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Ingrid Kogelknabner - One of the best experts on this subject based on the ideXlab platform.
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non cellulosic neutral sugar contribution to mineral associated organic matter in top and subsoil horizons of two acid forest soils
Soil Biology & Biochemistry, 2010Co-Authors: Cornelia Rumpel, Karin Eusterhues, Ingrid KogelknabnerAbstract:We investigated the polysaccharide composition of bulk and mineral-bound (density fractions >2 g cm−3) organic matter in topsoil and subsoil horizons of a Podzol and a Cambisol. Total sugar contents were generally higher in the Cambisol than in the Podzol. For most horizons of both soils, the sugars were enriched in the mineral-bound organic matter fraction. This fraction showed a monosaccharide distribution typical for microbial sugars, whereas in bulk soil horizons higher contributions of plant-derived sugars were observed. A strong relationship with the 14C activity of the dense fraction suggests that microbial-derived polysaccharides are most likely stabilised preferentially by mineral interactions compared to plant-derived polysaccharides.
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composition and radiocarbon age of hf resistant soil organic matter in a podzol and a Cambisol
Organic Geochemistry, 2007Co-Authors: Karin Eusterhues, Cornelia Rumpel, Ingrid KogelknabnerAbstract:Hydrofluoric acid (HF) is able to dissolve most minerals, so it is often used to enrich organic matter (OM) in soils and sediments, though significant OM losses sometimes occur. The objective of this study was to examine these carbon losses and the hypothesis that HF dissolves the mineral-associated OM along with its mineral carrier. We compared composition, radiocarbon activity and particle morphology of untreated and HF-treated soil samples, using bulk samples, density fractions > 2 g cm � 3 and fine particle size fractions < 6.3 lm from a Haplic Podzol and a Dystric Cambisol. A positive correlation between HF-soluble organic carbon and organic carbon in the dense fraction confirms a linkage between the dissolved fraction and the mineral-associated OM fraction. However, treatment of heavy soil fractions shows that removal of the mineral-associated OM fraction is not complete. In the topsoil carbon losses amount to only 20–30% of the mineral-associated C, compared to 40–55% for the sub-soil of the Dystric Cambisol and 70–85% for the sub-soil of the Haplic Podzol. Compositional OM change as a consequence of HF treatment was not detected in upper soil horizons, but was substantial for the lower horizons. With depth or age of soil horizon, the HF-soluble OM becomes enriched in O-alkyl C, aryl C, and carbonyl C compared to the HF-resistant OM. The HF-soluble material in all horizons of the Dystric Cambisol is dominated by high alkyl C content, whereas O-alkyl C dominates in deeper horizons of the Haplic Podzol. In A horizons, radiocarbon ages of the HF-resistant OM fraction were similar, but slightly younger than for bulk soil radiocarbon ages. In contrast, in the subsoil horizons the HF-resistant fraction was up to 2000 yr older than the bulk soil age. � 2007 Elsevier Ltd. All rights reserved.
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stabilization of soil organic matter isolated via oxidative degradation
Organic Geochemistry, 2005Co-Authors: Karin Eusterhues, Cornelia Rumpel, Ingrid KogelknabnerAbstract:Formation of long residence time carbon pools in soils is crucial for understanding the global carbon cycle. Acting on the assumption that chemical oxidation mimics natural oxidative processes, we treated forest floor, topsoil and subsoil samples from two acid forest soil profiles (Dystric Cambisol, Haplic Podzol) with H2O2. The oxidation-resistant organic carbon fraction was dated using 14C and found to be 500–3900 years older than the bulk soil material. A positive correlation between the oxidation-resistant organic carbon and the amount of total iron oxides (dithionite-extractable Fe) exists for the subsoil samples of the Dystric Cambisol. In subsoils of the Haplic Podzol total iron oxides and the clay content are correlated with the oxidation-resistant organic carbon. This suggests that stabilization of the oxidation-resistant, old carbon fraction is caused by its interaction with iron oxides and/or other clay minerals rather than by chemical recalcitrance. In contrast to the subsoil, the topsoil samples have much higher concentrations of residual carbon relative to their iron oxide contents. Like forest floor horizons they probably contain additional, non-mineral-protected, but chemically recalcitrant, aliphatic organic matter, which is resistant to H2O2 treatment.
