column,unit,note
year,,Respective year
GEOID,,Unique numerical geographic identifier of administrative boundary of counties; Federal Information Processing System (FIPS)
state_alpha,,Two-letter abbreviation of each state
state_ansi,,Unique numerical identifier of each state; American National Standards Institute (ANSI)
county_ansi,,Unique numerical identifier of each county; American National Standards Institute (ANSI)
county_name,,Name of each county
Yield_Mg_ha,Mg/ha,Mean county corn yield measured in Mg per hectare in the respective year
ssurgo_soc_mean,g C/m2,Soil organic carbon stock - weighted average in grams C per square meters
ssurgo_clay_mean,%,% Clay in soil
ssurgo_sand_mean,%,% Sand in soil
ssurgo_silt_mean,%,% Silt in soil
ssurgo_om_mean,"%, or g/100 g",Soil organic matter in the root-zone depth - weighted average in % or grams organic matter per 100 grams soil
ssurgo_awc_mean,%,Available water capacity in the root-zone depth - weighted average in %
ssurgo_aws_mean,mm,Available water storage within the root-zone depth - weighted average in mm
ssurgo_cec_mean,meq/100 g,Cation exchange capacity in miliequivalent per 100 grams soil
ssurgo_ph_mean,,Soil pH within the root-zone depth - weighted average
summer_spei,,"SPEI (standardized precipitation evapotranspiration index) of summer months (i.e., May to August); Vicente-Serano et al. (2010)"
spei.cat,,SPEI categories in the study; Mahmood et al. (2023)
ORDER,,"Soil orders based on % sand, silt, and clay; USDA"
Suborder,,Suborder classes; Nunes et al. (2021)
Texture,,Texture classes; Nunes et al. (2021)
OC,"%, or g/100 g",Soil organic carbon calculated from soil organic matter
map,mm,Mean annual precipitation
mat,°C,Mean annual temperature
Score_Mean,,Mean soil health score