EVALUATION OF SODIUM ION ADSORPTION USING SOME THERMODYNAMIC INDICATORS FOR SOIL SAMPLES AT DIFFERENT LOCATIONS

Abstract

The study included the selection of soils from three different locations (AlQasim district, Al-Kifl district, Al-Mahaweel district) with varying electrical conductivity, and the electrical conductivity values ranged between 2-4 decisions m-1 and others ranging between 8-6 decisions m-1 and more than 12, according to American classification according to plant tolerance. Soil samples were taken from a depth of (0-20) cm (and the results of using thermodynamic criteria for the soil of the study using the Abed (2002) program indicated that the ionic strength ranged between 0.032- 0.162 mol.l-1, and the values of ionic activity ranged between 37.922-5.949 mmol L-1, and the results indicated that the arrangement of the ion pair is as follows and for all sites, CaSO40 and MgSO40 > Na(SO4)- > K(SO4)-, and the arrangement of the ions in terms of their participation in the ion pair was It was as follows: sulfate SO4-2 > calcium Ca+2 or magnesium Mg+2 > bicarbonate HCO3-1 > sodium Na+1. The free ions were arranged as follows Na+1 > SO4-2 > Mg2+ > Ca+2 > HCO3- 1 > K+. Based on the previous thermodynamic calculations, the concentration of the main ions present was corrected to obtain the actual concentrations and thus reassess the sodium adsorption ratio (SAR). These values were compared with the ratios before the correction, as the SAR values ranged between 2.321-8.765 before the coupling, while after the ion coupling (ions AlHurra) ranged between 2.693 - 9.396