However, RA, which is generated by the hydrolysis of relatively insoluble Fe/Al hydroxy sulfate minerals (e.
NAS] in mixed schwertmannite/jarosite-containing soil materials may suffer from substantial interference from schwertmannite (due to variable recovery as observed from two schwertrnannite samples tested here) and also perhaps from other A1 hydroxy sulfate minerals such as basaluminite.
This acidity is measured as titratable actual acidity b3 titrating 1 M KCl extract of soil with dilute NaOH RA Retained acidity--acidity stored in poorly soluble secondary Fe/Al hydroxy sulfate minerals such as schwertmannite, jarosite, and basaluminite This acidity is not considered to be readily available but considered to release slowly by the hydrolysis of those minerals PSA Potential sulfidic acidity--acidity that can be generated by the oxidation of reduced inorganic sulfur ABA Acid base accounting used to derive the net acidity of a soil material.
2004), and/or poorly soluble iron sulfide oxidation products, such as Fe/Al hydroxy sulfate minerals (e.
Thus, some of the increase in TAA with time for these soils could have been due to dissolution of jarosite or other sparingly soluble sulfate minerals, in addition to the oxidation of sulfides.
2] as extractant for TAA titrations in ASS was to measure the acidity retained in insoluble sulfate minerals such as jarosite.
2000a) point out that titrating a 1 M KCl soil suspension allows contact between acid-bearing soil particles and the added titrant (NaOH), resulting in the release of soluble and exchangeable acidity, as well as some acidity carried by `protonated variably charged particles' and basic sulfate minerals (though the release from the latter 2 components during titration is slow).