I know Steve P. gets pretty excited when it comes to talking about CEC, so I thought I would find some hard values to discuss. CEC, for those who may not understand, is defined as the sum of the exchangeable cations of a soil. It's expressed as milliequivalents or me. It's a reversible chemical reaction. Cations are held on the surface of soil minerals and held within the crystal framework of some mineral species.
Cations are also a part of certain organic compounds.
All these cations can be reversibly replaced by those of salt solutions and acids. 9081A CEC of soils by sodium acetate. A sample is mixed with an excess of sodium acetate solution, resulting in an exchange of the added sodium cations for matrix cations. An ammonium acetate solution is then added, which replaces the absorbed sodium with ammonium. The conc. of displaced sodium is then determined.