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location and chemical composition of stabilized organic carbon in topsoil and subsoil horizons of two acid forest soils
Soil Biology & Biochemistry, 2004Co-Authors: Karin Eusterhues, Cornelia Rumpel, Ingrid KogelknabnerAbstract:The 14 C age of soil organic matter is known to increase with soil depth. Therefore, the aim of this study was to examine the stabilization of carbon compounds in the entire soil profile using particle size fractionation to distinguish SOM pools with different turnover rates. Samples were taken from a Dystric Cambisol and a Haplic Podzol under forest, which are representative soil types under humid climate conditions. The conceptual approach included the analyses of particle size fractions of all mineral soil horizons for elemental composition and chemical structure of the organic matter by 13 C cross-polarization magic angle spinning nuclear magnetic resonance (CPMAS NMR) spectroscopy. The contribution of phenols and hydroxyalkanoic acids, which represent recalcitrant plant litter compounds, was analyzed after CuO oxidation. In the Dystric Cambisol, the highest carbon concentration as well as the highest percentage of total organic carbon are found in the , 6.3 mm fractions of the B and C horizons. In the Haplic Podzol, carbon distribution among the particle size fractions of the Bh and Bvs horizons is influenced by the adsorption of dissolved organic matter. A relationship between the carbon enrichment in fractions ,6.3 mm and the 14 C activity of the bulk soil indicates that stabilization of SOM occurs in fine particle size fractions of both soils. 13 C CPMAS NMR spectroscopy shows that a high concentration of alkyl carbon is present in the fine particle size fractions of the B horizons of the Dystric Cambisol. Decreasing contribution of O-alkyl and aromatic carbon with particle size as well as soil depth indicates that these compounds are not stabilized in the Dystric Cambisol. These results are in accordance with data obtained by wet chemical analyses showing that cutin/suberin-derived hydroxyalkanoic acids are preserved in the fine particle size fractions of the B horizons. The organic matter composition in particle size fractions of the top- and subsoil horizons of the Haplic Podzol shows that this soil is acting like a chromatographic system preserving insoluble alkyl carbon in the fine particle size fractions of the A horizon. Small molecules, most probably organic acids, dominate in the fine particle size fractions of the C horizons, where they are stabilized in clay-sized fractions most likely due to the interaction with the mineral phase. The characterization of lignin-derived phenols indicated, in accordance with the NMR measurements, that these compounds are not stabilized in the mineral soil horizons. q 2003 Elsevier Ltd. All rights reserved.
Cornelia Rumpel - One of the best experts on this subject based on the ideXlab platform.
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relative importance of sorption versus aggregation for organic matter storage in subsoil horizons of two contrasting soils
European Journal of Soil Science, 2010Co-Authors: C. Moni, Cornelia Rumpel, Inigo Virto, Abad Chabbi, Claire ChenuAbstract:Summary Soil organic matter (OM) stabilization by the mineral phase can take place through sorption and aggregation. In this study we examined both of these processes, (i) organic carbon (OC) sorption onto clay-sized particles and (ii) OC occlusion in silt-size aggregates, with the objective of evaluating their relative importance in OM storage and stabilization in soil. We studied two loamy soil profiles (Haplic Luvisol and Plinthic Cambisol) currently under agricultural use down to a depth of 2 m. Ou ra pproach was based on two parallel fractionation methods using different dispersion intensities; these methods isolated a free clay fraction (non-occluded) and a clay fraction occluded within water-stable silt-size aggregates. The two clay fractions were analysed for their Cc ontent and 14 Ca ctivity. The proportion of sorbed OC was estimated as OC loss after hydrof luoric acid (HF) demineralization. Our results showed an important contribution to SOM stabilization by occlusion of OC into silt-size aggregates with depth through both soi lp rof iles. In the Haplic Luvisol, OC associated with clay and located in silt-size aggregates accounted for 34‐64% of the total soil OC, whereas in the Plinthic Cambisol this occluded material represented 34‐40% of total OC. In the Haplic Luvisol, more OC was located in silt-size aggregates than was sorbed onto clay-size minerals, suggesting that silt-size aggregation plays a dominant role in OC storage in this soil. In the Plinthic Cambisol, the abundance of sorbed OC increased with depth and contributed more to the stored C than that associated with silt-size aggregates. Radiocarbon dating of both clay fractions (either occluded within silt-size aggregates or not) suggests, in the case of the Plinthic Cambisol, a preferential stabilization of OC within silt-size aggregates.
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non cellulosic neutral sugar contribution to mineral associated organic matter in top and subsoil horizons of two acid forest soils
Soil Biology & Biochemistry, 2010Co-Authors: Cornelia Rumpel, Karin Eusterhues, Ingrid KogelknabnerAbstract:We investigated the polysaccharide composition of bulk and mineral-bound (density fractions >2 g cm−3) organic matter in topsoil and subsoil horizons of a Podzol and a Cambisol. Total sugar contents were generally higher in the Cambisol than in the Podzol. For most horizons of both soils, the sugars were enriched in the mineral-bound organic matter fraction. This fraction showed a monosaccharide distribution typical for microbial sugars, whereas in bulk soil horizons higher contributions of plant-derived sugars were observed. A strong relationship with the 14C activity of the dense fraction suggests that microbial-derived polysaccharides are most likely stabilised preferentially by mineral interactions compared to plant-derived polysaccharides.
