Soil Particle Size Distribution and Solid Fractal Dimension as Influenced by Pretreatments

Soil particle-size distributions can provide valuable information on the processes and products of soil formation. The purpose of this study was to assess the pretreatment effect on the particle size distribution and corresponding fractal dimension of particle size (Ds). Twenty nine soil samples were collected from diverse climatic and pedogenic conditions with diverse particle size distributions, calcium carbonate and organic matter contents. To evaluate the effect of pretreatment on soil particle-size distribution, four different types of particle size distributions and fractal dimension values were obtained. Treatments included, 1) no pretreated, 2) organic matter removed with H2O2, 3) calcite (CaCO3) removed with NaOAc, and 4) organic matter and calcium carbonate removed. Clay content ranged from 12.5 to 66.5%, organic matter varied from 0.05 to 4.25%, and calcium carbonate content ranged from 5.57 to 60.09%. The difference in clay content before (42.36%) and after (44.61%) pretreatment of organic matter was significant (P 0.05) but the same pretreatment didn’t yield any significant differences in sand, silt and fractals. However, fractal and sand content obtained after calcium carbonate removal were significantly different from those of non-pretreated samples (P 0.01 and P 0.05, respectively). Dissolving calcium carbonate probably removed the clay sized calcium carbonate particles which were considered within the clay fraction. Therefore, the lowest mean fractal values (Dsc=2.8343 and Dsoc=2.8336) were obtained after calcium carbonate removal. The study results revealed that pretreatments affected the rates of particle size distributions. However, the differences in clay, silt, and sand contents obtained when pretreated together with H2O2 and NaOAc were not significantly different.