A new method for the estimation of total dissolved salts in saturation extracts of soils from electrical conductivity

We have determined electrical conductivity (E_e) and total dissolved salts (S) in saturation extracts from 39 soil samples from the Baza basin (Province of Granada, south-east Spain). E_e ranged from 2.8 to 110dS m^?3, and S from 2 to 444 8 dm^?3. The relationship between S and E_e was not linear. When the saturation extracts were diluted with progressively larger quantities of distilled water and their electrical conductivity calculated (E_ec) with the equation where E_d and E_w are the conductivity of the diluted extract and the distilled water and f is the dilution factor, the relationship between S and E_ec tended to become linear. The highest linear correlation coefficient relating S (mg dm^?3) and E_ec (dS m^?1) was reached when E_ec, values were calculated for dilutions with a conductivity (E_d) between 0.1 and 0.3 dS m^?1 (E*_ec). The regression equation was S= 490 E*_ec with r²= 0.999. This relationship can be used in all saturation extracts, regardless of the concentration and type of ions present.