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composition and radiocarbon age of hf resistant soil organic matter in a podzol and a Cambisol
Organic Geochemistry, 2007Co-Authors: Karin Eusterhues, Cornelia Rumpel, Ingrid KogelknabnerAbstract:Hydrofluoric acid (HF) is able to dissolve most minerals, so it is often used to enrich organic matter (OM) in soils and sediments, though significant OM losses sometimes occur. The objective of this study was to examine these carbon losses and the hypothesis that HF dissolves the mineral-associated OM along with its mineral carrier. We compared composition, radiocarbon activity and particle morphology of untreated and HF-treated soil samples, using bulk samples, density fractions > 2 g cm � 3 and fine particle size fractions < 6.3 lm from a Haplic Podzol and a Dystric Cambisol. A positive correlation between HF-soluble organic carbon and organic carbon in the dense fraction confirms a linkage between the dissolved fraction and the mineral-associated OM fraction. However, treatment of heavy soil fractions shows that removal of the mineral-associated OM fraction is not complete. In the topsoil carbon losses amount to only 20–30% of the mineral-associated C, compared to 40–55% for the sub-soil of the Dystric Cambisol and 70–85% for the sub-soil of the Haplic Podzol. Compositional OM change as a consequence of HF treatment was not detected in upper soil horizons, but was substantial for the lower horizons. With depth or age of soil horizon, the HF-soluble OM becomes enriched in O-alkyl C, aryl C, and carbonyl C compared to the HF-resistant OM. The HF-soluble material in all horizons of the Dystric Cambisol is dominated by high alkyl C content, whereas O-alkyl C dominates in deeper horizons of the Haplic Podzol. In A horizons, radiocarbon ages of the HF-resistant OM fraction were similar, but slightly younger than for bulk soil radiocarbon ages. In contrast, in the subsoil horizons the HF-resistant fraction was up to 2000 yr older than the bulk soil age. � 2007 Elsevier Ltd. All rights reserved.
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stabilization of soil organic matter isolated via oxidative degradation
Organic Geochemistry, 2005Co-Authors: Karin Eusterhues, Cornelia Rumpel, Ingrid KogelknabnerAbstract:Formation of long residence time carbon pools in soils is crucial for understanding the global carbon cycle. Acting on the assumption that chemical oxidation mimics natural oxidative processes, we treated forest floor, topsoil and subsoil samples from two acid forest soil profiles (Dystric Cambisol, Haplic Podzol) with H2O2. The oxidation-resistant organic carbon fraction was dated using 14C and found to be 500–3900 years older than the bulk soil material. A positive correlation between the oxidation-resistant organic carbon and the amount of total iron oxides (dithionite-extractable Fe) exists for the subsoil samples of the Dystric Cambisol. In subsoils of the Haplic Podzol total iron oxides and the clay content are correlated with the oxidation-resistant organic carbon. This suggests that stabilization of the oxidation-resistant, old carbon fraction is caused by its interaction with iron oxides and/or other clay minerals rather than by chemical recalcitrance. In contrast to the subsoil, the topsoil samples have much higher concentrations of residual carbon relative to their iron oxide contents. Like forest floor horizons they probably contain additional, non-mineral-protected, but chemically recalcitrant, aliphatic organic matter, which is resistant to H2O2 treatment.
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location and chemical composition of stabilized organic carbon in topsoil and subsoil horizons of two acid forest soils
Soil Biology & Biochemistry, 2004Co-Authors: Karin Eusterhues, Cornelia Rumpel, Ingrid KogelknabnerAbstract:The 14 C age of soil organic matter is known to increase with soil depth. Therefore, the aim of this study was to examine the stabilization of carbon compounds in the entire soil profile using particle size fractionation to distinguish SOM pools with different turnover rates. Samples were taken from a Dystric Cambisol and a Haplic Podzol under forest, which are representative soil types under humid climate conditions. The conceptual approach included the analyses of particle size fractions of all mineral soil horizons for elemental composition and chemical structure of the organic matter by 13 C cross-polarization magic angle spinning nuclear magnetic resonance (CPMAS NMR) spectroscopy. The contribution of phenols and hydroxyalkanoic acids, which represent recalcitrant plant litter compounds, was analyzed after CuO oxidation. In the Dystric Cambisol, the highest carbon concentration as well as the highest percentage of total organic carbon are found in the , 6.3 mm fractions of the B and C horizons. In the Haplic Podzol, carbon distribution among the particle size fractions of the Bh and Bvs horizons is influenced by the adsorption of dissolved organic matter. A relationship between the carbon enrichment in fractions ,6.3 mm and the 14 C activity of the bulk soil indicates that stabilization of SOM occurs in fine particle size fractions of both soils. 13 C CPMAS NMR spectroscopy shows that a high concentration of alkyl carbon is present in the fine particle size fractions of the B horizons of the Dystric Cambisol. Decreasing contribution of O-alkyl and aromatic carbon with particle size as well as soil depth indicates that these compounds are not stabilized in the Dystric Cambisol. These results are in accordance with data obtained by wet chemical analyses showing that cutin/suberin-derived hydroxyalkanoic acids are preserved in the fine particle size fractions of the B horizons. The organic matter composition in particle size fractions of the top- and subsoil horizons of the Haplic Podzol shows that this soil is acting like a chromatographic system preserving insoluble alkyl carbon in the fine particle size fractions of the A horizon. Small molecules, most probably organic acids, dominate in the fine particle size fractions of the C horizons, where they are stabilized in clay-sized fractions most likely due to the interaction with the mineral phase. The characterization of lignin-derived phenols indicated, in accordance with the NMR measurements, that these compounds are not stabilized in the mineral soil horizons. q 2003 Elsevier Ltd. All rights reserved.
