Variability and compatibility in determining soil particle size distribution by sieving, sedimentation and laser diffraction methods

A range of methods and applications are in use to determine soil particle size distribution. Due to the differences in measurement technology, the analytical results may deviate more or less from each other, which has implications for the matching with historical soil databases. There is a need for studies to critically evaluate their results, both concerning subsample variabilities and compatibilities. In the present study the more recent integral suspension pressure (ISP) and laser diffraction (LDM) methods were compared with the reference sieve and pipette (SPM) method. Samples from topsoil and subsoil of four agricultural soils with sandy clay loam to clay textures were analyzed. A protocol, comparing alternative pre-sievings at the meshes 0.063 (ps0.063), 0.2 (ps0.2) and 2.0 mm (ps2) for the sedimentation (SPM, ISP) and laser diffraction (LDM) measurements, was used. Here we report, based on particle size fraction contents for clay (