Pyrogenic carbon in Australian soils

Qi, Fangjie and Naidu, Ravi and Bolan, Nanthi S and Dong, Zhaomin and Yan, Yubo and Lamb, Dane and Bucheli, Thomas D. and Choppala, Girish and Duan, Luchun and Semple, Kirk T (2017) Pyrogenic carbon in Australian soils. Science of the Total Environment, 586. pp. 849-857. ISSN 0048-9697

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Abstract

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 50 cm in 6 locations and at another 7 locations at 0–10 cm. Results showed that PyC in Australian soils typically ranged from 0.27–5.62 mg/g, with three Dermosol soils ranging within 2.58–5.62 mg/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 (0–10 cm) or bottom (30–50 cm) soil layers, with the highest PyC:TOC ratio in the bottom (30–50 cm) 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).

Item Type:
Journal Article
Journal or Publication Title:
Science of the Total Environment
Additional Information:
This is the author’s version of a work that was accepted for publication in Science of the Total Environment. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Science of the Total Environment, 586, 2017 DOI: 10.1016/j.scitotenv.2017.02.064
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2300/2311
Subjects:
ID Code:
84810
Deposited By:
Deposited On:
24 Feb 2017 09:34
Refereed?:
Yes
Published?:
Published
Last Modified:
27 Sep 2020 03:46