Carbon-13 NMR and chemical characterization of particle-size separates of peats differing in degree of decomposition

Preston, Caroline M.; Axelson, David E.; Lévesque, M.; Mathur, Shivani; Dinel, H.; Dudley, Robert L.

doi:10.1016/0146-6380(89)90005-3

Cited by 55 publications

(34 citation statements)

References 39 publications

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“…However, PCA highlighted the importance of site differences, as spectra showed patterns characteristic of decayed wood, tannins (mainly from roots) and charcoal. The PCA analysis of the <2 mm fraction also showed that increasing decomposition was associated with an increasing ratio of alkyl/O-alkyl C, consistent with previous studies (Preston et al 1989b;Baldock and Preston 1995;Baldock et al 1997), as well as an increase in carboxyl C. Preston et al (2000) recently used data from NMR, proximate and elemental analyses in PCA and cluster analysis of 37 litter types. This resulted in six clusters that could be related to botanical groupings.…”

Section: Discussionsupporting

confidence: 53%

“…Principal component analysis (PCA) can be useful in the interpretation of NMR data (Nordén and Albano 1989;Preston et al 1989bPreston et al , 2000Nordén et al 1992;Trofymow et al 1995;Almendros et al 2000). In a recent study of successional forests of Vancouver Island (Preston et al 1998a), spectra were obtained for five carbon pools: fine woody debris, forest floor (LFH), roots from LFH, and two water floatable fractions (<2 and 2-8 mm) from the 10-30 cm mineral soil.…”

Section: Discussionmentioning

confidence: 99%

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Carbon-13 solid-state NMR of soil organic matter - using the technique effectively

Preston¹

2001

Can. J. Soil. Sci.

112

104

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).Preston, C. M. 2001. Carbon-13 solid-state NMR of soil organic matter -using the technique effectively. Can. J. Soil Sci. 81: 255-270. Solid-state 13 C CPMAS NMR offers many options for characterizing carbon in soil organic matter (SOM). Its effectiveness, however, is often limited by a poor understanding of the techniques, and lack of hands-on access and training opportunities for students. Of nearly 250 modern NMR systems in Canada, approximately one is genuinely available for SOM studies, and there is poor communication between NMR operators and SOM users. While quantitative reliability can be addressed to some extent by multiple contact-time experiments or single-pulse (Bloch decay) spectra, it is also important to consider the effects of spectrometer background, spinning sidebands (especially with higher magnetic fields) and processing operations such as linebroadening, phasing and baseline correction. In many studies, more consideration needs to be given to instrument specifications, the type of information needed, and whether sample fractionation or pretreatment should be used. Structural information can be greatly enhanced by dipolar-dephasing and sideband suppression sequences. Sequences based on relaxation differences can reveal pools of carbon with different structures. Data analysis can be enhanced by principal component analysis, spectrum deconvolution and difference spectra. Studies of xenobiotics and C metabolism can be greatly aided by 13 C-labeling. However, a key limitation to SOM applications remains the gap in culture and expectations of the users.Key words: Soil organic matter, 13 C CPMAS NMR, Bloch decay, dipolar dephasing, spinning sidebands Preston, C. M. 2001. Analyse de la matière organique du sol par RMN au 13 C électronique -de l'importance de bien utiliser la technique. Can. J. Soil Sci. 81: 255-270. La RMN CPMAS 13 C électronique permet de caractériser le carbone présent dans la matière organique du sol (MOS) de diverses manières. Il arrive souvent cependant que cette technique perde de son efficacité parce qu'on la connaît mal et parce que les étudiants n'ont pas eu la chance de l'examiner ou de l'expérimenter. Sur les 250 systèmes modernes de RMN existant au Canada, un seul, à peu près, est vraiment réservé à l'étude de la MOS; de plus, la communication passe mal entre les opérateurs de systèmes RMN et les utilisateurs de MOS. Bien qu'on puisse remédier dans une certaine mesure au problème de la fiabilité quantitative en multipliant les expériences sur la durée de contact ou en recourant au spectre obtenu après une seule impulsion (décroissance de Bloch), il ne faut pas négliger les effets de l'arrière-plan du spectromètre, de la rotation des bandes latérales (surtout quand le champ magnétique est puissant) et des opérations de traitement comme l'élargissement des lignes, la mise en phase et la correction de la ligne de base. Dans de nombreux cas, on devrait accorder plus d'attention aux paramètres de l'instrument, au genre de données requises et à la nécessité de fractionner et...

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Section: Discussionsupporting

confidence: 53%

Section: Discussionmentioning

confidence: 99%

Carbon-13 solid-state NMR of soil organic matter - using the technique effectively

Preston¹

2001

Can. J. Soil. Sci.

