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RESEARCH ARTICLE

Carbon stability in a texture contrast soil in response to depth and long-term phosphorus fertilisation of grazed pasture

Elizabeth C. Coonan A B , Alan E. Richardson https://orcid.org/0000-0003-0708-1299 A D , Clive A. Kirkby A , Lynne M. Macdonald C , Martin R. Amidy B , Craig L. Strong B and John A. Kirkegaard A
+ Author Affiliations
- Author Affiliations

A CSIRO Agriculture and Food, PO Box 1700 Canberra, ACT, 2601, Australia.

B Fenner School of Environment and Society, Australian National University, Acton, ACT 2601, Australia.

C CSIRO Agriculture and Food, PMB 2, Glen Osmond, SA, 5064, Australia.

D Corresponding author. Email: alan.richardson@csiro.au

Soil Research 58(1) 21-34 https://doi.org/10.1071/SR19065
Submitted: 20 March 2019  Accepted: 2 September 2019   Published: 10 October 2019

Abstract

It is important to understand the stability of soil organic matter (SOM) sequestered through land management changes. In this study we assessed differences in carbon (C) stability of pasture soils that had high and low C content (2.35% vs 1.73% whole soil C in the 0–10 cm layer) resulting from long-term phosphorus fertilisation. We used soil size fractionation (fine fraction, coarse fraction and winnowing) to assess the amount of stable C and indicators of microbial decomposition capacity (catabolic profiles, metabolic quotient) to assess C stability. As a main effect throughout the 60-cm profile, C concentrations were higher in the fine fraction soil in the high (excess P fertiliser; P2) than low (no P fertiliser; P0) treatments, demonstrating a larger stable C fraction. For both P2 and P0, there was a strong correlation between C measured in the fine fraction and winnowed fraction in the 0–30 cm layer (R = 0.985, P < 0.001), but no correlation was observed for the 30–60 cm layer (R = 0.121, P > 0.05). In addition, we conducted two incubation experiments to assess C stability in the treatments with depth and to assess C stability in the physical soil fractions. For the surface soils (0–10 cm), the highest respiration occurred in fractions containing plant material, including roots (coarse fraction, 0.65 g CO2-C kg–1 soil; whole soil, 1.48 g CO2-C kg–1 soil), which shows that the plant material was less stable than the fine and winnowed soil fractions (0.43 and 0.40 g CO2-C kg–1 soil respectively). Soil respiration, microbial metabolic quotient and substrate utilisation were similar in P0 and P2. Collectively, the data show that the increased C in P2 was associated with increased C concentrations in the more stable fine soil fraction, but with no change in the stability of the C within the fractions.

Additional keywords: carbon fractions, fine fraction soil carbon, mid-infrared spectroscopy, nutrient stoichiometry, soil carbon stocks, soil organic matter.


References

Adams JL, Tipping E, Thacker SA, Quinton JN (2018) An investigation of the distribution of phosphorus between free and mineral associated soil organic matter, using density fractionation. Plant and Soil 427, 139–148.
An investigation of the distribution of phosphorus between free and mineral associated soil organic matter, using density fractionation.Crossref | GoogleScholarGoogle Scholar |

Baldock JA, Hawke B, Sanderman J, Macdonald LM (2013) Predicting contents of carbon and its component fractions in Australian soils from diffuse reflectance mid-infrared spectra. Soil Research 51, 577–595.
Predicting contents of carbon and its component fractions in Australian soils from diffuse reflectance mid-infrared spectra.Crossref | GoogleScholarGoogle Scholar |

Balesdent J, Balabane M (1996) Major contribution of roots to soil carbon storage inferred from maize cultivated soils. Soil Biology & Biochemistry 28, 1261–1263.
Major contribution of roots to soil carbon storage inferred from maize cultivated soils.Crossref | GoogleScholarGoogle Scholar |

Balesdent J, Basile-Doelsch I, Chadoeuf J, Cornu S, Derrien D, Fekiacova Z, Hatté C (2018) Atmosphere–soil carbon transfer as a function of soil depth. Nature 559, 599–602.
Atmosphere–soil carbon transfer as a function of soil depth.Crossref | GoogleScholarGoogle Scholar | 29995858PubMed |

Balser TC, Kirchner JW, Firestone MK (2002) Methodological variability in microbial community level physiological profiles. Soil Science Society of America Journal 66, 519–523.
Methodological variability in microbial community level physiological profiles.Crossref | GoogleScholarGoogle Scholar |

