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.

Effects of aluminium and calcium in the soil solution of acid soils on root elongation of Glycine max cv. Forrest

1988 ◽  
Vol 39 (3) ◽  
pp. 319 ◽  
Author(s):  
RC Bruce ◽  
LA Warrell ◽  
DG Edwards ◽  
LC Bell
Keyword(s):  
Root Growth ◽  
Soil Solution ◽  
Soil Ph ◽  
Activity Ratio ◽  
Acid Soils ◽  
Exchange Capacity ◽  
Al Toxicity ◽  
Solution Ph ◽  
Diagnostic Indices ◽  
Exchangeable Ca

In the course of three experiments, soybean (Glycerine max (L.) Merr.) cv. Forrest was grown in 21 soils (four surface soils and 17 subsoils) amended with liming materials (CaCO3 and Mg CO3) and soluble Ca salts (CaSO4.2H20 and CaCl2.2H2O). In most soils, the soluble salts increased concentrations and activities of Al species in solution to levels that restricted root growth, and MgCO3, induced a Ca limitation to root growth. Root lengths after three days were related to so11 and soil solution attributes.Suitable diagnostic indices for the prediction of Ca limitations to root growth were either Ca saturation of the effective cation exchange capacity or Ca activity ratio of the soil solution, which was defined as the ratio of the activity of Ca to the sum of the activities of Ca, Mg, Na, and K. Values corresponding to 90% relative root length (RRL) of soybean were 0.05 for the Ca activity ratio and 11% for Ca saturation. Calcium activity and Ca concentration in the soil solution and exchangeable Ca were less useful for this purpose.Soil Al saturation was not a good predictor of Al toxicity, but soil solution measurements were. The activities of Al3+ and AlOH2+ gave the best associations with RRL, and values corresponding to 90% RRL were 4 8M and 0.5 8M respectively. The results suggested that Al(OH)3� , Al(OH)2+, and AlSO4+, were not toxic species. Soil solution pH and soil pH measured in water were more sensitive indicators of root growth than soil pH measured in 0.01 M CaCl2.Using a Ca activity ratio of 0.05 and an Al3+ activity of 4 8M as diagnostic indices, none of the 20 soils in two experiments were toxic in Al, while 13 (all subsoils) were deficient in Ca. Thus the first limitation on root growth was Ca deficiency and not Al toxicity, in spite of high Al saturations and relatively low pH in these soils. However, Al toxicity could be induced by increasing the ionic strengths of soil solutions.

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.

Changes in soil solution composition and aluminium speciation under legume based pastures in response to long term phosphate fertiliser applications

Soil Research ◽  
1996 ◽  
Vol 34 (6) ◽  
pp. 985 ◽  
Author(s):  
V Manoharan ◽  
P Loganathan ◽  
RL Parfitt ◽  
RW Tillman
Keyword(s):  
Soil Solution ◽  
Phosphate Rock ◽  
Surface Soil ◽  
Solution Ph ◽  
Single Superphosphate ◽  
Phosphate Fertiliser ◽  
Reactive Phosphate Rock ◽  
Subsurface Soil ◽  
Aluminium Speciation

This study describes some of the effects of 8 years of annual application of 6 types of phosphatic fertilisers on the chemical composition and aluminium (Al) speciation in soil solution extracted from a soil under pasture. Soil samples at 2 depths, 0-30 and 30-75 mm, were collected at the end of 8 years. Soil solutions were extracted by centrifuging at 12 000 RCF and analysed for Al, Na, K, Ca, Mg, F, NO3, Cl, and SO4, as well as pH and ionic strength. Soil and soil solution pH were significantly increased at both depths by application of North Carolina phosphate rock (NCPR) compared with the control. In contrast, diammonium phosphate (DAP) significantly decreased the soil and solution pH. Single superphosphate (SSP) did not have any significant effect on soil or solution pH compared with the untreated control. The surface soil (0-30 mm) solution pH was on average 0.6 of a unit higher than the subsurface soil (30-75 mm) solution pH. Total monomeric Al concentration [Al], measured by the pyrocatecol violet (PCV; 4 min) method, ranged from 1.5 to 4.8 �M in the surface soil and 2.5 to 12.2 �M in the subsurface soil. The DAP and higher rates of SSP application resulted in a large increase in total and inorganic monomeric [Al] in the soil solution extracted from the subsurface soil. Total soluble [F] ranged from 2.7 to 23.5 �M and 3.2 to 25.6 �M in the surface and subsurface soils, respectively, and was significantly increased by the application of NCPR and by higher rates of SSP. The predominant forms of inorganic monomeric Al present in the soil solution were estimated to be the non-phytotoxic Al-F complexes, AlF2+, and AlF2+. There was a marked decrease in toxic Al species (Al3+, Al(OH)2+, Al(OH)2+) in soil solution following NCPR and SSP application. This was due primarily to complexation of Al with F derived from these fertilisers forming non-toxic AI-F complexes. The results suggest that the long-term application of reactive phosphate rock such as NCPR may contribute to amelioration of soil acidity and Al toxicity under legume-based pastures. In contrast ammonium-containing phosphate fertilisers such as DAP probably decrease soil pH and increase the formation of toxic Al species in the soil solution.

