Soil solution pH measurements using in-line chambers with tension lysimeters

2000 ◽  
Vol 80 (2) ◽  
pp. 283-288 ◽  
Author(s):  
Bo Elberling ◽  
Bjarne H. Jakobsen
Keyword(s):  
Soil Solution ◽  
Soil Acidification ◽  
Solution Ph ◽  
Ph Change ◽  
Ph Measurements ◽  
Partial Pressures ◽  
Arctic Soil ◽  
Soil Solutions ◽  
Speciation Modelling ◽  
Ph Range

During soil water extraction, pH can change as a result of atmospheric gas exchange. The pH change is important for monitoring soil acidification and determination of mineralogic controls on the solution composition. As part of a global change programme in Greenland for monitoring long-term changes in Arctic soil solutions we observed that the pH of extracted soil solutions increased in the order of a half pH unit during traditional sampling and handling of the soil solution. CO2 degassing is often considered the most important factor causing such a pH increase. Thus, traditional as well as in-line pH measurements were performed during the summers 1997 and 1998. The in-line method was designed to eliminate atmospheric contact with soil solutions prior to pH measurements. The time-dependent pH error was quantified based on laboratory experiments with soil solution under controlled temperatures and CO2 partial pressures. Equilibrium speciation modelling was used to predict pH values observed in the field and in the laboratory and the model was found to reproduce the observations well. We conclude that traditional pH measurements on extracted soil solutions in the pH range from 5 to 7 are not appropriate for detailed pH measurements due to errors associated with CO2 degassing. In-line measurements provide more accurate measurement necessary for detailed studies on soil acidification dynamics. Key words: pH, carbon dioxide degassing, soil solution, tension lysimeter, arctic soil

The relationship between soil solution pH and Al3+concentrations in a range of South Island (New Zealand) soils

Soil Research ◽  
2000 ◽  
Vol 38 (1) ◽  
pp. 141 ◽  
Author(s):  
M. L. Adams ◽  
D. J. Hawke ◽  
N. H. S. Nilsson ◽  
K. J. Powell
Keyword(s):  
New Zealand ◽  
Soil Solution ◽  
Chelating Resin ◽  
Curvilinear Relationship ◽  
Published Data ◽  
Solution Ph ◽  
Resultant Data ◽  
Soil Solutions ◽  
Ph Range ◽  
The Relationship

Concentrations of Al3+ were calculated in soil solutions from concentrations of the monomeric ‘reactive Al’ species ([Al3+] + [Al(OH)2+] + [Al(OH)2+] + [AlF2+]) obtained using a recently reported flow injection analysis (FIA) chelating resin technique. Soil solution samples came from 7 sites encompassing a range of New Zealand soils (Brown, Gley, Pallic, Podzol, and Recent Soils) and vegetation types (pasture, shrub lands, and indigenous and exotic forest). Previously published data from a further 7 sites, obtained using a rapid (7 s) FIA technique, were transformed to give compatible results. The resultant data (n = 85) covered the pH range 2.7–7.6, and showed a single curvilinear relationship for log [Al3+] v. soil solution pH, regardless of vegetation or soil type. At pH >5.6, the data had a slope of –2.98 and fell between the amorphous Al(OH)3 and gibbsite solubility lines. At pH <5.0, the data had a slope of –0.46; further, the soil solutions were under-saturated with respect to both minerals. These results are interpreted as indicating control of Al solubility by Al(OH)3 (s) (at pH >5.6) and soil organic matter (at pH <5.0), respectively. This interpretation is supported by data from a pH-dependent Al–fulvic acid binding curve, for which calculated values of [Al3+] follow the same curvilinear relationship determined from the soil solution samples.

scholarly journals Analysis of the Bacterial Sulphur System

2013 ◽  
Vol 825 ◽  
pp. 190-193
Author(s):  
Rachel M. Candy ◽  
Kyle R. Blight ◽  
David E. Ralph
Keyword(s):  
Bacterial Cell ◽  
Mine Drainage ◽  
Solid Phase ◽  
Low Grade ◽  
Ph Measurements ◽  
Batch Cultures ◽  
Partial Pressures ◽  
S Oxidation ◽  
Ph Range

