A comparison of two methods for routine characterization of humus in pedological studies

Lowe, L. E.; Kumada, Kyoichi

doi:10.1080/00380768.1984.10434698

Cited by 7 publications

(4 citation statements)

References 6 publications

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“…Kumada's method of HA classification [ Kumada , 1987] (Figure 2) shows that compared to more comprehensive investigations from boreal soils [ Kumada , 1987; Ikeya and Watanabe , 2003], humification is generally low in the investigated soils. Lowe and Kumada [1984]characterized HA in the active layer of a Turbic Cryosol in the Canadian Arctic and found that the bulk SOM was composed of Rp and B‐type HAs, which is consistent with the findings in this study. Combining the results from extraction and classification of humic compounds with a GIS based SOC storage map for the Seida region (Figure 3) shows clear differences between the mineral soils versus peat deposits (especially in the uplifted peat plateaus).…”

Section: Discussionsupporting

confidence: 91%

Mapping the degree of decomposition and thaw remobilization potential of soil organic matter in discontinuous permafrost terrain

Hugelius¹,

Routh²,

Kuhry³

et al. 2012

J. Geophys. Res.

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[1] Soil organic matter (SOM) stored in permafrost terrain is a key component in the global carbon cycle, but its composition and lability are largely unknown. We characterize and assess the degree of decomposition of SOM at nine sites representing major land-cover and soil types (including peat deposits) in an area of discontinuous permafrost in the European Russian Arctic. We analyze the elemental and stable isotopic composition of bulk SOM, and the degree of humification and elemental composition of humic acids (HA). The degree of decomposition is low in the O-horizons of mineral soils and peat deposits. In the permafrost free non-peatland soils there is enrichment of 13 C and 15 N, and decrease in bulk C/N ratios indicating more decomposed material with depth. Spectral characterization of HA indicates low humification in O-horizons and peat deposits, but increase in humification in the deeper soil horizons of non-peatland soils, and in mineral horizons underlying peat deposits. GIS based maps indicate that less decomposed OM characteristic of the O-horizon and permafrost peat deposits constitute the bulk of landscape SOM (>70% of landscape soil C). We conclude, however, that permafrost has not been the key environmental factor controlling the current degree of decomposition of SOM in this landscape due to relatively recent permafrost aggradation. In this century, active layer deepening will mainly affect SOM with a relatively high degree of decomposition in deeper mineral soil horizons. Additionally, thawing permafrost in peat plateaus may cause rapid remobilization of less decomposed SOM through thermokarst expansion.Citation: Hugelius, G., J. Routh, P. Kuhry, and P. Crill (2012), Mapping the degree of decomposition and thaw remobilization potential of soil organic matter in discontinuous permafrost terrain,

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Section: Discussionsupporting

confidence: 91%

Mapping the degree of decomposition and thaw remobilization potential of soil organic matter in discontinuous permafrost terrain

Hugelius¹,

Routh²,

Kuhry³

et al. 2012

J. Geophys. Res.

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“…Consequently, the £4/£6 ratios were higher in the mineral horizons than in the 0 horizons. On the other hand, the £4/£6 ratios of HAs measured by the N aHC0 3 method shown in Table 1 (2.1-7.5) corresponded mostly to the threshold value of those reports by other authors (Schnitzer 1971;Lowe and Kumada 1984). The £4/£6 ratio of the total extract gave a similar value to that of HAs in N aHC0 3 only in the 0 and A horizons, suggesting that the total extract is not suitable for measuring the £4/£6 value in the mineral horizons, but that it can be used for a rapid measurement of the humification degree of humic substances without additional separation process for the HAs of the 0 horizons.…”

Section: Resultssupporting

confidence: 79%

“…Table 1 indicates that the values of the £4/£6 ratio in the 0 and A horizons displayed a wide range for the total extract (2.6-8.7). The £4/£6 ratios of HAs extracted from several great soil groups ranged from 3.0 to 5.0 (Schnitzer 1971) while the ratios of the gray forest soil and chernozenic dark brown soil (Lowe and Kumada 1984) ranged from 3.4 to 5.6. These values were very high in the mineral horizons for the total extract, presumably due to the high content of non-humic substances in the mineral horizons, which increased the absorbance at 400 nm.…”

Section: Resultsmentioning

confidence: 99%

Spectral features of humic substances in a perhumid subtropical montane forest ecosystem, Taiwan

Chen

Chiu

Nagatsuka

2001

Soil Science and Plant Nutrition

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“…In the present study, the yields of HAs and FAs were not determined, but they could be estimated from the results of the humus composition analysis reported previously (2,3,8). Preliminary experiments showed that about 90% of the coloured substances in the acid filtrate, the so-called FA fraction of the humus extract, was adsorbed on PVP, judging from the optical density values at 600 nm before and after addition of PVP to the FA.…”

Section: Resultsmentioning

confidence: 99%

Soils of a Mangrove Forest Composed ofRhizophora mucronataandBruguiera gymnorrhizafrom Ishigaki Island, Japan

Kumada

1985

Soil Science and Plant Nutrition

Self Cite

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Elementary composition and absorption spectra of humic acids (HAs) and fulvic acids (FAs) obtained from 4 Canadian and 2 Japanese soils were determined, and the relationships between these 2 properties were discussed. In this study, FA refers to the PVP adsorbed, i.e. coloured substances in what has been designated, in previous reports, as FA. In 3 soil samples, FA was divided into the acid (pH l.O)-precipitable FAI and non-precipitable FA. fractions.1. In the case of HAs, some correlations were observed between the carbon content and hydrogen content or C/H ratio. The hydrogen and nitrogen contents of the FA and FAl samples tended to be higher while those of the FA. samples tended to be lower than those of HAs obtained from the same soils. In all cases, conspicuous differences in the elementary composition were found between the FAI and FA, fractions.2. The absorption spectra (logE vs. ). curves, in 0.1 N NaOH) of S out of 17 samples of HAs and FAs showed absorption bands due to the dissociation of the dihydroxyperylene quinone moiety (Pg). The absorption spectra of the other 12 samples were almost featureless. E,(E~6f;nm)' E,(El6f;nm)' E,.a(E~~nm) ' EJE.(E400nmIE600nm) and Pg content were adopted as parameters characterizing the spectra.3. The pH dependency of the absorption spectra was examined in solutions having various pHs.4. Several correlations were found between the parameters and the elementary composition of HAs and FAs. Based on the relation between the carbon content and El% values, FAs were divided into 2 groups. The elementary composition of each group showed distinct regularities.

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A comparison of two methods for routine characterization of humus in pedological studies

Cited by 7 publications

References 6 publications

Mapping the degree of decomposition and thaw remobilization potential of soil organic matter in discontinuous permafrost terrain

Mapping the degree of decomposition and thaw remobilization potential of soil organic matter in discontinuous permafrost terrain

Spectral features of humic substances in a perhumid subtropical montane forest ecosystem, Taiwan

Soils of a Mangrove Forest Composed ofRhizophora mucronataandBruguiera gymnorrhizafrom Ishigaki Island, Japan

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