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Bruno Delvaux - One of the best experts on this subject based on the ideXlab platform.
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An Andosol–Cambisol toposequence on granite in the Austrian Bohemian Massif
CATENA, 2004Co-Authors: Bruno Delvaux, Vincent Brahy, F. Strebl, Emmanuel Maes, Adrien Herbillon, Martin H. GerzabekAbstract:In Europe, non-allophanic Andosols are linked with Hercynian basic and metabasic rocks in smoothed highlands with a cool and humid climate. We describe an Andosol-Cambisol toposequence derived from Variscan coarse-grained granite in Northern Austria (Bohemian Massif), where Andosols have formed on plateaus and Cambisols on steep slopes. The climate is continental, cool and humid (mean annual temperature and rainfall: 5.4 degreesC and 914 mm), with a 100-day mean annual period of snow cover. The forest is dominated by beech and spruce trees. Both soils are rich in organic matter and strongly acidic, but the Andosol is more strongly weathered than the Cambisol. Below the 15-cm-thick litter in the Andosol, the 38-cm-thick AB-Bw solum is dark reddish brown to strong brown, has a large C content (9.0-4.4%), and meets all the requirements of an andic horizon. In these horizons, oxalate extractable iron content (1.62.8% Fe-o) represents 76-84% of free iron, and is much larger than Al-o (0.8-1.5%). Both biotite and plagioclase are sources of Fe and Al. The fort-nation of non-allophanic Andosol from granite was likely due to the combination of the following factors: cool and humid climate, large accumulation of organic matter, high infiltration rate, intense water percolation during spring thawing and significant content of weatherable minerals. As such conditions are not rare in European highlands, andic soils are probably more widespread in Europe than is currently thought. (C) 2003 Elsevier B.V All rights reserved
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An Andosol-Cambisol toposequence on granite in the Austrian Bohemian Massif
Catena, 2003Co-Authors: Bruno Delvaux, Vincent Brahy, F. Strebl, Emmanuel Maes, Adrien Herbillon, Martin H. GerzabekAbstract:In Europe, non-allophanic Andosols are linked with Hercynian basic and metabasic rocks in smoothed highlands with a cool and humid climate. We describe an Andosol-Cambisol toposequence derived from Variscan coarse-grained granite in Northern Austria (Bohemian Massif), where Andosols have formed on plateaus and Cambisols on steep slopes. The climate is continental, cool and humid (mean annual temperature and rainfall: 5.4 degreesC and 914 mm), with a 100-day mean annual period of snow cover. The forest is dominated by beech and spruce trees. Both soils are rich in organic matter and strongly acidic, but the Andosol is more strongly weathered than the Cambisol. Below the 15-cm-thick litter in the Andosol, the 38-cm-thick AB-Bw solum is dark reddish brown to strong brown, has a large C content (9.0-4.4%), and meets all the requirements of an andic horizon. In these horizons, oxalate extractable iron content (1.62.8% Fe-o) represents 76-84% of free iron, and is much larger than Al-o (0.8-1.5%). Both biotite and plagioclase are sources of Fe and Al. The fort-nation of non-allophanic Andosol from granite was likely due to the combination of the following factors: cool and humid climate, large accumulation of organic matter, high infiltration rate, intense water percolation during spring thawing and significant content of weatherable minerals. As such conditions are not rare in European highlands, andic soils are probably more widespread in Europe than is currently thought. (C) 2003 Elsevier B.V All rights reserved.