Bernoux M, Cerri CC, Neill C, de Moraes JFL (1998) The use of stable carbon isotopes for estimating soil organic matter turnover rates. Geoderma 82, 43–58.
The use of stable carbon isotopes for estimating soil organic matter turnover rates.Crossref | GoogleScholarGoogle Scholar |

Beyer L, Deslis K, Vogt B (1998) Estimation of soil organic matter composition according to a simple thermoanalytical approach. Communications in Soil Science and Plant Analysis 29, 1277–1297.
Estimation of soil organic matter composition according to a simple thermoanalytical approach.Crossref | GoogleScholarGoogle Scholar |

Bird MI, Pousai P (1997) Variations of δ13C in the surface soil organic carbon pool. Global Biogeochemical Cycles 11, 313–322.
Variations of δ13C in the surface soil organic carbon pool.Crossref | GoogleScholarGoogle Scholar |

Bird M, Kracht O, Derrien D, Zhou Y (2003) The effect of soil texture and roots on the stable carbon isotope composition of soil organic carbon. Soil Research 41, 77–94.
The effect of soil texture and roots on the stable carbon isotope composition of soil organic carbon.Crossref | GoogleScholarGoogle Scholar |

Bissett A, Richardson AE, Baker G, Kirkegaard J, Thrall PH (2013) Bacterial community response to tillage and nutrient additions in a long-term wheat cropping experiment. Soil Biology & Biochemistry 58, 281–292.
Bacterial community response to tillage and nutrient additions in a long-term wheat cropping experiment.Crossref | GoogleScholarGoogle Scholar |

Blagodatskaya E, Kuzyakov Y (2013) Active microorganisms in soil: critical review of estimation criteria and approaches. Soil Biology & Biochemistry 67, 192–211.
Active microorganisms in soil: critical review of estimation criteria and approaches.Crossref | GoogleScholarGoogle Scholar |

Brandani CB, Abbruzzini TF, Conant RT, Cerri CEP (2017) Soil organic and organomineral fractions as indicators of the effects of land management in conventional and organic sugar cane systems. Soil Research 55, 145–161.
Soil organic and organomineral fractions as indicators of the effects of land management in conventional and organic sugar cane systems.Crossref | GoogleScholarGoogle Scholar |

Cambardella CA, Elliott ET (1992) Particulate soil organic-matter changes across a grassland cultivation sequence. Soil Science Society of America Journal 56, 777–783.
Particulate soil organic-matter changes across a grassland cultivation sequence.Crossref | GoogleScholarGoogle Scholar |

Campbell CD, Chapman SJ, Cameron CM, Davidson MS, Potts JM (2003) A rapid microtiter plate method to measure carbon dioxide evolved from carbon substrate amendments so as to determine the physiological profiles of soil microbial communities by using whole soil. Applied and Environmental Microbiology 69, 3593–3599.
A rapid microtiter plate method to measure carbon dioxide evolved from carbon substrate amendments so as to determine the physiological profiles of soil microbial communities by using whole soil.Crossref | GoogleScholarGoogle Scholar | 12788767PubMed |

Cayley JWD, McCaskill MR, Kearney GA (2002) Changes in pH and organic carbon were minimal in a long-term field study in the Western District of Victoria. Australian Journal of Agricultural Research 53, 115–126.
Changes in pH and organic carbon were minimal in a long-term field study in the Western District of Victoria.Crossref | GoogleScholarGoogle Scholar |

Condron L, Black A, Wakelin S (2012) Effects of long-term fertiliser inputs on the quantities of organic carbon in a soil profile under irrigated grazed pasture. New Zealand Journal of Agricultural Research 55, 161–164.
Effects of long-term fertiliser inputs on the quantities of organic carbon in a soil profile under irrigated grazed pasture.Crossref | GoogleScholarGoogle Scholar |

Coonan EC, Richardson AE, Kirkby CA, Kirkegaard JA, Amidy MR, Simpson RJ, Strong CL (2019) Soil carbon sequestration to depth in response to long-term phosphorus fertilization of grazed pasture. Geoderma 338, 226–235.
Soil carbon sequestration to depth in response to long-term phosphorus fertilization of grazed pasture.Crossref | GoogleScholarGoogle Scholar |

Crow SE, Swanston CW, Lajtha K, Brooks JR, Keirstead H (2007) Density fractionation of forest soils: methodological questions and interpretation of incubation results and turnover time in an ecosystem context. Biogeochemistry 85, 69–90.
Density fractionation of forest soils: methodological questions and interpretation of incubation results and turnover time in an ecosystem context.Crossref | GoogleScholarGoogle Scholar |

