Graduated PhD 2020
Fractionation methods to estimate the carbon sequestration potential of highly organic soils impacted by regular burning
The carbon sequestration potential of soils depends on the turnover time of the organic carbon inputs. Carbon turnover models partition soil carbon into distinct pools with different turnover times. Soil carbon fractionation methods can relate those model pools to measurable soil fractions. Approaches have been developed that successfully relate mineral soil fractions to model pools, but those approaches fail for highly organic soils. Carbon stabilisation is mostly achieved by physical protection in mineral soils, whereas organic soil stabilisation depends on environmental conditions and chemical recalcitrance. Based on existing approaches, a fractionation scheme that can potentially expand fractionation to organic soils is developed. The approach combines a widely tested mineral soil fractionation scheme with a chemical fractionation method to capture the full range of stabilisation mechanisms in mineral, organo-mineral and organic soils.
The fractions, ranging from labile to highly recalcitrant, are tested against modelled pools of the RothC/ECOSSE soil carbon turnover model. The approach is tested on mineral and peaty soil samples in Scotland and Tasmanian moorland peat samples to capture the processes of a wide range of peat forming materials and climates. Both the Scottish and the Tasmanian ecosystems are subjected to regular burning and the influence of those burning regimes of the formation of labile and stabilized carbon pools will also be investigated. These data can help to estimate the long term carbon storage capabilities of those locally and globally important ecosystems.
Research Project Supervisors
Professor Ian Anderson, Professor Jo Smith (University of Aberdeen), Professor Pete Smith (University of Aberdeen), and Dr Matthias Boer