scholarly journals Effects of redox processes on soil acidity.

1987 ◽  
Vol 35 (3) ◽  
pp. 271-279 ◽  
Author(s):  
N. van Breemen
Keyword(s):  
Ferrous Sulfate ◽  
Soil Surface ◽  
Chemical Components ◽  
Redox Processes ◽  
Acid Sulfate Soils ◽  
Alkaline Soils ◽  
Acid Sulfate ◽  
Simultaneous Formation ◽  
Seawater Sulfate ◽  
Sulfate Soils

Redox processes due to alternating aerobic and anaerobic conditions may give rise to strongly acidic or alkaline soils and waters. First, oxidized chemical components tend to be more acidic or less alkaline than their reduced counterparts. Second, and more important, redox processes often lead to the simultaneous formation of acidic (or potentially acidic) and alkaline substances with different mobility (dissolved or gaseous versus adsorbed or solid), so that one of the two substances can be exported, leaving a more acidic or more alkaline residue. Examples of acidification or alkalinization processes in wetlands based on these principles are: (1) formation of acid sulfate soils (transformation of seawater sulfate and sedimentary iron to immobile potential acidity (FeS2) and mobile alkalinity (HCO3-), followed by oxidation of FeS2 after the alkalinity has disappeared), (2) alkalinization of periodically flooded acid sulfate soils (formation of dissolved ferrous sulfate during reduction, and oxidation of the ferrous sulfate to ferric oxide and sulfuric acid at the soil surface, followed by drainage of the acid floodwater), (3) ferrolysis (immobilization of seasonally reduced ferric iron as exchangeable Fe2+, and removal of replaced bases by drainage, followed by oxidation of Fe2+ -clay to H+ -clay), and (4) soil alkalinization in closed depressions (reduction of sodium sulfate to sodium (hydrogen) carbonate and volatile H2S). (Abstract retrieved from CAB Abstracts by CABI’s permission)

Oxidation rate of pyrite in acid sulfate soils: in situ measurements and modelling

Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 499 ◽  
Author(s):  
F. J. Cook ◽  
S. K. Dobos ◽  
G. D. Carlin ◽  
G. E. Millar
Keyword(s):  
Oxidation Rate ◽  
Volume Ratio ◽  
Soil Surface ◽  
Biological Processes ◽  
Acid Sulfate Soils ◽  
Acid Sulfate ◽  
The Difference ◽  
Actual Acidity ◽  
Sulfate Soils

The generation of acidity from oxidation of pyrite in acid sulfate soils requires the transport of oxygen into the soil profile. The sink for this oxygen will not only be the chemical reaction with pyrite but the biological processes associated with both microbial and plant respiration. The biological sinks in burning the oxygen (O2) will release CO2. The respiratory quotient which is the molar volume ratio of O2 : CO2 varies between 1.3 and 0.7 depending on the source of the organic matter being oxidised, but is generally 1.0. The oxidation of pyrite by oxygen will, by comparison with the biological processes, produce minor amounts of CO2 (if any) by reaction with intrinsic carbonate minerals. Gas samplers were installed into the soil at various depths and samples collected from these at approximately fortnightly intervals. The samples were analysed by gas chromatography and the CO2 and O2 profiles obtained. The flux of these gases was calculated and the difference between these attributed to the oxidation of pyrite. The flux difference varied over the period of sampling and on average gave an in situ oxidation rate of 11.5 tonnes H2SO4/ha.year. This is considerably more that the rate of export of acidity from this site and would explain the considerable actual acidity storage in these soils. A model is developed for steady state transport of oxygen into soils with an exponentially decreasing biological sink with depth and an exponentially increasing chemical (pyrite) sink with depth. The model is developed in non-dimensional variables, which allows the relative strengths and rates of increase or decrease in sink terms to be explored. This model does not explicitly treat the flow of oxygen in macropores. Other models that do explicitly calculate macropore flow are compared and found to give similar results. These results suggest that the use of biological or other sinks near the soil surface could be a useful method for reducing the oxidation rate of pyrite in acid sulfate soils.

Upland active acid sulfate soils from construction of new Stafford County, Virginia, USA, Airport

Soil Research ◽  
2004 ◽  
Vol 42 (6) ◽  
pp. 527 ◽  
Author(s):  
D. S. Fanning ◽  
Cary Coppock ◽  
Z. W. Orndorff ◽  
W. L. Daniels ◽  
M. C. Rabenhorst
Keyword(s):  
Land Surface ◽  
Soil Surface ◽  
Great Difficulty ◽  
Acid Sulfate Soils ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Salt Minerals ◽  
Land Surfaces ◽  
Sulfate Soils ◽  
Steep Slopes

