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M. Bardy – One of the best experts on this subject based on the ideXlab platform.

  • OrgAnic complexAtion And trAnslocAtion of ferric iron in podzols of the Negro River wAtershed. SepArAtion of secondAry Fe species from Al species
    Geochimica et Cosmochimica Acta, 2009
    Co-Authors: E. Fritsch, M. Bardy, N.r. Do Nascimento, Th. Allard, M.f. Benedetti, G. Calas

    Abstract:

    The development of podzols in lAteritic lAndscApes of the upper AmAzon bAsin contributes to the exportAtion of orgAnic cArbon And AssociAted metAls in the blAck wAters of the Negro River wAtershed. We hAve investigAted the distribution of FeIII in the clAy-size frAction of eight orgAnic-rich Horizons of wAterlogged plAteAu podzols, to unrAvel the weAthering conditions And mechAnisms thAt control its trAnsfer to the rivers. The speciAtion And Amount of FeIII stored in residuAl minerAl phAses of lAterites, or bound to orgAnic compounds of weAkly And well-expressed podzols, were determined by electron pArAmAgnetic resonAnce spectroscopy combined with chemicAl AnAlyses. Reducing conditions restrict the production of orgAno-Fe complexes in the subsoil B-Horizons of wAterlogged podzols And most of the Fe2+ releAsed from the dissolution of Fe-oxides is exported to the rivers viA the perched groundwAter. However, significAnt Amounts of diluted FeIII bound to orgAnic ligAnds (FeIIIOM) And nAno Fe-oxides Are produced At the mArgin of the depression in the topsoil A Horizons of weAkly expressed podzols due to shorter periods of AnoxiA. The downwArd trAnslo- cAtion of orgAnicAlly bound metAls from topsoil A to subsoil B-Horizons of podzols occurs in shorter distAnces for Fe thAn it does for Al. This sepArAtion of secondAry Fe species from Al species is Attributed to the physicAl frActionAtion of their orgAnic cArriers in texture contrAsted B-Horizons of podzols, As well As to the effect of pH on metAl speciAtion in soil solutions And metAl binding onto soil orgAnic ligAnds (mostly for Al). This leAds us to consider the topsoil A Horizons of weAkly expressed podzols, As well As the subsoil Bh horizon of better-expressed ones, As the mAin sources for the trAnsfer of FeIIIOM to the riv- ers. The concentrAtion of FeIIIOM rises from soil sources to river colloids, suggesting drAstic biogeochemicAl chAnges in more oxygenAted blAck wAters of the Negro River wAtershed. The contribution of soil orgAnic mAtter to the trAnsfer of Fe to rivers is likely At the origin of the peculiAr Fe isotope pAttern recently recognized in podzolic environments.

  • micromorphology And spectroscopic chArActeristics of orgAnic mAtter in wAterlogged podzols of the upper AmAzon bAsin
    Geoderma, 2008
    Co-Authors: M. Bardy, E. Fritsch, S. Derenne, Thierry Allard, N Do R Nascimento, G.t. Bueno

    Abstract:

    In wAterlogged environments of the upper AmAzon bAsin, orgAnic mAtter is A mAjor driver in the podzolisAtion of clAy-depleted lAterites, especiAlly through its Ability to weAther clAy minerAls And chelAte metAls. Its structure in eight orgAnic-rich sAmples collected At the mArgin And in the centre of the podzolic AreA of A soil sequence wAs investigAted. The sAmples illustrAte the mAin steps in the development of wAterlogged podzols And belong either to eluviAted topsoil A Horizons or to illuviAted subsoil Bhs, Bh And 2BCs Horizons. OrgAnic mAtter micromorphology wAs described, And the overAll moleculAr structure of their clAy size frActions wAs Assessed using Fourier trAnsform infrAred (FTIR) spectroscopy And cross polArizAtion/mAgic Angle spinning (CP/ MAS) 13C nucleAr mAgnetic resonAnce (NMR). OrgAnic feAtures of the Horizons strongly vAry both verticAlly And lAterAlly in the sequence. Topsoil A Horizons Are dominAted by orgAnic residues juxtAposed to cleAn sAnds with A mAjor AliphAtic contribution. In the subsoil, numerous coAtings, chArActeristic of illuviAtion processes, Are observed in the following Horizons: (i) At the mArgin And bottom pArts of the podzolic AreA, dArk brown orgAnic compounds of low AromAcity with AbundAnt oxygen-contAining groups AccumulAte in Bhs And 2BCs Horizons. Their spectroscopic feAtures Agree with the observAtion of crAcked coAtings in 2BCs And the presence of orgAnometAllic complexes, whose AbundAnce decreAses towArds low lying positions. (ii) By contrAst, blAck orgAnic compounds of high AromAcity with few chelAting functions AccumulAte As coAtings And infills in the overlying sAndy Bh horizon of well-expressed wAterlogged podzols.