Diochon AC, Kellman L (2009) Physical fractionation of soil organic matter: destabilization of deep soil carbon following harvesting of a temperate coniferous forest. Journal of Geophysical Research. Biogeosciences 114, 1–9.
Physical fractionation of soil organic matter: destabilization of deep soil carbon following harvesting of a temperate coniferous forest.Crossref | GoogleScholarGoogle Scholar |

Dungait JAJ, Hopkins DW, Gregory AS, Whitmore AP (2012) Soil organic matter turnover is governed by accessibility not recalcitrance. Global Change Biology 18, 1781–1796.
Soil organic matter turnover is governed by accessibility not recalcitrance.Crossref | GoogleScholarGoogle Scholar |

Fontaine S, Barot S, Barré P, Bdioui N, Mary B, Rumpel C (2007) Stability of organic carbon in deep soil layers controlled by fresh carbon supply. Nature 450, 277–280.
Stability of organic carbon in deep soil layers controlled by fresh carbon supply.Crossref | GoogleScholarGoogle Scholar | 17994095PubMed |

Franzluebbers AJ, Hons FM, Zuberer DA (1994) Seasonal changes in soil microbial biomass and mineralizable C and N in wheat management systems. Soil Biology & Biochemistry 26, 1469–1475.
Seasonal changes in soil microbial biomass and mineralizable C and N in wheat management systems.Crossref | GoogleScholarGoogle Scholar |

George TS, Simpson RJ, Hadobas PA, Marshall DJ, Richardson AE (2007) Accumulation and phosphatase-lability of organic phosphorus in fertilised pasture soils. Australian Journal of Agricultural Research 58, 47–55.
Accumulation and phosphatase-lability of organic phosphorus in fertilised pasture soils.Crossref | GoogleScholarGoogle Scholar |

Godfree RC, Woods MJ, Young AG, Burdon JJ, Higgins TJV (2004) Growth, fecundity and competitive ability of transgenic Trifolium subterraneum subsp. subterraneum cv. Leura expressing a sunflower seed albumin gene. Hereditas 140, 229–244.
Growth, fecundity and competitive ability of transgenic Trifolium subterraneum subsp. subterraneum cv. Leura expressing a sunflower seed albumin gene.Crossref | GoogleScholarGoogle Scholar | 15198714PubMed |

Guo LB, Gifford RM (2002) Soil carbon stocks and land use change: a meta analysis. Global Change Biology 8, 345–360.
Soil carbon stocks and land use change: a meta analysis.Crossref | GoogleScholarGoogle Scholar |

Harrison RB, Footen PW, Strahm BD (2011) Deep soil horizons: contribution and importance to soil carbon pools and in assessing whole-ecosystem response to management and global change. Forest Science 57, 67–76.

Haynes RJ, Williams PH (1992) Accumulation of soil organic matter and the forms, mineralization potential and plant-availability of accumulated organic sulphur: effects of pasture improvement and intensive cultivation. Soil Biology & Biochemistry 24, 209–217.
Accumulation of soil organic matter and the forms, mineralization potential and plant-availability of accumulated organic sulphur: effects of pasture improvement and intensive cultivation.Crossref | GoogleScholarGoogle Scholar |

Hill JO, Simpson RJ, Moore AD, Graham P, Chapman DF (2004) Impact of phosphorus application and sheep grazing on the botanical composition of sown pasture and naturalised, native grass pasture. Australian Journal of Agricultural Research 55, 1213–1225.
Impact of phosphorus application and sheep grazing on the botanical composition of sown pasture and naturalised, native grass pasture.Crossref | GoogleScholarGoogle Scholar |

Isbell RF (1996) ‘The Australian soil classification.’ (CSIRO Publishing: Melbourne, Vic.)