112

104

View full text Add to dashboard Cite

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“…The ash content of the fibrist peat was almost twice that of saprist peat, which might be due to the different zones of formation and accumulation of inorganic materials such s silicon oxide at the upper layer of the bog. a [44][45][46][47] 100. 37 -129.43 Phenol, N-substituted aromatic [44,46] 150.78 -173.…”

Section: Discussionmentioning

confidence: 99%

“…a [44][45][46][47] 100. 37 -129.43 Phenol, N-substituted aromatic [44,46] 150.78 -173. 38 Carboxyl, amide, esters [44,46,47] The chemistry of metal binding in the two peat types might be different with the poorly humified peat being more influenced by inherent inorganic compounds present, a fact supported by the detection of silicon oxide (SiO 2 ) in the XRD spectrum of fraction < 75 µm.…”

Section: Discussionmentioning

confidence: 99%

“…37 -129.43 Phenol, N-substituted aromatic [44,46] 150.78 -173. 38 Carboxyl, amide, esters [44,46,47] The chemistry of metal binding in the two peat types might be different with the poorly humified peat being more influenced by inherent inorganic compounds present, a fact supported by the detection of silicon oxide (SiO 2 ) in the XRD spectrum of fraction < 75 µm. With the absence of clay minerals and any known inorganic substances in the highly humified peat (compared to the poorly humified peat sample), any metal uptake in this peat type may be due to the functional group chemistry and the readily available exchangeable cations initially present in this amorphous material.…”

Section: Discussionmentioning

confidence: 99%

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Characterization and Comparison of Saprist and Fibrist Newfoundland Sphagnum Peat Soils

Asapo¹,

Coles²

2012

JMMCE

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Saprist and fibrist sphagnum peat soils obtained from the same natural peat bog owned by Traverse Nurseries, Torbay, Newfoundland, Canada were characterized to study their potential for adsorbing metals. Both peat soils had a pH of 4.2. The saprist peat had the lower fiber content (68.6% versus 75%), higher cation exchange capacity (70 meq/100g versus 45 meq/100g), higher moisture content (86% versus 82%), higher organic matter content (91% versus 84%), higher wet bulk density (0.65 g/cm 3 versus 0.60 g/cm 3) and higher dry bulk density (0.28 g/cm 3 versus 0.20 g/cm 3 ). A crystallography study showed that the saprist peat was completely amorphous and the metal content analysis showed high calcium and iron concentrations in both types of peat with higher values in the fibrist peat. Carboxylic acid, alcoholic hydroxyl, phenolic hydroxyl, amine and amide functional groups were present and these could be responsible for binding metal ions via ion exchange and or complexation reactions.

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Tephra deposits and carbon dynamics in peatlands of a volcanic region: Lessons from the Hekla 4 eruption

et al. 2020

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Interactions between tephra deposits from volcanic eruptions and peatland carbon (C) dynamics are poorly understood despite the significant extent of peatlands influenced by tephra worldwide. Tephra falls can affect peat accumulation within a radius of at least 1,000 km. In Iceland, volcanic activity is amongst the highest in the world and it might even increase due to pressure release on subglacial volcanoes. A potent combination of sparse vegetation, low cohesion of Andosols, and frequent strong winds, facilitates the regular input of mineral aeolian material from eroded areas into peatlands in Iceland, in addition to tephra deposits. We present results of a study on the impact of a major tephra deposit, the Hekla 4 tephra, on C dynamics in Icelandic peatlands. We investigated three sites at differing distances from the active volcanic zones and major erosion areas in the interior of the country. A combination of variables was applied, including laboratory C mineralization at 5, 15 and 25°C and C structure obtained by solid‐state 13C NMR spectroscopy. Tephra deposits seem to affect C dynamics. Differences in C mineralization can only be partially explained by C structure. The C mineralization from soils with conspicuously similar C structure differs by a factor of up to 2.7. Temperature sensitivity of decomposition after the tephra deposition increases by a factor of up to 2.2. Changes in inorganic matter and the ratio of soil organic matter to soil organic carbon by a factor of up to 1.3 and 1.4, respectively, were also observed.

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Carbon-13 NMR and chemical characterization of particle-size separates of peats differing in degree of decomposition

Cited by 55 publications

References 39 publications

Carbon-13 solid-state NMR of soil organic matter - using the technique effectively

Carbon-13 solid-state NMR of soil organic matter - using the technique effectively

Characterization and Comparison of Saprist and Fibrist Newfoundland Sphagnum Peat Soils

Tephra deposits and carbon dynamics in peatlands of a volcanic region: Lessons from the Hekla 4 eruption

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