In this study,the relationships among electrical conductivity (EC), concentration of total soluble salts (TSS) , and chloride ion concentration in salt affected soils of Iran were investigated. For this purpose 96 soil samples from different areas of the country were collected and ECe ,pH and concentrations of Ca+Mg, Na, K and Cl in the saturation extracts of soils were determined.The following relation for estimation of TSS from EC of the soils was found using all 96 soils data:
log ISS(mmolcl-1)= 1.0379+1.0222 log ECe (dSm-1) r2=0.995 SEE=0.041 This equation is applicable in the range of 250> ECe (dSm-1)? 3. It was indicated that ,diversity in soil properties (i.e. type and concentration of soluble salts etc.) due to the effects local conditions did not have significant effect on the coefficients of this equation especially in moderately to high saline soils (EC>20 dSm-1), supporting the validity of the equation for TSS estimation in different parts of the country. Comparison of this equation with some popular equations indicate that, in our soils the US Salinity Laboratory and the corrected Marion & Babcock equations give a lower estimate of TSS at all ECe’S , while the Campbell et.al. give a higher estimate at. different soil salinities. Chloride ion was the dominant (>50%) anion in two thirds of the soil samples indicating the widespread presence of chloride salts in these soils. The following empirical equations were found for soils of Khuzestaii:
log TSS(mmolcl-1)= 0.9009+1.0905 log ECe (dSm-1) r2 = 0.996 SEE= 0.025
This equation is applicable in the range of 250>ECe (dSm-1) ?10.
log Cr(mmolcl-1)= 0.6454+ 1.1862 log ECe (dSm-1) r2 = 0.991 SEE= 0.039 This equation is applicable in the range of 250>ECe (dsm-1) ?20.
log TSS(mmolcl-1)= 0.2823+ 0.9269 Jog Ci(mmolcl-1) r2 = 0.988 SEE= 0.405 This equatiOn is applicable in the range of 3900>Cl (mmolcl-1) ?200.
It was argued that the presence of chloride salts in these soils is responsible or could explain the high correlation coefficients of the last two equations.
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