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Soil, land care and environmental research
RESEARCH ARTICLE

Quantifying the allocation of soil organic carbon to biologically significant fractions

J. A. Baldock A B , J. Sanderman A , L. M. Macdonald A , A. Puccini A , B. Hawke A , S. Szarvas A and J. McGowan A
+ Author Affiliations
- Author Affiliations

A CSIRO Land and Water/Sustainable Agriculture Flagship, PMB 2, Glen Osmond, SA 5064, Australia.

B Corresponding author. Email: jeff.baldock@csiro.au

Soil Research 51(8) 561-576 https://doi.org/10.1071/SR12374
Submitted: 21 December 2012  Accepted: 21 July 2013   Published: 20 December 2013

Abstract

Soil organic carbon (OC) exists as a diverse mixture of organic materials with different susceptibilities to biological decomposition. Computer simulation models constructed to predict the dynamics of soil OC have dealt with this diversity using a series of conceptual pools differentiated from one another by the magnitude of their respective decomposition rate constants. Research has now shown that the conceptual pools can be replaced by measureable fractions of soil OC separated on the basis of physical and chemical properties. In this study, an automated protocol for allocating soil OC to coarse (>50 µm) and fine (≤50 µm) fractions was assessed. Automating the size fractionation process was shown to reduce operator dependence and variability between replicate analyses. Solid-state 13C nuclear magnetic resonance spectroscopy was used to quantify the content of biologically resistant poly-aryl carbon in the coarse and fine size fractions. Cross-polarisation analyses were completed for coarse and fine fractions of 312 soils, and direct polarisation analyses were completed for 38 representative fractions. Direct polarisation analyses indicated that the resistant poly-aryl carbon was under-represented in the cross-polarisation analyses, on average, by a factor of ~2. Combining this under-representation with a spectral analysis process allowed the proportion of coarse- and fine-fraction OC existing as resistant poly-aryl C to be defined. The content of resistant OC was calculated as the sum of that found in the coarse and fine fractions. Contents of particulate and humus OC were calculated after subtracting the resistant OC from the coarse and fine fractions, respectively. Across the 312 soils analysed, substantial variations in the contents of humus, particulate, and resistant carbon were noted, with respective average values of 9.4, 4.0, and 4.5 g fraction C/kg soil obtained. When expressed as a proportion of the OC present in each soil, the humus, particulate, and resistant OC accounted for 56, 19, and 26%, respectively. The nuclear magnetic resonance analyses also indicated that the use of a 50-µm sieve to differentiate particulate (>50 µm) from humus (≤50 µm) forms of OC provided an effective separation based on extents of decomposition. The procedures developed in this study provided a means to differentiate three biologically significant forms of soil OC based on size, extent of decomposition, and chemical composition (poly-aryl content).

Additional keywords: charcoal, humus, nuclear magnetic resonance spectroscopy, particulate, resistant, soil organic carbon, SOC.


References

Baldock JA, Skjemstad JO (2000) Role of the soil matrix and minerals in protecting natural organic materials against biological attack. Organic Geochemistry 31, 697–710.
Role of the soil matrix and minerals in protecting natural organic materials against biological attack.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXmsFSqu70%3D&md5=7807fbdd530ca37c288cd9c5d4f62eb2CAS |

Baldock JA, Smernik RJ (2002) Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood. Organic Geochemistry 33, 1093–1109.
Chemical composition and bioavailability of thermally altered Pinus resinosa (Red pine) wood.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XmtlWjurk%3D&md5=85b722f62804c79e968e1188aa7d5670CAS |

Baldock JA, Oades JM, Nelson PN, Skene TM, Golchin A, Clarke P (1997) Assessing the extent of decomposition of natural organic materials using solid-state 13C NMR spectroscopy. Australian Journal of Soil Research 35, 1061–1084.
Assessing the extent of decomposition of natural organic materials using solid-state 13C NMR spectroscopy.Crossref | GoogleScholarGoogle Scholar |

Baldock JA, Masiello CA, Gélinas Y, Hedges JI (2004) Cycling and composition of organic matter in terrestrial and marine ecosystems. Marine Chemistry 92, 39–64.
Cycling and composition of organic matter in terrestrial and marine ecosystems.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXhtVChs7fE&md5=bbbf10a7d72d549d302ed8eb15529665CAS |

Denef K, Six J, Bossuyt H, Frey SD, Elliott ET, Merckx R, Paustian K (2001) Influence of dry-wet cycles on the interrelationship between aggregate, particulate organic matter, and microbial community dynamics. Soil Biology & Biochemistry 33, 1599–1611.
Influence of dry-wet cycles on the interrelationship between aggregate, particulate organic matter, and microbial community dynamics.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXotFOltbo%3D&md5=81a32c2d6ba11cbd5f199694958a5624CAS |

Denef K, Six J, Merckx R, Paustian K (2004) Carbon sequestration in microaggregates of no-tillage soils with different clay mineralogy. Soil Science Society of America Journal 68, 1935–1944.
Carbon sequestration in microaggregates of no-tillage soils with different clay mineralogy.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXpvVCkurg%3D&md5=2e1bc55e0e64c9503ceeecef3e8ac380CAS |

