Evaluation of soil texture determination using soil fraction data resulting from laser diffraction method

Abstract

There are global aspirations to harmonize soil particle-size distribution data measured by the laser diffraction method and by traditional sedimentation techniques, e.g. sieve-pipette methods. The need has arisen therefore to build up a database, containing particle-size distribution values measured by the sieving and pipette method according to the Hungarian standard (sieve-pipette methods-MSZ) and the laser diffraction method according to a widespread and widely used procedure. In our current publication, 155 soil samples measured with sieve-pipette methods-MSZ and laser diffraction method (Malvern Mastersizer 2000, HydroG dispersion unit) were compared. Through the application of the usual size limits at the laser diffraction method, the clay fraction was under-and the silt fraction was overestimated compared to the sieve-pipette methods-MSZ results, and subsequently the soil texture classes were determined according to the results of both methods also differed significantly from each other. Based on our previous experience, the extension of the upper size limit of the clay fraction from 2 to 7 µm increases the comparability of sievepipette methods-MSZ and laser diffraction method, in this way the texture classes derived from the particle-size distributions were also more in accordance with each other. The difference between the results of the two kinds of particle-size distribution measurement methods could be further reduced with the pedotransfer functions presented. K e y w o r d s: laser diffraction, particle-size distribution, pedotransfer function, soil texture triangle

Particle Size Distribution of Various Soil Materials Measured by Laser Diffraction—The Problem of Reproducibility

“…LDM, however widely used, still requires the works which allow the full characterization of its methodological characteristics. This method is considered precise [25] and a measure of a method's precision can be its repeatability. Repeatability can be defined as the degree of compliance of subsequent measurements of the same measured quantity, carried out under the same measurement conditions [26].…”

Spatial particle size distribution at intact sample surfaces of a Dystric Cambisol under forest use

“…Sand particles can easily stuck in the measurement cell of the Mastersizer (Malvern Panalytical Ltd, Malvern, UK), which is interface between the dispersion and the optical unit, causing an overestimation of the sand fraction (Mastersizer 3000 User Guide, 2020). Furthermore, an underestimation of the LDM-derived fine fraction as also found by Makó et al (2019) can be attributed to the platy shape of clay particles being different than spherical (Bieganowski et al, 2018).…”

“…It should be considered that the LDM itself is a repeatable method in contrast to SPM (e.g., Makó et al, 2019) and the reproducibility of the measurements depends on the texture (Goosens, 2008;Polakowski et al, 2021). Nevertheless, reproducible measurements require a clean, stable background, because particulate contaminations cause fluctuations on the background over time (Mastersizer 3000 User Guide, 2020).…”

“…Based on finding of Makó et al (2019), the upper limit of the clay fraction was increased from 2 µm to 7 µm for better comparability of PSD's derived by SPM and LDM (Table 5). The results in Table 5 show no significant differences between the SPM-derived and LDM-derived sand, silt, and clay fraction, even though the LDM-derived clay content is overestimated compared to the SPM, except for the AE horizon.…”

Testing the integral suspension pressure method for soil particle size analysis across a range of soil organic matter contents

“…The sand, silt, and clay fractions obtained using the ISP and hydrometer methods were compared using a paired t-test with a significance level of 0.05. Comparisons of the three fractions were obtained using coefficients of determination (R 2 ) and root mean square error (RMSE) (Mako et al, 2019). The soil textures obtained using both methods were also compared by classifying them into three grouped textural classes: 1) clayey: clay and silty clay; 2) loamy: clay loam, loam, sandy clay loam, sandy loam, silt loam, and silty clay loam; and 3) sandy: sand and loamy sand (Thiam et al, 2019).…”