Soil test conversions lb/acre to ppm

We had a great question this week that is worth sharing.

"MLSN guidelines are reported in ppm (parts per million or mg/kg), but my soil test reports elements in lb/acre (pounds per acre). How do I convert from lb/acre to ppm?"

Under "typical" circumstances, the conversion between lb/acre to ppm is simple, just divide lb/acre by 2 (or multiply by 0.5). For example, if your soil test reports 100 lbs K/acre the soil contains 50 ppm K. The caveat is…