Journal article
Organic carbon compounds associated with deep soil carbon stores
Plant and Soil
2022
Appears in Open Access via Read & Publish Agreements
Abstract
Aims
Organic carbon has been reported in deep regolithic profiles to depths of tens of metres, but the composition of the carbon compounds is unknown.
Methods
Residual carbon in the form of non-volatile low molecular weight compounds (LMWC) was characterised in three deep soil profiles to a depth of 19 m under farmland in south-western Australia following extraction with ethyl acetate and analysis by GC/MS. Pyrolysis and off-line thermochemolysis were used to characterise macromolecular organic carbon (MOC) to a depth of 29 m at a fourth site.
Results
Three compound classes occurred across the three different field locations: (1) terpenes, (2) fatty acids, amides and alcohols, and (3) plant steroids; indicating the influence of input of the past and present vegetation. Compounds related to fatty acids were the predominant residual carbon species in deep soils, and may be derived from plants and microorganisms. Biomarkers such as lignin, polysaccharides, proteins and terpenes at 0–0.1 m implied influences of vegetation, fire events and microorganisms. Pyrolysis found that polysaccharides were distributed mainly from 0 to 0.1 m, while aromatic compounds were consistently detected down to 29 m.
Conclusions
Carbon was stabilised in the form of aromatic compounds in deep soil, whereas other carbon sources such as cellulose, chitin, and N-containing compounds were confined to the surface soil. LMWC (Z)-docos-13-enamide and bis(6-methylheptyl) phthalate, were the main components throughout the soil profiles representing 53–81% of the LMWC, and were a greater proportion of the organic matter at depths of 18–19 m.
Details
- Title
- Organic carbon compounds associated with deep soil carbon stores
- Authors/Creators
- P. Sangmanee (Author/Creator) - Uttaradit Rajabhat UniversityB. Dell (Author/Creator)R.J. Harper (Author/Creator)S. George (Author/Creator)D.J. Henry (Author/Creator)
- Publication Details
- Plant and Soil
- Publisher
- Kluwer Academic Publishers
- Identifiers
- 991005542074607891
- Copyright
- © 2022 The Authors.
- Murdoch Affiliation
- Food Futures Institute
- Language
- English
- Resource Type
- Journal article
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Source: InCites
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- Collaboration types
- Domestic collaboration
- International collaboration
- Citation topics
- 3 Agriculture, Environment & Ecology
- 3.45 Soil Science
- 3.45.112 Soil Carbon Dynamics
- Web Of Science research areas
- Agronomy
- Plant Sciences
- Soil Science
- ESI research areas
- Agricultural Sciences