Two terms for soil organic matter

We recommend using the term "soil organic matter" to refer to the organic fraction of the soil excluding undecayed plant residues. That's the value reported from a standard soil nutrient analysis. Undecayed living and dead plant residues are removed from the soil prior to testing for soil organic matter (SOM).

We recommend using the term "total organic material" to refer to the mass loss on ignition of organic material in a soil sample that has not passed through a sieve.…