Karin Eusterhues - One of the best experts on this subject based on the ideXlab platform.
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non cellulosic neutral sugar contribution to mineral associated organic matter in top and subsoil horizons of two acid forest soils
Soil Biology & Biochemistry, 2010Co-Authors: Cornelia Rumpel, Karin Eusterhues, Ingrid KogelknabnerAbstract:We investigated the polysaccharide composition of bulk and mineral-bound (density fractions >2 g cm−3) organic matter in topsoil and subsoil horizons of a Podzol and a Cambisol. Total sugar contents were generally higher in the Cambisol than in the Podzol. For most horizons of both soils, the sugars were enriched in the mineral-bound organic matter fraction. This fraction showed a monosaccharide distribution typical for microbial sugars, whereas in bulk soil horizons higher contributions of plant-derived sugars were observed. A strong relationship with the 14C activity of the dense fraction suggests that microbial-derived polysaccharides are most likely stabilised preferentially by mineral interactions compared to plant-derived polysaccharides.
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composition and radiocarbon age of hf resistant soil organic matter in a podzol and a Cambisol
Organic Geochemistry, 2007Co-Authors: Karin Eusterhues, Cornelia Rumpel, Ingrid KogelknabnerAbstract:Hydrofluoric acid (HF) is able to dissolve most minerals, so it is often used to enrich organic matter (OM) in soils and sediments, though significant OM losses sometimes occur. The objective of this study was to examine these carbon losses and the hypothesis that HF dissolves the mineral-associated OM along with its mineral carrier. We compared composition, radiocarbon activity and particle morphology of untreated and HF-treated soil samples, using bulk samples, density fractions > 2 g cm � 3 and fine particle size fractions < 6.3 lm from a Haplic Podzol and a Dystric Cambisol. A positive correlation between HF-soluble organic carbon and organic carbon in the dense fraction confirms a linkage between the dissolved fraction and the mineral-associated OM fraction. However, treatment of heavy soil fractions shows that removal of the mineral-associated OM fraction is not complete. In the topsoil carbon losses amount to only 20–30% of the mineral-associated C, compared to 40–55% for the sub-soil of the Dystric Cambisol and 70–85% for the sub-soil of the Haplic Podzol. Compositional OM change as a consequence of HF treatment was not detected in upper soil horizons, but was substantial for the lower horizons. With depth or age of soil horizon, the HF-soluble OM becomes enriched in O-alkyl C, aryl C, and carbonyl C compared to the HF-resistant OM. The HF-soluble material in all horizons of the Dystric Cambisol is dominated by high alkyl C content, whereas O-alkyl C dominates in deeper horizons of the Haplic Podzol. In A horizons, radiocarbon ages of the HF-resistant OM fraction were similar, but slightly younger than for bulk soil radiocarbon ages. In contrast, in the subsoil horizons the HF-resistant fraction was up to 2000 yr older than the bulk soil age. � 2007 Elsevier Ltd. All rights reserved.
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stabilization of soil organic matter isolated via oxidative degradation
Organic Geochemistry, 2005Co-Authors: Karin Eusterhues, Cornelia Rumpel, Ingrid KogelknabnerAbstract:Formation of long residence time carbon pools in soils is crucial for understanding the global carbon cycle. Acting on the assumption that chemical oxidation mimics natural oxidative processes, we treated forest floor, topsoil and subsoil samples from two acid forest soil profiles (Dystric Cambisol, Haplic Podzol) with H2O2. The oxidation-resistant organic carbon fraction was dated using 14C and found to be 500–3900 years older than the bulk soil material. A positive correlation between the oxidation-resistant organic carbon and the amount of total iron oxides (dithionite-extractable Fe) exists for the subsoil samples of the Dystric Cambisol. In subsoils of the Haplic Podzol total iron oxides and the clay content are correlated with the oxidation-resistant organic carbon. This suggests that stabilization of the oxidation-resistant, old carbon fraction is caused by its interaction with iron oxides and/or other clay minerals rather than by chemical recalcitrance. In contrast to the subsoil, the topsoil samples have much higher concentrations of residual carbon relative to their iron oxide contents. Like forest floor horizons they probably contain additional, non-mineral-protected, but chemically recalcitrant, aliphatic organic matter, which is resistant to H2O2 treatment.
