Electron Spin Resonance as a Guide to the Degree of Humification of Peats

Schnitzer, M.; Lévesque, M.

doi:10.1097/00010694-197903000-00003

Cited by 67 publications

(38 citation statements)

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“…Stout Measurements of gaseous CO2 levels below the soil surface have been widely reported, and carbon dioxide fluxes below the soil surface have been modelled from such CO2 profiles (de Jong and Schappert 1972). However, their accuracy is limited by the CO, which goes into solution (Enoch and Dasenberg 1970) humisol (Schnitzer and Levesque 1979) In the second experiment, the column of undisturbed soil from Ste-Clothilde tended to be warmer, > 24"C, and less aerated, with oxygen levels ( 40 units in the laboratory, than the same soil in situ (Fig. 3).…”

mentioning

confidence: 97%

MEASUREMENT OF CO₂ EVOLVED FROM ORGANIC SOIL AT DIFFERENT DEPTHS IN SITU

Campbell¹,

Frascarelli²

1981

Can. J. Soil. Sci.

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A new technique for measuring CO2 evolved from organic soil at different depths in situ was used to monitor CO2 evolution in four experimental sites in southwestern Quebec and in an undisturbed soil column in the laboratory. The technique can be used in conjunction with in situ measurements of surface evolution of CO2, which are used as indicators of total subsidence by oxidation. Subsurface measurements of CO2 evolution provide more detailed estimates of where oxidation is occurring within the profile in organic soils. It also provides a simpler, more direct way of measuring CO2 fluxes below the soil surface than modelling from concentration profiles.

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mentioning

confidence: 97%

MEASUREMENT OF CO₂ EVOLVED FROM ORGANIC SOIL AT DIFFERENT DEPTHS IN SITU

Campbell¹,

Frascarelli²

1981

Can. J. Soil. Sci.

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“…Complex and highly condensed aromatic structures are believed to stabilize quinone moieties in HA (Schnitzer & Levesque, 1979;Senesi, 1990;MartinNeto et al, 1998;Bayer et al, 2002). In this study, the HA values for these aromatic compositions (Table 4) were considerably different and varied with the sample origin.…”

Section: Resultsmentioning

confidence: 56%

Redox index of soil carbon stability

Baldotto

Canela²,

Canellas

et al. 2010

Rev. Bras. Ciênc. Solo

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SUMMARYAs an alternative to the relatively complex and expensive spectroscopic methods, the redox properties of humic acids, determined by potentiometric titrations, have been used to evaluate the stability of soil organic C. The objective of the present study was to establish a Redox Index of C Stability (RICS) and to correlate it with some properties of the humic acids extracted from different modal soils in Brazil (distinct weathering stages or management) to facilitate system comparison. The RICS was efficient for soil comparison and variations were comparable to those of the chemical and spectroscopic methods used for humic acid characterization. The values of soil pH, point of zero salt effect, sum of bases, exchangeable Ca content, weathering index, as well as the humic acid O/C ratio, quinone and semiquinone free radical contents, aromatic C and fluorescence intensity were closely related with the RICS. The RICS was higher in less weathered soils, with more active clays and higher fertility. The RICS values of soils under long-term sugarcane management were ranked in decreasing order: unburned, burned with vinasse, burned without vinasse.Index terms: soil chemistry, soil organic matter, humic substances, oxidation capacity.(1) Part of the doctoral and post doctoral works from the first author developed at the State University of the North Fluminense "Darcy Ribeiro" -UENF.

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“…Ortho-biphenol are good metal ion chelating groups. They are also indicators of the VC humification level [27][28][29][30] .…”

Section: Epr Spectroscopymentioning

confidence: 99%