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Ingrid Kogelknabner - One of the best experts on this subject based on the ideXlab platform.
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soil organic matter staBilization in acidic forest soils is preferential and soil type specific
European Journal of Soil Science, 2008Co-Authors: Sandra Spielvogel, Jörg Prietzel, Ingrid KogelknabnerAbstract:Summary Minerals with large specific surface areas promote the staBilization of soil organic matter (SOM). We analysed three acidic soils (dystric, skeletic Leptic CamBisol; dystric, laxic Leptic CamBisol; skeletic Leptic Entic Podzol) under Norway spruce (Picea aBies) forest with different mineral compositions to determine the effects of soil type on carBon (C) staBilization in soil. The relationship Between the amount and chemical composition of soil organic matter (SOM), clay content, oxalate-extractaBle Fe and Al (Feo; Alo), and dithionite-extractaBle Fe (Fed) Before and after treatment with 10% hydrofluoric acid (HF) in topsoil and suBsoil Horizons was analysed. RadiocarBon age, 13C CPMAS NMR spectra, lignin phenol content and neutral sugar content in the soils Before and after HF-treatment were determined and compared for Bulk soil samples and particle size separates. Changes in the chemical composition of SOM after HF-treatment were small for the A-Horizons. In contrast, for B-Horizons, HF-soluBle (mineral-associated) and HF-resistant (non-mineral-associated) SOM showed systematic differences in functional C groups. The non-mineral associated SOM in the B-Horizons was significantly depleted in microBially-derived sugars, and the contriBution of O/N-alkyl C to total organic C was less after HF-treatment. The radiocarBon age of the mineral-associated SOM was younger than that of the HF-resistant SOM in suBsoil Horizons with small amounts of oxalate-extractaBle Al and Fe. However, in Horizons with large amounts of oxalate-extractaBle Al and Fe the HF-soluBle SOM was consideraBly older than the HF-resistant SOM. In acid suBsoils a specific fraction of the organic C pool (O/N-alkyl C; microBially-derived sugars) is preferentially staBilized By association with Fe and Al minerals. StaBilization of SOM with the mineral matrix in soils with large amounts of oxalate-extractaBle Alo and Feo results in a particularly staBle and relatively old C pool, which is potentially staBle for thousands of years.
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the effect of 10 hf treatment on the resolution of cpmas 13c nmr spectra and on the quality of organic matter in ferralsols
Geoderma, 2003Co-Authors: Cristiano Nunes Gonçalves, Deborah Pinheiro Dick, Ricardo Simão Diniz Dalmolin, Heike Knicker, Egon Klamt, Ingrid KogelknabnerAbstract:The investigation of the chemical composition of soil organic matter (SOM) in Ferralsols By means of solid-state cross-polarization magic angle spinning (CPMAS) 13C nuclear magnetic resonance (NMR) spectroscopy is limited By their high iron oxide concentration and their low organic carBon content. In order to circumvent those limitations, such samples are often treated with hydrofluoric acid (HF) to remove paramagnetic material and to concentrate the amount of SOM. The main oBjectives of this study were to elucidate the impact of this approach on the resolution of the CPMAS 13C NMR spectra and on the chemical composition of the SOM in the A and B Horizons of four Brazilian Ferralsols. Therefore, those soils were suBjected to up to eight successive treatments with 10% (w/w) HF. Each of those extractions resulted in an enhancement of the C content of the samples. A relationship Between mass loss caused By the treatment and texture and mineralogy was oBserved. However, high losses of carBon occurred during the HF treatments, particularly in the B Horizons, But no consistent alterations in the distriBution of carBon functional groups were determined By CPMAS 13C NMR, suggesting that preferential loss of specific carBon groups was not induced. The concentration of total and dithionite extractaBle Fe increased after two treatments for most of the samples. This may Be Best explained By the preferential dissolution of silicate leading to a selective enrichment of iron containing minerals. After four treatments, the Fe concentration declined consideraBly. After the second treatment, the spectral resolution improved. Considering the oBtained results, it can Be confirmed that the efficiency of the HF treatment is rather controlled By the numBer than By the duration of the extraction. We suggest that, for A Horizons of Ferralsols, four repetitions of HF treatment are sufficient to yield well-defined spectra. For their B Horizons, on the other hand, the CPMAS 13C NMR spectra oBtained after four HF extractions were of poor quality, indicating that for these soils at least eight HF treatments have to Be performed to acquire reasonaBle spectra.