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location and chemical composition of stabilized organic carbon in topsoil and subsoil horizons of two acid forest soils
Soil Biology & Biochemistry, 2004Co-Authors: Karin Eusterhues, Cornelia Rumpel, Ingrid KogelknabnerAbstract:The 14 C age of soil organic matter is known to increase with soil depth. Therefore, the aim of this study was to examine the stabilization of carbon compounds in the entire soil profile using particle size fractionation to distinguish SOM pools with different turnover rates. Samples were taken from a Dystric Cambisol and a Haplic Podzol under forest, which are representative soil types under humid climate conditions. The conceptual approach included the analyses of particle size fractions of all mineral soil horizons for elemental composition and chemical structure of the organic matter by 13 C cross-polarization magic angle spinning nuclear magnetic resonance (CPMAS NMR) spectroscopy. The contribution of phenols and hydroxyalkanoic acids, which represent recalcitrant plant litter compounds, was analyzed after CuO oxidation. In the Dystric Cambisol, the highest carbon concentration as well as the highest percentage of total organic carbon are found in the , 6.3 mm fractions of the B and C horizons. In the Haplic Podzol, carbon distribution among the particle size fractions of the Bh and Bvs horizons is influenced by the adsorption of dissolved organic matter. A relationship between the carbon enrichment in fractions ,6.3 mm and the 14 C activity of the bulk soil indicates that stabilization of SOM occurs in fine particle size fractions of both soils. 13 C CPMAS NMR spectroscopy shows that a high concentration of alkyl carbon is present in the fine particle size fractions of the B horizons of the Dystric Cambisol. Decreasing contribution of O-alkyl and aromatic carbon with particle size as well as soil depth indicates that these compounds are not stabilized in the Dystric Cambisol. These results are in accordance with data obtained by wet chemical analyses showing that cutin/suberin-derived hydroxyalkanoic acids are preserved in the fine particle size fractions of the B horizons. The organic matter composition in particle size fractions of the top- and subsoil horizons of the Haplic Podzol shows that this soil is acting like a chromatographic system preserving insoluble alkyl carbon in the fine particle size fractions of the A horizon. Small molecules, most probably organic acids, dominate in the fine particle size fractions of the C horizons, where they are stabilized in clay-sized fractions most likely due to the interaction with the mineral phase. The characterization of lignin-derived phenols indicated, in accordance with the NMR measurements, that these compounds are not stabilized in the mineral soil horizons. q 2003 Elsevier Ltd. All rights reserved.
Claire Chenu - One of the best experts on this subject based on the ideXlab platform.
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Heterogeneity of the chemical composition and thermal stability of particulate organic matter in French forest soils
Geoderma, 2019Co-Authors: Laure Soucémarianadin, Lauric Cecillon, Claire Chenu, François Baudin, Manuel Nicolas, Cyril Girardin, Amicie Delahaie, Pierre BarréAbstract:In temperate forests, soils contain a significant part of the ecosystem carbon (C) stock that can be subjected to C losses upon global changes. In forest soils, particulate organic matter (POM) is a major contributor to the labile C pool and its dynamics can significantly influence the overall total soil organic carbon stock. However, POM has been overlooked in forest soils, specifically in deep horizons. We isolated the POM fraction of mineral soil samples collected in 52 French forest sites, using a size- (> 50 μm) and density- (< 1.6 g·cm−3) fractionation scheme. These soil samples presented variability in terms of depth (0–10 cm; 40–80 cm), soil class (dystric Cambisol, eutric Cambisol, entic Podzol) and vegetation type (deciduous, coniferous). First, we determined the POM chemical composition and thermal stability using elemental analysis, mid infrared-attenuated total reflectance spectroscopy and Rock-Eval thermal analysis. Then, we assessed how depth, soil class and vegetation type influenced POM chemistry and thermal stability in these temperate forest soils. Depth, soil class and vegetation type were all important factors influencing POM chemistry and thermal stability. Variations in POM chemistry (higher C/N ratio, lower ether + alcohol and carbonyl + carboxyl ratios and decrease in hydrogen-rich compounds) and increase in thermal stability with depth suggested different POM input sources for the surface and deep soil layers and an increased biogeochemical stability of POM in deep soil layers. Whatever the vegetation, POM in eutric Cambisols had lower aliphatic and higher aromatic ratios than POM in dystric Cambisols. POM in soils under deciduous trees had higher aliphatic and carbonyl + carboxyl ratios and lower aromatic ratio, more hydrogen-rich and less oxygen-rich compounds than POM in soils under coniferous trees, reflecting the difference in litter chemistry between the two vegetation types. POM from deciduous plots was also significantly more thermally stable than from coniferous plots, suggesting a higher biogeochemical stability for POM in deciduous forest soils. This study highlights the variations in POM chemistry and thermal stability existing within and among soil profiles and the role of depth, soil class and vegetation type in these variations. It appears that if POM can be regarded as a labile carbon fraction in soils, its lability varies depending on the ecosystem (soil, vegetation) and depth considered.
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Environmental factors controlling soil organic carbon stability in French forest soils
Plant and Soil, 2018Co-Authors: Laure Soucémarianadin, Lauric Cecillon, Claire Chenu, Bertrand Guenet, François Baudin, Manuel Nicolas, Cyril Girardin, Pierre BarréAbstract:Aims In temperate forests, soils contain a large part of the ecosystem carbon that can be partially lost or gained upon global change. Our aim was to identify the factors controlling soil organic carbon (SOC) stability in a wide part of French forests. Methods Using a set of soils from 53 French forest sites, we assessed the effects of depth (up to 1 m), soil class (dystric Cambisol; eutric Cambisol; entic Podzol), vegetation types (deciduous; coniferous) and climate (continental influence; oceanic influence; mountainous influence) on SOC stability using indicators derived from laboratory incubation, physical fractionation and thermal analysis. Results Labile SOC pools decreased while stable SOC pool increased with depth. Soil class also significantly influenced SOC stability. Eutric Cambisols had less labile SOC in surface layers but had more labile SOC at depth (> 40 cm) than the other soil classes. Vegetation influenced thermal indicators of SOC pools mainly in topsoils (0–10 cm). Mountainous climate forest soils had a low thermal SOC stability. Conclusions On top of the expected effect of depth, this study also illustrates the noticeable effect of soil class on SOC stability. It suggests that environmental variables should be included when mapping climate regulation soil service.
