Abstract

PEREZ ROSALES, Alejandro et al. Cation exchange capacity: description of the silver thiourea method (AgTU ⁺ _n ). Rev. Mex. Cienc. Agríc [online]. 2017, vol.8, n.1, pp.171-177. ISSN 2007-0934.  https://doi.org/10.29312/remexca.v8i1.80.

The cation exchange capacity (CIC) is an indirect indicator of soil damping capacity. The methods used to estimate the CIC are based on soil saturation with an index cation. The silver thiourea method (AgTU + n) is a technique for estimating CIC, since AgTU + n is not Found naturally in the soil; however, Ag + is sensitive to the visible spectrum and the alkaline pH of the solution, forming Ag0 and Ag2O. In the study soils, the amount of sample required for the estimation of CIC was 0.8 g. The protection of glassware with aluminum foil and the storage of extracts in the dark increased the shelf life of AgTU + n. the CICSI, as a function of CCICI of 166 soils, has a linear relationship, that is, that the variation in the CIC estimation is due to the adsorption of AgTU + n on the clays of the soils, and not by sources of variation generated by other ions. The AgTU + n method makes it possible to estimate the CIC quickly and inexpensively, taking into account the aforementioned considerations.

Keywords : : bentonite; flocs and adsorption.