Particle densities of wetland soils in northern Alberta, Canada

Abstract

Redding, T. E. and Devito, K. J. 2006. Particle densities of wetland soils in northern Alberta, Canada. Can. J. Soil Sci. 86: 57-60. Particle density is a fundamental soil physical property, yet values of soil and organic matter particle density (ρ s and ρ o ) vary widely in the literature. We measured particle density of organic soils from five wetland types, and from exposed sediments of drying ponds, in northern Alberta, Canada. Our measured values of organic soil and pond sediment ρ s varied widely (1.43-2.39 Mg m -3 ); however, calculated values of ρ o (1.34-1.52 Mg m -3 ) were relatively constant. The measured and calculated ρ s and ρ o values were similar to those obtained in published studies using similar methods, but were higher than the values provided in many reference texts. Given the relatively small variability in ρ o , the use of mean values of ρ o , combined with measurements of organic matter loss-on-ignition, shows promise as a simple method for obtaining reliable estimates of ρ s across a range of wetland types. The physical properties (e.g., bulk density, particle density, porosity, organic carbon content) of surface soils exert a strong influence on the exchanges of energy and water between the atmosphere and deeper soils (Baldocchi et al. 2000). Data on particle density (ρ s ), the mass of solids per unit volume of solids (Brady and Weil 1999), is of particular importance in hydrological studies because ρ s is required for the calculation of porosity and heat capacity. Specific applications of particle density data include the measurement and modelling of soil thermal conductivity and heat capacity (de Vries 1963), quantification of shrink-swell behaviour of wetland soils (Price 2003), and calculation of surface saturation and hydrological connectivity from remotely sensed soil moisture data (Wolniewicz 2002).Values of wetland soil ρ s reported in the literature range from 0.84 to 1.67 Mg m -3 (Table 1). The ρ s of wetland soils is a function of the relative proportions of organic (ρ o , organic matter particle density) and mineral materials (ρ m , mineral particle density) present in the soil. While ρ m is generally assumed to be 2. (Table 1). Values of ρ s for wetland soils are not provided in common wetlands reference texts (e.g., Mitsch and Gosselink 2000) or hydrology reference texts (e.g., Dingman 2002), while soils reference texts tend to concentrate on mineral soils from an agricultural perspective (e.g., Brady and Weil 1999; Skopp 2002). The primary literature contains measurements of ρ s and ρ o made with pycnometers that are fairly consistent between wetland types and geographical locations (Table 1), but are at odds with the values presented in common reference texts (Brady and Weil 1999; Skopp 2002;Lide 2002). Given the wide range of ρ o and wetland ρ s values reported in the literature, it is difficult to know which values to employ for the variety of wetland types encountered on the Boreal Plain of northern Alberta, Canada. The objectives of this research were to determine ...

Ground-penetrating radar study of the Cena Bog, Latvia: linkage of reflections with peat moisture content

“…In the course of calculations α was set to 0.35 as commonly used for peat (Strack & Mierau, 2010), ε w was set to 83.83 (selected for in the field measured average temperature of peat 10 °C) and it was assumed that gas content is negligible (ϕ = θ). For peat particles density values reported by Redding & Devito (2006) were used. Using with CRIM calculated values of ε b and from obtained radar images determined two-way travel times, depths from which the reflections have been received were calculated.…”

Peat Accretion Histories During the Past 6,000 Years in Marshes of the Sacramento–San Joaquin Delta, CA, USA

“…1. This value was also checked against particle density values in the literature and found to be very similar to sedge peat measured by Redding and Devito (2006).…”

Response of aquatic plants to abiotic factors: a review

“…The dewatering of sediment with low cohesive strength can help increase its density (Redding and Devito 2006). Such a density increase, together with an increase in exchangeable sediment [NH 4 -N] levels (Baldwin and Mitchell 2000;James et al 2004), can alter significantly the recruitment of aquatic species after the dry period, potentially increasing plant recruitment and growth (Brock et al 2003;Harwell and Havens 2003).…”