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Sulfur (Sulfates)

Extractable total sulfur is determined on request and on subsoil samples where the argillic horizon is less than 20 inches from the surface if requested.

Sulfate Extracting Solution (0.5N NH4OAC in 0.25N CH3COOH)

  1. Dissolve 38.5 g NH4OAC in deionized water in a 1 liter volumetric flask. Add 14.2 mL of glacial acetic acid (CH3COOH) and bring to volume with deionized water. Or, add 66.5 mL of concentrated NH4OH to approximately 1000 mL of deionized water in a 2 liter volumetric flask. Add 86.0 mL of glacial acetic acid (CH3COOH) and bring to volume with deionized water.
  2. To prepare 18 liters, add 600 mL of concentrated NH4OH to approximately 10 liters of deionized water in a 20 liter carboy. Add 770 mL of glacial acetic acid (CH3COOH) and dilute to 18 liters with deionized water.

Procedure

  1. Samples are extracted using sulfate free glassware, with sulfate extracting solution, following the same procedure used in the Mehlich I soil extraction.
  2. After shaking, samples are filtered through number 42 Whatman filter paper or equivalent, and the extract saved for S analysis on the ICP. Record results in lb/A with no decimal.