240
240 SAR (SODIUM ADSORPTION RATIO) AND ESP(EXCHANGEABLE SODIUM PERCENTAGE)
Saturated Paste Extract: SAR, ESP
Sodium Adsorption Ratio estimated calculation from calcium, magnesium and sodium on saturated paste extract. Exchangeable Sodium Percentage calculated from SAR values.
Summary: The exchangeable sodium percentage (ESP) and the sodium adsorption ratio (SAR) are calculated after determining Ca, Mg and Na concentrations in a saturation extract (SOP# 235).
U.S. Salinity Laboratory Staff. 1954. Choice of determinations and interpretation of data. p. 26. In: L. A. Richards (ed.) Diagnosis and improvement of saline and alkali soils. USDA Agric. Handb. 60. U.S. Government Printing Office, Washington, D.C.