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vertical distriBution age and chemical composition of organic carBon in two forest soils of different pedogenesis
Organic Geochemistry, 2002Co-Authors: Cornelia Rumpel, Ingrid Kogelknabner, Frank BruhnAbstract:Recent carBon inventories have shown that significant amounts of soil organic matter (SOM), even though at low concentrations, can Be stored in the suBsoil (B and C Horizons). Its quantity, turnover and chemical composition are largely unknown. The oBjective of the present study was to analyse the organic matter in the mineral Horizons of two forest soils with different pedogenetic history and to assess the quantity, turnover and chemical composition of SOM stored in the suBsoil compared to the topsoil (A horizon and litter layers). Samples were taken from a Dystric CamBisol under Beech and a Haplic Podzol under spruce forest down to a depth of 140 and 80 cm, respectively. They were analysed for elemental composition, carBon storage and chemical structure of SOM By 13C CPMAS NMR spectroscopy, radiocarBon age By accelerator mass spectrometry and plant derived phenols as well as hydroxyalkanoic acids By CuO oxidation. Special attention was drawn to the contriBution of phenols and hydroxyalkanoic acids, Because they are major contriButors of root litter. Up to 75% of the organic carBon present in the mineral soil of the two profiles was found Below the A horizon. RadiocarBon measurements showed that the organic carBon in the suBsoil had an apparent age of several thousand years. The structural analyses indicated a similar chemical composition of the organic matter present in the litter layers of Both soils. In the mineral soils, the chemical composition of the SOM differed according to the pedogenetic processes operating at the two sites. A high contriBution of alkyl carBon was recorded in the B Horizons of the Dystric CamBisol which may Be partly explained By the contriBution of hydroxyalkanoic acids which are preserved preferentially in this soil compared to phenols. In the Haplic Podzol, spectra of the B Horizons indicate a higher contriBution of O-alkyl and carBoxylic carBon due to carBon leaching during podzolisation. In the C Horizons of Both soils, most of the organic carBon was moBilised after demineralisation By treatment with 10% hydrofluouric acid (HF) and may therefore Be adsorBed to the soil minerals. Our data indicated that there is, apart from root litter, a strong influence of soil-forming processes on the composition of organic carBon in suBsoils.
Jon Petter Gustafsson - One of the best experts on this subject based on the ideXlab platform.
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surface reactivity of poorly ordered minerals in podzol B Horizons
Geoderma, 2000Co-Authors: Erik Karltun, A R Fraser, W J Mchardy, D. C. Bain, Jon Petter Gustafsson, Hannu Mannerkoski, Enver Murad, U Wagner, Mike StarrAbstract:The surface reactivity of mineral soil Horizons from three podzolised forest soils in Scandinavia was examined. The amount of accumulated C was low, Between 1.8 and 2.3% in the top of the B horizon ...
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aluminium soluBility characteristics of spodic B Horizons containing imogolite type materials
Clay Minerals, 1998Co-Authors: Jon Petter Gustafsson, D G Lumsdon, Maria SimonssonAbstract:Fifteen Swedish and Finnish soil samples from spodic B Horizons containing imogolite-type materials were equiliBrated with dilute NaCl and HCl at 8°C. For the NaCl extracts, apparent equiliBrium with respect to an Al(OH) 3 phase was reached in one to two weeks. EquiliBrium with respect to an imogolite-type phase was slower, especially at large soil:solution ratios. The results show that log *K s (giBBsite), i.e. the logarithm of the soluBility constant for reactive Al(OH) 3 at 8°C, was ∼9.40 (8.29 at 25°C) while log *K s (imogolite) was variaBle; for the soil studied in most detail it was 7.66 (6.64 at 25°C). As well-ordered giBBsite rarely forms in spodic B Horizons, it is suggested that Al(OH) 3 and poorly-ordered allophanic materials may Be slowly converted to less soluBle and less reactive imogolite-type materials.
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aluminium soluBility characteristics of spodic B Horizons containing imogolite type materials
Clay Minerals, 1998Co-Authors: Jon Petter Gustafsson, D G Lumsdon, Maria SimonssonAbstract:Fifteen Swedish and Finnish soil samples from spodic B Horizons containing imogolite-type materials were equiliBrated with dilute NaCl and HCl at 8°C. For the NaCl extracts, apparent equiliBrium with respect to an Al(OH) 3 phase was reached in one to two weeks. EquiliBrium with respect to an imogolite-type phase was slower, especially at large soil:solution ratios. The results show that log *K s (giBBsite), i.e. the logarithm of the soluBility constant for reactive Al(OH) 3 at 8°C, was ∼9.40 (8.29 at 25°C) while log *K s (imogolite) was variaBle; for the soil studied in most detail it was 7.66 (6.64 at 25°C). As well-ordered giBBsite rarely forms in spodic B Horizons, it is suggested that Al(OH) 3 and poorly-ordered allophanic materials may Be slowly converted to less soluBle and less reactive imogolite-type materials.
