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Scholars Day 2005, Wednesday, April 13

Application of a Rapid Extraction Method for the Determination of Exchangeable Cations in Various Soil Orders

Cation exchange capacity (CEC) and exchangeable bases are important properties of soils and sediments. They relate information on a soils ability to sustain plant growth, retain nutrients, buffer acid deposition or sequester toxic heavy metals. Several standard methods exist for the determination of cation exchange capacity (Sumner and Miller, 1996). A new method was developed using a Dionex ASE 100 accelerated solvent extraction system. To demonstrate the applicability of the method, characterized soil samples were obtained from the USDA Lincoln Laboratory and the University of Delaware Soil Testing Laboratory covering 6 different soil orders. Initially, problems arose in applying the method to fine textured soils. To provide better flow in the reaction cell, diatomaceous earth was mixed with the soil samples. Results for extractions of the 6 different soils used in the study were variable. Individual cation concentrations were found to vary by as much as 20% from the characterization data, but total CEC as determined by the sum of the exchangeable cations were found to vary by no more than 10%.

Presenter: Nathan Raduns (Undergraduate Student)
Topic: Earth Science
Location: 218 Lennon
Time: 1:15 pm (Session III)