Sulfide oxidation and acidification of acid sulfate soil materials treated with CaCO3 and seawater-neutralised bauxite refinery residue

Soil Research ◽  
2002 ◽  
Vol 40 (6) ◽  
pp. 1057 ◽  
Author(s):  
Nicholas J. Ward ◽  
Leigh A. Sullivan ◽  
Richard T. Bush
Keyword(s):  
Sulfide Oxidation ◽  
Pyrite Oxidation ◽  
Application Rate ◽  
The Other ◽  
Optimal Rate ◽  
Initial Increase ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Application Rates ◽  
Incubation Experiments

Acid sulfate soil (ASS) materials that are subject to oxidation are often treated with neutralising agents to minimise the export of acidity that may result from pyrite oxidation. The effects of additions of both CaCO3 and seawater-neutralised bauxite refinery residue (SNBRR) on the oxidation of sulfides and acidification were assessed for 4 ASS materials using laboratory incubation experiments. As the application of sub-optimal rates of neutralising materials can occur for a variety of reasons, the effect of application rates were also examined. Two application rates were chosen; a sub-optimal rate [approximately 20% of the theoretical neutralising requirement (NR)] and an excessive application rate (>250% of the NR). There was minimal sulfide oxidation and no acidification after the addition of excess CaCO3 over the 180 days of incubation. The addition of excess SNBRR prevented acidification, but substantial sulfide oxidation still occurred. Following a brief initial increase in pH when sub-optimal rates of CaCO3 and SNBRR were applied, the treated ASS materials rapidly acidified. For three of the ASS materials the addition of sub-optimal amounts of CaCO3 had little impact on the rate of sulfide oxidation. However, for the other ASS material (a peat) both the rates of sulfide oxidation and acidification were accelerated by the addition of sub-optimal rates of CaCO3, resulting in higher soluble Fe and Al concentrations than in the untreated ASS materials. For some of the ASS materials, sub-optimal applications of SNBRR resulted in elevated soluble Al.

Soil pH, oxygen availability, and the rate of sulfide oxidation in acid sulfate soil materials: implications for environmental hazard assessment

Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 509 ◽  
Author(s):  
Nicholas J. Ward ◽  
Leigh A. Sullivan ◽  
Richard T. Bush
Keyword(s):  
Hazard Assessment ◽  
Oxygen Diffusion ◽  
Sulfide Oxidation ◽  
Oxygen Availability ◽  
Environmental Hazard ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Plastic Bags ◽  
Actual Acidity ◽  
Environmental Hazard Assessment

The potential environmental hazard of acid sulfate soil (ASS) materials is directly related to both the net acidity and the rate that actual acidity is released from these soil materials into the environment. While current environmental hazard assessment techniques for ASS materials are able to quantify the net acidity, they do not take account of differences in the rate of sulfide oxidation (the dominant source of actual acidity) and differences in the rate of acidification. In this study the rate of sulfide oxidation during incubation was examined for 4 ASS materials. The effect of pH and oxygen availability on the rate of sulfide oxidation was assessed. The ASS materials were incubated in: (i) gauze where oxygen diffusion was not restricted, and (ii) sealed 100-µm-thick plastic bags which greatly limited oxygen diffusion. When oxygen diffusion was not restricted, an accelerated oxidation of sulfide occurred when the pH decreased below pH 4.0. The accelerated rate of sulfide oxidation at such low pH did not occur when oxygen diffusion was limited. This study indicates that the initial pH of an ASS material is a useful additional indicator of the potential environmental hazard of an ASS material when oxygen is expected to be non-limiting, such as when ASS materials are excavated and stockpiled. The recommended action criteria need to be reassessed, as the data indicate that the current criteria are conservative for alkaline and neutral ASS materials, but should be lowered for all acidic ASS materials (i.e. pH <5.5) to 0.03% sulfide regardless of texture.

