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

Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 595 ◽  
Author(s):  
Mark A. Rosicky ◽  
Leigh A. Sullivan ◽  
Peter G. Slavich ◽  
Mike Hughes
Keyword(s):  
Sulfur Content ◽  
Surface Soil ◽  
New South ◽  
New South Wales ◽  
Low Ph ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Soil Layers ◽  
Ph Values ◽  
South Wales

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.

Land-use and historical management effects on soil organic carbon in grazing systems on the Northern Tablelands of New South Wales

Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 668 ◽  
Author(s):  
Brian R. Wilson ◽  
Vanessa E. Lonergan
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Surface Soil ◽  
Soil Depth ◽  
New South ◽  
New South Wales ◽  
Soil Layers ◽  
South Wales ◽  
Native Pasture ◽  
Historical Management

We examined soil organic carbon (SOC) concentration (mg g–1) and total organic carbon (TOC) stock (Mg ha–1 to 30 cm soil depth) in three pasture systems in northern New South Wales: improved pasture, native pasture, and lightly wooded pasture, at two sampling times (2009 and 2011). No significant difference was found in SOC or TOC between sample times, suggesting that under the conditions we examined, neither 2 years nor an intervening significant rainfall event was sufficient to change the quantity or our capacity to detect SOC, and neither represented a barrier to soil carbon accounting. Low fertility, lightly wooded pastures had a slightly but significantly lower SOC concentration, particularly in the surface soil layers. However, no significant differences in TOC were detected between the three pasture systems studied, and from a carbon estimation perspective, they represent one, single dataset. A wide range in TOC values existed within the dataset that could not be explained by environmental factors. The TOC was weakly but significantly correlated with soil nitrogen and phosphorus, but a more significant pattern seemed to be the association of high TOC with proportionally larger subsoil (0.1–0.3 m) organic carbon storage. This we attribute to historical, long-term rather than contemporary management. Of the SOC fractions, particulate organic carbon (POC) dominated in the surface layers but diminished with depth, whereas the proportion of humic carbon (HUM) and resistant organic carbon (ROC) increased with soil depth. The POC did not differ between the pasture systems but native pasture had larger quantities of HUM and ROC, particularly in the surface soil layers, suggesting that this pasture system tends to accumulate organic carbon in more resistant forms, presumably because of litter input quality and historical management.

Factors contributing to the acid sulfate soil scalding process in the coastal floodplains of New South Wales, Australia

Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 587 ◽  
Author(s):  
Mark A. Rosicky ◽  
Leigh A. Sullivan ◽  
Peter G. Slavich ◽  
Mike Hughes
Keyword(s):  
New South ◽  
New South Wales ◽  
Pyrite Oxidation ◽  
Soil Surface ◽  
Soil Parameters ◽  
Soil Core ◽  
Acid Sulfate Soil ◽  
Vegetative Cover ◽  
Acid Sulfate ◽  
South Wales

Acid sulfate soil (ASS) scalds are persistently bare areas of land, occurring in the coastal backswamps of New South Wales (NSW), Australia. This study aims to understand why particular areas become ASS scalds, while adjacent areas remain vegetated. Some important soil parameters are compared and field observations are summarised. Soil core sampling in both ASS-scalded land and surrounding areas of permanently vegetated paddocks has demonstrated similar pyrite concentrations and depth occurrence, soil salinity, and soil acidity (pH). As conditions are similar beneath both vegetated and non-vegetated land, there must be some additional factors influencing which areas become denuded. Several disparate (usually human-induced) events were found to cause initial loss of vegetative cover. Once the soil is bare, surface evaporation causes toxic solutes to build up quickly at the soil surface and ASS scalding is perpetuated. Some of the intervening events include fire, flood, flood-scouring, deliberate topsoil removal, surface pyrite oxidation, saltwater inundation of freshwater paddocks, saltwater exclusion from saltmarsh or mangroves, changes to the vegetation regimes, excessive vehicular traffic, and over-grazing. Backswamp management needs to ensure that land underlain by shallow pyritic layers (or with soil-water that is enriched with the toxic by-products of pyrite oxidation) is not laid bare by accident or design. Similar soil chemical conditions underlying both ASS scalds and the surrounding permanently vegetated paddocks suggest that much larger areas are potentially at risk of ASS scalding.

