MEDICIÓN DE CATIONES INTERCAMBIABLES EN SUELOS AFECTADOS POR SALES DE LA REGIÓN SEMIÁRIDA PAMPEANA.

The determination of exchangeable cations in salt- and/or sodium-affected soils using ammonium acetate does not allow to distinguish between exchangeable cations and their forms in soil solution. To quantify only the exchangeable cations in this type of soils, two alternative methods were evaluated: 1) pre-washing with ethanol of the ions in soil solution and 2) difference between the cations extracted with ammonium acetate and in the saturated soil paste extract. The alternative methods allowed to quantify calcium, magnesium and sodium in < 40 dS m-1electrical conductivity soils. Due to operative simplicity, method 1 proved to be the best alternative. [ABSTRACT FROM AUTHOR]