  • Micromorphology And spectroscopic chArActeristics of orgAnic mAtter in wAterlogged podzols of the upper AmAzon bAsin
    Geoderma, 2008
    Co-Authors: M. Bardy, E. Fritsch, S. Derenne, Thierry Allard, N.r. Do Nascimento, G.t. Bueno

    Abstract:

    In wAterlogged environments of the upper AmAzon bAsin, orgAnic mAtter is A mAjor driver in the podzolisAtion of clAy-depleted lAterites, especiAlly through its Ability to weAther clAy minerAls And chelAte metAls. Its structure in eight orgAnic-rich sAmples collected At the mArgin And in the centre of the podzolic AreA of A soil sequence wAs investigAted. The sAmples illustrAte the mAin steps in the development of wAterlogged podzols And belong either to eluviAted topsoil A Horizons or to illuviAted subsoil Bhs, Bh And 2BCs Horizons. OrgAnic mAtter micromorphology wAs described, And the overAll moleculAr structure of their clAy size frActions wAs Assessed using Fourier trAnsform infrAred (FTIR) spectroscopy And cross polArizAtion/mAgic Angle spinning (CP/ MAS) 13C nucleAr mAgnetic resonAnce (NMR). OrgAnic feAtures of the Horizons strongly vAry both verticAlly And lAterAlly in the sequence. Topsoil A Horizons Are dominAted by orgAnic residues juxtAposed to cleAn sAnds with A mAjor AliphAtic contribution. In the subsoil, numerous coAtings, chArActeristic of illuviAtion processes, Are observed in the following Horizons: (i) At the mArgin And bottom pArts of the podzolic AreA, dArk brown orgAnic compounds of low AromAcity with AbundAnt oxygen-contAining groups AccumulAte in Bhs And 2BCs Horizons. Their spectroscopic feAtures Agree with the observAtion of crAcked coAtings in 2BCs And the presence of orgAnometAllic complexes, whose AbundAnce decreAses towArds low lying positions. (ii) By contrAst, blAck orgAnic compounds of high AromAcity with few chelAting functions AccumulAte As coAtings And in

E. Fritsch – One of the best experts on this subject based on the ideXlab platform.

  • AccumulAtion of orgAno-metAllic complexes in lAterites And the formAtion of AluAndic Andosols in the Nilgiri Hills (southern IndiA): similArities And differences with Umbric Podzols
    European Journal of Soil Science, 2011
    Co-Authors: Laurent Caner, E. Fritsch, S. Petit, Emmanuel Joussein, A J Herbillon

    Abstract:

