Abstract

HENRIQUEZ, Manuel; PEREZ, Juana; GASCO, José M.  and  RODRIGUEZ, Orlando. Cation exchange capacity in sand and kaolin using ammonium acetate, sodium acetate, and ammonium chloride. Bioagro [online]. 2005, vol.17, n.1, pp.59-62. ISSN 1316-3361.

The soil cation exchange capacity (CEC) depends on its determination conditions. There are reports stating that the ammonium acetate and sodium acetate modify the soil natural CEC values, and other reports point out that the ammonium chloride method, eliminates the sources of error introduced by the use of acetates. In the current study, the CEC determined by extraction and cation sum with CH₃COONH₄ 1N pH 7 and CH₃COONa 1N pH 8.2 in sand and kaolin (clay) were compared against the CEC by sum determined using NH₄Cl 0.2N at the sample natural pH. Results were statistically compared through a completely randomized design with five replicates and mean discrimination by LSD test. For the sand, the values were statistically different, so no correlation could be established. For the kaolin, no statistic differences were found between CEC results obtained with CH₃COONH₄ and with NH₄Cl, so the values were considered to be similar. The low standard deviation found for the values of the CEC obtained with the use of ammonium chloride proved that this method could be reliable to be routinely used for CEC determination in clay soils.

Keywords : Soil chemistry; laboratory analysis; CEC.