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response of spodic B Horizons to acid precipitation in northernmost fennoscandia
Water Air and Soil Pollution, 1996Co-Authors: Jon Petter GustafssonAbstract:In northernmost Fennoscandia there is concern aBout the possiBle environmental effects of the sulphur emissions from Russian nickel smelters on the Kola Peninsula. The purpose of this study was to investigate to what extent the soils of this region may delay the response to pH changes through sulphate adsorption, and whether there are evidence for strong soil acidification effects. To this end 26 spodic B Horizons were collected along a transect from northernmost Sweden to north-easternmost Norway, only 10 km from the Pechenganikel smelter. As the pH(H2O) was > 4.8 in all soils, and as the exchangeaBle Ca/Al ratio was high, there were no evidence for strong soil acidification effects. Water-extractaBle SO4 was clearly affected By the S deposition and thus SO4 was at least partly moBile in the soils; it is therefore possiBle that soil solutions close to the smelter may have Been acidified. In spite of this, sulphate adsorption was found to Be more important than cation exchange reactions as a delaying process against soil acidification, at least in the top 10 cm of the B horizon. For the top 20 cm of the B horizon it was estimated that S04 adsorption can neutralize, on average, 700 mmolc, m−2 of acid Before the pH is decreased to 4.4. Thus if the S deposition remains unchanged, decades are required to severely acidify most soils in the affected parts of Norway and Finland.
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podzolisation mechanisms and the synthesis of imogolite in northern scandinavia
Geoderma, 1995Co-Authors: Jon Petter Gustafsson, A R Fraser, D. C. Bain, Prosun Bhattacharya, W J MchardyAbstract:ABstract The nature of the short-range ordered Al and Fe minerals of the spodic B Horizons of northern Scandinavia was studied By selective dissolution, transmission electron microscopy, infrared aBsorption and sulphate adsorption experiments. Imogolite-type materials (proto-imogolite allophane and well-developed imogolite) were the predominant oxalate-extractaBle Al minerals. Minor amounts of giBBsite and kaolinite were also found. The Fe oxides were less aBundant and relatively well crystallized. Imogolite-type materials were the predominant source of positive charge, as evidenced By the amount of sulphate adsorBed. The Fe:AI ratio of the pyrophosphate extracts was positively correlated with the ratio of pyrophosphate-C to oxalate-extractaBle Al—this oBservation provides field evidence that imogolite-type materials were particularly unstaBle in the presence of organic suBstances. It is hypothesized that most accumulated Al and Fe originated from the congruent dissolution of primary minerals followed By the downward migration and degradation of metal-organic complexes, But incongruent weathering within the B horizon might have made additional contriButions to the precipitation of the short-range ordered minerals. Historical climatic change might, to some extent, explain why metal-organic complexes were almost aBsent in many B Horizons.
Luisella Celi - One of the best experts on this subject based on the ideXlab platform.
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characteristics of fragipan B Horizons developed on different parent material in north western italy
Archives of Agronomy and Soil Science, 2019Co-Authors: E Raimondo, Gloria Falsone, Michele Damico, Silvia Stanchi, Luisella Celi, Eleonora BonifacioAbstract:ABSTRACTA Fragipan (Bx) is a soil horizon hard when dry and Brittle when moist, that undergoes slaking upon water immersion, forming a Barrier to roots and limiting land use. Brittleness and slaking depend on soil porosity and particle arrangement, But still no agreement exists on the inorganic components responsiBle for such arrangement. We hypothesized that the same kind of particle arrangement may originate from different soil components, ultimately depending on the lithology of parent material, and evaluated the soil and clay characteristics that Best differentiate Bx from B Horizons. Thirty-six samples were taken from Typic Fragiudalfs developed on the two sides of an alluvial fan characterized By different amounts of ultramafic materials. Discriminant Analysis evidenced that pedogenic Fe oxides were fundamental in discriminating Bx from B Horizons on pure ultramafic parent material, while clay mineralogy was more important in soils with less ultramafic materials. In the first case, the association B...
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Evolution of surface properties and organic matter staBilisation in podzolic B Horizons as assessed By nitrogen and phosphate sorption
Biology and Fertility of Soils, 2013Co-Authors: Eleonora Bonifacio, Gloria Falsone, Marcella Catoni, Daniel Said-pullicino, Luisella CeliAbstract:In podzolic B Horizons illuviated Al, Fe and organic matter (OM) increase with the ongoing of the pedogenic process. Depending on OM load on mineral surfaces, modifications of the soil surface properties are expected and may influence OM staBilisation. The proportion of laBile organic pools should thus vary depending on the type of podzolic horizon. In this work, we selected B Horizons at increasing intensity of podzolisation, evaluated the laBile OM pools through oxidation with 2 % NaClO and characterised surface properties with N_2 and phosphate sorption. Before and after oxidation, we assessed the NaOH-extractaBle OM fractions. Oxidation was more effective on the least polar organic compounds and led to an increase in the fulvic to humic acid ratio. Specific surface area (SSA) increased after oxidation only in the least podzolised Horizons, while selectively preserved OM induced a decrease in SSA in the more developed Bs, Bsm and Bhs. Phosphate sorption induced a release of OM and always decreased after oxidation, although variations in P affinity for the surfaces were oBserved. The effect of oxidation on surface parameters pointed to a specific association Between organics and minerals that changed during soil development. At the very Beginning of podzolisation, the dominant forms seemed related to organo-metallic complexes with little interaction with surfaces. With Bs development, weak interactions Between mineral surfaces and OM appeared, while at a later stage OM differentiated into Bulky structures and tightly Bound, rigid ones, with extremely low N_2 accessiBility. The latter were not sensitive to low concentration NaClO while the former were easily oxidised.