The response of partially oxidised acid sulfate soil materials to anoxia

Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 515 ◽  
Author(s):  
Nicholas J. Ward ◽  
Leigh A. Sullivan ◽  
Richard T. Bush
Keyword(s):  
Organic Matter ◽  
Sulfide Oxidation ◽  
Management Strategies ◽  
Oxidation Products ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Anoxic Conditions ◽  
Inorganic Sulfur

Four acid sulfate soil (ASS) materials were subjected to anoxia after varying periods of oxidation to determine the geochemical response of these types of soils to flooding. The response of the partially oxidised ASS materials to the exclusion of oxygen was variable. The rate of sulfide oxidation, acidification, and the production of soluble oxidation products such as sulfate, iron, and aluminium generally decreased markedly when subjected to anoxia. However, especially in the highly acidic ASS materials (i.e. pH <3.5), sulfide oxidation and acidification generally continued (albeit at much slower rates), most probably due to oxidation by Fe3+. Rapid sulfide re-formation occurred in the peat ASS material that had been oxidised for 63 days, with 0.47% reduced inorganic sulfur (SCR) formed over 60 days of anoxia. This substantial sulfide re-formation was accompanied by only a slight increase in pH. Minimal sulfide re-formation occurred in 2 of the ASS materials when placed in anoxic conditions, most likely due to a lack of readily available organic matter in these materials. The results show that the imposition of anoxic conditions on partially oxidised ASS materials is generally effective in decreasing the rates of further sulfide oxidation, acidification, and the production of soluble sulfide oxidation products. Biogeochemical sulfide formation consumes acidity; however, sulfide re-formation was ineffective in reversing acidification under the conditions of this experiment. The results indicate that the treatment of sites containing actual ASS materials by management strategies relying on oxygen exclusion need to be accompanied by other strategies that include acidty neutralisation or containment.

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.

scholarly journals Rice Straw Composting by Cellulolytic Bacteria Isolate and Its Application on Rice in Acid Sulfate Soils

2020 ◽  
Vol 20 ◽  
pp. 01006
Author(s):  
Yuli Lestari ◽  
Eni Maftu’ah ◽  
Wahida Annisa
Keyword(s):  
Water Content ◽  
Pyrite Oxidation ◽  
Dry Weight ◽  
Acid Sulfate Soils ◽  
Acid Sulfate Soil ◽  
Cellulolytic Bacteria ◽  
Acid Sulfate ◽  
Rice Growth ◽  
Randomized Design ◽  
Sulfate Soils

High acidity in acid sulfate soils due to pyrite oxidation results in increased Al3+ and Fe2+ activity which inhibits the growth of rice plants. The application of organic matter (compost) is one of the technology to manage acid sulfate soil. This study aims to obtain cellulolytic bacterial isolates that are superior in composting and improving rice growth in acid sulfate soil. The experiment carries out in the laboratory and glasshouse of the Indonesian Swampland Agriculture Research Institute (ISARI), Banjarbaru, Indonesia on May-November 2017. The experimental to obtain cellulolytic bacteria and water content that can accelerate composting is arranged by factorial using a complete randomized design with three replication First factor were cellulolytic bacteria application (without application/control, BS 1.6, BS 1.9, BS 2.2 and BS 2.5), while the second factor was water content (50%, 100%, and 150%). The effect of compost application with cellulolytic bacterial to rice growth arranged by factorial completely randomized design with 3 replications. The first factor was cellulolytic bacteria application (without application/control, BS 1.6, BS 1.9, and BS 2.2), while the second factor was composting condition (muddy waterlogged and waterlogged 5 cm depth). The result showed that the ability of cellulolytic bacteria to reduce C/N straw was not different. Only differences in water content affect the reducing C/N ratio of straw. The average C/N ratio of straw compost made with 50%, 100%, and 150% water content is 35.59; 29.71, and 29.21. Application of compost made under muddy waterlogged and inoculated BS1.9 and BS2.2 can increase the number of tillers, while those inoculated BS1.6 and BS1.9 can increase the rice shoot dry weight of Inpara 2. The suggest that cellulolytic bacterial inoculation can improve the quality of compost so that the growth of rice is better.

