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  • 11
    Electronic Resource
    Electronic Resource
    Organic matter in particle-size fractions from A and B horizons of a Haplic Alisol (2002)
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 53 (2002), S. 0 
    Details
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: The organic matter in soils may be stabilized by its interactions with minerals. We have studied such interactions in a Haplic Alisol under forest in which clay and organic matter have migrated from an eluvial A horizon to accumulate in an illuvial B horizon. We have tried to trace the fate of organic matter in these horizons (Ah and Bvt) by determining clay mineralogy, carbon and nitrogen content, hydrolysable amino acids, lignin signature by alkaline CuO oxidation and carbon species by 13C CPMAS NMR of bulk soils and particle-size fractions. In both horizons, most of the organic matter was present in O–alkyl and methylene structures, each contributing one-third to the bulk organic matter. In the Ah horizon the ratios of carbon-to-nitrogen, and yields for lignin and hydrolysable amino acids decreased as the particle-size class decreased, but side-chain oxidation of lignin compounds increased with decreasing particle size. In contrast to previous observations, the proportions of O–alkyl carbon increased as particle size decreased, constituting a major proportion of the organic carbon in the clay-size fractions from both the Ah and Bvt horizons (≥ 38%), while proportions of methylene carbon decreased. Illite was the dominant mineral in the fraction ≤ 6 μm, whereas the mobile fine clay fraction (〈0.2 μm) was rich in smectites – minerals with large surface areas. Our results support the hypothesis that potentially labile organic matter, such as O–alkyl carbon typically present in polysaccharides, may be stabilized against further degradation in organomineral complexes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2389.2002.00460.x
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  • 12
    Electronic Resource
    Electronic Resource
    Changes in the chemical composition of soil organic matter after application of compost (2002)
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 53 (2002), S. 0 
    Details
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Is the composition of soil organic matter changed by adding compost? To find out we incubated biowaste composts with agricultural soils and a humus-free mineral substrate at 5°C and 14°C for 18 months and examined the products. Organic matter composition was characterized by CuO oxidation of lignin, hydrolysis of cellulosic and non-cellulosic polysaccharides (CPS and NCPS) and 13C cross-polarization magic angle spinning nuclear magnetic resonance (CPMAS 13C-NMR) spectroscopy. The lignin contents in the compost-amended soils increased because the composts contained more lignin, which altered little even after prolonged decomposition of the composts in soil. A pronounced decrease in lignin occurred in the soils amended with mature compost only. Polysaccharide C accounted for 14–20% of the organic carbon at the beginning of the experiment for both the compost-amended soils and the controls. During the incubation, the relative contents of total polysaccharides decreased for 9–20% (controls) and for 20–49% (compost-amended soils). They contributed preferentially to the decomposition as compared with the bulk soil organic matter, that decreased between 〈 2% and 20%. In the compost-amended agricultural soils, cellulosic polysaccharides were decomposed in preference to non-cellulosic ones. The NMR spectra of the compost-amended soils had more intense signals of O–alkyl and aromatic C than did those of the controls. Incubation for 18 months resulted mainly in a decline of O–alkyl C for all soils. The composition of the soil organic matter after compost amendment changed mainly by increases in the lignin and aromatic C of the composts, and compost-derived polysaccharides were mineralized preferentially. The results suggest that decomposition of the added composts in soil is as an ongoing humification process of the composts themselves. The different soil materials affected the changes in soil organic matter composition to only a minor degree.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1351-0754.2002.00453.x
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  • 13
    Electronic Resource
    Electronic Resource
    Fate of anthracene in contaminated soil: transport and biochemical transformation under unsaturated flow conditions (2002)
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 53 (2002), S. 0 
    Details
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: To obtain reliable estimates for the loss of polycyclic aromatic hydrocarbons (PAHs) from contaminated soils, one has to distinguish between (i) losses due to release and solute transport and (ii) losses resulting from degradation. We studied the interplay of these processes in a column experiment representing a typical soil contamination scenario: in the upper part of the column was a contaminated layer, spiked with 9-13C-labelled anthracene, and beneath it uncontaminated pristine soil. The experimental course comprised a steady-state flow phase (constant irrigation for 4 months) followed by several periods during which flow was halted. The effects of varied residence time on anthracene biodegradation and on anthracene mass transfer were investigated. We monitored labelled anthracene and its transformation products, dissolved organic carbon, electric conductivity (EC), pH, and inorganic carbonate content in the column effluent, and the CO2 evolved.Under steady-state flow, pH, dissolved organic C, and EC approached steady states after 350 pore volumes. Concentrations of anthracene in the effluent, however, increased continuously and levelled off after 800 pore volumes. This marked retardation reflects the great affinity of anthracene to soil organic matter. The response to interruptions in the flow revealed that mass is transferred without equilibrium between solid and liquid phase for both anthracene and dissolved organic C. Thus, residence time is one factor controlling the concentration of anthracene in the effluent and therefore the export of contaminant to the aquifer. In the course of the experiment several labelled anthracene degradation products appeared in the effluent. At least three of them were identified as transformation products showing a dramatic increase in mobility relative to the parent compound. A third of the overall anthracene loss from the column was due to solute transport, and biodegradation was responsible for the remaining two thirds. The incomplete degradation of anthracene leads to the formation of highly mobile transformation products and thus promotes the export of carbon, derived from the contaminant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2389.2002.00427.x
