Unit Conversions and Constants

Unit Conversions

ppm = mg/L = ug/g = mg/kg

ppb = ug/L = ug/kg

ppm/10000 = %

ppm x 2=lb/ac (If 1 acre of soil and 6 inches deep weighs 2000000lb)

lb/ac x 1.12 =kg/ha

Unit Constants

Milli-Equivalent Weights (meq wt)

ppm/meq wt=meq/L

meq/L x % Saturation/1000=meq/100g

mS/cm=dS/m

EC (dS/m)=10 x (Ca + Mg + Na + K in meq/L)

Where Na, Ca, + Mg, are expressed in meq/L.