Heterogeneous bacterial sulphur systems are inherently complicated. However, developing an understanding of the influence of environmental factors such as pH,Iand PCO2is important for a number of fields. Examples of these include minimising acid mine drainage and maximising metal recovery from low-grade sulphide minerals. Measuring the effect of these factors on the extent and rate of sulphur (S) oxidation is complicated by the presence and nature of solid phase elemental S. The rate and extent of S oxidation can be determined indirectly via the reaction product, H2SO4, which was quantified using pH measurements in this study. The method was critically dependent on the quality of pH data but proved effective in providing rate constants for the catalysed S oxidation reaction and yield (biomass/substrate) estimates in the range pH > 1.5. IncreasingIover the range 0.176 0.367 mol L-1decreased bacterial cell yields but increased the rate of sulphur oxidation significantly. Partial pressures of CO2in the range of 0.039 1.18% v/v produced no significant effect on the rates of S oxidation or bacterial cell yields. Bacterial cell yields were not affected in the pH range 1.5 2.5, however the rate of S oxidation increased significantly from pH 2.0 2.5. In the range pH < 1.5 the batch cultures progressed and although no reliable rate data was recorded cell yields decreased from 7.43 to 2.05 (× 1012cells mol-1) at pH 1.5 to 1.0 respectively.

Zinc speciation in soil solutions of Vertisols

Soil Research ◽  
1996 ◽  
Vol 34 (3) ◽  
pp. 369 ◽  
Author(s):  
YP Dang ◽  
KG Tiller ◽  
RC Dalal ◽  
DG Edwards
Keyword(s):  
Soil Solution ◽  
Strong Acid ◽  
Weak Acid ◽  
Solution Ph ◽  
Chelex 100 ◽  
Inorganic Species ◽  
Soil Solutions ◽  
Cation Exchange Resins ◽  
Highly Correlated ◽  
Exchange Resins

Soil solutions were obtained by a centrifugation method from 14 unfertilised and fertilised Vertisols. The soil solutions were analysed for all major cations and anions and organic carbon (C). Chemical speciation of zinc (Zn) in the soil solutions calculated with the aid of the computer program GEOCHEM showed that Zn in tile soil solution exists mainly as free Zn2+ ions in these soils. Complexation of total soluble Zn by organic and inorganic ligands constituted 40% and 50%, respectively, of total soluble Zn in fertilised and unfertilised soil solutions. The organo-Zn complexes constituted <10% of the total soluble Zn. The inorganic Zn complexes, ZnHCO3+ and ZnCO3, constituted 60–75% of the total inorganic Zn complexes. The Zn complexes with SO24- and OH- were less than or equal to 5% each of the total inorganic species in unfertilised soils; ZnSOo4 complexes were more common in fertilised soils. The activities of Zn were extremely low (0.01–0.1 µM) in unfertilised soils and were inversely related to soil solution pH. The experimentally determined solubility lines for Zn2+ in the soil solution were undersaturated with respect to the solubility of any known mineral form of Zn. Zn2+ activity was mainly determined by adsorption-desorption reactions. The weak acid ion exchangers, Chelex-100 and Bio Rex-70, retained smaller amounts of Zn front the soil solutions than the strong acid exchangers, AG 50W X2, AG 50W X4, and AG 50w X8. Soil solution pH strongly affected Zn concentrations in soil solutions. The amount of total soluble Zn present as Zn2+ ions as calculated by GEOCHEM was highly correlated with tile amount of soluble Zn retained by the cation exchange resins. In the case of Chelex-100, these amounts were equal, confirming the usefulness of Chelex-100 to estimate Zn2+ ions.

