anchor.diff:  layer,vwc,Volumetric % Moisture - percent,vwc,,,sample,numeric,value,percent,,,
   layer,soc,Bulk Layer Calculated Soil Organic Carbon Stock - g cm-2,soc,soil organic carbon,,sample,numeric,value,g cm-2,,,
   layer,soc_type,Bulk Layer Calculated Soil Organic Carbon Stock Type - (ccon_type),soc,,,sample,character,method,,,,
  -layer,soc_sigma,Bulk Layer Calculated Soil Organic Carbon Stock Standard Deviation - g cm-2,soc,,,sample,numeric,sigma,g cm-2,,,
  +layer,soc_sigma,Bulk Layer Calculated Soil Organic Carbon Stock Standard Deviation - g cm-2,soc,,,sample,numeric,sigma,,,,
   layer,soc_method,Bulk Layer Calculated Soil Organic Carbon Stock Method - ,soc,,,sample,character,method,,,,
   layer,c_tot,Bulk Layer Total Carbon - percent,c_tot,carbon concentration in a dry combustion analysis,,sample,numeric,value,percent,,,
   layer,oc,Bulk Layer Organic Carbon - percent,oc,organic carbon either acidification+dry combustion or Walkly-Black,,sample,numeric,value,percent,,,
  
positive.code: layer,c_method,Bulk Layer Carbon Analysis Method - ,(soc)|(c_tot),,,sample,character,method,,,,
  layer,color,Moist Munsell Color - ,color,soil color,,field,character,,,,,
  layer,burn_ev,Evidence of Burning - (burn),burn_ev,,,field,factor,,,,,
  layer,bd_method,Bulk Density Method - ,^bd,,,sample,character,method,,,,
  layer,bd_samp,"Bulk Density, Coarse Fragments Removed - g cm-3",bd_sample,bulk density of the <2mm (fine earth) over-dried fraction,,sample,numeric,value,g cm-3,,,
  layer,bd_tot,Bulk Density With Coarse Fragments - g cm-3,bd_tot,whole soil bulk density - includes fine earth fraction and rocks,,sample,numeric,value,g cm-3,,,
  layer,bd_whole,Bulk Density Minus Estimated Coarse Fragments - g cm-3,bd_whole,whole soil bulk density by clod method at 1/3 bar moisture content,,sample,numeric,value,g cm-3,,,
  layer,bd_other,Bulk Density Other - g cm-3,bd_other,non-standard,,sample,numeric,value,g cm-3,,,
  layer,ph_method,pH Method - ,^ph,,,sample,character,method,,,,
  layer,ph_cacl,Soil pH CaCl2 - ,ph_cacl,pH from 1:2 Soil-CaCl2 suspension,,sample,numeric,value,,,,
  layer,ph_h2o,Soil pH 1:1 - ,ph_h2o,pH from 1:1 Soil-water suspension,,sample,numeric,value,,,,
  layer,ph_other,Soil pH Other - ,ph_other,pH non-standard,,sample,numeric,value,,,,
  
negative.code: fraction,fraction_mass_perc,Fraction proportion of sample mass - percent,,,,sample,numeric,value,percent,,,
  gas,gas_name,Gas Sample Name - ,,,,sample,,,,,,
  gas,gas_number,Laboratory Gas Sample Number - ,,,,sample,character,method,,,,
  gas,gas_type,Gas Type - (gas_type),,,,sample,factor,method,,,,
  gas,gas_note,Gas Sample Notes - ,,,,sample,character,method,,,,
  gas,gas_time_series,Gas Time Series Name - ,,,,sample,character,method,,,,
  gas,c_method,Gas Carbon Analysis Method - ,,,,sample,character,method,,,,
  gas,collection_method,Gas Sample Collection Method - (core_pit),,,,sample,factor,method,,,,
  gas,collection_loc,Field Vs. Incubation - ,,,,sample,character,method,,,,
  gas,15n,Gas δ15N - permil,,,,sample,numeric,value,permil,,,
  gas,c_conc_CO2,CO2 Concentration - ppm,,,,sample,numeric,value,ppm,,,
  gas,13c_CO2,Gas δ13C (C02) - permil,,,,sample,numeric,value,permil,,,
  gas,14c_CO2,Gas Δ14C (C02) - permil,,,,sample,numeric,value,permil,,,
  gas,14c_CO2_sigma,Gas Δ14C Standard Deviation (CO2) - permil,,,,sample,numeric,sigma,,,,
  gas,14c_age_CO2,Gas Uncalibrated Radiocarbon Age (CO2) - ,,,,sample,numeric,value,,,,
  gas,14c_age_CO2_sigma,Gas Uncalibrated Radiocarbon Age Standard Deviation (CO2) - ,,,,sample,numeric,sigma,,,,
  gas,fraction_modern_CO2,Gas Fraction Modern (CO2) - ,,,,sample,numeric,value,,,,
  