    We hAve investigAted the speciAtion And distribution of iron (Fe) And Aluminium (Al) between minerAls And orgAnic species in A And B Horizons of two AluAndic Andosols with X-rAy diffrAction, thermAl AnAlyses, visible diffuse reflectAnce And Fourier trAnsform infrAred (FTIR) spectroscopies, together with selective And totAl chemicAl extrActions. The two AluAndic Andosols of the Nilgiri HighlAnds (south IndiA) hAve formed At the expense of intensively weAthered lAteritic formAtions of the Eocene. DAtA reveAled thAt Al And Fe were predominAntly stored in end-weAthering products of lAterites, mAinly As gibbsite And Fe (hydr)oxides in B Horizons of the AluAndic Andosols. These secondAry minerAls Are grAduAlly replAced by orgAno-metAllic complexes in the topsoil A Horizons exhibiting Andic properties. We then indicAte thAt formAtion of the orgAno-metAllic complexes results from weAthering of the dominAnt crystAlline Al- And Fe-(hydr)oxides mediAted by the orgAnic ligAnds And complexAtion of the polyvAlent metAls following the AccumulAtion of orgAnic mAtter. Such weAthering And complexAtion mechAnisms Are therefore similAr to those recently Ascribed to deferrAlitizAtion And the formAtion of freely drAined Umbric Podzols (Humus-Podzols) in the upper AmAzon BAsin. In the present cAse, lArge supplies of both Al- And Fe-beAring minerAls provide lArge metAl:cArbon rAtios thAt prevent the mobility of the orgAno-metAllic complexes And induce the formAtion of AluAndic Andosols rAther thAn Podzols.

  • minerAl And geochemicAl chArActerizAtion of A leptic AluAndic soil And A thApto AluAndic ferrAlsol developed on trAchytes in mount bAmbouto cAmeroon volcAnic line
    Geoderma, 2009
    Co-Authors: P Tematio, E. Fritsch, Mark E Hodson, Yves Lucas, D Bitom, P Bilong

    Abstract:

    MinerAl And geochemicAl investigAtions were cArried out on soil sAmples And fresh rock (trAchytes) from two selected soil profiles (TM profile on leptic AluAndic soils And TL profile on thApto AluAndic-ferrAlsols) from Mount BAmbouto to better understAnd geochemicAl processes And minerAl pArAgenesis involved in the development of soils in this environment. In TM profile, the hydrAted hAlloysites And goethite occur in the weAthered sAprolite boulders of BC horizon while dehydrAted hAlloysite, gibbsite And goethite dominAte the soils mAtrices of BC And A Horizons. In TL profile, the dehydrAted hAlloysites And goethite Are the most AbundAnt secondAry minerAls in the weAthered sAprolites of C And BC Horizons while gibbsite, hemAtite And kAolinite occur in the soil mAtrices of BC, B And A Horizons. The highest gibbsite content is in the plAty nodules of B horizon. In both soil profiles, orgAno-metAl complexes (most likely of AI And Fe) Are present in the surfAce A horizon. GeochemicAlly, between the fresh rock And the weAthered sAprolites in both soils, SiO2, K2O, CAO, NA2O And MgO contents decreAse strongly while Fe2O3 And Al2O3 tend to AccumulAte. The molAr rAtio of SiO2/Al2O3 (Ki) And the sum of CA, Mg, K And NA ions (TRB) Also decreAses Abruptly between fresh rocks And the weAthered sAprolites, but increAses significAntly At the soil surfAce. The TM profile shows intense Al enrichment whereAs the TL profile highlights enrichment in both AI And Fe As the weAthering progresses upwArds. Both soil profiles Are enriched in Ni, Cu, BA And Co And depleted in U, Th, TA, Hf, Y, Sr, Pb, Zr And Zn relAtive to fresh rock. They Also show A relAtively low frActionAtion of the rAre eArth elements (REE: LA, Nd, Sm, Eu, Tb, Yb And Lu), except for Ce which tends to be enriched in soils compAred to CI chondrite. All these results give evidence of intense hydrolysis At soil deep in Mount BAmbouto resulting in the formAtion of hAlloysite which progressively trAnsforms into gibbsite And/or dehydrAted hAlloysite. At the soil surfAce, the prominent pedogenetic process refers to AndosolizAtion with formAtion of orgAno-metAl complexes. In TL profile, the presence of kAolinite in soil mAtrices BC And B Horizons is consistent with ferrAlitizAtion At soil deep. In conclusion, soil forming processes in Mount BAmbouto Are strongly influenced by locAl climAte: (i) in the upper mountAin (>2000 m), the fresh, misty And humid climAte fAvors AndosolizAtion; whereAs (ii) in the middle lAnds (1700-2000 m) with A relAtively dry climAte, both AndosolizAtion At the soil surfAce And ferrAlitizAtion At soil deep Act together. (C) 2009 Elsevier B.V. All rights reserved.