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Metal complexing properties of forest floor leachates might promote incipient podzolization in a Cambisol under deciduous forest
Geoderma, 2001Co-Authors: Hugues Titeux, Vincent Brahy, Bruno DelvauxAbstract:The characteristics of both the mineral substrate and the humus layer are of key importance in podzol formation. However, the properties of the forest floor leachates are seldom considered. We measured the complexation capacity by Cu2+ titration (CuCC), the optical density (E-4/E-6), as well as the concentrations of dissolved organic carbon (DOC) and of major and trace ions in the liquid extracts of forest floors of two Cambisols and two Luvisols on loess under deciduous forest. The vegetation consists of a mixture of beech, oak and maple. The humus type is a fibrimor in one Cambisol and a moder in the three other soils. Both in the solid phase and in the liquid extracts of the forest floors, the Si/(Al + Fe) and C/(Al + Fe) atomic ratios are much larger in the fibrimor than in the moders. In the liquid extracts, the complexation capacity (CuCC) and the density of metal binding sites (CuCC/DOC are larger in the fibrimor than in the moders. These large CuCC and CuCC/DOC in the fibrimor leachate are linked with relatively small stability constant of the humus-Cu complex and relatively large E-4/E-6 ratio, i.e. with reactive organic ligands with low molecular weight and weak aromatic character. These characteristics are associated with current incipient podzolization in the Cambisol with a fibrimor, and might be considered as an indicator of a substantial podzolizing potential of the forest floor. (C) 2002 Elsevier Science B.V. All rights reserved.
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Cation exchange resin and test vermiculite to study soil processes in situ in a toposequence of Luvisol and Cambisol on loess
European Journal of Soil Science, 2001Co-Authors: Vincent Brahy, Bruno DelvauxAbstract:Both the ion accumulation on cation exchange resin and the transformation of test vermiculite in situ have been used to identify current processes in acid forest soils. We used such test materials to study weathering in a toposequence Dystric Luvisol-Spodo-Dystric Cambisol on loess under deciduous forest in Belgium. The resin and a trioctahedral vermiculite were inserted for 2 years in the major horizons, down to a depth of 60 cm. The cation accumulation on the resin revealed that four main acid-consuming systems are currently active in the toposequence. With decreasing acid neutralizing capacity, these systems are in the Luvisols: (i) the pool of exchangeable bases, (ii) the Al-bearing minerals controlling the Al concentration in the liquid phase; and in the podzolized Cambisols: (iii) the less weatherable K-bearing minerals, (iv) the Mg-bearing phyllosilicates made free of Al interlayers in complexing conditions. The loss of cation exchange capacity in the test vermiculite is related to Al interlayering. However, this process masks a significant interlayer accumulation of magnesium, which is generated by the weathering of the test mineral itself. The largest interlayer accumulation of Mg occurs in the podzolized Cambisol, suggesting more intense weathering of the test vermiculite in this soil.
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Surface podzolization in Cambisols under deciduous forest in the Belgian loess belt
European Journal of Soil Science, 2000Co-Authors: Vincent Brahy, Hugues Titeux, Anne Iserentant, Bruno DelvauxAbstract:Surface podzolization involves the migration of metal-humus complexes to a depth of a few centimetres. In acid soils derived from loess, this process has been diagnosed mainly by morphological observation. We investigated this process in a toposequence of Luvisols and Cambisols on loess using selective extraction and mineralogical data as well as characteristics of the leaf litter. The humus type (O and OAh horizons) is a moder in the three Luvisols and one of the Cambisols, whereas it is a fibrimor in the two other Cambisols. The contents in total alkaline and alkaline-earth cations range from 35 to 60 cmol(c) kg(-1) in the fibrimor and from 40 to 90 cmol(c) kg(-1) in the moder humus. In the two Cambisols with fibrimor smectite occurs in the clay fraction of the Ah horizon; Fe-humus complexes seem to have moved, but no more than 9 cm, from the Ah to the AB horizon beneath. Relative to the Ah horizon, the upper part of the AB has larger tetraborate-extractable Fe/Al ratio and optical density of the oxalate extract. Such features converge to diagnose surface podzolization in the Cambisols with fibrimor. However, they were not detected in the Cambisol and Luvisols with moder. In the two Cambisols with fibrimor, surface podzolization is consistent with (i) their smaller iron content, (ii) their more advanced weathering stage and (iii) their lower acid neutralizing capacity.