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Effects of depth, soil and vegetation types on indicators of soil organic carbon lability in forest soils
2017Co-Authors: Laure Soucémarianadin, Lauric Cecillon, Claire Chenu, Bertrand Guenet, François Baudin, Manuel Nicolas, Pierre BarréAbstract:Soil organic matter is a key property as it influences soil ecosystem services like productivity, water storage, etc. In particular, the labile soil organic carbon (SOC) fraction plays a central role in short- to medium-term nutrient availability and soil structural stability. There is little evidence to differentiate the relative importance of factors influencing the labile SOC fraction in contrasted pedological and vegetation conditions. Soil respiration tests and particulate organic matter (POM) obtained by different fractionation schemes are considered as classical indicators of the labile soil organic carbon (SOC) pool. Thermal analyses, in particular Rock-Eval 6 (RE6) analysis, have also shown promising results in the determination of SOC biogeochemical stability. Using a large set of samples of French forest soils representing contrasted pedoclimatic conditions we assessed the effects of depth (n = 5; up to 1 m), soil class (entic Podzol; dystric Cambisol; Calcisol) and vegetation types (deciduous; coniferous) on SOC biogeochemical and thermal stability. We explored how respired-C isolated by a 10-week laboratory soil respiration test, POM-C isolated by a physical SOC fractionation scheme (particle-size > 50 μm and d < 1.6 g·cm-3) and four RE6 parameters, correlated to short- or long-term SOC persistence, evolved in a set of 233 soils samples from 53 forest sites. Results showed that depth was the dominant discriminating factor, affecting significantly all parameters. With depth, we observed a decrease of both classical labile SOC indicators and the thermally labile SOC pool and an increase of the thermally stable SOC pool, along with an oxidation and a depletion of hydrogen-rich moieties of the SOC. Soil class and vegetation type had contrasted effects. For instance, entic Podzols and dystric Cambisols had relatively more thermally stable SOC in the deepest layer than Calcisols but more labile SOC in the surface layer than Calcisols. Soils in deciduous stands tend to contain a higher proportion of thermally stable SOC than soils in coniferous stands. This study shows that both vegetation and soil types influenced SOC stability at various depths and thus should be considered when mapping soil climate regulation ecosystem service.
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Geo-pedological control of soil organic carbon and nitrogen stocks at the landscape scale
2017Co-Authors: Pierre Barré, H. Durand, Daniel Billiou, Guillaume Castel, David Montagne, Claire Chenu, Philippe Meunier, Lauric CecillonAbstract:Geo-pedology, here defined as soil type (or Reference Soil Group) and parent material, can have a major impact on ecosystem (vegetation and soil) functioning. Geo-pedology can therefore deeply influence soil organic matter (SOM) stock. Nonetheless, the effect of geo-pedology on soil organic C (SOC) and N stocks has seldom been investigated. Indeed, factors known to influence SOM stocks such as land use and climate frequently co-vary with geo-pedology, so that testing the influence on SOM stocks of the factor "geo-pedology" alone is challenging. In this work, we studied SOM stocks of forest and cropland soils in a small landscape (17 km²) of the Paris basin (AgroParisTech domain, Thiverval-Grignon, France). We collected soil samples (0-30 cm) in 50 forest and cropland plots, located in five geo-pedological contexts: Luvisols developed on loess deposit, Cambisols developed on hard limestone, Cambisols developed on shelly limestone, Cambisols developed on chalk and Cambisols developed on calcareous clay deposits. We then determined SOM stocks (organic C and total N) and SOM distribution across different particle size fractions (coarse sand, fine sand and silt-clay). As expected, SOC stocks were much higher in forests (~ 83 tC ha-1) than in cultivated soils (~ 49 tC ha-1). Interestingly, Cambisols had higher SOC stocks than Luvisols (69 vs 56 tC ha-1) and the difference between SOC stocks in forest and cultivated soils was much higher for Cambisols compared to Luvisols. Within Cambisols, parent material did not influence SOC stocks but the interaction between parent material and land use was significant, indicating that the effect of land use on SOC stocks was modulated by parent material. Similar trends were observed for soil N stocks. Conversely, soil type and parent material did not control SOM distribution in soil size fractions, while forest soils showed a higher distribution of SOC and N in the sand-size fraction than cropland soils. Overall, our study evidenced a geo-pedological control of SOM stocks and clearly indicates that the change in SOM stocks resulting from a land-use change is strongly modulated by soil type. A good knowledge of the Reference Soil Group distributions is therefore needed to reduce the uncertainty on SOC stock evolutions in a changing environment from the landscape to the global scale.
