Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 2004
Publication Date: November 4, 2004
Citation: Olness, A.E., Rinke, J.L. 2004. Particle size distribution in a Hamerly clay loam soil [CD-ROM]. ASA-CSSA-SSSA Annual Meeting Abstracts. Madison, Wisconsin. Technical Abstract: Particle size distributions (PSD) of soil mineral separates are critical for modeling water retention characteristics and estimating available water-holding capacity. The particle size distribution of a Hamerly clay loam soil was examined using a Micromeritic model 5100 sedigraph. After an oxidation with H2O2, soil was suspended in Na-hexametaphosphate and macro-structure was destroyed with a blender. Mass percent finer than arbitrary limits were plotted and fitted with both a power function, f(aDn), and with a f tanh(D) function. No single model described the PSD accurately, but multiple f tanh(D) functions described the data very closely. A combination of three logistic models was needed to describe the distribution of particles <50 um. At least one additional function is required to accommodate particles <2mm; this suggests either a technical flaw in the method of determination, incomplete dispersion of micro-aggregates and/or the existence of four or more independent distributions within the 100-nm to 2.0-mm diameter range of particles. A power function fit to the data gave a patterned residual and demonstrates that this model is inadequate to describe the PSD of this soil.