AASHTO T 267-22

The Loss on Ignition method for the determination of organic content is most applicable to those materials identified as peats, organic mucks, and soils containing relatively undecayed or undecomposed vegetative matter or fresh plant materials such as wood, roots, or grass, or carbonaceous materials such as lignite, coal, etc. This method determines the quantitative oxidation of organic matter in these materials and gives a valid estimate of organic content. The Wet Combustion method (AASHTO T 194) is recommended when it is desired to determine the percentage of humus-like, easily oxidized organic material to provide information relating to the suitability of a soil for plant growth.