scale topographic position indices; TWI: Wetness-related topographic index; TRI/Roughness/VRM: Terrain variation, roughness, and ruggedness metrics; Curvature: Local terrain-curvature proxy; tmmx/tmmn: Mean maximum and minimum air temperature; pr/MAT: Mean annual precipitation and temperature; RH/SRAD/VS: Relative humidity, solar radiation, and wind speed; ETR/VPD/BI: Reference evapotranspiration, vapor pressure deficit, and burning index; clay/sand/silt: Soil particle-size fractions; nitrogen: Total soil nitrogen content; phh2o: Soil pH in water; cfvo: Coarse-fragment content; cec: Cation-exchange capacity; bdod: Bulk density of the fine-earth fraction; taxsuborder: USDA Soil Taxonomy suborder; NLCD_LandCover:2011NLCD land-cover class; pmkind: Representative soil parent-material kind.