Reliability of 1:1, 1:2 and 1:5 Weight Extracts for Expressing Salinity in Light-Textured Soils of Saudi Arabia.

Electrical conductivity (EC) and concentrations of Ca2+, Mg2+, Na+ and Cl- were determined in saturation as well as in 1:1, 1:2 and 1:5 (soil:water) weight extracts of 122 Saudi soils. They were mainly of sandy loam and loamy sand classes of texture. Linear regression analysis showed that EC of the 1:1, 1:2 and 1:5 extracts correlated significantly well (r2 = 0.974-0.896) with that of saturation extracts (ECe). It was possible to derive regression equations via which the ECe corresponding to each of the dilutions could be predicted. Similar procedure was adopted and similar results were obtained for expressing concentrations of Ca2+, Mg2+, Na+ and Cl- in various soil extracts. However, whereas the effect on concentration of Na+ and particularly Cl- were near to mere dilution (r2=0.782-0.940), that of Ca2+ and Mg2+ showed wider deviations (r2 =0.48M.929) indicating that other physio-chemical processes had influence upon their concentrations as dilution was increased