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Soil properties in and around acid sulfate soil scalds in the coastal floodplains of New South Wales, Australia

Mark A. Rosicky A C , Leigh A. Sullivan A , Peter G. Slavich B and Mike Hughes B

A Centre for Acid Sulfate Soil Research, Southern Cross University, Lismore, NSW 2480, Australia.

B New South Wales Agriculture, Wollongbar Agricultural Institute, Bruxner Highway, Wollongbar, NSW 2477, Australia.

C Corresponding author; email:

Australian Journal of Soil Research 42(6) 595-602
Submitted: 16 May 2003  Accepted: 10 May 2004   Published: 17 September 2004


Soil profiles in 10 persistently bare areas (i.e. scalds), mainly located in coastal backswamps of New South Wales, Australia, were examined for chromium-reducible sulfur content and selected chemical properties. At 5 of the sites, the adjacent paddocks with vegetation cover were also examined. All of the tested sites had been affected by the extensive drainage of the surrounding acid sulfate soil (ASS) landscapes and the consequent oxidation of pyrite. All sites had low pH values in the surface soil layers and these low pH values extended for up to 150 cm into the underlying unoxidised blue/grey pyritic estuarine gels. This can be attributed to the downward diffusion of acidity, either produced in the overlying oxidised zones of these soils or transported laterally across the landscape to these low-lying areas. Acidified unoxidised pyritic zones 120 cm thick can evidently form within several decades after drainage disturbance. At the scalded sites the depth from the soil surface to the main pyritic zone varied from the surface to >200 cm depth, indicating that this variable is not critical to ASS scald formation. For most of the sites examined, the chromium-reducible sulfur contents in the surface soil layers were appreciably higher than those in the immediately underlying soil layers. In most of the vegetated sites the chromium-reducible sulfur content in the surface layers was considerably higher than for the adjacent scalded site. The conditions necessary for pyrite formation (i.e. adequate supplies of organic matter, soluble iron, sulfate, and waterlogging) were found to exist at all sites, and the pyrite accumulations in these surface soil layers are considered to be neo-formed. The vegetated soil-profile pyrite and pH results were very similar to their scalded counterparts except that they had an extra 20–40 cm layer of vegetation and mulch that was missing from the scalded profiles. This indicates that there is considerable potential for more extensive scalding in these ASS areas.

Additional keywords: subsurface pyrite, surface pyrite, pyrite oxidation, pyrite re-formation, acid sulfate soil pH, backswamp management, backswamp drainage.


Ahern CR Stone Y Blunden B 1998 Acid sulfate soils assessment guidelines. Acid Sulfate Soil Management Advisory Committee (ASSMAC) Wollongbar, NSW

Atkinson G 1993 Potential acid sulphate soil risk maps from soil landscapes maps. ‘Proceedings of the National Conference on Acid Sulphate Soils’. Bush R 149 Tweed Shire Council, CSIRO, NSW Agriculture Coolangatta, Qld

Bush RT Sullivan LA 2002 Pyrite formation in estuarine sediments of eastern Australia. ‘Acid sulfate soils in Australia and China’. Lin C Melville MD Sullivan LA 177 191 Science Press Beijing

Bush RT Sullivan LA Prince K White I 2000 Contemporary pyrite formation at the oxidation front in a coastal floodplain acid sulfate soil. ‘Australian and New Zealand Second Joint Soils Conference’. Adams JA Metherell AK Sullivan LA 41 42 New Zealand Society of Soil Science Lincoln University, New Zealand

Bush RT Sullivan LA White I 2001 Acid sulfate soil processes and management. ‘Describing, analysing and managing our soil. Proceedings of the DAMOS ’99 Workshop’. I Cattle SR George BH Sullivan LA 259 275 The University of Sydney Printing Service Sydney

Davies M Mumby B 1999 Acid sulfate soil management priority areas in the Shoalhaven floodplain-Broughton Creek. Department of Land and Water Conservation, Sydney.

Dent DLPons LJ1995A world perspective on acid sulphate soils.Geoderma67263276

Evangelou VPZhang YL1995A review: Pyrite oxidation mechanisms and acid mine drainage prevention.Critical Reviews in Environmental Science and Technology25141199

Giblin AE1988Pyrite formation in marshes during early diagenesis.Geomicrobiology Journal67797

Kemsley R 1997 Investigating surface soil salt accumulation in the Gumma region of the Mid North Coast of NSW. Southern Cross University, Lismore, NSW.

Lin CMelville MD1993Control of soil acidification by fluvial sedimentation in an estuarine floodplain, eastern Australia.Sedimentary Geology85271284

Lin CMelville MDWhite IWilson BP1995Human and natural controls on the accumulation, acidification and drainage of pyritic sediments: Pearl River Delta, China and coastal NSW.Australian Geographical Studies337788

Lin CRosicky MMcConchie DSullivan LALancaster G2001Coastal land scalding in NSW, Australia: Soil chemical characteristics and their implications for the remediation of the scalded lands.Land Degradation and Development12293303

Mulvey P 1993 Pollution, prevention and management of sulphidic clays and soils. ‘Proceedings National Conference on Acid Sulphate Soils’. Bush R 116 129 Tweed Shire Council, CSIRO, NSW Agriculture Coolangatta, Qld

Pons LJ 1972 Outline of genesis, characteristics, classification and improvement of acid sulphate soils. ‘Proceedings of the International Symposium on Acid Sulphate Soils’. Dost H 3 27 International Institute for Land Reclamation and Improvement Wageningen, The Netherlands

Portnoy JWGiblin AE1997Biogeochemical effects of seawater restoration to diked salt marshes.Ecological Applications710541063

Rosicky MA Slavich PG Sullivan LA Hughes M Wood M 2000 Acid sulfate scalds on the NSW coast: characterisation and potential revegetation. ‘Proceedings of Workshop on Remediation and Assessment of Broadacre Acid Sulfate Soils’. Slavich P 111 121 Acid Sulfate Soils Management Advisory Committee (ASSMAC) Southern Cross University, Lismore, NSW

Rosicky MA Sullivan LA Slavich PG 2002 Characterisation and management of acid sulphate soil scalds on the New South Wales coast of southeast Australia. ‘Acid sulfate soils in Australia and China’. Lin C Melville MD Sullivan LA 177 191 Science Press Beijing

Sullivan LA Bush R McConchie D Lancaster G Clark M Norris N Southon R Saenger P 1998 Chromuim reducible sulfur: SCR - method 228. ‘Acid sulfate soils laboratory methods guidelines’. Ahern CR Blunden B Stone Y 9.1 9.4 Acid Sulfate Soil Management Advisory Committee (ASSMAC) Wollongbar, NSW

Tulau MJ 1999 Acid sulfate soil management priority areas in the Lower Richmond floodplain. Department of Land and Water Conservation, Sydney.

Tulau MJ Naylor SD 1999 Acid sulfate soil management priority areas in the Lower Macleay floodplain. Department of Land and Water Conservation, Sydney.

White I Melville MD 1993 Treatment and containment of potential acid sulphate soils: Formation, distribution, properties and management of potential acid sulphate soils. Technical Report No. 53, November 1993, CSIRO Centre for Environmental Mechanics, Canberra.

White IMelville MDWilson BPSammut J1997Reducing acidic discharges from coastal wetlands in eastern Australia.Wetlands Ecology and Management55572

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