Janzen HH, Campbell CA, Brandt SA, Lafond GP, Townley-Smith L (1992) Light-fraction organic matter in soils from long-term crop rotations. Soil Science Society of America Journal 56, 1799–1806.
Light-fraction organic matter in soils from long-term crop rotations.Crossref | GoogleScholarGoogle Scholar |

Kaiser M, Ellerbrock RH, Sommer M (2009) Separation of coarse organic particles from bulk surface soil samples by electrostatic attraction. Soil Science Society of America Journal 73, 2118–2130.
Separation of coarse organic particles from bulk surface soil samples by electrostatic attraction.Crossref | GoogleScholarGoogle Scholar |

Keesstra S, Mol G, de Leeuw J, Okx J, de Cleen M, Visser S (2018) Soil-related sustainable development goals: four concepts to make land degradation neutrality and restoration work. Land (Basel) 7, 133
Soil-related sustainable development goals: four concepts to make land degradation neutrality and restoration work.Crossref | GoogleScholarGoogle Scholar |

Kirkby C, Kirkegaard J, Richardson A, Wade L, Blanchard C, Batten G (2011) Stable soil organic matter: a comparison of C : N : P : S ratios in Australian and other world soils. Geoderma 163, 197–208.
Stable soil organic matter: a comparison of C : N : P : S ratios in Australian and other world soils.Crossref | GoogleScholarGoogle Scholar |

Kirkby C, Richardson A, Wade L, Conyers M, Kirkegaard J (2016a) Inorganic nutrients increase humification efficiency and C-sequestration in an annually cropped soil. PLoS One 11, e0153698
Inorganic nutrients increase humification efficiency and C-sequestration in an annually cropped soil.Crossref | GoogleScholarGoogle Scholar | 27144282PubMed |

Kirkby CA, Richardson AE, Wade LJ, Batten GD, Blanchard CL, Mclaren G, Zwart AB, Kirkegaard JA (2016b) Accurate measurement of resistant soil organic matter and its stoichiometry. European Journal of Soil Science 67, 695–705.
Accurate measurement of resistant soil organic matter and its stoichiometry.Crossref | GoogleScholarGoogle Scholar |

Lehmann J, Kleber M (2015) The contentious nature of soil organic matter. Nature 528, 60–68.
The contentious nature of soil organic matter.Crossref | GoogleScholarGoogle Scholar | 26595271PubMed |

Lerch TZ, Nunan N, Dignac M-F, Chenu C, Mariotti A (2011) Variations in microbial isotopic fractionation during soil organic matter decomposition. Biogeochemistry 106, 5–21.
Variations in microbial isotopic fractionation during soil organic matter decomposition.Crossref | GoogleScholarGoogle Scholar |

Li S-J, Hua Z-S, Huang L-N, Li J, Shi S-H, Chen L-X, Kuang J-L, Liu J, Hu M, Shu W-S (2014) Microbial communities evolve faster in extreme environments. Scientific Reports 4, 6205
Microbial communities evolve faster in extreme environments.Crossref | GoogleScholarGoogle Scholar | 25158668PubMed |

Magid J, Kjærgaard C (2001) Recovering decomposing plant residues from the particulate soil organic matter fraction: size versus density separation. Biology and Fertility of Soils 33, 252–257.
Recovering decomposing plant residues from the particulate soil organic matter fraction: size versus density separation.Crossref | GoogleScholarGoogle Scholar |

Lützow Mv, Kögel‐Knabner I, Ekschmitt K, Matzner E, Guggenberger G, Marschner B, Flessa H (2006) Stabilization of organic matter in temperate soils: mechanisms and their relevance under different soil conditions – a review. European Journal of Soil Science 57, 426–445.
Stabilization of organic matter in temperate soils: mechanisms and their relevance under different soil conditions – a review.Crossref | GoogleScholarGoogle Scholar |

Magid J, Gorissen A, Giller KE (1996) In search of the elusive ‘active’ fraction of soil organic matter: three size-density fractionation methods for tracing the fate of homogeneously 14C-labelled plant materials. Soil Biology & Biochemistry 28, 89–99.
In search of the elusive ‘active’ fraction of soil organic matter: three size-density fractionation methods for tracing the fate of homogeneously 14C-labelled plant materials.Crossref | GoogleScholarGoogle Scholar |

McLaren TI, Simpson RJ, McLaughlin MJ, Smernik RJ, McBeath TM, Guppy CN, Richardson AE (2015) An assessment of various measures of soil phosphorus and the net accumulation of phosphorus in fertilised soils under pasture. Journal of Plant Nutrition and Soil Science 178, 543–554.
An assessment of various measures of soil phosphorus and the net accumulation of phosphorus in fertilised soils under pasture.Crossref | GoogleScholarGoogle Scholar |

Murphy BW (2015) Impact of soil organic matter on soil properties – a review with emphasis on Australian soils. Soil Research 53, 605–635.
Impact of soil organic matter on soil properties – a review with emphasis on Australian soils.Crossref | GoogleScholarGoogle Scholar |