Forbes MS, Raison RJ, Skjemstad JO (2006) Formation, transformation and transport of black carbon (charcoal) in terrestrial and aquatic ecosystems. The Science of the Total Environment 370, 190–206.
Formation, transformation and transport of black carbon (charcoal) in terrestrial and aquatic ecosystems.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XpvF2nsrc%3D&md5=71239df85c7fca129cb5db0f5cf0faf9CAS | 16860374PubMed |

Golchin A, Baldock JA, Oades JM (1997) A model linking organic matter decomposition, chemistry and aggregate dynamics. In ‘Soil processes and the carbon cycle’. (Eds R Lal, JM Kimble, RF Follett, BA Stewart) pp. 245–266. (CRC Press: Boca Raton, FL)

Grandy AS, Neff JC (2008) Molecular C dynamics downstream: The biochemical decomposition sequence and its impact on soil organic matter structure and function. The Science of the Total Environment 404, 297–307.
Molecular C dynamics downstream: The biochemical decomposition sequence and its impact on soil organic matter structure and function.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtFOjs7jE&md5=fd3918e0a196e0f8b64dee4c00e511a5CAS | 18190951PubMed |

Gregorich EG, Monreal CM, Schnitzer M, Schulten HR (1996) Transformation of plant residues into soil organic matter: Chemical characterization of plant tissue, isolated soil fractions, and whole soils. Soil Science 161, 680–693.
Transformation of plant residues into soil organic matter: Chemical characterization of plant tissue, isolated soil fractions, and whole soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XmsFOgu7g%3D&md5=6ba00840b5732c477452aaa156abe11dCAS |

Hamer U, Marschner B, Brodowski S, Amelung W (2004) Interactive priming of black carbon and glucose mineralisation. Organic Geochemistry 35, 823–830.
Interactive priming of black carbon and glucose mineralisation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXksFKju7k%3D&md5=1b42ff4b19f16d2e6219325993677367CAS |

Hammes K, Schmidt MWI, Smernik RJ, Currie LA, Ball WP, Nguyen TH, Louchouarn P, Houel S, Gustafsson O, Elmquist M, Cornelissen G, Skjemstad JO, Masiello CA, Song J, Peng P, Mitra S, Dunn JC, Hatcher PG, Hockaday WC, Smith DM, Hartkopf-Froeder C, Boehmer A, Luer B, Huebert BJ, Amelung W, Brodowski S, Huang L, Zhang W, Gschwend PM, Flores-Cervantes DX, Largeau C, Rouzaud JN, Rumpel C, Guggenberger G, Kaiser K, Rodionov A, Gonzalez-Vila FJ, Gonzalez-Perez JA, de la Rosa JM, Manning DAC, Lopez-Capel E, Ding L (2007) Comparison of quantification methods to measure fire-derived (black/elemental) carbon in soils and sediments using reference materials from soil, water, sediment and the atmosphere. Global Biogeochemical Cycles 21,
Comparison of quantification methods to measure fire-derived (black/elemental) carbon in soils and sediments using reference materials from soil, water, sediment and the atmosphere.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXht1ynsLjO&md5=e44482fa5093c1eb919ffc75cdd39ae5CAS |

Isbell RF (2002) ‘The Australian Soil Classification.’ Revised edn (CSIRO Publishing: Melbourne)

Jenkinson DS (1990) The turnover of organic carbon and nitrogen in soil. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 329, 361–368.
The turnover of organic carbon and nitrogen in soil.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3MXkslSgtb0%3D&md5=2803bd174c62cf09e8eb9340677378f4CAS |

Kögel-Knabner I (2002) The macromolecular organic composition of plant and microbial residues as inputs to soil organic matter. Soil Biology & Biochemistry 34, 139–162.
The macromolecular organic composition of plant and microbial residues as inputs to soil organic matter.Crossref | GoogleScholarGoogle Scholar |

Marschner B, Brodowski S, Dreves A, Gleixner G, Gude A, Grootes PM, Hamer U, Heim A, Jandl G, Ji R, Kaiser K, Kalbitz K, Kramer C, Leinweber P, Rethemeyer J, Schaeffer A, Schmidt MWI, Schwark L, Wiesenberg GLB (2008) How relevant is recalcitrance for the stabilization of organic matter in soils? Journal of Plant Nutrition and Soil Science 171, 91–110.
How relevant is recalcitrance for the stabilization of organic matter in soils?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXisFyhurw%3D&md5=465be009fb87333896fca611f6171c85CAS |

Parton WJ, Hartman M, Ojima D, Schimel D (1998) DAYCENT and its land surface submodel: description and testing. Global and Planetary Change 19, 35–48.
DAYCENT and its land surface submodel: description and testing.Crossref | GoogleScholarGoogle Scholar |

