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| Titel |
Anthropogenic Charcoal Deposits: Analogues for the Long-Term Functioning and Stability of Biochar in European Soils? |
| VerfasserIn |
Ian Mugford, Alayne Street-Perrot, Cristina Santin, Huw Denman |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094428
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| Publikation (Nr.) |
 EGU/EGU2014-9835.pdf |
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| Zusammenfassung |
| Anthropogenic charcoal deposits, characterised by thick charcoal-rich soil horizons, offer an
invaluable Late Quaternary record of pyrogenic carbon (PyC) additions to soils. A
traditional source of archaeological, anthracological and palaeoecological data,
the potential contribution of anthropogenic charcoal deposits to soil science and
assessment of carbon (C) sequestration is often overlooked. If addition of biochar to
soils is to form a key component of a low-C economy, crucial questions must be
addressed relating to its longevity and behaviour in the soil environment. With rare
exceptions, previous studies have focussed on short-term incubation experiments
and field or pot trials, often neglecting important natural soil and environmental
processes.
This study addresses these issues by comparing the physicochemical properties of
European anthropogenic charcoal-rich deposits, with 14C ages ranging from > 43 ka to
Modern, to native soils (nearby control sites). We will present results from a study of 23
charcoal-rich soil cores, collected from a “Pre-historic” ditch mound, a Bronze Age burnt
mound, a Roman furnace, and post-mediaeval and Modern Meilers, situated along a climatic
gradient from Mediterranean (Southern Italy) to Humid Temperate (South Wales). The ability
of charcoal to alter fertility and retain plant-available nutrients was assessed by measuring
soil cation- exchange capacity. Retention of refractory C by the charcoal deposits was
evaluated from their total organic C (TOC) contents, atomic H:C and O:C ratios, and
residues after acid- dichromate oxidation. Picked charcoal fragments were also
compared with modern biochars and biomass using: 1) their thermogravimetric
recalcitrance (R50) indices (Harvey et al. 2012); and 2) attenuated total reflectance (ATR)
FT-IR data, to gauge the development of functional groups linked to the long-term
oxidation of the particle surfaces. Radiocarbon dating was used to assess the ages of the
deposits.
Our study attests to the considerable potential of anthropogenic charcoal deposits as a tool
to predict the fate, functioning and C-sequestration potential of PyC in soils on long (102 –
103yr) time scales, which are inaccessible to field and laboratory experiments. Centuries to
millennia after charcoal addition, these charcoal-rich soils have undergone limited
environmental degradation and still display significant recalcitrance and C-sequestration
potential. |
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