Assessing Methods for Developing Phosphorus Desorption Isotherms from Soils using Anion Exchange Membranes

Abstract

Developing desorption isotherms for inorganic phosphorus (P) is a time-consuming and non-standardized procedure. Anion exchange membranes (AEMs) have been successfully used in studies of P desorption kinetics and total membrane-desorbable P, but rarely have they been used for developing P desorption isotherms. Our study had two objectives: (1) to evaluate the suitability of using multiple strips of AEMs (termed the Multiple AEM Method) to develop P desorption isotherms; and (2) to compare the Multiple AEM Method with a sequential-extraction approach using AEMs (termed the Sequential AEM Method) to determine if the manner in which AEMs were used would influence the slope of the desorption isotherm, i.e. the partition coefficient. Both methods yielded well-defined, but numerically different desorption isotherms for all levels of sorbed P. However, estimated K d values among methods were equivalent in the low and medium levels of P sorbed. The Multiple AEM method was quicker than the Sequential AEM method, but both gave similar K d values in an agriculturally significant range of soil solution concentrations. These methods should be tested on a range of soil type to determine their suitability in developing P desorption isotherms and to move toward method standardization for desorption isotherms.Abbreviation: AEM -anion exchange membrane

Leaf litter inputs decrease phosphate sorption in a strongly weathered tropical soil over two time scales

“…Resin extractable phosphate and pH also showed trends related to the litter treatment (Table 2). Resin extractable phosphate quantifies the pool of phosphate that is easily removed by solution disequilibrium (Sato and Comerford 2006) (Table 3).…”

Evaluation of phosphorus mobility in soil using different extraction methods

“…Exchangeable sorbed P (P ex ) is another important source of bioavailable P. it is the part of soil P that is exchangeable and adsorbed on the surface of soil particles and can be easily released to the soil solution. this fraction can be estimated for example with anion resins (tiessen and Moir 1993, lewis andMcGechan 2002), or recently, via anion exchange (aE) membranes (Kuono et al 1995, Sato andComerford 2006). the most commonly used methods are those for estimating total bioavailable P in soils: e.g.…”

Analysis of Macro and Micronutrients in Soils from Palestine Using Ion Exchange Membrane Technology

“…Determination of index of available phosphorous is still a matter of interest [25]. The pool of bioavailable phosphorous is indexed by extraction of a portion of labile pool of inorganic phosphorous using chemical extractants such as Bray 1, Mehlich 1 or 3, and Olsen's solution [10,28]. In the present work, the available form of phosphate was tested ( Table 1).…”

“…In the last decades Ion exchange resin has been used to assess the availability of plant nutrients where anion and cation exchange resins are used in numerous ways in soil and plant analysis [7,8]. The method simulates removing ions from soil by plant roots to prevent equilibrium of ions between the solid and the solution phases [9,10]. A major problem in using bead resins is the difficulty in their separation from the soil following the extraction [9,11].…”

“…Ion exchange membrane technique (IEM) was developed as an alternative to chemical extraction methods to measure nutrients bioavailability [10,11]. In addition to its simplicity, rapidness and accuracy compared to other existing methods, the technique was found to be highly suitable for soil testing because multi-element in soil can be tested [9,11].…”