Surface and sub-surface salinity in and around acid sulfate soil scalds in the coastal floodplains of New South Wales, Australia

Soil Research ◽  
2006 ◽  
Vol 44 (1) ◽  
pp. 17 ◽  
Author(s):  
Mark A. Rosicky ◽  
Peter Slavich ◽  
Leigh A. Sullivan ◽  
Mike Hughes
Keyword(s):  
New South ◽  
New South Wales ◽  
Pyrite Oxidation ◽  
Soil Surface ◽  
Acid Sulfate Soil ◽  
Surface Salinity ◽  
Deep Soil ◽  
Acid Sulfate ◽  
South Wales ◽  
Land Denudation

Two-metre-deep soil profiles at 10 acid sulfate soil (ASS) scalds along the coast of New South Wales (NSW), Australia, were examined for salinity indicators. At 5 of the sites, permanently vegetated areas adjacent to the ASS-scalded land were also tested. Throughout the profiles, most sites had high soluble chloride (Cl−) concentrations (≤17 mg/g soil) and high soluble sulfate (SO42−) concentrations (≤17 mg/g soil). Very low Cl− : SO42− ratios (≤3) indicated active pyrite oxidation. Soil salinity (measured as electrical conductivity, EC) was extremely high in the top 2 m of most of the ASS scalds when related to the growth requirements of the typical introduced pasture species that were planted in these areas following drainage. This allows salinity, in addition to the extremely low pH of the surface soils, to contribute to land denudation, which can instigate or perpetuate pyrite oxidation and ASS-related land scalding. Although the sites had shallow watertables and soil-moisture content was high, the surface soil (top 0.10 m) of the scalds had consistently higher soluble Cl− and SO42− concentrations and EC than adjacent vegetated areas. All coastal ASS areas investigated, typically freshwater backswamps used for cattle grazing, were underlain by estuarine-derived sediments containing saline ground water. The results demonstrate that revegetation of ASS scalds must include investigation and management of salinity, in addition to acidity, within the soil profile and at the soil surface.

Techniques for revegetation of acid sulfate soil scalds in the coastal floodplains of New South Wales, Australia: ridging, mulching and liming in the absence of stock grazing

2006 ◽  
Vol 46 (12) ◽  
pp. 1589 ◽  
Author(s):  
M. A. Rosicky ◽  
P. Slavich ◽  
L. A. Sullivan ◽  
M. Hughes
Keyword(s):  
Soil Moisture ◽  
Root Zone ◽  
New South ◽  
Combined Treatment ◽  
New South Wales ◽  
Soil Parameters ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
South Wales ◽  
Vegetation Species

Two revegetation field trials were undertaken on chronically bare acid sulfate soil scalds on grazing properties in the Hawkesbury and Macleay catchments of New South Wales, Australia. The aim was to test the effectiveness of various low cost and readily accessible techniques to encourage revegetation (via existing seedbank or surrounding vegetation) of the scalded sites. The trial at the more efficiently drained Hawkesbury site used a combined treatment of ridging (R), mulching (M) and liming (L) (i.e. R–M–L) compared with a control, within a fenced area. At the more waterlogged Macleay site, various elements of the combined treatment (i.e. R, M, R–M, R–L, R–M–L) were compared with a control, within a fenced area. Vegetation occurrence, biomass and species were tested, along with pertinent soil parameters (pH, salinity, soil moisture, soluble metals). Soil testing was undertaken at 2 depth levels to represent the seed germination zone (0–1 cm), and the potential root zone (1–10 cm). At the Hawkesbury site, the combined treatment (R–M–L) caused significantly greater vegetation occurrence and biomass, lower salinity, higher pH and increased soil moisture. At the Macleay site, results were more variable, but similar to the Hawkesbury trial as the site dried out. Mulching was the single most important treatment. All mulched sites had significantly more vegetation than the control, reaching 100% coverage in the R–M–L plots. Stock exclusion alone produced minimal results. Ridging alone was counterproductive. Liming without mulching caused proliferation of an insubstantial and transient vegetation species (Isolepis inundata). Most interesting was the different vegetation species encouraged by the different mulch treatments: treatment M was dominated by the sedge, Eleocharis acuta; treatment R–M was an even mix of Eleocharis acuta and native water-tolerant grasses (Paspalum distichum and Pseudoraphis paradoxa); treatment R–M–L was dominated by the aforementioned native grasses. These grasses are highly favoured for both economic (highly palatable to stock) and environmental (thick mulch cover, self seeding) objectives. The results demonstrate that revegetation of acid sulfate soil scalds is possible, and different treatments can influence vegetation species composition.