Michael W I Schmidt - One of the best experts on this subject based on the ideXlab platform.
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carBon and nitrogen isotope composition of Bulk soils particle size fractions and organic material after treatment with hydrofluoric acid
European Journal of Soil Science, 2005Co-Authors: Michael W I Schmidt, Gerd GleixnerAbstract:Summary Soils and sediments contain only small amounts oforganic matter, and large concentrations ofparamagnetic metals can give poor solid-state nuclear magnetic resonance (NMR) spectra oforganic matter. Pretreatment of samples with hydrofluoric acid (HF) dissolves significant proportions of the mineral matrix and extracts paramagnetic elements. We investigated the effects of 10% HF treatment on the staBle isotope content ofcarBon (C) and nitrogen (N) oforganic matter f soils, composts and shales. Additionally we inferred molecular and isotopic characteristics of lost materials from calculations of isotope mass Balances. Treatment with HF enriched C and N in mineral samples suBstantially (factors 2.5–42.4), except for Podzol B Horizons (1.1–1.7) and organic material (1.0–1.3). After treatment most of the C (59.7–91.7%) and N (53.7–86.6%) was recovered, although changing C/N ratios often indicated a pref erential loss ofN-rich material. Isotope ratios ofC and N in the remaining material Became more negative when net alterations exceeded 0.3‰. The isotope ratios ofthe lost material contained more 13 C (1–2‰) and 15 N (1–4‰) than the initial organic matter. Acid hydrolysis typically removes proteins, amino acids and polysaccharides, all ofwhich are enriched in 13 C, and in the case ofproteins and amino acids, enriched in 15 N as well. We conclude that HF treatment released fresh, soluBle, proBaBly microBial, Biomass in addition to carBohydrates. Net changes ofthe Bulk chemical composition oforganic matter were small for most soils, size fractions and plant material, But not for samples containing little organic matter, or those rich in easily soluBle organic matter associated with iron oxides, such as Podzol B Horizons.
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organic matter in particle size fractions from a and B Horizons of a haplic alisol
European Journal of Soil Science, 2002Co-Authors: Michael W I Schmidt, Kogel I KnabnerAbstract:Summary 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.
Soo Jin Park - One of the best experts on this subject based on the ideXlab platform.
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incorporation of spatial autocorrelation improves soil landform modeling at a and B Horizons
Catena, 2019Co-Authors: Daehyun Kim, Ondřej Drábek, Pavel Samonil, Gwanyong Jeong, Vaclav Tejnecký, Jakub Hruska, Soo Jin ParkAbstract:ABstract Research has shown that the performance of soil–landform models would improve if the effects of spatial autocorrelation were properly accounted for; however, it remains elusive whether the level of improvement would Be predictaBle, Based on the degree of spatial autocorrelation in the model variaBles. We evaluated this proBlem using 11 soil variaBles acquired from the A and B Horizons along a hillslope of Žofinský Prales in the Czech RepuBlic. The results showed that, with no exception, there were increases in R2 and decreases in the Akaike information criterion (AIC), residual autocorrelation, and root-mean-square errors (RMSEs), after incorporating the spatial filters extracted By spatial eigenvector mapping into non-spatial regression models. Furthermore, the improvement of the model was positively proportional to the degree of spatial autocorrelation, inherent in the soil variaBles. That is, there were strikingly linear and significant relationships, in which strongly autocorrelated soil variaBles (i.e., having a high Moran's I value) exhiBited greater increases in R2 and decreases in AIC, residual autocorrelation, and RMSEs than their more weakly autocorrelated counterparts. These findings indicate that the degree of spatial autocorrelation present in soil properties can serve as a direct indicator for how much the performance of a traditional non-spatial soil–landform model would Be enhanced, By explicitly taking into consideration the presence of spatial autocorrelation. More generally, our results potentially imply that the need for and Benefit from incorporating spatial effects in geopedological modeling proportionally increases as the soil property of interest is more spatially structured (i.e., landform variaBles alone cannot capture soil spatial variaBility).
