Recommendations for soil sample preparation, pretreatment, and data conversion for texture classification in laser diffraction particle size analysis

With regard to the differences between soil particle size distribution (PSD) obtained by sieve-sedimentation methods (SSMs), e.g., sieve-pipette method (SPM) and laser diffraction (LDM), usually, clay fraction content in LDM measurements is lower than SSM. Two groups of reasons can be identified for this. Firstly, resulting from features themselves. Secondly, sample preparation (after sampling) pretreatment (disaggregation). These not only cause difficulties PSDs comparability but also make it difficult, sometimes even impossible, apply results texture classification. The solution this difficulty may use pedotransfer functions standardization measurement procedures. aim work was validate function proposed Makó et al. (2017) on a Polish physics database recalculating compare them with SPM assess how influenced PSD Using function, 74 % accuracy achieved, which comparable other reported literature. Comparing found literature after sampling (analysis fresh, air dry oven-dried – 105 °C soil) before (breaking aggregates chemically physically) allows recommending conducting using soils ultrasound disaggregation.