K. Pustovoytov - One of the best experts on this subject based on the ideXlab platform.
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late pleistocene holocene palaeosols in the north of sonora mexico chronostratigraphy pedogenesis and implications for environmental history
European Journal of Soil Science, 2014Co-Authors: Tamara Cruzycruz, Sergey Sedov, Guadalupe Sanchez, K. Pustovoytov, Teresa Pipuig, Hermenegildo Barceinascruz, Beatriz Ortegaguerrero, Elizabeth SolleirorebolledoAbstract:Summary Red palaeosols of the late Pleistocene-early Holocene, both buried and non-buried, were studied recently in Sonora (NW Mexico) to reconstruct their pedogenesis as well as the palaeoenvironmental conditions. The alluvial palaeosol-sedimentary sequence of the La Playa archaeological site is a key locality for the buried San Rafael palaeosol, which exhibits a 2Ah-2Bw-2BCk-3Bgk profile and was defined as a Chromic Cambisol. Radiocarbon dates from pedogenic carbonates and charcoal set the soil formation interval between >18000 and 4300calibrated years before present (cal. year BP). Micro-morphological observations together with profile distribution of clay, carbonates, organic carbon, pedogenic iron oxides and rock magnetic properties indicated a strong eluvial-illuvial redistribution of carbonates, moderate silicate weathering and gleying in the lower horizon. Although this soil was much more developed than the overlying syn-sedimentary late Holocene Fluvisols, clay mineral composition and stable carbon isotope signatures of humus and carbonates were similar in both soils. We suggest that pedogenesis of the San Rafael palaeosol took place under a slightly more humid climate and relative geomorphic stability. This agrees with the regional palaeoclimate reconstruction, which indicates a moister climate during the Late Wisconsin glaciation (MIS 2). An abrupt termination of the San Rafael pedogenesis marked by disturbance and aridization features in the Ap horizon of the palaeosol could be linked to a global drought around 4200years cal. year BP. Surface Chromic Cambisols in northern Sonora show similar pedogenetic characteristics to the buried red palaeosols of La Playa. They appear to be a relict component of the present day soil mantle.
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Late Pleistocene ‐ Holocene palaeosols in the north of Sonora, Mexico: chronostratigraphy, pedogenesis and implications for environmental history
European Journal of Soil Science, 2014Co-Authors: Tamara Cruz-y-cruz, Sergey Sedov, Guadalupe Sanchez, Teresa Pi-puig, K. Pustovoytov, Hermenegildo Barceinas-cruz, Beatriz Ortega-guerrero, Elizabeth Solleiro-rebolledoAbstract:Summary Red palaeosols of the late Pleistocene-early Holocene, both buried and non-buried, were studied recently in Sonora (NW Mexico) to reconstruct their pedogenesis as well as the palaeoenvironmental conditions. The alluvial palaeosol-sedimentary sequence of the La Playa archaeological site is a key locality for the buried San Rafael palaeosol, which exhibits a 2Ah-2Bw-2BCk-3Bgk profile and was defined as a Chromic Cambisol. Radiocarbon dates from pedogenic carbonates and charcoal set the soil formation interval between >18000 and 4300calibrated years before present (cal. year BP). Micro-morphological observations together with profile distribution of clay, carbonates, organic carbon, pedogenic iron oxides and rock magnetic properties indicated a strong eluvial-illuvial redistribution of carbonates, moderate silicate weathering and gleying in the lower horizon. Although this soil was much more developed than the overlying syn-sedimentary late Holocene Fluvisols, clay mineral composition and stable carbon isotope signatures of humus and carbonates were similar in both soils. We suggest that pedogenesis of the San Rafael palaeosol took place under a slightly more humid climate and relative geomorphic stability. This agrees with the regional palaeoclimate reconstruction, which indicates a moister climate during the Late Wisconsin glaciation (MIS 2). An abrupt termination of the San Rafael pedogenesis marked by disturbance and aridization features in the Ap horizon of the palaeosol could be linked to a global drought around 4200years cal. year BP. Surface Chromic Cambisols in northern Sonora show similar pedogenetic characteristics to the buried red palaeosols of La Playa. They appear to be a relict component of the present day soil mantle.
