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Poster De Conférence Année : 2014

Sensitivity of deep soil C to climate change: Mineralization of soil organic matter at different moistures in an Amazonian PODZOSOL

Résumé

Changesinsoilswaterregimewillbeakeycomponentoffuture climatechange.Whilemany recentstudiesfocusedontheeffectoftemperatureonsoilCd ynamicsmuchlessstudiesare devotedtotheimpactofwaterregimes,althoughsoilmoisture stronglyinfluencesmicrobial activity(Moyano et al. ,2013).BphhorizonsofAmazonianpodzolsrepresentahugesto ckof organiccarbon,i.e.,13.6PgC(Montes et al .,2011).Thesehorizonsareoftenwater‐‐saturated, whichishypothesisedtolimitdecomposition.Predictedchanges inclimateforthisAreawill resultindrierandmorevariableswaterregimesascomparedto thepresentsituation.Weinves‐ tigatedhowheterotrophicrespir ationofthedifferentsoilhor izonsofthesesoilsreactstosoil moisture.Forthisweincubatedundisturbedsoilcoresfromthe OH,E,Bph,andIIMsoilhori‐ zonsatdifferentmatricpotentials(pF0,1.7,2.5,3.5,4.2) andmonitoredtheCmineralisationby measuringtheevolvedCO 2 usingaμGC.TheresultsshowedverylittlevariationofCmin eraliza‐ tionrateswithintheconsidered rangeofmatricpotentials.Th isisexplained,fortheBphhori‐ zons,bythedominanceofsoilporesbyverysmall(dia<0.95 μm)pores,whichremainwater saturatedevenatpF4.2.Absenc eofimpactofmatricpotential variationsmayalsobeexplained byotherfactorslimitingdecompositioninthesesoils.Wedisc ussthepossibleimpactsofpre‐ dictedvariationsofthewaterre gimeofthese.Soilswithclim atechangechangingclimateonthe stabilityoftheirC
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Dates et versions

hal-01629855 , version 1 (06-11-2017)

Identifiants

  • HAL Id : hal-01629855 , version 1
  • PRODINRA : 411231

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Kevin Potard, Naoise Nunan, Claire Chenu, Yves Lucas. Sensitivity of deep soil C to climate change: Mineralization of soil organic matter at different moistures in an Amazonian PODZOSOL. Biogeochemical Interfaces Conference, Oct 2014, Leipzig, Germany. , 129 p., 2014. ⟨hal-01629855⟩
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