Aggregate and Particle Size Distribution of the Soil Sediment Eroded on Steep Artificial Slopes

Abstract

In this study, the particle size distribution (PSD) of the soil sediment from topsoil obtained from soil erosion experiments under different conditions was measured. Rainfall simulators were used for rain generation on the soil erosion plots with slopes 22°, 30°, 34° and length 4.25 m. The influence of the external factors (slope and initial state) on the particle and aggregate size distribution were evaluated by laser diffractometer (LD). The aggregate representation percentage in the eroded sediment was also investigated. It has been found that when the erosion processes are intensive (steep slope or long duration of the raining), the eroded sediment contains coarser particles and lower amounts of aggregates. Three methods for the soil particle analyses were tested: (i) conventional–sieving and hydrometer method; (ii) PARIO Soil Particle Analyzer combined with sieving; and (iii) laser diffraction (LD) using Mastersizer 3000. These methods were evaluated in terms of reproducibility of the results, time demands, and usability. It was verified that the LD has significant advantages compared to other two methods, especially the short measurement time for one sample (only 15 min per sample for LD) and the possibility to destroy soil aggregates using ultrasound which is much easier than using hexametaphosphate.

Short-term effects of compost amendments to soil on soil structure, hydraulic properties, and water regime

“…The combined sieve-pipette method is used routinely to assess micro-aggregate stability (Bieganowski et al, 2010), however, it cannot be used reliably for soils with high organic matter content. At present, the laser diffraction method (LDM) is not commonly used to determine aggregate stability (Amézketa et al, 2003;Kubinova et al, 2021;Mukherjee and Lal, 2013), therefore the LDM is a relatively new option to investigate soils with organic amendments.…”

Determination of Particle Size Distribution: Comparison of Standard Hydrometer Method and Laser Diffraction Analysis for Use in Forestry

“…Mie's theory considers all particles to be spherical; this assumption is comparable with ARM. The dispersant refractive index was 1.33, the particle absorption index was 0.01 and distilled water was used as a medium [23]. The device was operated by the selected predefined measurement sequence (standard operating procedure).…”

“…Since the sedimentation and optical methods are based on different principles, the PSD analysis does not result in the same representation of specific grain size fraction. The published literature provides an explanatory description of the differences and relationships between the results of PSD comparing the pipette method with LDA [5,[18][19][20][21][22], the hydrometer method (ARM), and LDA [7,14,[23][24][25]. However, most of these studies classified the samples using certain international soil textural classifications, such as the U.S. Department of Agriculture (USDA) [26] textural triangle or the Food and Agriculture Organization of the United Nations (FAO) [27] textural triangle.…”

The Need to Accurately Define and Measure the Properties of Particles

“…Although each technique has its own basis (mass, number, volume) where it yields the most reliable data, results will be fairly comparable if presented on the same basis and scale in a logarithmic or normalized distribution, even for very wide PSD [33][34][35].…”