2022 journal article
Comparison of soil particle density determined by a gas pycnometer using helium, nitrogen, and air
Soil Science Society of America Journal.
UN Sustainable Development Goal Categories
2. Zero Hunger
(Web of Science)
Source: ORCID
Added: February 10, 2023
AbstractSoil particle density (ρs) is often assumed as 2.65 g cm−3 (density of quartz). The objectives of this study were to compare the use of different gases for determining ρs in a gas pycnometer and relate measured ρs to soil particle size distributions. The ρs of 36 natural soil samples representing 12 USDA textural classes, fine glass beads, crushed granite rock, kaolinite, and bentonite were measured by a commercial gas pycnometer using He, N2, and dry air. The ρs of 30 of the soil samples, glass beads, and crushed rock were also determined with a water pycnometer. The ρs of 36 soil samples determined by He and 30 samples determined by water had narrow ranges with averages of 2.65 and 2.59 g cm−3, respectively. The ρs determined by air and N2 had much wider ranges with averages of 2.93 and 2.97 g cm−3, respectively. There was a near 1:1 relationship between ρs of all samples determined by air and N2 with a highly significant (p < .001) correlation coefficient (r = .99). The average ratio of ρs determined by He and water was 1.03, but the correlation coefficient for their relationship was only .416. Although the relationship between ρs determined by He and either air or N2 was relatively strong (r < .61), the regression coefficient was <.17. There was a strong relationship between soil clay content and ρs determined by N2 or air but a weaker, yet statistically significant (p < .05) relationship when using He.