Environmental and site factors controlling the vertical distribution and radiocarbon ages of organic carbon in a sandy soil

dc.contributor.authorHobley, Een_AU
dc.contributor.authorWillgoose, Gen_AU
dc.contributor.authorFrisia, Sen_AU
dc.contributor.authorJacobsen, GEen_AU
dc.date.accessioned2015-10-12T23:03:01Zen_AU
dc.date.available2015-10-12T23:03:01Zen_AU
dc.date.issued2013-04-16en_AU
dc.date.statistics2015-10-01en_AU
dc.description.abstractSoil organic carbon (SOC) content and radiocarbon concentration were measured in three particle-size fractions and charcoal fragments at four depths to bedrock in a sandy soil from SE Australia. SOC content declined with depth for all fractions. The enrichment factors of SOC showed that the finest particles are most important for SOC storage throughout the soil profile, and their importance for SOC storage increased with depth. In the topsoil, all particle-size fractions contained modern SOC. In contrast, charcoal from this depth gave radiocarbon ages of 85–165 years Before Present (BP). This difference was more pronounced at 30–60 cm, where the charcoal was dated at 2,540 years BP, over 12 times as old as the youngest fraction at that depth. These results confirm charcoal as a highly stable form of SOC. The radiocarbon data in the topsoil and near bedrock indicate that neither microaggregation nor mineral association is important for SOC stability in this soil. At intermediate sampling depths, the mid-sized fraction was the oldest. We believe that this is the result of charcoal accumulation in this fraction, inducing a shift in radiocarbon age. However, near bedrock (100–120 cm), radiocarbon concentration did not differ significantly between fractions, despite greater SOC retention in smaller fractions. In addition, radiocarbon ages at 100–120 cm indicate that charcoal is not present at this depth. We propose that environmental and soil conditions (substrate limitation, water and oxygen availability, and temperature) are responsible for the stabilization of SOC at this depth, where SOC concentrations were very low (0.1–0.3 %). Our results demonstrate that, although fine particles retain more SOC than coarse ones, they do not stabilize SOC in this sandy soil. Instead, environmental (bushfires and climate) and site factors (soil texture and soil mineralogy) control the distribution and stability of SOC throughout the soil profile. © 2013, Springer-Verlag.en_AU
dc.identifier.citationHobley, E., Willgoose, G., Frisia, S., & Jacobsen, G. (2013). Environmental and site factors controlling the vertical distribution and radiocarbon ages of organic carbon in a sandy soil. Biology and Fertility of Soils, 49(8), 1015-1026. doi:10.1007/s00374-013-0800-zen_AU
dc.identifier.govdoc6127en_AU
dc.identifier.issn0178-2762en_AU
dc.identifier.issue8en_AU
dc.identifier.journaltitleBiology and Fertility of Soilsen_AU
dc.identifier.pagination1015-1026en_AU
dc.identifier.urihttp://dx.doi.org/10.1007/s00374-013-0800-zen_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/6298en_AU
dc.identifier.volume49en_AU
dc.language.isoenen_AU
dc.publisherSpringeren_AU
dc.subjectSoilsen_AU
dc.subjectAustraliaen_AU
dc.subjectStabilizationen_AU
dc.subjectCharcoalen_AU
dc.subjectParticlesen_AU
dc.subjectBiodegradationen_AU
dc.titleEnvironmental and site factors controlling the vertical distribution and radiocarbon ages of organic carbon in a sandy soilen_AU
dc.typeJournal Articleen_AU
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