Petersen BM, Berntsen J, Hansen S, Jensen LS (2005) CN-SIM—a model for the turnover of soil organic matter. I. Long-term carbon and radiocarbon development. Soil Biology & Biochemistry 37, 359–374.
CN-SIM—a model for the turnover of soil organic matter. I. Long-term carbon and radiocarbon development.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXhtVahu7%2FF&md5=06a5ca421d6a2ad2d4c51918b4d63c5bCAS |

Preston CM, Schmidt MWI (2006) Black (pyrogenic) carbon: a synthesis of current knowledge and uncertainties with special consideration of boreal regions. Biogeosciences 3, 397–420.
Black (pyrogenic) carbon: a synthesis of current knowledge and uncertainties with special consideration of boreal regions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXivF2hsbs%3D&md5=ee852f47b806b82725be0b7192f41cc6CAS |

Schmidt MWI, Noack AG (2000) Black carbon in soils and sediments: Analysis, distribution, implications, and current challenges. Global Biogeochemical Cycles 14, 777–793.
Black carbon in soils and sediments: Analysis, distribution, implications, and current challenges.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXmsVymt7s%3D&md5=bd61f450f085e7a9cc92c6345867d6aaCAS |

Skjemstad JO, Clarke P, Taylor JA, Oades JM, Newman RH (1994) The removal of magnetic materials from surface soils—a solid state 13C CP/MAS NMR study. Australian Journal of Soil Research 32, 1215–1229.
The removal of magnetic materials from surface soils—a solid state 13C CP/MAS NMR study.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2MXis1Git7c%3D&md5=ba3e7681cccf32cc292fd7102d196526CAS |

Skjemstad JO, Clarke P, Taylor JA, Oades JM, McClure SG (1996) The chemistry and nature of protected carbon in soil. Australian Journal of Soil Research 34, 251–271.
The chemistry and nature of protected carbon in soil.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XisV2is74%3D&md5=c848111db6c0a6c2faa42762b0faadb3CAS |

Skjemstad JO, Taylor JA, Smernik RJ (1999) Estimation of charcoal (char) in soils. Communications in Soil Science and Plant Analysis 30, 2283–2298.
Estimation of charcoal (char) in soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXmt1GltLw%3D&md5=e7e5bc9c6718cd791b4bb5d84414f44fCAS |

Skjemstad JO, Spouncer LR, Cowie B, Swift RS (2004) Calibration of the Rothamsted organic carbon turnover model (RothC ver. 26.3), using measurable soil organic carbon pools. Australian Journal of Soil Research 42, 79–88.
Calibration of the Rothamsted organic carbon turnover model (RothC ver. 26.3), using measurable soil organic carbon pools.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXht1ahsbo%3D&md5=f58a7b007189fd273e84549532aa1f3bCAS |

Smernik RJ, Oades JM (2000a) The use of spin counting for determining quantitation in solid state 13C NMR spectra of natural organic matter. 1. Model systems and the effects of paramagnetic impurities. Geoderma 96, 101–129.
The use of spin counting for determining quantitation in solid state 13C NMR spectra of natural organic matter. 1. Model systems and the effects of paramagnetic impurities.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXit1WjtLw%3D&md5=c21d0d042b9e49e0b69f58b0f278e6fcCAS |

Smernik RJ, Oades JM (2000b) The use of spin counting for determining quantitation in solid state 13C NMR spectra of natural organic matter. 2. HF-treated soil fractions. Geoderma 96, 159–171.
The use of spin counting for determining quantitation in solid state 13C NMR spectra of natural organic matter. 2. HF-treated soil fractions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXjt1Shtbo%3D&md5=eb6ea83b7dbd6b9788f547e515824857CAS |

Smernik R, Baldock JA, Oades JM (2002) Impact of remote protonation on 13C CPMAS NMR quantitation of charred and uncharred wood. Solid State Nuclear Magnetic Resonance 22, 71–82.
Impact of remote protonation on 13C CPMAS NMR quantitation of charred and uncharred wood.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XmvFCltLk%3D&md5=03045f1af646c546b4458bd7d767f649CAS | 12421090PubMed |

Statsoft Inc (2007) ‘STATISTICA (data analysis software system), version 8.0.’ (StatSoft Inc.: Tulsa, OK) Available at: www.statsoft.com

Tan K (2003) ‘Humic matter in soil and the environment.’ (Marcel Dekker, Inc.: New York)

Wilson MA (Ed.) (1987) ‘N.M.R. Techniques and applications in geochemistry and soil chemistry.’ (Pergamon Press: Oxford, UK)

Zimmermann M, Leifeld J, Schmidt MWI, Smith P, Fuhrer J (2007) Measured soil organic matter fractions can be related to pools in the RothC model. European Journal of Soil Science 58, 658–667.
Measured soil organic matter fractions can be related to pools in the RothC model.Crossref | GoogleScholarGoogle Scholar |

Zimmermann M, Bird MI, Wurster C, Saiz G, Goodrick I, Barta J, Capek P, Santruckova H, Smernik R (2012) Rapid degradation of pyrogenic carbon. Global Change Biology 18, 3306–3316.
Rapid degradation of pyrogenic carbon.Crossref | GoogleScholarGoogle Scholar |