The process of sulfide oxidation in some acid sulfate soil materials

Soil Research ◽  
2004 ◽  
Vol 42 (4) ◽  
pp. 449 ◽  
Author(s):  
N. J. Ward ◽  
L. A. Sullivan ◽  
D. M. Fyfe ◽  
R.T. Bush ◽  
A. J. P. Ferguson
Keyword(s):  
Sulfide Oxidation ◽  
Water Soluble ◽  
Oxidation Products ◽  
Total Acid ◽  
Sulfur Species ◽  
Acid Sulfate ◽  
Incubation Experiments ◽  
O2 Concentration ◽  
Order Of Magnitude ◽  
Sulfate Soils

The process of sulfide oxidation in acid sulfate soils (ASS) is complex, involving the formation of numerous oxidation products. In this study the sulfide oxidation process was examined in 2 ASS materials over a period of 36 days using laboratory incubation experiments. Both ASS materials experienced substantial sulfide oxidation and acidification during incubation. The oxidation of pyrite was the primary cause of acidification in these ASS materials. Although a decrease in magnetic susceptibility (χ) over the initial 4 days of incubation suggested the rapid oxidation of ferromagnetic iron monosulfide greigite (Fe3S4), the total acid volatile sulfur (SAV) fraction increased in concentration by an order of magnitude over the initial 8 days of incubation. Oxygen (O2) concentration profiles indicated the presence of anoxic conditions in the centre of the incubating materials even after 16 days of exposure to the atmosphere enabling SAV formation to occur. The oxidation of the SAV fraction did not result in substantial acidification. A large proportion of the water-soluble iron released by sulfide oxidation was precipitated as iron oxides and hydroxides. Sulfate (SO42–) was the dominant sulfur species produced from sulfide oxidation in both ASS materials, although water-soluble SO42– was a poor indicator of the extent of sulfide oxidation. The sulfoxyanion intermediates, thiosulfate (S2O32–) and tetrathionate (S4O62–), were detected only in the early stages of incubation, with minimal amounts being detected after the initial 4 days. The relative abundance of these 2 intermediate sulfur species appeared to be dependent on the soil pH, with S4O62– dominating S2O32– in the more acidic ASS material (i.e. pH <6) as has been observed in previous studies. The diminishing presence of sulfoxyanion intermediates as oxidation progressed was indicative that ferric ion (Fe3+) and bacterial catalysis were driving the oxidation processes. While these sulfoxyanion intermediates only constituted a small percentage of the reduced inorganic sulfur (RIS) fraction, they accounted for up to 9.3% of the total soluble sulfur fraction. Elemental sulfur (S0) was not an important sulfide oxidation product in the ASS materials examined in this study.

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.

The acid flux dynamics of two artificial drains in acid sulfate soil backswamps on the Clarence River floodplain, Australia

Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 623 ◽  
Author(s):  
S. G. Johnston ◽  
P. Slavich ◽  
P. Hirst
Keyword(s):  
Temporal Dynamics ◽  
Sulfide Oxidation ◽  
Soil Surface ◽  
Drainage Density ◽  
Oxidation Products ◽  
Acid Sulfate Soil ◽  
Flux Dynamics ◽  
Acid Sulfate ◽  
High K ◽  
Very High

The export of acidity, iron, aluminium, and sulfate to an estuary from 2 drains in acid sulfate soil backswamps was monitored over 18 months. The backswamps had similar geomorphology, stratigraphy, and drainage density, and comparable soil and groundwater acidity. However, the flux rates, temporal dynamics, and export pathways of acid and other sulfide oxidation products varied greatly and were controlled to first order by (i) the saturated hydraulic conductivity (K) of sulfuric horizons and (ii) the tidally influenced groundwater gradients. The site with very high K and large tidally influenced groundwater gradients had high acid flux rates (5300 mol H+/ha.year), chronic acid discharge, high drain water acid and metal concentrations, and the primary flux pathway was direct groundwater seepage (interflow/bypass flow) to the drain. The site with lower K and smaller groundwater gradients displayed low acid flux rates (50 mol H+/ha.year), infrequent, highly episodic discharge, and the primary flux pathway was dilute surface runoff following dissolution of sulfide oxidation products accumulated on the soil surface. Importantly, the majority of acid export at both sites occurred while the backswamp groundwater level was within a very narrow elevation range.

