Particle Size Distribution Of Soil Samples Research Articles

Fractal Features of Soil Particles as an Index of Land Degradation under Different Land-Use Patterns and Slope-Aspects

This study examines the effects of land use and slope aspect on soil erodibility (K-factor) and the fractal dimension (D) of soil particle size distribution (PSD) in calcareous soils at the watershed scale in western Iran. The study analyzed 113 soil samples collected from four land uses (slope-farmland, farmland, pasture, and woodland) at a depth of 0–20 cm, measuring common soil properties such as soil texture, soil organic matter (SOM), calcium carbonate (CaCO3), pH, and cation exchange capacity (CEC). The PSD of soil samples was measured using the international system of soil size fractions, and the D for PSD was calculated. The K-factor was calculated using the RUSLE model. The results showed that the K-factor was highest in slope farmlands with SOM at 1.6% and lowest in woodlands at 0.02 Mg h MJ−1 mm−1 with SOM at 3.5%. The study also found that there were significant correlations between D and clay content (r = 0.52), sand content (r = −0.29), and CEC (r = 0.36). Woodland soils had the highest SOM content, with a mean D value of 2.895, significantly higher than the mean D value of slope farmland soils, which had the lowest SOM at 1.6%. The study concludes that woodland soils retain finer particles, particularly clay, resulting in lower soil loss and land degradation compared to other land uses. Finally, the study suggests that shady slope aspects (south aspect) contain more organic matter due to less solar radiation and higher soil water content, resulting in lower soil erodibility (0.02 Mg h MJ−1 mm−1) and higher D values compared to other slope aspects.

Particle size distribution of soils (0–500 cm) in the Loess Plateau, China

To investigate the spatial variability of soil particle size distribution (PSD) in the Loess Plateau (LP) region of China, 2673 disturbed soil samples were collected in the 243 soil profiles (0–500cm) across the typical loess zone. The PSD of soil samples were determined using the laser diffraction technique and the regional spatial distribution patterns of PSD were analyzed through classical statistical and geo-statistical methods. The results showed that silt loam was the dominant soil texture (92.6%) at the 0–500cm soil layer. Sand, silt and clay contents varied slightly with increasing soil depth, suggesting that soil texture was almost homogeneous across the soil profile. Soils were overall sandy in the north and clayey in the south, but soil texture variation uneven with increasing latitude. PSD pattern across the typical LP region depicted latitudinal zonality. Fractal analysis showed a strong relationship between fractal dimension (D) and clay content (R2=0.98), demonstrating that D was controlled by the clay content rather than the coarse particles at the regional scale. The limited changes of PSD in the soil profile and the moderate variation of soil texture across the LP will provide a reference to regional scale hydrological, erosion and ecological models in the Loess Plateau of China.

Petrographic And Physico-Chemical Characterisation Of Tailings Dump And Soils Around A Nickel-Copper Mining And Smelting Environment

Recent concerns of mining and smelting of nickel-copper (Ni-Cu) in Selebi Phikwe, Botswana possibly affecting the environmental physico-chemistry motivated this study. Physico-chemical analyses which included particle size distribution (PSD), pH, electrical conductivity (EC), cation exchange capacity (CEC), color and descriptive petrography on samples of tailings dump and soils were performed in order to understand the significance of these properties on the surrounding physical environment. The PSD of soil samples revealed the average wt % of the 2 μ m to 50 μ m to KEY WORDS: tailings dump; soils; physico-chemistry; particle size distribution; petrography; environment Global Journal of Environmental Sciences Vol.4(1) 2005: 31-39