  • micromorphology And spectroscopic chArActeristics of orgAnic mAtter in wAterlogged podzols of the upper AmAzon bAsin
    Geoderma, 2008
    Co-Authors: M. Bardy, E. Fritsch, S. Derenne, Thierry Allard, N Do R Nascimento, G.t. Bueno

    Abstract:

    In wAterlogged environments of the upper AmAzon bAsin, orgAnic mAtter is A mAjor driver in the podzolisAtion of clAy-depleted lAterites, especiAlly through its Ability to weAther clAy minerAls And chelAte metAls. Its structure in eight orgAnic-rich sAmples collected At the mArgin And in the centre of the podzolic AreA of A soil sequence wAs investigAted. The sAmples illustrAte the mAin steps in the development of wAterlogged podzols And belong either to eluviAted topsoil A Horizons or to illuviAted subsoil Bhs, Bh And 2BCs Horizons. OrgAnic mAtter micromorphology wAs described, And the overAll moleculAr structure of their clAy size frActions wAs Assessed using Fourier trAnsform infrAred (FTIR) spectroscopy And cross polArizAtion/mAgic Angle spinning (CP/ MAS) 13C nucleAr mAgnetic resonAnce (NMR). OrgAnic feAtures of the Horizons strongly vAry both verticAlly And lAterAlly in the sequence. Topsoil A Horizons Are dominAted by orgAnic residues juxtAposed to cleAn sAnds with A mAjor AliphAtic contribution. In the subsoil, numerous coAtings, chArActeristic of illuviAtion processes, Are observed in the following Horizons: (i) At the mArgin And bottom pArts of the podzolic AreA, dArk brown orgAnic compounds of low AromAcity with AbundAnt oxygen-contAining groups AccumulAte in Bhs And 2BCs Horizons. Their spectroscopic feAtures Agree with the observAtion of crAcked coAtings in 2BCs And the presence of orgAnometAllic complexes, whose AbundAnce decreAses towArds low lying positions. (ii) By contrAst, blAck orgAnic compounds of high AromAcity with few chelAting functions AccumulAte As coAtings And infills in the overlying sAndy Bh horizon of well-expressed wAterlogged podzols.

Laurent Caner – One of the best experts on this subject based on the ideXlab platform.

  • Occurrence of iron And Aluminum sesquioxides And their implicAtions for the P sorption in subtropicAl soils
    Applied Clay Science, 2015
    Co-Authors: Edson Bortoluzzi, Carlos Gustavo Pérez, Jose Ardisson, Tales Tiecher, Laurent Caner

    Abstract:

    The effect of the pedo-climAtic vAriAtion in quAlitAtive And quAntitAtive soil sesquioxide contents And soil phosphorus (P) sorption cApAcities hAs been studied. In four soils (sAmples from A Horizons) locAted Along A southern BrAziliAn environmentAl grAdient (EG) shown A decreAse in crystAllized iron oxides with the increAse of Altitude. HemAtite And goethite were found At low EG Altitudes in AssociAtion with low soil orgAnic cArbon content, And goethite-ferrihydrite And gibbsite were found At high Altitudes in AssociAtion with high orgAnic cArbon content. The Adsorbed soil P (meAsured by the remAining P) wAs predicted by the goethite content, And the desorbed P (meAsured by successive P extrActions using Anion exchAnge resin membrAnes) wAs predicted mAinly by the goethite And clAy content. In subtropicAl soils, even A smooth environmentAl grAdient could determine the quAlitAtive And quAntitAtive iron And Aluminum sesquioxide distributions thAt control soil P sorption cApAcities.

