Pyrogenic carbon in Australian soils.

Qi F; Naidu R; Bolan NS; Dong Z; Yan Y; Lamb D; Bucheli TD; Choppala G; Duan L; Semple KT

doi:10.1016/j.scitotenv.2017.02.064

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Journal article

Pyrogenic carbon in Australian soils.

Qi F Global Centre for Environmental Research, ATC Building, Faculty of Science and Information Technology, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of Environment (CRC CARE), The University of Newcastle, PO Box 18, Callaghan, NSW 2308, Australia.
Naidu R Global Centre for Environmental Research, ATC Building, Faculty of Science and Information Technology, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of Environment (CRC CARE), The University of Newcastle, PO Box 18, Callaghan, NSW 2308, Australia. Electronic address: Ravi.Naidu@newcastle.edu.au.
Bolan NS Global Centre for Environmental Research, ATC Building, Faculty of Science and Information Technology, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of Environment (CRC CARE), The University of Newcastle, PO Box 18, Callaghan, NSW 2308, Australia.
Dong Z Global Centre for Environmental Research, ATC Building, Faculty of Science and Information Technology, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of Environment (CRC CARE), The University of Newcastle, PO Box 18, Callaghan, NSW 2308, Australia.
Yan Y Global Centre for Environmental Research, ATC Building, Faculty of Science and Information Technology, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
Lamb D Global Centre for Environmental Research, ATC Building, Faculty of Science and Information Technology, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of Environment (CRC CARE), The University of Newcastle, PO Box 18, Callaghan, NSW 2308, Australia.
Bucheli TD Agroscope Reckenholz-Tänikon Research Station ART, Reckenholzstrasse 191, 8046 Zürich, Switzerland.
Choppala G Southern Cross GeoScience, Southern Cross University, PO Box 157, Lismore 2480, NSW, Australia.
Duan L Global Centre for Environmental Research, ATC Building, Faculty of Science and Information Technology, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of Environment (CRC CARE), The University of Newcastle, PO Box 18, Callaghan, NSW 2308, Australia.
Semple KT Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom.

2017-02-21

Published in:

The Science of the total environment. - 2017

English Pyrogenic carbon (PyC), the combustion residues of fossil fuel and biomass, is a versatile soil fraction active in biogeochemical processes. In this study, the chemo-thermal oxidation method (CTO-375) was applied to investigate the content and distribution of PyC in 30 Australian agricultural, pastoral, bushland and parkland soil with various soil types. Soils were sampled incrementally to 50cm in 6 locations and at another 7 locations at 0-10cm. Results showed that PyC in Australian soils typically ranged from 0.27-5.62mg/g, with three Dermosol soils ranging within 2.58-5.62mg/g. Soil PyC contributed 2.0-11% (N=29) to the total organic carbon (TOC), with one Ferrosol as high as 26%. PyC was concentrated either in the top (0-10cm) or bottom (30-50cm) soil layers, with the highest PyC:TOC ratio in the bottom (30-50cm) soil horizon in all soils. Principal component analysis - multiple linear regression (PCA-MLR) suggested the silt-associated organic C factor accounted for 38.5% of the variation in PyC. Our findings suggest that PyC is an important fraction of the TOC (2.0-11%, N=18) and chemically recalcitrant organic C (ROC) obtained by chemical C fractionation method accounts for a significant proportion of soil TOC (47.3-84.9%, N=18). This is the first study comparing these two methods, and it indicates both CTO-375 and C speciation methods can determine a fraction of recalcitrant organic C. However, estimated chemically recalcitrant organic carbon pool (ROC) was approximately an order of magnitude greater than that of thermally stable organic carbon (PyC).

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