Guillaume Echevarria - One of the best experts on this subject based on the ideXlab platform.
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Effect of nickel concentration and soil pH on metal accumulation and growth in tropical agromining ‘metal crops’
Plant and Soil, 2019Co-Authors: Philip Nti Nkrumah, Guillaume Echevarria, Peter D. Erskine, Rufus L. Chaney, Sukaibin SumailAbstract:Aims This study investigated the physico-geochemical properties of three types of ultramafic substrates in Sabah (Malaysia) and further characterised their influence on nickel (Ni) accumulation in two selected tropical ‘metal crops’ ( Phyllanthus rufuschaneyi and Rinorea cf. bengalensis ). Methods Three experiments, consisting of a randomised block growth trial in large pots over 12 months in Sabah, were conducted: i) soil ratio experiment (Cambisol:Ferralsol:Leptosol), ii) soluble Ni dosing experiment with added 0, 60, 240, 600 mg Ni kg^−1, and iii) soil pH adjustments (pH 5.2, 5.8 and 6.4) experiment. Results The results show that the low pH status of Ferralsol did not result in increased extractable Ni concentrations, indicating that Ni-bearing phases and mineralogy play a major role in Ni extractability in these substrates. The increasing order of extractable Ni concentrations was Ferralsol < Leptosol < Cambisol. The selected ‘metal crops’ had remarkable shoot biomass (~40 g pot^−1) and foliar Ni concentrations (>15 g kg^−1 in P. rufuschaneyi ) in the Cambisol, >5-fold higher relative to that recorded in Leptosol and Ferralsol. Mixing the Cambisol with the other substrates significantly improved Ni yield in both species relative to the individual substrates. The effect of Ni addition on the selected ‘metal crops’ was species-dependent, whereas reduction of soil pH in Cambisol significantly reduced Ni yield in both species. Conclusions Nickel accumulation patterns in ‘metal crops’ in response to the diverse ultramafic soils in the tropics are influenced by the physico-geochemical characteristics of the soil types. Soil Ni extractability in these soils is more dependent on the Ni-bearing phases and mineralogy rather than the pH status. This study provides useful information on plant-soil interactions required for identifying suitable substrates for implementing tropical Ni agromining.
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Genesis and Behaviour of Ultramafic Soils and Consequences for Nickel Biogeochemistry
2018Co-Authors: Guillaume EchevarriaAbstract:Ultramafic outcrops represent less than 1% of the terrestrial surface but their unusual geochemistry makes them a global hotspot for biodiversity. Ultramafic soils are a peculiarity for soil scientists in all climatic zones of the world. These soils lack essential pedogenetic elements: Al, Ca, K, and P. Whereas serpentinites will most likely give birth to Eutric Cambisols with little influence by climate, peridotites will induce an acceleration of weathering processes; this over-expressed weathering is due to their deficiency in Si and Al and lack of secondary clay formation. Soils evolve towards Ferralsols in tropical conditions. Results from isotopic dilution techniques show that Ni borne by primary minerals is unavailable. Secondary 2:1 clay minerals (e.g. Fe-rich smectite) and amorphous Fe oxyhydroxides are the most important phases that bear available Ni. Therefore, smectite-rich soils developed on serpentinite and poorly weathered Cambisols on peridotite (only in temperate conditions) are the soils with highest availability of Ni. Although soil pH conditions are amajor factor in controlling available Ni, the chemical bounds of Ni to containing phases are even more important to consider. Plants take up significant amounts of Ni, and its biogeochemical recycling seems an essential factor that explains Ni availability in the surface horizons of ultramafic soils.