Exchange and solution phase chemistry of acid, highly weathered soils .I. Characteristics of soils and the effects of lime and gypsum amendments

Soil Research ◽  
1994 ◽  
Vol 32 (2) ◽  
pp. 251 ◽  
Author(s):  
NW Menzies ◽  
LC Bell ◽  
DG Edwards
Keyword(s):  
Soil Solution ◽  
Exchange Capacity ◽  
Solution Phase ◽  
Exchangeable Cation ◽  
Solution Ph ◽  
Ph Change ◽  
Median Concentration ◽  
Surface Samples ◽  
Weathered Soils ◽  
Highly Weathered Soils

Exchange and solution phase characteristics were evaluated on surface and subsoil horizons of 60 acid, highly weathered soils in the unamended state, and on 39 of the surface horizons following addition of CaCO3 or CaSO4.2H2O. Soil solutions from unamended surface samples were dominated by Na (median concentration 0.65 mM), while the other major cations were present at lower levels (median concentrations: Ca, 0.09; Mg, 0.14; K, 0.28 mM). This pattern was more pronounced in the subsoil samples where the median concentrations of the nutrient cations were < 0.05 mM, whereas the median concentration of Na was 0.28 mM. The cation exchange capacity of surface samples was dominated by Ca, Mg and Al, while Al was the major exchangeable cation in the subsoil. Addition Of CaSO4.2H2O decreased soil solution pH and increased electrical conductivity and the concentration of Ca, Mg, Na, K and Al in the soil solution. The soil solution pH change resulting from CaSO4.2H2O addition could not be predicted on the basis of the characteristics of the soil in the unamended state.

Concentrations of rare earth elements in some Australian soils

Soil Research ◽  
1996 ◽  
Vol 34 (5) ◽  
pp. 735 ◽  
Author(s):  
E Diatloff ◽  
CJ Asher ◽  
FW Smith
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Soil Solution ◽  
New South ◽  
Total Concentration ◽  
Acid Soils ◽  
Solution Ph ◽  
South Wales ◽  
Low Concentrations ◽  
Soil Solutions

Total, exchangeable, and soil solution concentrations were measured for 15 rare earth elements (REEs) in 9 soils from Queensland and New South Wales. In a further 10 acid soils, effects of amendment with CaCO3 or CaSO4 . 2H2O were measured on the concentrations of REEs in soil solution. The total concentration of the REEs in soil solutions from unamended soils ranged from below the detection limit (0.007 µM) to 0.64 µM. Lanthanum (La) and cerium (Ce) were the REEs present in the greatest concentrations, the highest concentrations measured in the diverse suite of soils being 0.13 µM La and 0.51 µM Ce. Rare earth elements with higher atomic numbers were present in very low concentrations. Exchangeable REEs accounted for 0.07 to 12.6% of the total REEs measured in the soils. Addition of CaCO3 increased soil solution pH and decreased REE concentrations in soil solution, whilst CaSO4 . 2H2O decreased soil solution pH and increased the concentrations of REEs in soil solution. Solubility calculations suggest that CePO4 may be the phase controlling the concentration of Ce in soil solution.

Interrelations between soil pH measurements in various electrolytes and soil solution pH in acidic soils

Soil Research ◽  
1991 ◽  
Vol 29 (4) ◽  
pp. 483 ◽  
Author(s):  
RL Aitken ◽  
PW Moody
Keyword(s):  
Ionic Strength ◽  
Soil Solution ◽  
Soil Ph ◽  
Low Ph ◽  
Acidic Soils ◽  
Solution Ph ◽  
Ph Measurements ◽  
The Best Approximation ◽  
Water Ph ◽  
The Difference

Ninety soil samples (81 surface, 9 subsurface) were collected from eastern Queensland and soil pH (1:5 soi1:solution) was measured in each of deionized water (pH,), 0.01 M CaCl2, 0-002 M CaCl2 and 1 M KCl. Soil solution was extracted from each soil after incubation for 4 days at the 10 kPa matric suction moisture content, and pH (pHss) and electrical conductivity were measured. The objectives of this work were to investigate interrelationships between soil pH measurements in various electrolytes and soil solution pH in a suite of predominantly acidic soils. Although the relationships between pHw and pH measured in the other electrolytes could be described by linear regression, the fitting of quadratic equations improved the coefficients of determination, indicating the relationships were curvilinear. The majority of soils exhibited variable charge characteristics (CEC increases with soil pH) and the curvilinear trend is explained on this basis. At low pH, the difference between pH, and pH measured in an electrolyte will be small compared with the difference at higher pH values because, in general, at low pH, soils will be closer to their respective PZSE (pH at which electrolyte strength has no effect). Of the electrolytes used, pH measured in 0.002 M CaCl2 gave the closest approximation to pHs,. However, when soils with ionic strengths greater than 0.018 M were selected (predominantly cultivated surface soils), pH in 0.01 M CaCl2 gave the best approximation to pHss. For predicting pHss, the ionic strength of the electrolyte will need to be matched to that of the soils studied. For a suite of soils with a large range in soil solution ionic strength (as in this study), it is preferable to measure pHss directly.

