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Sorption Isotherm Spreadsheet

Spreadsheet from the paper entitled: On the Use of Linearized Langmuir Equations by C.H. Bolster and G.M. Hornberger, Soil Science Society of America Journal, 2007, 71(6): 1796-1806.

Spreadsheet has been modified to correct the following errors:


In earlier versions the initial guess for the n parameter in the Freundlich model did not update when data were added to spreadsheet. This has now been corrected in the new vesrion (1.6)


  1. In the original spreadsheet the L-F model (Eq. [2]) did not have the K value raised to the n power. The attached spreadsheet has corrected this.
  2. There was a typo in the units with the Langmuir K parameter in the spreadsheet. The units should have read L/mg rather than L/kg when C is in mg/L. To avoid confusion, in the updated version the units have been removed since they are dependent on the units used for C and S.
  3. I have recently shown that the traditional method of weighting data by the inverse of the variance in the dependent variable can lead to poorer parameter estimates and uncertainties than with unweighted least squares regression when applied to sorption data (C.H. Bolster and J. Tellinghuisen. 2010. On the Significance of Properly Weighting Sorption Data for Least-Squares Analysis. Soil Science Society of America 74:670-679). Therefore, the weighting option has been removed from the spreadsheet (3/2010). If weighting of data is needed, please contact me at carl.bolster@ars.usda.gov for a modified version of the spreadsheet.
  4. wiin the denominator in Eq. [5] of Bolster and Hornberger (2007 SSSAJ) should be outside of the parenthesis. (This only applies to weighted dat

a and therefore is not applicable to current spreadsheet)

This research was originally part of the former USDA-ARS National Program 206: Manure and By-product Utilization.

Release Date
United States Department of Agriculture
Contact Name
Bolster, Carl
Contact Email
Public Access Level
Program Code
005:040 - Department of Agriculture - National Research
Bureau Code
005:18 - Agricultural Research Service