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  • 14
    Electronic Resource
    Electronic Resource
    Soil organic matter transformations induced by Hieracium pilosella L. in tussock grassland of New Zealand (2000)
    Springer
    Biology and fertility of soils 32 (2000), S. 194-201 
    Details
    ISSN: 1432-0789
    Keywords: Key words Carbon-13 nuclear magnetic resonance ; Nitrogen-15 nuclear magnetic resonance ; Lignin ; Phenols ; Organic nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  To study the effect of Hieracium pilosella L. invasion on the transformations of soil organic matter of New Zealand tussock grassland soils (Ustochrepts), plant material and soils underneath Hieracium, the surrounding halo, and the adjacent herbfield (depleted tussock grassland) were examined for their chemical composition. An attempt was made to reveal possible changes in chemical composition of the soil organic matter induced by H. pilosella invasion. Small differences were detected by solid-state 13C nuclear magnetic resonance (NMR) spectroscopy in the composition of the plant and soil materials from these zones. Most of the differences in soil organic matter occurred due to differences in the amount and quality of plant-residue inputs. Comparable amounts of phenolic C were detected in the solid-state 13C NMR spectra of H. pilosella and herbfield vegetation, while alkaline CuO oxidation yielded considerable lower lignin oxidation products for H. pilosella. A slightly higher proportion of these compounds in H. pilosella soil revealed an accumulation and a low degradation rate of lignin compounds under H. pilosella. The HCl hydrolysis and solid-state 15N NMR spectroscopy showed similar chemical compositions of the N fractions of the three different soils. The absence of 15N NMR signal intensity assignable to aniline derivatives or aromatic heterocyclic N indicates that the condensation of phenolic compounds with N groups plays a minor role in N sequestration in these soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740000234
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  • 15
    Electronic Resource
    Electronic Resource
    Organic matter composition and degree of humification in lignite-rich mine soils under a chronosequence of pine (1999)
    Springer
    Plant and soil 213 (1999), S. 161-168 
    Details
    ISSN: 1573-5036
    Keywords: 14C activity ; 13C CPMAS NMR spectroscopy ; lignite ; mine soils ; soil organic matter ; wet chemical analyses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In the Lusatian mining district, in the eastern part of the Federal Republic of Germany, organic matter of reclaimed mine soils consists of a mixture of lignite and recently formed soil organic matter (recent carbon). The aim of the study was to investigate the recent carbon accumulation and the degree of humification of a chronosequence of young mine soils under forest. The lignite content of the forest floor, Ai (0–5 cm) and Cv horizons (1 m depth) was determined by 14CU activity measurements and the structural composition of the organic matter was characterised by 13C CPMAS NMR spectroscopy. To obtain a characterisation of the degree of humification, the soil samples were analysed for the content of polysaccharides, proteins, lignin and lipids by wet chemical methods. 14C activity measurements indicate that at the oldest site, comparable amounts of carbon accumulated in the first few centimetres of the soil profile than in natural forest soils. 13C CPMAS NMR spectra of the organic matter in the Ai horizons of the three soil profiles were dominated by aromatic and alkyl carbon species characteristic for lignite, but indicated as well an increasing contribution of carbon species from decomposing plant litter with soil age. When the results from wet chemical analyses were normalised to the total carbon content no changes with age could be noticed. After normalisation of the amount of litter compounds to the recent carbon content, the carbon identified by plant litter compound analysis decreased with increasing depth and increasing age of the soils. After 32 years the values are comparable to those of natural forest soils. These observations were confirmed by increasing degree of lignin alteration with stand age and soil depth. The data of wet chemical analyses complement data obtained by 14C activity measurements and 13C CPMAS NMR spectroscopy and lead to the conclusion that 32 years after reforestation the degree of humification of the soil organic matter is in the same range as those of natural sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004454826537
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  • 16
    Electronic Resource
    Electronic Resource
    Airborne Contamination of Immature Soil (Lusatian Mining District) by Lignite-Derived Materials: Its Detection and Contribution to the Soil Organic Matter Budget (1998)
    Springer
    Water, air & soil pollution 105 (1998), S. 481-492 
    Details
    ISSN: 1573-2932
    Keywords: 13C CPMAS NMR ; Germany ; lignite dust ; soil chemistry ; soil contamination ; soil organic matter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Large areas in eastern Germany have been subjected to substantial airborne contamination by fly ash, soot and lignite dust. The objective of the study was to detect the input of lignite-derived airborne contamination into forest soils and to examine the chemical and structural characteristics of the soil organic matter, consisting of natural humic material and lignite-derived carbon in reforested immature mine soils. The mine soil developed on sandy overburden material that was excavated in open-cast lignite mines and had been relocated and deposited at a spoil bank. Samples were taken from the forest floor (L, Oh), the humic surface horizon (Ai), and the parent substrate (Cv) of an immature mine soil under a 25-year-old red oak (Quercus rubra), situated close to a briquette factory. The conceptual approach includes analyses of bulk soil as well as particle-size fractions for C and N contents, magnetic susceptibility, radiocarbon age and chemical structure by using 13C CPMAS NMR spectroscopy. High magnetic susceptibility of the Oh and Ai horizon is the result of airborne contamination by lignite-derived ash. Fly ash contamination consisting of ferrimagnetic minerals contributes mainly to the 〈20 μm fractions. In the Oh and Ai horizon, 44% and 46% of the C was found to be of anthropogenic origin. Structural information indicates that lignite-derived dust and/or soot are present in the coarse particle size fractions (6.3-200 μm). Anthropogenic C increased the C content as well as the contribution of alkyl and aromatic C species in the organic matter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005080820520
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