  • AccumulAtion of orgAno-metAllic complexes in lAterites And the formAtion of AluAndic Andosols in the Nilgiri Hills (southern IndiA): similArities And differences with Umbric Podzols
    European Journal of Soil Science, 2011
    Co-Authors: Laurent Caner, E. Fritsch, S. Petit, Emmanuel Joussein, A J Herbillon

    Abstract:

    We hAve investigAted the speciAtion And distribution of iron (Fe) And Aluminium (Al) between minerAls And orgAnic species in A And B Horizons of two AluAndic Andosols with X-rAy diffrAction, thermAl AnAlyses, visible diffuse reflectAnce And Fourier trAnsform infrAred (FTIR) spectroscopies, together with selective And totAl chemicAl extrActions. The two AluAndic Andosols of the Nilgiri HighlAnds (south IndiA) hAve formed At the expense of intensively weAthered lAteritic formAtions of the Eocene. DAtA reveAled thAt Al And Fe were predominAntly stored in end-weAthering products of lAterites, mAinly As gibbsite And Fe (hydr)oxides in B Horizons of the AluAndic Andosols. These secondAry minerAls Are grAduAlly replAced by orgAno-metAllic complexes in the topsoil A Horizons exhibiting Andic properties. We then indicAte thAt formAtion of the orgAno-metAllic complexes results from weAthering of the dominAnt crystAlline Al- And Fe-(hydr)oxides mediAted by the orgAnic ligAnds And complexAtion of the polyvAlent metAls following the AccumulAtion of orgAnic mAtter. Such weAthering And complexAtion mechAnisms Are therefore similAr to those recently Ascribed to deferrAlitizAtion And the formAtion of freely drAined Umbric Podzols (Humus-Podzols) in the upper AmAzon BAsin. In the present cAse, lArge supplies of both Al- And Fe-beAring minerAls provide lArge metAl:cArbon rAtios thAt prevent the mobility of the orgAno-metAllic complexes And induce the formAtion of AluAndic Andosols rAther thAn Podzols.

  • Occurrence of sombric-like subsurfAce A Horizons in some Andic soils of the Nilgiri Hills (Southern IndiA) And their pAlAeoecologicAl significAnce
    Geoderma, 2003
    Co-Authors: Laurent Caner, François Toutain, G. Bourgeon, A J Herbillon

    Abstract:

    This pAper deAls with four pedons (three FulvudAnds And one Andic HAplorthox), locAted At high elevAtions (2000-2400 m A.s.l.) in the Nilgiri Hills on An old lAterized surfAce of South IndiA, And chArActerized by thick (50-100 cm) epipedons whose colour tends to dArken with depth. In two of them, the colour contrAst between the top And the bottom A Horizons wAs so well expressed thAt they were morphologicAlly very similAr to the AfricAn Oxisols reported to hAve sombric subsurfAce Horizons. Soil orgAnic mAtter (SOM) of the different selected A Horizons wAs chArActerized by its meAn residence time And its d13C vAlue, whereAs their humic Acids were exAmined by techniques thAt mAde it possible to determine their chemicAl composition And their chromAtic properties. It wAs found thAt the dArker colour of the subsurfAce A Horizons of these soils wAs relAted to three joined chArActeristics: A SOM d13C signAture indicAting A C4-type vegetAtion (i.e. A grAsslAnd-type) origin, the presence of humic Acids belonging to the A-type (i.e. melAnic) cAtegory of KumAdA (1987), And lArge meAn residence time vAlues. In contrAst, the top A Horizons hAd A more recent SOM, mAinly inherited from A C3-type vegetAtion, And humic Acids (HAs) thAt were less condensed thAn the A-type HAs. It wAs Also found thAt where the presence of sombric-like subsurfAce A Horizons wAs the most evident, the vegetAtion chAnge recorded by the soils (i.e. the chAnge from A grAsslAnd-type vegetAtion towArds A C3-type vegetAtion) wAs expressed on the thickest pArt of their epipedon. These observAtions led us to propose thAt the occurrence of sombric-like subsurfAce A Horizons resulted from the following sequence of events: (i) An exceptionAlly thick AccumulAtion of orgAnic mAtter deriving from grAsslAnd followed by (ii) its progressive replAcement by less dArk orgAnic mAtter deriving from A C3-type vegetAtion. This proposAl wAs found to be in reAsonAble Agreement with the history of the vegetAtion chAnges experienced by the Nilgiri Hills since the end of the Pleistocene. On the other hAnd, it is Also very similAr to one of the hypotheses proposed by VAn WAmbeke (1992) to explAin the frequent occurrence of sombric Horizons in the Oxisols And Ultisols of the high-Altitude AreAs of CentrAl AfricA.