This paper reports on a situation where severe active acid sulfate soils were brought into existence by the construction of a new (opened in 2002) airport in Stafford County, VA, approximately 60 km south-west of Washington, DC. About 290 ha of new land surface was brought into existence that consisted of both scalped land surfaces on steep slopes, and spoil (fill), some of which was graded to provide level land surfaces for paved runways. Over 150 ha of ultra acidic (pH <3.5 at soil surface) post-construction acid sulfate soils remained barren for over 2 years before the acid sulfate soil situation was properly recognised. Construction took place in an originally dissected landscape with about 30 m of local relief. The construction was designed to balance the cut and fill areas so that soil materials would not need to be taken from the area or brought to it from other locations. This resulted in some deep cuts (scalped surfaces) in the higher parts of the landscapes, which retained slopes of about 25%. Great difficulty was encountered in establishing vegetation on these surfaces. The exposed sulfidic materials were dense, commonly on steep slopes, and developed low pHs, some <pH 2, after exposure. After a dry period in the autumn of 2001, sulfuric horizons crusted over with bitter hydrated sulfate salt minerals had formed in the surface of sulfidic materials originally exposed in 1999. By X-ray diffraction, halotrychite, Fe2+Al2(SO4)4.22H2O, was identified as a main white salt mineral and copiapite group minerals, e.g. Al2/3Fe3+4(SO4)6(OH)2.20H2O for aluminocopiapite, were identified as a yellow salt minerals. Information about, and photographs of, the site, soils, and drainage waters are presented, including examples of deleterious environmental impacts. Intensive reclamation/revegetation measures were initiated in 2002. These involved the application of high rates of lime stabilised biosolids (sewage sludge) incorporated to a depth of about 0.15 m to neutralise acidity and add organic matter and nutrients to the soils. These measures permitted the establishment of acid- and salt-tolerant grasses on the acid sulfate soils and caused dramatic increases in pH and drops in Fe and Al levels in stream waters leaving the site. However, they also caused initial large increases in ammonia/ammonium-N in the waters and subsequent increases in NO3-N in the waters. Experience with this and other similar sites demonstrates the need for engineers involved with earth-moving construction activities to be educated in the principles of acid sulfate soils so that the number of such disturbances that result in the creation of active acid sulfate soils can be lessened or, preferably, eliminated. Plans for recognition and reclamation of acid sulfate soil situations should be built into the construction plans and designs when it is necessary to disturb sulfidic materials.

PEUBAH KUALITAS AIR YANG MEMPENGARUHI PERTUMBUHAN RUMPUT LAUT (Gracilaria verrucosa) DI TAMBAK TANAH SULFAT MASAM KECAMATAN ANGKONA KABUPATEN LUWU TIMUR PROVINSI SULAWESI SELATAN

2009 ◽  
Vol 4 (1) ◽  
pp. 125
Author(s):  
Akhmad Mustafa ◽  
Rachmansyah Rachmansyah ◽  
Dody Dharmawan Trijuno ◽  
Ruslaini Ruslaini
Keyword(s):  
Water Quality ◽  
Growth Rate ◽  
Ammonium Phosphate ◽  
Gracilaria Verrucosa ◽  
Acid Sulfate Soils ◽  
Acid Sulfate Soil ◽  
Acid Sulfate ◽  
Independent Variables ◽  
Water Quality Variables ◽  
Sulfate Soils

Rumput laut (Gracilaria verrucosa) telah dibudidayakan di tambak tanah sulfat masam dengan kualitas dan kuantitas produksi yang relatif tinggi. Oleh karena itu, dilakukan penelitian yang bertujuan untuk mengetahui peubah kualitas air yang mempengaruhi laju pertumbuhan rumput laut di tambak tanah sulfat masam Kecamatan Angkona Kabupaten Luwu Timur Provinsi Sulawesi Selatan. Pemeliharaan rumput laut dilakukan di 30 petak tambak  terpilih selama 6 minggu. Bibit rumput laut dengan bobot 100 g basah ditebar dalam hapa berukuran 1,0 m x 1,0 m x 1,2 m. Peubah tidak bebas yang diamati adalah laju pertumbuhan relatif, sedangkan peubah bebas adalah peubah kualitas air yang meliputi: intensitas cahaya, salinitas, suhu, pH, karbondioksida, nitrat, amonium, fosfat, dan besi. Analisis regresi berganda digunakan untuk menentukan peubah bebas yang dapat digunakan untuk memprediksi peubah tidak bebas. Hasil penelitian menunjukkan bahwa laju pertumbuhan relatif rumput laut di tambak tanah sulfat masam berkisar antara 1,52% dan 3,63%/hari dengan rata-rata 2,88% ± 0,56%/hari. Di antara 9 peubah kualitas air yang diamati ternyata hanya 5 peubah kualitas air yaitu: nitrat, salinitas, amonium, besi, dan fosfat yang mempengaruhi pertumbuhan rumput laut secara nyata. Untuk meningkatkan pertumbuhan rumput laut di tambak tanah sulfat masam Kecamatan Angkona Kabupaten Luwu Timur dapat dilakukan dengan pemberian pupuk yang mengandung nitrogen untuk meningkatkan kandungan amonium dan nitrat serta pemberian pupuk yang mengandung fosfor untuk meningkatkan kandungan fosfat sampai pada nilai tertentu, melakukan remediasi untuk menurunkan kandungan besi serta memelihara rumput laut pada salinitas air yang lebih tinggi, tetapi tidak melebihi 30 ppt.Seaweed (Gracilaria verrucosa) has been cultivated in acid sulfate soil-affected ponds with relatively high quality and quantity of seaweed production. A research has been conducted to study water quality variables that influence the growth of seaweed in acid sulfate soil-affected ponds of Angkona Sub-district East Luwu Regency South Sulawesi Province. Cultivation of seaweed was done for six weeks in 30 selected brackishwater ponds. Seeds of seaweed with weight of 100 g were stocked in hapa sized 1.0 m x 1.0 m x 1.2 m. Dependent variable that was observed was specific growth rate, whereas independent variables were water quality variables including light intensity, salinity, temperature, pH, carbondioxide, nitrate, ammonium, phosphate, and iron. Analyses of multiple regressions were used to determine the independent variables which could be used to predict the dependent variable. Research result indicated that relative growth rate of seaweed in acid sulfate soils-affected brackishwater ponds ranged from 1.52% to 3.63%/day with 2.88% ± 0.56%/day in average. Among nine observed water quality variables, only five variables namely: nitrate, salinity, ammonium, phosphate and iron influence significantly on the growth of seaweed in acid sulfate soils-affected brackishwater ponds. The growth of seaweed in acid sulfate soils-affected brackishwater ponds of Angkona District East Luwu Regency, can be improved by using nitrogen-based fertilizers to increase ammonium and nitrate contents and also fertilizers which contain phosphorus to improve phosphate content to a certain level. Pond remediation to decrease iron content and also rearing seaweed at higher salinity (but less than 30 ppt) can also be alternatives to increase the growth of seaweed.