Effect of depth and lime or phosphorus-fertilizer applications on the soil solution chemistry of some New Zealand pastoral soils

Soil Research ◽  
1995 ◽  
Vol 33 (3) ◽  
pp. 461 ◽  
Author(s):  
DM Wheeler ◽  
DC Edmeades
Keyword(s):  
Soil Solution ◽  
Soil Ph ◽  
Maximum Yield ◽  
Solution Chemistry ◽  
Phosphorus Fertilizer ◽  
Solution Ph ◽  
Soil Solutions ◽  
P Fertilizer ◽  
P Rate ◽  
Mn Concentrations

Thirteen trails were sampled to investigate the effects of depth, or the surface application of lime and phosphorus (P) fertilizer, on solution composition. Soil solutions were extracted by centrifuge from field moist soils within 24 h of sampling. Solution Ca, Mg, Na and K, Al, Mn and Fe concentrations generally decreased and Al, Mn and Fe concentrations generally increased with depth; although exceptions occurred. The largest decrease occurred in the first 25-50 mm of soil. Higher solution Al concentrations occurred in a band at a depth of between 50 and 100 mm in some soils. Lime generally increased solution pH and solution Ca, Mg and HCO3 concentrations, and reduced solution Al, Fe and Mn concentrations in the topsoils. In one soil (Matapiro silt loam) 2 years after lime was applied, lime increased solution pH down to a depth of 100 mm, Ca and HCO3 down to 75 mm and Mg down to 50 mm. Lime also decreased solution Al and Mn down to 75 mm and Fe down to 50 mm. In one series of trials, lime increased solution Ca concentrations at a depth of 50-100 mm 4 years after application in six out of the eight sites. In the same trial series, the application of P fertilizer increased solution P concentrations at 0-50 mm from a mean of 5 �M in the no-added P plots up to a mean of 56 �M at the highest P rate. The highest solution P concentration recorded was 194 �M. The increase in solution P concentrations for a given application of fertilizer P varied from 0.05 to 1.03 �M P per kg P ha-1 applied. Maximum pasture yield and 90% maximum yield occurred when solution P concentrations were about 28 and 14 �M respectively. Solution P concentrations determined from P adsorption isotherms were not a good indicator of solution P concentrations measured in soil. Solution pH was higher than soil pH (1:2.5 soil:water ratio, 2 h equilibration) with a solution pH of 6.0 corresponding to a soil pH in water of about 5.2.

scholarly journals Theoretical Modelling of Immobilization of Cadmium and Nickel in Soil Using Iron Nanoparticles

2017 ◽  
Vol 9 (4) ◽  
pp. 381-386
Author(s):  
Vaidotas Danila ◽  
Saulius Vasarevičius
Keyword(s):  
Heavy Metals ◽  
Soil Solution ◽  
Metal Ion ◽  
Iron Nanoparticles ◽  
Theoretical Modelling ◽  
Solution Ph ◽  
Soil Solutions ◽  
Insoluble Compounds ◽  
Zero Valent Iron Nanoparticles ◽  
Complexation Reactions

Immobilization using zero valent using iron nanoparticles is a soil remediation technology that reduces concentrations of dissolved contaminants in soil solution. Immobilization of heavy metals in soil can be achieved through heavy metals adsorption and surface complexation reactions. These processes result in adsorption of heavy metals from solution phase and thus reducing their mobility in soil. Theoretical modelling of heavy metals, namely, cadmium and nickel, adsorption using zero valent iron nanoparticles was conducted using Visual MINTEQ. Adsorption of cadmium and nickel from soil solutions were modelled separately and when these metals were dissolved together. Results have showed that iron nanoparticles can be successfully applied as an effective adsorbent for cadmium and nickel removal from soil solution by producing insoluble compounds. After conducting the modelling of dependences of Cd+2 and Ni+2 ions adsorption on soil solution pH using iron nanoparticles, it was found that increasing pH of solution results in the increase of these ions adsorption. Adsorption of cadmium reached approximately 100% when pH ≥ 8.0, and adsorption of nickel reached approximately 100% when pH ≥ 7.0. During the modelling, it was found that adsorption of heavy metals Cd and Ni mostly occur, when one heavy metal ion is chemically adsorbed on two sorption sites. During the adsorption modelling, when Cd+2 and Ni+2 ions were dissolved together in acidic phase, it was found that adsorption is slightly lower than modelling adsorption of these metals separately. It was influenced by the competition of Cd+2 and Ni+2 ions for sorption sites on the surface of iron nanoparticles.

