This Standard specifies a method for the determination of hydrochloric acid extractable sulfur (S_HCl), calcium (C_aHCl) and magnesium (Mg_HCl) in acid sulfate soil following extraction with 4 M hydrochloric acid.

NOTES:

1 This extraction procedure recovers soluble and exchangeable sulfate, sulfate from gypsum, the relatively insoluble iron and aluminium hydroxy-sulfate compounds (e.g. jarosite, natrojarosite, basaluminite) as well as some sulfur from organic matter. It also recovers soluble and exchangeable calcium and magnesium, calcium from gypsum, as well as calcium and magnesium from oxides, hydroxides and carbonates of these two elements.

2 The SHCl, CaHCl and MgHCl measurements can be used in combination with KCl extractable sulfur (S_KCl), calcium (C_aKCl) and magnesium (M_gKCl) (AS 4969.4) to determine the net acidsoluble sulfur (S_NAS), calcium (C_aNAS) and magnesium (M_gNAS) (AS 4969.11).