scholarly journals Bacillus Cyclic Lipopeptides Iturin and Fengycin Control Rice Blast Caused by Pyricularia oryzae in Potting and Acid Sulfate Soils by Direct Antagonism and Induced Systemic Resistance

2021 ◽  
Vol 9 (7) ◽  
pp. 1441
Author(s):  
Van Bach Lam ◽  
Thibault Meyer ◽  
Anthony Arguelles Arias ◽  
Marc Ongena ◽  
Feyisara Eyiwumi Oni ◽  
...  
Keyword(s):  
Rice Blast ◽  
Induced Systemic Resistance ◽  
Pyricularia Oryzae ◽  
Blast Disease ◽  
Systemic Resistance ◽  
Acid Sulfate Soils ◽  
Acid Sulfate ◽  
Wide Range ◽  
Bacillus Spp ◽  
Sulfate Soils

Rice monoculture in acid sulfate soils (ASSs) is affected by a wide range of abiotic and biotic constraints, including rice blast caused by Pyricularia oryzae. To progress towards a more sustainable agriculture, our research aimed to screen the biocontrol potential of indigenous Bacillus spp. against blast disease by triggering induced systemic resistance (ISR) via root application and direct antagonism. Strains belonging to the B. altitudinis and B. velezensis group could protect rice against blast disease by ISR. UPLC–MS and marker gene replacement methods were used to detect cyclic lipopeptide (CLiP) production and construct CLiPs deficient mutants of B. velezensis, respectively. Here we show that the CLiPs fengycin and iturin are both needed to elicit ISR against rice blast in potting soil and ASS conditions. The CLiPs surfactin, iturin and fengycin completely suppressed P. oryzae spore germination resulting in disease severity reduction when co-applied on rice leaves. In vitro microscopic assays revealed that iturin and fengycin inhibited the mycelial growth of the fungus P. oryzae, while surfactin had no effect. The capacity of indigenous Bacillus spp. to reduce rice blast by direct and indirect antagonism in ASS conditions provides an opportunity to explore their usage for rice blast control in the field.

CARACTÉRISTIQUES DES SOLS SULFATÉS ACIDES DE LA SÉRIE DE L'ANSE EN MILIEU ESTUARIEN (QUÉBEC)

1988 ◽  
Vol 68 (3) ◽  
pp. 577-592
Author(s):  
C. R. DE KIMPE ◽  
M. R. LAVERDIERE ◽  
R. W. BARIL
Keyword(s):  
Key Words ◽  
Lower Limit ◽  
Marine Sediments ◽  
Acid Sulfate Soils ◽  
Acid Sulfate ◽  
Organic C ◽  
South Shore ◽  
Sulfate Soils ◽  
Sulfate Leaching ◽  
St Lawrence River

Acid sulfate soils were sampled according to the transect method in four bays along the south shore of the St. Lawrence river to determine their properties in their area of distribution. In each bay, six profiles of cultivated soils were sampled along a transect perpendicular to the river. One non-cultivated profile was also sampled at l'Isle-Verte. The lower limit of the B horizons, between 79 and 89 cm, suggested a homogeneous development of these soils across the area. Most profiles contained jarosite in the lower Bg and, sometimes, in the C horizons; this mineral was absent in the upper part of the profiles of soils that had been limed prior to cultivation. Total S content increased with depth, but only a few horizons had a content > 0.75% presumably because of sulfate leaching once the soils were drained. Organic C content in the de l'Anse soils decreased less rapidly with depth than in other gleysolic soils, because vegetation grew while sediments were being deposited. Key words: Acid sulfate soils, total S, recent marine sediments, jarosite

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