scholarly journals Acid sulfate soils and acid drainage, Lower Shoalhaven floodplain, New South Wales

2010 ◽  
Vol 16 (2) ◽  
pp. 56 ◽  
Author(s):  
M I Pease ◽  
A G Nethery ◽  
A R. M Young
Keyword(s):  
New South ◽  
New South Wales ◽  
Acid Sulfate Soils ◽  
Acid Sulfate ◽  
Acid Drainage ◽  
South Wales ◽  
Sulfate Soils

Scattered native trees and soil patterns in grazing land on the Northern Tablelands of New South Wales, Australia

Soil Research ◽  
2007 ◽  
Vol 45 (3) ◽  
pp. 199 ◽  
Author(s):  
Brian R. Wilson ◽  
Ivor Growns ◽  
John Lemon
Keyword(s):  
New South ◽  
New South Wales ◽  
Tree Canopy ◽  
Deep Drainage ◽  
Grazing Land ◽  
Near Surface ◽  
Soil Layers ◽  
South Wales ◽  
Eastern Australia ◽  
Canopy Effect

Over large areas of south-eastern Australia, the original cover of native woodland has been extensively cleared or modified, and what remains is often characterised by scattered trees beneath which the ground-storey vegetation is largely grazed or otherwise managed. This study investigated the influence of scattered Blakely’s red gum (Eucalyptus blakelyi) trees on both near-surface and deeper soil layers in temperate grazed pastures on the Northern Tablelands of New South Wales, Australia. A significant canopy effect was observed with elevated soil pH, carbon, and nutrient status inside the tree canopy indicating soil enrichment in a zone around the tree. This effect, however, was largely restricted to the surface (0–0.20 m) soil layers. Chloride concentrations were elevated near to trees but only in the deeper soil layers, suggesting that a modified water use and deep drainage mechanism occurred near the trees. Close to the tree, however, a significant acidification was observed between 0.40–0.60 m depth in the soil, without any obvious depletion in other soil element concentrations. It is concluded that this acidification provides strong evidence in support of a ‘biological pumping’ mechanism that has been proposed elsewhere. Key questions remain as to the management implications of these results, whether the subsurface acidification that was observed is common among native Australian trees, if it might be persistent through time, and if this might be a soil issue that requires management.

Effect of tillage practice on the persistence of atrazine in two contrasting soils in northern New South Wales

1989 ◽  
Vol 29 (6) ◽  
pp. 849 ◽  
Author(s):  
IG Ferris ◽  
WL Felton ◽  
JF Holland ◽  
MS Bull
Keyword(s):  
Surface Soil ◽  
Initial Rate ◽  
New South ◽  
New South Wales ◽  
Grain Sorghum ◽  
Tillage Practice ◽  
Red Clay ◽  
Post Harvest ◽  
Tillage Practices ◽  
South Wales

Grain sorghum was sown at 2 sites at Tamworth in northern New South Wales in 1980 in order to examine the influence of fallow tillage practices and post harvest cultivation on the persistence of atrazine. In a non-cracking red clay (pH 5.7) atrazine (3.2 kg/ha) was applied both to the sorghum fallow and at sowing (1.8 kg/ha). The concentration of carryover atrazine 3 months after sorghum harvest was 0.11 µg/g in the 0-5 cm mil layer and 0.06 µg/g in the 5-15 cm layer. By contrast, the same treatment resulted in 0.61 and 0.52 µg/g in the 0-5 and 5-15 cm zones of a grey clay (pH 7.5). Cultivation after the sorghum was harvested reduced the atrazine residue in the surface soil (0-5 cm) by 20-40%, depending on the initial rate of application. There was no associated increase in the 5-15 cm zone. Despite the reduction in the amount of atrazine residue, cultivation increased the severity of atrazine injury to wheat sown at the grey clay site. There was no evidence of phytotoxicity at the red clay site.

