Dynamics of soil organic matter based on new Rock-Eval indices

Sebag, David; Verrecchia, Éric P.; Cécillon, Lauric; Adatte, Thierry; Albrecht, Remy; Aubert, Michaël; Bureau, Fabrice; Cailleau, Guillaume; Copard, Yoann; Decaëns, Thibaud; Disnar, Jean-Robert; Hetényi, Magdolna; Nyilas, Tünde; Trombino, Luca

doi:10.1016/j.geoderma.2016.08.025

Cited by 75 publications

(97 citation statements)

References 63 publications

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“…Peat organic matter properties were assessed by Rock-Eval 6 pyrolysis configured in standard mode [25]. Organic matter properties were assessed using the following selected parameters: (i) total organic carbon (TOC RE6 ); (ii) Hydrogen Index (HI), a measure of released hydrocarbons relative to TOC RE6 ; (iii) Oxygen Index (OI), corresponding to the oxygen released as CO and CO 2 relative to TOC RE6 ; (iv) the I index, describing thermally labile organic matter; (v) the R-index describing highly thermostable mature organic matter [26]. Detailed methods are provided in supplementary information.…”

Section: Plant and Peat Propertiesmentioning

confidence: 99%

Root oxygen mitigates methane fluxes in tropical peatlands

Girkin

Vane

Turner

et al. 2020

Environ. Res. Lett.

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Tropical peatlands are a globally important source of methane, a potent greenhouse gas. Vegetation is critical in regulating fluxes, providing a conduit for emissions and regular carbon inputs. However, plant roots also release oxygen, which might mitigate methane efflux through oxidation prior to emission from the peat surface. Here we show, using in situ mesocosms, that root exclusion can reduce methane fluxes by a maximum of 92% depending on species, likely driven by the significant decrease in root inputs of oxygen and changes in the balance of methane transport pathways. Methanotroph abundance decreased with reduced oxygen input, demonstrating a likely mechanism for the observed response. These first methane oxidation estimates for a tropical peatland demonstrate that although plants provide an important pathway for methane loss, this can be balanced by the influence of root oxygen inputs that mitigate peat surface methane emissions.

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Section: Plant and Peat Propertiesmentioning

confidence: 99%

Root oxygen mitigates methane fluxes in tropical peatlands

Girkin

Vane

Turner

et al. 2020

Environ. Res. Lett.

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“…The cation exchange capacity (CEC) was were extracted by neutral 1 N ammonium acetate (Chapman, 1965) and analysed by flame photometer (Sherwood model 420) for K and Ca and by Atomic Absorption spectrophotometer (Shimadzu AA 6200) for Mg. Carbon content was analysed using a Rock-Eval 6 pyrolyzer (Vinci Technologies) at Lausanne University (Disnar et al, 2003;Sebag et al, 2016). Analyses were carried out with 30 to 70 mg of powder samples.…”

Section: Soil Physico-chemical Analysesmentioning

confidence: 99%

Rubber plantation ageing controls soil biodiversity after land conversion from cassava

Peerawat

Blaud

Trap

et al. 2018

Agriculture, Ecosystems & Environment

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“…For the HC pyrolysis thermogram we also determined three parameters reflecting a proportion of thermally resistant or labile hydrocarbons: a parameter representing the proportion of hydrocarbons evolved between 200 °C and 450 °C (thermo-labile 20 hydrocarbons, TLHC-index, modified from Saenger et al, 2015), the I-index representing the preservation of thermally labile immature hydrocarbons (after Sebag et al, 2016), and the R-index representing the proportion of hydrocarbons thermally stable at 400°C (after Sebag et al, 2016). Those three RE6 parameters were calculated as follows: …”

Section: Thermal Analysis Of Soil Samples By Rock-evalmentioning

confidence: 99%

“…the TLHC-index, the I-index, and the R-index, had originally been proposed as useful qualitative metrics of soil carbon dynamics, reflecting a proportion of thermally resistant or labile hydrocarbons (Disnar et al, 2003;Sebag et al, 2006;Saenger et al, 2013Saenger et al, , 2015Sebag et al, 2016), those parameters were weakly correlated (TLHC-index) or not correlated (I-index, R-index) to the CP SOC proportion. Furthermore, they also had a 15 weak importance in the random forests model predictions of the CP SOC proportion ( Table 2).…”

Section: A Quantitative Link Between the Long-term Biogeochemical Stamentioning

confidence: 99%

A model based on Rock-Eval thermal analysis to quantify the size of the centennially persistent organic carbon pool in temperate soils

Cécillon¹,

Baudin²,

Chenu³

et al. 2018

Preprint

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Abstract. Changes in global soil carbon stocks have considerable potential to influence the course of future climate change.However, a portion of soil organic carbon (SOC) has a very long residence time (> 100 years) and may not contribute 15 significantly to terrestrial greenhouse gas emissions during the next century. The size of this persistent SOC reservoir is presumed to be large. Consequently, it is a key parameter required for the initialization of SOC dynamics in ecosystem and Earth system models, but there is considerable uncertainty in the methods used to quantify it. Thermal analysis methods provide cost-effective information on SOC thermal stability that has been shown to be qualitatively related to SOC biogeochemical stability. The objective of this work was to build the first quantitative thermal analysis based model of the 20 size of the centennially persistent SOC pool. We used a unique set of soil samples from four agronomic experiments in Northwestern Europe with long-term bare fallow and non-bare fallow treatments (e.g. manure amendment, cropland and grassland), as a sample set for which estimating the size of the centennially persistent SOC pool is relatively straightforward.At each experimental site, we estimated the average concentration of centennially persistent SOC and its uncertainty by applying a Bayesian curve fitting method on the observed declining SOC concentration over the duration of the long-term 25 bare fallow treatment. Overall, the estimated concentrations of centennially persistent SOC ranged from 5 to 11 gC.kg-1 soil (lowest and highest boundaries of four 95% confidence intervals). Then, by dividing site-specific concentrations of persistent SOC by the total SOC concentration of 118 archived soil samples from long-term bare fallow and non-bare fallow treatments, we could estimate the proportion of centennially persistent SOC in the samples and the associated uncertainty.The proportion of centennially persistent SOC ranged from 0.14 (standard deviation of 0.01) to 1 (standard deviation of 30 0.15). Samples were subjected to thermal analysis by Rock-Eval 6 that generated a series of 30 parameters reflecting their SOC thermal stability and bulk chemistry. The sample set was split into a calibration set (n = 88) and a validation set (n = 30). We trained a non-parametric machine learning algorithm (random forests multivariate regression model) that accurately samples from similar pedoclimates. Our study strengthens the evidence for a link between the thermal and biogeochemical stability of soil organic matter, and demonstrates that Rock-Eval 6 thermal analysis can be used to quantify the size of the centennially persistent organic carbon pool in temperate soils.

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Dynamics of soil organic matter based on new Rock-Eval indices

Cited by 75 publications

References 63 publications

Root oxygen mitigates methane fluxes in tropical peatlands

Root oxygen mitigates methane fluxes in tropical peatlands

Rubber plantation ageing controls soil biodiversity after land conversion from cassava

A model based on Rock-Eval thermal analysis to quantify the size of the centennially persistent organic carbon pool in temperate soils

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