08/1491 - MCU - Detached House [As Published] · 132008.1491

8.4 GLOSSARY OF TERMS

Source: Acid Sulfate Soils Laboratory Methods Guidelines, Version 2.1 June 2004
Authors: QASSIT, Qid NRM&E, SCU, NatCASS, GASSMAC, ASSMAC
Published: Department of natural Resources, Mines and Energy, Indooroopilly, Queensiand, Australia, June 2004

(Acid) Fizz test: The field tast used for soils to test for the presence of carbonate minerals, whereby dilute hydrochloric acid is added to the soil. An effervescent
fizzing reaction indicates the presence of carbonate minerals.

Acid Base Accounting (ABA): The process by which the various acid-producing components of the soil are compared with the acid neutralising components
so that the soil’s net acidity can be calculated.

Action ertterla: The critical net acidity values (expressed in units of equivalent % pyrite sulfur, or equivalent mol H+/t) for different sail texture groups and sizes
of soll disturbance that trigger the need for ASS management,

Actual Acidity: A component of existing acidity. The soluble and exchangeable acidity already presentin the soil, often as a consequence of previous oxidation

of sulfides. It ts this acidity that will be mobilised and discharged fallowing a rainfall event. It is measured in the laboratory using tha TAA method. It does not
include the less soluble acidity (le. retained acidity) held in hydroxy-sulfate minerals such as jarosite.

ANC: Acid neutralising capacity. A measure of a soil's Inherent ability to buffer acidity and resist the jowering of the soil pH.

ANCBT: Acid neutralising capacity by back titration. Acid neutralising capacity measured by acid digest followed by back titration of the acid that has not bean

consumed.

®. Excess acid neutralising capacity. Found in solls with acld neutralising capacity in excess of that needed to neutralise the acidity generated by oxidation
of sulfides. The soil is oxidised with peroxide, then a titration Is performed with dilute hydrochtaric acid to a pH of 4, followed by a second peroxide digestion.
(fa soil nas a positive ANCE result then the TPA result is zero and vice versa,

CaA: Reacted calclum. The caicium soluble after the peroxide digest and TPA titration that was not soluble following KCl-extraction and T AA titration. (Cap
-CaKCl). It can be used (in combination with MgA) to provide an estimate of the soil carbonate content, but may be an underestimate if the HCl-titration to pH

4 has not beon performad as part of the TPA/ ANC,
procedure.

CaHCl: Calclum soluble in 4 M HCI, which Includes soluble and exchangeable calcium as well as calcium found in certain carbonate minerals (eg. dolomite,
calcite, aragonite).

Cake: Potassium chloride extractable calcium measured followiig the T AA anatysis, which inctudes soluble and exchangeable calclum as well as calclum
from gypsum.

CaNAS: Net acid soluble calcium. The calcium soluble in 4 M HCI that ls not soluble In 1M KCI. (CaHC!-CaKCl. It can be used (in combination with MgNAS)
to provide an estimate of the soll carbonate content, but may be an overestimate If calcium Is dissolved from non-carbonate or non-acid-neutralising minerals.

&. Peroxide calcium. Calcium measured following the TPA analysis, which includes soluble and exchangeable calcium, calcium from gypsum, as well as
calcium (eg. from carbonates) dissolved as a result of acid produced due to oxidation of sulfides by peroxide.

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