Relationships between soil solution aluminium and extractable aluminium in some moderately acid New Zealand soils

Soil Research ◽  
1996 ◽  
Vol 34 (5) ◽  
pp. 769 ◽  
Author(s):  
HJ Percival ◽  
KM Giddens ◽  
R Lee ◽  
JS Whitton
Keyword(s):  
New Zealand ◽  
Soil Solution ◽  
Colorimetric Method ◽  
Al Toxicity ◽  
Poor Correlation ◽  
Soil Solutions ◽  
The Individual ◽  
Pasture Plant ◽  
The Relationship ◽  
Extractable Al

This work investigates the relationship between soil solution aluminium (Al) and extractable Al in some New Zealand soils giving high extractable Al levels, yet with pH(H2O) values ≥ 5.2. Total Al in 1 M KCl extracts ranged from 0.8 to 11.6 cmol(+)/kg, and in corresponding 0.02 M CaCl2 extracts from 0.002 to 0.39 cmol(+)/kg. Soil solutions had low total Al concentrations, ranging from < 0.5 to 12.5 µM, with < 10% of the Al in the monomeric Al form as determined by the chromeazurol S colorimetric method. There was a poor correlation between Al in soil solution and that extracted by either 1 M KCl or 0.02 M CaCl2. The measured monomeric Al concentrations in the soil solutions did not exceed levels corresponding to Al toxicity threshold activities set at 10 or 2 µM, related to a range of pasture plant tolerances, whether based on the activity of Al3+ species alone, or on the sum of the individual activities of Al3+, Al(OH)2+ and Al(OH)2+ species. The high 1 M KCl-extractable and 0.02 M CaCl2-extractable Al values provided a misleading indication of potential Al toxicity status, probably due to the generation of artificially high extracted Al concentrations from these particular types of soils.

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.

Effect of banded fertilizers on soil solution composition and short-term root-growth .2. Mono-ammonium and di-ammonium phosphates

Soil Research ◽  
1995 ◽  
Vol 33 (4) ◽  
pp. 689 ◽  
Author(s):  
PW Moody ◽  
DG Edwards ◽  
LC Bell
Keyword(s):  
Root Growth ◽  
Soil Solution ◽  
Root Elongation ◽  
Ammonium Phosphate ◽  
Contact Period ◽  
Solution Composition ◽  
Solution Ph ◽  
Organic C ◽  
Precipitation Reactions ◽  
Relative Root

A layer of mono- or di-ammonium phosphate (MAP and DAP, respectively) was placed in contact for 5 days with duplicate columns of soil at a water content equivalent to 10 kPa matric suction. This was designed to simulate the effects of banded fertilizer on soil solution composition. Five soils were used: 0-10 cm samples from a Kurosol, a Ferrosol, a Vertosol and a Kandosol, and a 50-60 cm sample from the Kandosol. After the contact period, soil sections were recovered at successive 5 mm intervals from the fertilizer layer, the last section being 45-60 mm from the layer. Soybean (Glycine max (L.) Merr.) seedlings were grown for 48 h in each section and relative root elongation was determined. Soil solution was then extracted from each section and analysed. The amount of inorganic P in the soil solution (P-i) was summed over all soil sections for each soil and each P source and was found to be correlated with distance of P movement from the simulated band (r = 0 . 792, P < 0.01). Of several soil chemical parameters of the control (unfertilized) soils regressed against Pi, the following showed significant (P = 0.05) negative correlations: Ca and Mg concentrations in the soil solution for Pi from both MAP and DAP, exchangeable Ca and Mg for DAP, and citrate-dithionite extractable Fe and Al for MAP. These results suggest that adsorption (and possibly precipitation) reactions with Fe and Al hydrous oxides contributed to the removal of P-i from solution in the presence of MAP. However, with DAP as the fertilizer source, precipitation reactions involving Ca and Mg were the predominant factors. Dissolved organic C in the soil solution increased adjacent to both DAP and MAP, with larger amounts in proximity to DAP being a consequence of the higher soil solution pH (~ 7). Soil solution Si increased in all soils adjacent to both DAP and MAP, with concentrations being higher in the MAP treatments. Dissolution of aluminosilicates in the acidic conditions near MAP (pH ~5) was the probable cause. Relative root elongation (RRE) of soybean was restricted in soil sections close to the fertilizer. When RRE was plotted against each of soil solution EC, NH3 activity, and calcium activity ratio (CAR), a single curvilinear function described the relationship between RRE and CAR for all soils and both P sources. It is concluded that a salt-induced Ca deficiency was the cause of restricted root growth in proximity to DAP and MAP, rather than an osmotic effect or NH3 toxicity.

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.

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 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.

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

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