Aluminium speciation in seasonally dry high country soils, South Island, New Zealand

Soil Research ◽  
1999 ◽  
Vol 37 (5) ◽  
pp. 1005 ◽  
Author(s):  
M. L. Adams ◽  
P. D. McIntosh ◽  
R. D. Patterson ◽  
K. J. Powell
Keyword(s):  
Soil Solution ◽  
Root Elongation ◽  
S Phase ◽  
Al Toxicity ◽  
Uv Absorbance ◽  
Solution Ph ◽  
Seasonally Dry ◽  
Soil Solutions ◽  
Aluminium Speciation ◽  
Legume Growth

Soil solutions from an altitude sequence of South Canterbury high country soils (730– 1190 m) were analysed using a recently developed technique to obtain values for ‘free Al’ ([Al 3+ ]+[Al(OH) 2+ ]+[Al(OH)2 + ]+[AlF 2+ ]), an ‘organic-bound Al’ fraction, and the Al- complexation capacity (Al-CC). From 1979 these soils have been fertilised, oversown, and grazed. Since 1978, topsoils (0–7 . 5 cm) have become more acid, and average pH(H 2 O) (1 : 2 . 5 soil : H2O; n = 38) has fallen from 5 . 79 in 1978 to 5 . 25 in 1996. Despite this soil acidification, the current ‘free Al’ values are low (0 . 31–0 . 75 µМ) and are unlikely to limit legume growth. This conclusion was supported by root elongation experiments using Medicago sativa (Wairau lucerne). No significant correlation was observed between measured root elongation and either soil solution pH or ‘free Al’. Sunny aspects had higher ‘organic-bound Al’ and lower ‘free Al’ values. The values of p[Al 3+ ] calculated from ‘free Al’ were consistent with control of [Al 3+ ] by an Al(OH)3(s) phase rather than by organic matter. ‘Organic-bound Al’ correlated strongly with the concentration of humic substances in soil solution as estimated by the UV absorbance at 250 nm. The Al-CC decreased with a decrease in soil solution pH. Relative to the total reactive Al, the capacity of soil solutions to complex Al, as may be generated by acidification, was lower for the soils at lower elevations, pointing to potential for an earlier onset of Al toxicity at these sites.

Manganese equilibrium in submerged sodic soils as influenced by application of gypsum and green manuring

1985 ◽  
Vol 104 (2) ◽  
pp. 257-261 ◽  
Author(s):  
U. S. Sadan ◽  
M. S. Bajwa
Keyword(s):  
Soil Solution ◽  
Green Manure ◽  
Pot Experiment ◽  
Solution Ph ◽  
Sodic Soils ◽  
Green Manuring ◽  
Concentration Maximum ◽  
Soil Solutions ◽  
Mn Concentration

SummaryA pot experiment studied the effect of gypsum and green manuring on equilibrium soil solution pH, pE, Mn concentration and Mn equilibrium in three sodic soils. Submergence decreased soil solution pH and increased Mn concentration in all the soils. Addition of gypsum with green manure further decreased soil solution pH and increased Mn concentration. Maximum Mn concentration in all the treatments was observed at 4 weeks of submergence in Kaheru soil and at 6 weeks of submergence in Jagjitpur and Langrian soil followed by a decline up to 12 weeks. In spite of wide variations in pH, pE and Mn concentration in soil solutions, the solubility of Mn after peak values appeared to be mainly controlled by the MnC03-Mn2+ system irrespective of the treatments, and the Mn2O3-Mn3O4 system appeared to operate after 2 weeks of submergence in the control and gypsum-treated soils.

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