Particle-size distribution analysis of soils using laser diffraction

The use of laser diffraction for the particle size distribution analysis of the sub-63 μm fraction of soil samples is described. Each sub-63 μm fraction was obtained from the wet sieving of 1500 mg of whole soil. Using similarity probabilities, the data obtained, when combined with other information from wet sieving and/or organic matter content, will enable the correct identity of a given soil sample with that of an unknown to be made. Although the sub-63 μm fraction can account for 450 mg or more of the total soil content, analyses of this fraction can be conducted on sample sizes as small as 100 mg.