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relative importance of sorption versus aggregation for organic matter storage in subsoil horizons of two contrasting soils
European Journal of Soil Science, 2010Co-Authors: C. Moni, Cornelia Rumpel, Inigo Virto, Abad Chabbi, Claire ChenuAbstract:Summary Soil organic matter (OM) stabilization by the mineral phase can take place through sorption and aggregation. In this study we examined both of these processes, (i) organic carbon (OC) sorption onto clay-sized particles and (ii) OC occlusion in silt-size aggregates, with the objective of evaluating their relative importance in OM storage and stabilization in soil. We studied two loamy soil profiles (Haplic Luvisol and Plinthic Cambisol) currently under agricultural use down to a depth of 2 m. Ou ra pproach was based on two parallel fractionation methods using different dispersion intensities; these methods isolated a free clay fraction (non-occluded) and a clay fraction occluded within water-stable silt-size aggregates. The two clay fractions were analysed for their Cc ontent and 14 Ca ctivity. The proportion of sorbed OC was estimated as OC loss after hydrof luoric acid (HF) demineralization. Our results showed an important contribution to SOM stabilization by occlusion of OC into silt-size aggregates with depth through both soi lp rof iles. In the Haplic Luvisol, OC associated with clay and located in silt-size aggregates accounted for 34‐64% of the total soil OC, whereas in the Plinthic Cambisol this occluded material represented 34‐40% of total OC. In the Haplic Luvisol, more OC was located in silt-size aggregates than was sorbed onto clay-size minerals, suggesting that silt-size aggregation plays a dominant role in OC storage in this soil. In the Plinthic Cambisol, the abundance of sorbed OC increased with depth and contributed more to the stored C than that associated with silt-size aggregates. Radiocarbon dating of both clay fractions (either occluded within silt-size aggregates or not) suggests, in the case of the Plinthic Cambisol, a preferential stabilization of OC within silt-size aggregates.
Pierre Barré - One of the best experts on this subject based on the ideXlab platform.
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Heterogeneity of the chemical composition and thermal stability of particulate organic matter in French forest soils
Geoderma, 2019Co-Authors: Laure Soucémarianadin, Lauric Cecillon, Claire Chenu, François Baudin, Manuel Nicolas, Cyril Girardin, Amicie Delahaie, Pierre BarréAbstract:In temperate forests, soils contain a significant part of the ecosystem carbon (C) stock that can be subjected to C losses upon global changes. In forest soils, particulate organic matter (POM) is a major contributor to the labile C pool and its dynamics can significantly influence the overall total soil organic carbon stock. However, POM has been overlooked in forest soils, specifically in deep horizons. We isolated the POM fraction of mineral soil samples collected in 52 French forest sites, using a size- (> 50 μm) and density- (< 1.6 g·cm−3) fractionation scheme. These soil samples presented variability in terms of depth (0–10 cm; 40–80 cm), soil class (dystric Cambisol, eutric Cambisol, entic Podzol) and vegetation type (deciduous, coniferous). First, we determined the POM chemical composition and thermal stability using elemental analysis, mid infrared-attenuated total reflectance spectroscopy and Rock-Eval thermal analysis. Then, we assessed how depth, soil class and vegetation type influenced POM chemistry and thermal stability in these temperate forest soils. Depth, soil class and vegetation type were all important factors influencing POM chemistry and thermal stability. Variations in POM chemistry (higher C/N ratio, lower ether + alcohol and carbonyl + carboxyl ratios and decrease in hydrogen-rich compounds) and increase in thermal stability with depth suggested different POM input sources for the surface and deep soil layers and an increased biogeochemical stability of POM in deep soil layers. Whatever the vegetation, POM in eutric Cambisols had lower aliphatic and higher aromatic ratios than POM in dystric Cambisols. POM in soils under deciduous trees had higher aliphatic and carbonyl + carboxyl ratios and lower aromatic ratio, more hydrogen-rich and less oxygen-rich compounds than POM in soils under coniferous trees, reflecting the difference in litter chemistry between the two vegetation types. POM from deciduous plots was also significantly more thermally stable than from coniferous plots, suggesting a higher biogeochemical stability for POM in deciduous forest soils. This study highlights the variations in POM chemistry and thermal stability existing within and among soil profiles and the role of depth, soil class and vegetation type in these variations. It appears that if POM can be regarded as a labile carbon fraction in soils, its lability varies depending on the ecosystem (soil, vegetation) and depth considered.
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Environmental factors controlling soil organic carbon stability in French forest soils
Plant and Soil, 2018Co-Authors: Laure Soucémarianadin, Lauric Cecillon, Claire Chenu, Bertrand Guenet, François Baudin, Manuel Nicolas, Cyril Girardin, Pierre BarréAbstract:Aims In temperate forests, soils contain a large part of the ecosystem carbon that can be partially lost or gained upon global change. Our aim was to identify the factors controlling soil organic carbon (SOC) stability in a wide part of French forests. Methods Using a set of soils from 53 French forest sites, we assessed the effects of depth (up to 1 m), soil class (dystric Cambisol; eutric Cambisol; entic Podzol), vegetation types (deciduous; coniferous) and climate (continental influence; oceanic influence; mountainous influence) on SOC stability using indicators derived from laboratory incubation, physical fractionation and thermal analysis. Results Labile SOC pools decreased while stable SOC pool increased with depth. Soil class also significantly influenced SOC stability. Eutric Cambisols had less labile SOC in surface layers but had more labile SOC at depth (> 40 cm) than the other soil classes. Vegetation influenced thermal indicators of SOC pools mainly in topsoils (0–10 cm). Mountainous climate forest soils had a low thermal SOC stability. Conclusions On top of the expected effect of depth, this study also illustrates the noticeable effect of soil class on SOC stability. It suggests that environmental variables should be included when mapping climate regulation soil service.
