Humic Substances from Podzols Under Oak Forest and a Cleared Forest Site II. Spectroscopic Studies

Simpson, André J.; Burdon, J.; Graham, C.L.; Hayes, M.H.B.

doi:10.1016/b978-1-85573-805-8.50011-2

Cited by 6 publications

(2 citation statements)

References 2 publications

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“…Humic substance solubility gives us some information about their structure. For example, in Irish soil grasslands, humic acids extracted at pH 7 showed almost double the aromaticity than did humic acids isolated at pH 10 and 12 (McGrath, 1987); the same pattern was observed in podzols under oak trees and cleared forests (Simpson et al, 1997). Aromaticity is related to the transformed state of OM; the more aromatic the more transformed.…”

Section: Discussionmentioning

confidence: 70%

Denitrification Potential and Organic Matter as Affected by Vegetation Community, Wetland Age, and Plant Introduction in Created Wetlands

Hernández

Mitsch

2007

J of Env Quality

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Denitrification potential (DP) and organic matter (OM) in soils were compared in three different vegetation communities-emergent macrophyte, open water, and forested edge-in two 10-yr-old created riverine wetlands. Organic matter, cold water-extractable organic matter (CWEOM), anaerobic mineralizable carbon (AnMC), and DP varied significantly (P<0.05) among vegetation communities. The surface (0 to 9 cm) soils in the emergent macrophyte community (EMC) showed highest DP (0.07+/-0.01 mg N h-1 kg-1), OM (84.90+/-5.60 g kg-1), CWEOM (1.12+/-0.20 g kg-1), and AnMC (1.50+/-0.10 mg C h-1 kg-1). In the deeper layer (9 to 18 cm), DP and CWEOM (0.04+/-0.01 mg N h-1 kg-1 and 1.13+/-0.20 g kg-1, respectively) were significantly higher in the open water community (OWC) than in the emergent macrophyte and forested edge communities. Plant introduction did not affect DP or OM content and characteristics. After 10 yr of wetland development, mean DP increased 25-fold in the surface layer (from 0.002 to 0.053 mg N h-1 kg-1); OM content more than doubled to 90.80+/-19.22 g kg-1, and CWEOM and HWEOM increased 2.5 and 2.7 times respectively from 1993 (prewetland conditions) to 2004. Humic acids were the most abundant form of OM in 2004 and 1993 samples. Significant (P<0.05) positive relationships between DP and OM, CWEOM, and AnMC were found in the surface layer; in the 9- to 18-cm layer, significant positive relationships were found between DP and CWEOM and AnMC.

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Section: Discussionmentioning

confidence: 70%

Denitrification Potential and Organic Matter as Affected by Vegetation Community, Wetland Age, and Plant Introduction in Created Wetlands

Hernández

Mitsch

2007

J of Env Quality

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“…The major aliphatic components have faster diffusivities (−log( D ) = 9.45−9.58) than the sugars and have been identified as fatty acids and fatty esters/ethers of varying lengths that can reach in excess of 25 carbons ( , ). Peaks I and II (Figures and ), which have been assigned to aliphatic CH 2 units adjacent to ester and ether, respectively, are of particular interest.…”

Section: Resultsmentioning

confidence: 99%

Separation of Structural Components in Soil Organic Matter by Diffusion Ordered Spectroscopy

Simpson

Kingery

Spraul

et al. 2001

Environ. Sci. Technol.

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Diffusion ordered spectroscopy (DOSY) was applied to two extracts of organic matter from the surface horizon of an oak forest soil. It was possible to identify and confirm the presence of numerous aliphatic, aromatic, sugar, and amino acid components that could be separated on the basis of diffusion in DMSO-d6 and D2O. On average, sugar components were identified as the largest molecules in solution, with molecular masses up to approximately 1500 Da followed by the aliphatic and aromatic components. Amino acids with a range of molecular weights were also identified in the mixture. The summation of the individual slices from the DOSY experiment closely resembles the conventional 1H spectra of the material, indicating that the components identified with DOSY represent all the components present in the mixture. The separation of components in the mixture in organic solvent supports new findings that fulvic and humic acids are not cross-linked, high molecular weight macromolecules but are instead aggregates composed of relatively simple molecules that take on colloidal properties in the presence of metal ions in aqueous solution. Using the knowledge that these organic mixtures are combinations of relatively simple entities with well-documented reactivities and behavior will improve our ability to predict and model their interactions and fate under natural conditions.

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The role of various compounds in humic acids stability studied by TG and DTA

Kučerík

Kamenářová

Válková

et al. 2006

J Therm Anal Calorim

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Humic Substances from Podzols Under Oak Forest and a Cleared Forest Site II. Spectroscopic Studies

Cited by 6 publications

References 2 publications

Denitrification Potential and Organic Matter as Affected by Vegetation Community, Wetland Age, and Plant Introduction in Created Wetlands

Denitrification Potential and Organic Matter as Affected by Vegetation Community, Wetland Age, and Plant Introduction in Created Wetlands

Separation of Structural Components in Soil Organic Matter by Diffusion Ordered Spectroscopy

The role of various compounds in humic acids stability studied by TG and DTA

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