The use of ignition loss to estimate bulk density of forest soils

SUMMARY 136 samples were collected from soils under wet schlerophyll forest in southern Tasmania. The samples were from different depths and covered a wide range of bulk density and organic matter content. A simple linear relationship between specific volume (the reciprocal of bulk density) and low‐temperature ignition loss was established. Since the variance about the regression tended to be homogeneous with bulk density rather than specific volume, the relationship was fitted as a generalized linear model using bulk density as the dependent variable with an ‘inverse’ link and normal error assumption. For soils with loss‐on‐ignition at 375 ± 5°C ( I ) ranging from 1.8% to 87.9%, the bulk density, p b was given by an equation of the form l / pb =α+β I , where α and β are constants related to the bulk densities of the mineral and organic matter of the soils studied. The existence of the simple linear relationship in the deterministic part of the model implies that these soils are made up of a mineral framework and organic matter, with neither of the two components penetrating the interstices of the other.