Comparison of Colorimetric and ICP Methods of Phosphorus Determination in Soil Extracts

Adesanwo, O. O.; Ige, D V; Thibault, Lesne; Flaten, Don; Akinremi, Wolé

doi:10.1080/00103624.2013.832771

Cited by 33 publications

(20 citation statements)

References 12 publications

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“…The colorimetrically-determined MRP concentrations in the M3 extracts ranged from 29 to 378 mg kg −1 , representing 47–100% of the P concentrations determined by ICP (Table 5 ). This is also consistent with previous studies [ 9 – 12 , 14 – 16 ]. However, previous reports have suggested that the differences between colorimetry and ICP are greater at lower concentrations [ 10 , 12 , 13 ].…”

Section: Resultssupporting

confidence: 94%

“…This is also consistent with previous studies [ 9 – 12 , 14 – 16 ]. However, previous reports have suggested that the differences between colorimetry and ICP are greater at lower concentrations [ 10 , 12 , 13 ]. This was not consistent with the results for this study, where there was no clear trend for high or low P concentrations.…”

Section: Resultssupporting

confidence: 94%

“…Following the advent of inductively coupled plasma-based spectrometry (ICP), new soil tests were developed in the 1970s and 1980s to enable the simultaneous measurement of multiple elements from a single soil extract [ 9 – 12 ]. Unlike colorimetry, ICP determines total P in solution, which includes both MRP and molybdate-unreactive P (MUP), with MUP being the difference between ICP-determined P and MRP.…”

Section: Introductionmentioning

confidence: 99%

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Characterizing the phosphorus forms extracted from soil by the Mehlich III soil test

et al. 2018

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Phosphorus (P) can limit crop production in many soils, and soil testing is used to guide fertilizer recommendations. The Mehlich III (M3) soil test is widely used in North America, followed by colorimetric analysis for P, or by inductively coupled plasma-based spectrometry (ICP) for P and cations. However, differences have been observed in M3 P concentrations measured by these methods. Using 31P nuclear magnetic resonance (P-NMR) and mass spectrometry (MS), we characterized P forms in M3 extracts. In addition to the orthophosphate that would be detected during colorimetric analysis, several organic P forms were present in M3 extracts that would be unreactive colorimetrically but measured by ICP (molybdate unreactive P, MUP). Extraction of these P forms by M3 was confirmed by P-NMR and MS in NaOH-ethylenediaminetetraacetic acid extracts of whole soils and residues after M3 extraction. The most abundant P form in M3 extracts was myo-inositol hexaphosphate (myo-IHP, phytate), a compound that may not contribute to plant-available P if tightly sorbed in soil. Concentrations of myo-IHP and other organic P forms varied among soils, and even among treatment plots on the same soil. Extraction of myo-IHP in M3 appeared to be linked to cations, with substantially more myo-IHP extracted from soils fertilized with alum-treated poultry litter than untreated litter. These results suggest that ICP analysis may substantially over-estimate plant-available P in samples with high MUP concentrations, but there is no way at present to determine MUP concentrations without analysis by both colorimetry and ICP. This study also tested procedures that will improve future soil P-NMR studies, such as treatment of acid extracts, and demonstrated that techniques such as P-NMR and MS are complimentary, each yielding additional information that analysis by a single technique may not provide.

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Section: Resultssupporting

confidence: 94%

Section: Resultssupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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Characterizing the phosphorus forms extracted from soil by the Mehlich III soil test

et al. 2018

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“…Considering that P concentrations analyzed by inductively coupled plasma (ICP) are generally higher than colorimetric values by 15%-20% (Adesanwo et al 2013), we considered a scenario with 0.8 × measured Pw concentration. This difference is generally ascribed to the presence of organic P, which is included in ICP determination but not in colorimetric (Adesanwo et al 2013 (Piñeiro et al 2008). The RMSD was calculated as follows:…”

Section: Statistical Analysesmentioning

confidence: 99%

Phosphorus saturation index and water-extractable phosphorus in high-legacy phosphorus soils in southern British Columbia, Canada

Messiga

Lam

2021

Can. J. Soil. Sci.

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Understanding of the risk of phosphorus (P) loss to the environment is crucial to monitor soil P and implement policies for P management. We assessed P sorption characteristics and adapted a P saturation index (PSI) for silage corn and blueberry fields in south coastal British Columbia (BC), Canada. We used 284 composite soil samples with contrasting P levels collected from eight silage corn and 23 blueberry fields across south coastal BC. The P sorption maximum (Smax) varied between 982 and 2532 mg P·kg−1 and was influenced by aluminum concentration and organic matter content. The degree of P saturation was related to water-extractable P (Pw) by a quadratic regression with R2 = 0.85. A critical Pw = 3.7 mg·kg−1 was established across the two cropping systems. The silage corn fields with pH > 5.5 had critical PSI value of 10.4%, and blueberry fields with pH < 4.7 had critical PSI value of 18.0%. These results showed that the risk of P loss from soil in the silage corn was high, but it was low for blueberry because the critical PSI for silage corn fields was lower than for blueberry fields, and therefore, saturation would be more easily reached, even though more P is applied to blueberry fields. The combination of a critical PSI and Pw as agri-environmental indicators will help farmers and professionals to identify fields with risk of P loss, to implement a nutrient management plan, and to monitor how this risk changes with time.

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“…The ratio of their concentrations falls from 10 at pH 6 to 0.1 at pH 8; at pH > 9.5 the ion PO may occur in the soil solution. A substantial, yet highly variable proportion of total P in soil solution is P o ; published data range from 20 to 90% ( Adesanwo et al, 2013 : fertilized and non - fertilized soils in Manitoba) and > 80 to 99% ( Shand et al, 1994 : P poor Cambisols in Scotland). It appears that the contribution of P o to soil solution P increases with decreasing total P concentration, but published data are surprisingly sparse.…”

Section: The Soil P Cycle In a Nutshellmentioning

confidence: 99%

Innovative methods in soil phosphorus research: A review

Kruse

Abraham

Amelung

et al. 2015

J. Plant Nutr. Soil Sci.

296

195

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Phosphorus (P) is an indispensable element for all life on Earth and, during the past decade, concerns about the future of its global supply have stimulated much research on soil P and method development. This review provides an overview of advanced state-of-the-art methods currently used in soil P research. These involve bulk and spatially resolved spectroscopic and spectrometric P speciation methods (1 and 2D NMR, IR, Raman, Q-TOF MS/MS, high resolution-MS, NanoSIMS, XRF, XPS, (µ)XAS) as well as methods for assessing soil P reactions (sorption isotherms, quantum-chemical modeling, microbial biomass P, enzymes activity, DGT, 33P isotopic exchange, 18O isotope ratios). Required experimental set-ups and the potentials and limitations of individual methods present a guide for the selection of most suitable methods or combinations.

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Comparison of Colorimetric and ICP Methods of Phosphorus Determination in Soil Extracts

Cited by 33 publications

References 12 publications

Characterizing the phosphorus forms extracted from soil by the Mehlich III soil test

Characterizing the phosphorus forms extracted from soil by the Mehlich III soil test

Phosphorus saturation index and water-extractable phosphorus in high-legacy phosphorus soils in southern British Columbia, Canada

Innovative methods in soil phosphorus research: A review

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