An investigation in laser diffraction soil particle size distribution analysis to obtain compatible results with sieve and pipette method

Recent studies have shown that soil particle size analyses using laser diffraction method (LDM) can give compatible results compared with traditional sedimentation based methods, if the clay-silt cutoff is transformed. Additionally, procedures including separation of sand fraction by wet sieving and running a well dispersed sample only fractions smaller than during measurement, given promising results. The main purpose present study was to test combination these approaches for determining transformed LDM values on 44 samples from agricultural sites spread over Sweden, its compatibility sieve pipette (SPM). Furthermore, were pedotransfer functions between measured SPM. Also related aspects concerning scattering parameters, repeatability organic matter calculations studied. To find optimum cutoff, Lin’s concordance correlation coefficient (Lin’s CCC) calculated. highest value (0.977) found 3.409–3.905 µm bin (a refractive index 1.52 an absorption 0.1 used). pedotransfer-transformed approach showed equally high Lin´s CCC as cutoff-transformed different classes. With approach, 36 out assigned same texture class SPM, LDM, corresponding number similar (34 samples). here are application in routine analyses, but more specific cutoffs versus SPM should ideally be established types soils. For this, microscopy image analysis methods help understand quantify influence shapes obtained distributions useful. • Laser determined clay content 34% determined. Pedotransfer transformation improved method. Changing Optimum at 3.9 µm. 80% modified pipette.