This Standard specifies a method for the determination of potassium chloride extractable sulfur (S_KCl), calcium (Ca_KCl) and magnesium (Mg_KCl) in acid sulfate soil after the determination of pH_KCl and TAA in AS 4969.2.

NOTES:

1 This extraction procedure recovers soluble and exchangeable sulfate, sulfate from gypsum, as well as some sulfate from aluminium hydroxy-sulfate compounds (such as basaluminite). Sulfate from jarosite and similar iron hydroxy-sulfate minerals is not significantly recovered. Methods to determine the residual sulfur held in these iron hydroxy-sulfate minerals are given in AS 4969.6 and AS 4969.11.

2 This extraction procedure recovers soluble and exchangeable calcium and magnesium, and calcium from gypsum.

3 The KCl extractable sulfur (S_KCl), calcium (Ca_KCl) and magnesium (Mg_KCl) measurements can be used in combination with HCl extractable sulfur, calcium and magnesium (AS 4969.8) to determine the net acid-soluble sulfur, calcium and magnesium (AS 4969.11).