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Pedogenesis and nickel biogeochemistry in a typical Albanian ultramafic toposequence
Environmental Monitoring and Assessment, 2014Co-Authors: Aida Bani, Guillaume Echevarria, Emmanuelle Montarges-pelletier, Fran Gjoka, Sulejman Sulce, Louis Morel JeanAbstract:This study aimed at relating the variability of Ni biogeochemistry along the ultramafic toposequence to pedogenesis and soil mineralogy. Hypereutric Cambisols dominate upslope; Cambic Vertisols and Fluvic Cambisols occur downslope. The soil mineralogy showed abundance of primary serpentine all over the sequence. It is predominant upslope but secondary smectites dominate in the Vertisols. Free Fe-oxides are abundant in all soils but slightly more abundant in the upslope soils. Whereas serpentines hold Ni in a similar and restricted range in every soil (approx. 0.3 %), Ni contents in smectites may vary a lot and Mg-rich and Al-poor smectites in the Vertisol could hold up to 4.9 % Ni. Ni was probably adsorbed onto amorphous Fe-oxides and was also exchangeable in secondary smectites. High availability of Ni in soils was confirmed by DTPA extractions. However, it varied significantly along the toposequence, being higher in upslope soils, where Ni-bearing amorphous Fe-oxides were abundant and total organic carbon higher and sensibly lower downslope on the Vertisols: Ni-DTPA varied from 285 mg kg(-1) in the surface of soil I (upslope) to 95.9 mg kg(-1) in the surface of Fluvic Cambisols. Concentration of Ni in Alyssum murale shoots varied from 0.7 % (Hypereutric Cambisols) to 1.4 % (Hypereutric Vertisol). Amazingly, Ni uptake by A. murale was not correlated to Ni-DTPA, suggesting the existence of specific edaphic conditions that affect the ecophysiology of A. murale upslope.
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Nickel bioavailability in an ultramafic toposequence in the Vosges Mountains (France)
Plant and Soil, 2007Co-Authors: Vanessa Chardot, Guillaume Echevarria, Michel Gury, Stamatia Massoura, Jean-louis MorelAbstract:A serpentinised harzburgite outcrop located in the Vosges Mountains hosts a population of the Ni-hyperaccumulator Thlaspi caerulescens J. & C. Presl. A complete study was undertaken to relate the variability of Ni availability along the ultramafic toposequence to pedogenesis, soil mineralogy and functioning with X-Ray Diffraction, Transmission Electron Microscope observations coupled with Isotopic Exchange Kinetics and diethylenetriamine pentaacetic acid extraction of Ni. The soil profiles ranging from Dystric Cambisol to Hypermagnesic Hypereutric Cambisol were distributed unevenly along the toposequence probably due to geochemical variability of the bedrock and also complex quaternary erosion features. The richest soils were characterised by slight mineral weathering leading to Ni, Cr and Fe accumulation in the B horizons whereas the lowest saturated soils had very low-metal contents. Most soil minerals were inherited from the parent materials and there were only few traces of formation of secondary minerals. Primary minerals (e.g. serpentine, chlorite) contained low Ni concentrations (0.2%) whereas neoformed goethite, mainly in the B horizons of the richest soils, contained up to 4.3% Ni. Ni was probably sorbed onto amorphous Fe oxy−hydroxide particles (oxalate extraction) rather than incorporated within the crystal lattice of goethite. Ni availability in the B horizon of Hypereutric Cambisols was extremely high and so was the oxalate extractable Fe. At the toposequence level, there was a high level of Ni availability in the least weathered soils and a very low-availability level in the more intensively weathered soils (strongly acidic pH). Ni availability was unexpectedly positively correlated to pH and was controlled by soil mineralogy and Ni-bearing mineral phases. Ni hyperaccumulation (above 1,000 mg kg−1) by native T. caerulescens was only reached in the Ni-rich soils as a consequence of the local edaphic factors. Ni uptake by T. caerulescens is strongly regulated by Ni availability in soils and therefore related to pedogenesis.
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.
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.
