I have done soil testing of black soil of mainly clay texture. But when SAR(>13) and ESP ( is estimated to mark it as saline-sodic (high EC value) , the pH seldom falls above 8.5. Why pH is not going above 8.5
Here is sample data, check sr. 1 to 6
The formula for SAR= Na/ Sqrt((Ca+Mg)/2) and ESP=Na/(Ca+Mg)*100. All ions meq/L extracted from 1:2 dilution.
Am I making mistake in calculation of ion concentrations.
Although older references associated saline sodic and sodic soils with high pH, that is not necessarily the case: there can be sodic soils with low pH. Normally associating sodicity with pH only works for calcareous soils.
Maybe you should try saturated soil paste extraction rather than 1:2 diluition if you are having doubts. Also pH can be directly measured in the soil paste.
Hi sachin,
i guess the formula you used for the calclation of ESP may be worng. ESp can be calculated as ESP= 100* Na / ( Ca+ Mg+Na+ K). You can ignore Al and H as your soil is alkaline.
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