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Effects of depth, soil and vegetation types on indicators of soil organic carbon lability in forest soils
2017Co-Authors: Laure Soucémarianadin, Lauric Cecillon, Claire Chenu, Bertrand Guenet, François Baudin, Manuel Nicolas, Pierre BarréAbstract:Soil organic matter is a key property as it influences soil ecosystem services like productivity, water storage, etc. In particular, the labile soil organic carbon (SOC) fraction plays a central role in short- to medium-term nutrient availability and soil structural stability. There is little evidence to differentiate the relative importance of factors influencing the labile SOC fraction in contrasted pedological and vegetation conditions. Soil respiration tests and particulate organic matter (POM) obtained by different fractionation schemes are considered as classical indicators of the labile soil organic carbon (SOC) pool. Thermal analyses, in particular Rock-Eval 6 (RE6) analysis, have also shown promising results in the determination of SOC biogeochemical stability. Using a large set of samples of French forest soils representing contrasted pedoclimatic conditions we assessed the effects of depth (n = 5; up to 1 m), soil class (entic Podzol; dystric Cambisol; Calcisol) and vegetation types (deciduous; coniferous) on SOC biogeochemical and thermal stability. We explored how respired-C isolated by a 10-week laboratory soil respiration test, POM-C isolated by a physical SOC fractionation scheme (particle-size > 50 μm and d < 1.6 g·cm-3) and four RE6 parameters, correlated to short- or long-term SOC persistence, evolved in a set of 233 soils samples from 53 forest sites. Results showed that depth was the dominant discriminating factor, affecting significantly all parameters. With depth, we observed a decrease of both classical labile SOC indicators and the thermally labile SOC pool and an increase of the thermally stable SOC pool, along with an oxidation and a depletion of hydrogen-rich moieties of the SOC. Soil class and vegetation type had contrasted effects. For instance, entic Podzols and dystric Cambisols had relatively more thermally stable SOC in the deepest layer than Calcisols but more labile SOC in the surface layer than Calcisols. Soils in deciduous stands tend to contain a higher proportion of thermally stable SOC than soils in coniferous stands. This study shows that both vegetation and soil types influenced SOC stability at various depths and thus should be considered when mapping soil climate regulation ecosystem service.
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Geo-pedological control of soil organic carbon and nitrogen stocks at the landscape scale
2017Co-Authors: Pierre Barré, H. Durand, Daniel Billiou, Guillaume Castel, David Montagne, Claire Chenu, Philippe Meunier, Lauric CecillonAbstract:Geo-pedology, here defined as soil type (or Reference Soil Group) and parent material, can have a major impact on ecosystem (vegetation and soil) functioning. Geo-pedology can therefore deeply influence soil organic matter (SOM) stock. Nonetheless, the effect of geo-pedology on soil organic C (SOC) and N stocks has seldom been investigated. Indeed, factors known to influence SOM stocks such as land use and climate frequently co-vary with geo-pedology, so that testing the influence on SOM stocks of the factor "geo-pedology" alone is challenging. In this work, we studied SOM stocks of forest and cropland soils in a small landscape (17 km²) of the Paris basin (AgroParisTech domain, Thiverval-Grignon, France). We collected soil samples (0-30 cm) in 50 forest and cropland plots, located in five geo-pedological contexts: Luvisols developed on loess deposit, Cambisols developed on hard limestone, Cambisols developed on shelly limestone, Cambisols developed on chalk and Cambisols developed on calcareous clay deposits. We then determined SOM stocks (organic C and total N) and SOM distribution across different particle size fractions (coarse sand, fine sand and silt-clay). As expected, SOC stocks were much higher in forests (~ 83 tC ha-1) than in cultivated soils (~ 49 tC ha-1). Interestingly, Cambisols had higher SOC stocks than Luvisols (69 vs 56 tC ha-1) and the difference between SOC stocks in forest and cultivated soils was much higher for Cambisols compared to Luvisols. Within Cambisols, parent material did not influence SOC stocks but the interaction between parent material and land use was significant, indicating that the effect of land use on SOC stocks was modulated by parent material. Similar trends were observed for soil N stocks. Conversely, soil type and parent material did not control SOM distribution in soil size fractions, while forest soils showed a higher distribution of SOC and N in the sand-size fraction than cropland soils. Overall, our study evidenced a geo-pedological control of SOM stocks and clearly indicates that the change in SOM stocks resulting from a land-use change is strongly modulated by soil type. A good knowledge of the Reference Soil Group distributions is therefore needed to reduce the uncertainty on SOC stock evolutions in a changing environment from the landscape to the global scale.
