Phosphorus Adsorption by Ceramic Suction Lysimeters

Abstract

Ceramic tension lysimeters are often used to sample soil water; however, the chemical composition and adsorption capability of the ceramic cup material may introduce uncertainties in the P concentration of the leachate being sampled. The goal of this study was to test a methodology for evaluating ceramic tension lysimeters to sample soil water containing PO4–P. Our results indicated varying chemical composition of the three ceramic materials evaluated (referred to here as Ceramics A, B, and C) with Ceramic A having the greatest P, Al, Ca, Mg, and K concentrations. Phosphorus sorption for Ceramics A and C was best described by the Freundlich isotherm, while the P sorption of Ceramic B was best described by the Langmuir isotherm. Ceramic A accurately estimated solutions of 0.1, 0.5, 1.0, and 20 mg P kg−1, while Ceramics B and C accurately estimated only the 20 mg P kg−1 solution. Ceramics B and C underestimated the 0.1, 0.5, and 1.0 mg P kg−1 solutions by 23 to 89%. This underestimation of the P concentration was attributed to P adsorption due to the presence of Al, Fe, Ca, and Mg in the ceramics. These findings imply that before ceramic lysimeters are used to collect soil water samples, the effect of the ceramic samplers on the composition of the water sample should be assessed to explore the P concentration range appropriate for a given ceramic lysimeter.

Electrical Conductivity and Chemical Composition of Soil Solution: Comparison of Solution Samplers in Tropical Soils

“…Depending on the type and physical and chemical properties of the sampler membrane, there may be limitations on evaluating the contents of chemical elements in solution due to the adsorption or desorption of cations and anions in the samplers (Silva et al, 2004;Kiggundu et al, 2010). Components used in the manufacture of porous cups may also increase solution sampling time, due to biochemical reactions between the sampler membrane and the solution (Ross and Bartlett, 1990;Wolt, 1994).…”

“…A big problem of a ceramic sampler is its capacity to adsorb anions and release cations, such as Ca 2+ , Mg 2+ and Al 3+ (Litaor, 1988). Adsorption of ions (Menendez et al, 2003;Kiggundu et al, 2010) and even increased release of Ca 2+ and Mg…”

Accuracy of Lysimeters for Dissolved Copper, Antimony, Lead, and Zinc Sampling under Small Arms Backstop

“…Zero‐tension lysimeters sample only gravitational water because a positive pressure needs to be developed in the soil to allow water to enter the pipe and be sampled. The volume of soil water sampled differs for the two systems: TLs often have a small sample volume compared with zero‐TLs (Kiggundu et al, 2010).…”

“…Porous cups are mainly made of ceramic, nylon, or stainless steel. Ceramic cups are made from a formulation of kaolin, talc, alumina, ball clay, and feldspathic materials (Soilmoisture Equipment Corporation, 2007; Kiggundu et al, 2010). Sampling quality is dependent on parameters such as: (i) the quality and characteristics of the porous material; (ii) the strength of the negative pressure that needs to be applied; and (iii) the way it has been washed before use. A zero‐tension lysimeter (zero‐TL), in its simplest design the box lysimeter (BL), consists of an open‐top receiver and a pipe connected on the lower end.…”

“…The ceramic cups have a tendency to adsorb dissolved metals (Wenzel et al, 1997; Rais et al, 2006; McGuire et al, 1992) such as Cu, Zn, Pb, Cd, Cr, As, Co, Mn, and Ni but not Ca, Mg, or P (Levin and Jackson, 1977). The effectiveness of three ceramic TLs were compared and showed a significant adsorption–desorption capacity affecting P concentrations (Kiggundu et al, 2010). Nagpal (1982) demonstrated that ortho‐P and K were retained by TLs.…”