Natural enrichment of topsoils with chromium and other heavy metals, Port Macquarie, New South Wales, Australia

Soil Research ◽  
1997 ◽  
Vol 35 (5) ◽  
pp. 1165 ◽  
Author(s):  
Bernd G. Lottermoser
Keyword(s):  
Heavy Metal ◽  
Surface Soil ◽  
New South ◽  
New South Wales ◽  
Soil Samples ◽  
Metal Concentrations ◽  
Mean Values ◽  
Heavy Metal Concentrations ◽  
Environmental Investigation ◽  
South Wales

Total heavy metal concentrations [cobalt (Co), chromium (Cr), copper(Cu), iron (Fe), mangnese (Mn), nickel (Ni), lead (Pb), and zinc (Zn)]were determined in surface soil samples from Port Macquarie, New South Wales,Australia. Composite topsoil samples (0–10 cm depth) had mean values(per kg) of 13 mg Co, 1020 mg Cr, 59 mg Cu, 136·7 g Fe, 719 mg Mn, 149mg Ni, 20 mg Pb, and 47 mg Zn. The topsoils were generally characterised by alow pH (3·8–5·2) and a mineralogy dominated by haematite,magnetite, quartz, and kaolinite. Chromium was predominantly present in thetopsoils as Cr3+ in microcrystalline chromite(FeCr2O4) and, to a lesser degree,in kaolinite and haematite. Differences in Cr soil concentrations with depthwere due to variations in the relative abundance of the various soilcomponents, rather than Cr3+ mobility within the soilprofile. The elevated heavy metal concentrations are the result of soildevelopment over metal-rich bedrock (serpentinite matrix melange) andassociated enrichment of relatively immobile elements (Cr, Fe, Ni) in theresidual soil profile. The ANZECC and NH&MRC (Australian and New ZealandEnvironment and Conservation Council and National Health & MedicalResearch Council) environmental investigation limits were exceeded for100% of the sample sites for Cr, 47% for Cu, 61% for Mn,and 58% for Ni.

The fate of nitrogen fertilisers added to red gradational soils at Batlow, New South Wales, and its implications with respect to soil acidity

Soil Research ◽  
1997 ◽  
Vol 35 (4) ◽  
pp. 863 ◽  
Author(s):  
I. P. Little
Keyword(s):  
Ammonium Sulfate ◽  
Soil Acidity ◽  
Surface Soil ◽  
Soil Analysis ◽  
New South ◽  
New South Wales ◽  
Soil Profiles ◽  
Eucalypt Forest ◽  
South Wales ◽  
Exchangeable Ca

Red gradational soils at Batlow, in New South Wales, which are used for apple growing, have acid subsoils with exchangeable aluminium (Al) frequently in excess of exchangeable calcium (Ca). There is often inadequate Ca in the fruit cortex of post-harvest apples to maintain good fruit quality and this can lead to losses in cool-store. It is possible that Al in these acid subsoils has interfered with Ca uptake by the trees. The excessive use of nitrogenous fertilisers leads to soil acidity, and it was thought likely that this was exacerbating the subsoil acidity common in the district. In October 1992, soil analysis detected considerable ammonium in the surface 0·3 m at orchard sites at Batlow monitored for mineral nitrogen (N). This probably came from heavy spring dressings of fertiliser. One site examined in detail showed that about half of the ammonium had disappeared by January 1993, but a large nitrate envelope appeared with a peak at 0·6 m which in turn disappeared by April that year. This establishes that heavy applications of ammonium are nitrified, leached into the subsoil, and lost. Under such a high N regime, orchard soil profiles should be more acid than adjacent forest soils. However, it was found that the acidity of the surface soil was less, and the exchangeable Ca greater in the orchard soils, compared with soil profiles in the adjacent eucalypt forest, although amelioration of the subsoils had not occurred. Samples taken from representative sites at Batlow, at the 0–0·1, 0·1–0·2, and 0·3–0·4 m depths, were dosed with ammonium sulfate and leached with water in the laboratory for 23 days in a free-draining environment. Nitrate and ammonium were determined in the leachates. At the end of the experiment, the pH and exchangeable Ca, Mg, and Mn were determined in the leached samples. Only the neutral surface soils were able to nitrify ammonium effectively and nitrification was positively correlated with pH, and with exchangeable Ca and Mg. From this it is argued that the acidity produced by the addition of ammonium sulfate or urea will be nitrified in the surface but the acidity produced will be neutralised, provided it is accompanied by an adequate dressing of lime. Ammonium tends to remain in the surface soil, but if leached, it will not be nitrified in the subsoil. Nitrate leached into the subsoil will not be acid-forming but, if denitrified, may help to reduce acidity. For this work, the soil pH was measured in 1 KCl. So that readers can refer this to the pH in 0·01 CaCl2, a relationship was established between the two measures.

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