scholarly journals Influence of Bark, Dolomite, and Fertilizer Sources on Leachate pH of Nursery Medium

HortScience ◽  
1997 ◽  
Vol 32 (4) ◽  
pp. 592E-592
Author(s):  
Allen D. Owings ◽  
Edward W. Bush ◽  
Mitchell W. Goyne
Keyword(s):  
Block Design ◽  
Application Rate ◽  
The Other ◽  
Evaluation Period ◽  
Dolomitic Lime ◽  
Application Rates ◽  
Randomized Complete Block Design ◽  
Lime Application ◽  
One Year ◽  
The One

Leachates were collected at 3-month intervals over 12 months to determine the influence of bark, controlled-release fertilizer, and dolomitic lime sources and dolomitic lime application rates on pH of nursery media. The randomized complete-block design was arranged as a factorial and included three bark sources (pinebark, hardwood, and pinebark + hardwood), two fertilizer sources (Nutricote 17-7-8 and SierraBlen 18-7-10), and two dolomitic lime sources (microencapsulated granular and pulverized). Dolomitic lime application rates were 0, 5, 10, and 15 pounds per cubic yard. Leachate pH was influenced over the one-year evaluation period by fertilizer source, bark source, and application rate of dolomitic lime. Dolomitic lime source was not a significant factor in adjustment of leachate pH. Pinebark medium had lower leachate pHs than hardwood medium and the medium containing hardwood and pinebark. Dolomitic lime influenced leachate pH of pinebark medium more than the other bark sources. SierraBlen was more acid-forming than Nutricote.

scholarly journals Growth of Tree Species in Response to Controlled-release Fertilizer Sources and Application Rates in a Commercial Nursery Setting

HortScience ◽  
1998 ◽  
Vol 33 (4) ◽  
pp. 603b-603
Author(s):  
Allen D. Owings ◽  
Edward W. Bush
Keyword(s):  
Controlled Release ◽  
Visual Quality ◽  
Application Rate ◽  
The Other ◽  
Control Treatment ◽  
Red Maple ◽  
Shoot Height ◽  
Controlled Release Fertilizer ◽  
Application Rates ◽  
Quality Ratings

A study was initiated at Bracy's Nursery, Amite, La., in Apr. 1997 to evaluate the influence of seven controlled-release fertilizer sources and three top-dressed application rates in production of 4-gal (15.7-L) containers of `LaFeliciana' peach and swamp red maple. The fertilizers tested were Osmocote Plus 15-9-11, Osmocote Plus 16-8-12, Woodace 20-5-10, Woodace 20-4-11, Customblen 24-4-6, Nutricote (Type 270) 17-7-8, and Nutricote (Type 360) 17-6-8. Application rates were 1.75, 2.25, and 2.75 lb N per cubic yard. The experiment was completely randomized within blocks (species) and each treatment was replicated five times. A control treatment was also included. For `LaFeliciana' peach, Nutricote and Osmocote yielded the superior results when shoot height and visual quality ratings were determined in October (6 months after initiation). Increases in application rate did not significantly increase shoot height or visual quality ratings in most cases. For swamp red maple, shoot height was not affected by fertilizer source or application rate. Caliper ranged from 19.2 to 23.0 mm but was only slightly influenced by fertilizer source and application rate. Visual quality ratings were significantly higher for Osmocote Plus 16-8-12 when compared to some of the other fertilizer sources.

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