Novara A, Pulido M, Rodrigo-Comino J, Di Prima S, Smith P, Gristina L, Gimenez-Morera A, Terol E, Salesa D, Keesstra S (2019) Long-term organic farming on a citrus plantation results in soil organic carbon recovery. Cuadernos de Investigación Geográfica 45, 271–286.
Long-term organic farming on a citrus plantation results in soil organic carbon recovery.Crossref | GoogleScholarGoogle Scholar |

Olsen SR, Cole CV, Watanabe FS, Dean LA (1954) Estimation of available phosphorus in soils by extraction with sodium bicarbonate. US Department of Agriculture Circular No. 939, USDA, Washington, DC.

Oorts K, Vanlauwe B, Recous S, Merckx R (2005) Redistribution of particulate organic matter during ultrasonic dispersion of highly weathered soils. European Journal of Soil Science 56, 77–91.
Redistribution of particulate organic matter during ultrasonic dispersion of highly weathered soils.Crossref | GoogleScholarGoogle Scholar |

Oksanen J, Blanchet FG, Friendly M, Kindt R, Legendre P, McGlinn D, Minchin PR, O’Hara RB, Simpson GL, Solymos P, Stevens MHH, Szoecs E, Wagner H (2018). vegan: Community Ecology Package. R package version 2.5-1. Available at https://CRAN.R-project.org/package=vegan [Verified 16 September 2019]

Poeplau C, Don A (2013) Sensitivity of soil organic carbon stocks and fractions to different land-use changes across Europe. Geoderma 192, 189–201.
Sensitivity of soil organic carbon stocks and fractions to different land-use changes across Europe.Crossref | GoogleScholarGoogle Scholar |

Poeplau C, Don A, Six J, Kaiser M, Benbi D, Chenu C, Cotrufo MF, Derrien D, Gioacchini P, Grand S, Gregorich E, Griepentrog M, Gunina A, Haddix M, Kuzyakov Y, Kühnel A, Macdonald LM, Soong J, Trigalet S, Vermeire M-L, Rovira P, van Wesemael B, Wiesmeier M, Yeasmin S, Yevdokimov I, Nieder R (2018) Isolating organic carbon fractions with varying turnover rates in temperate agricultural soils – a comprehensive method comparison. Soil Biology & Biochemistry 125, 10–26.
Isolating organic carbon fractions with varying turnover rates in temperate agricultural soils – a comprehensive method comparison.Crossref | GoogleScholarGoogle Scholar |

Rasse DP, Rumpel C, Dignac M-F (2005) Is soil carbon mostly root carbon? Mechanisms for a specific stabilisation. Plant and Soil 269, 341–356.
Is soil carbon mostly root carbon? Mechanisms for a specific stabilisation.Crossref | GoogleScholarGoogle Scholar |

Rumpel C, Kögel-Knabner I (2011) Deep soil organic matter – a key but poorly understood component of terrestrial C cycle. Plant and Soil 338, 143–158.
Deep soil organic matter – a key but poorly understood component of terrestrial C cycle.Crossref | GoogleScholarGoogle Scholar |

Sanderman J, Baldock J, Hawke B, Macdonald L, Massis-Puccini A, Szarvas S (2011). ‘National soil carbon research programme: field and laboratory methodologies.’ (CSIRO Land and Water: Adelaide, SA)

Schipper LA, Dodd MB, Pronger J, Mudge PL, Upsdell M, Moss RA (2013) Decadal changes in soil carbon and nitrogen under a range of irrigation and phosphorus fertiliser treatments. Soil Science Society of America Journal 77, 246–256.
Decadal changes in soil carbon and nitrogen under a range of irrigation and phosphorus fertiliser treatments.Crossref | GoogleScholarGoogle Scholar |

Schrumpf M, Kaiser K, Guggenberger G, Persson T, Kögel-Knabner I, Schulze ED (2013) Storage and stability of organic carbon in soils as related to depth, occlusion within aggregates, and attachment to minerals. Biogeosciences 10, 1675–1691.
Storage and stability of organic carbon in soils as related to depth, occlusion within aggregates, and attachment to minerals.Crossref | GoogleScholarGoogle Scholar |

Sikora LJ, Rawls WJ (2000) In situ respiration determination as tool for classifying soils according to soil organic matter content. Communications in Soil Science and Plant Analysis 31, 2793–2801.
In situ respiration determination as tool for classifying soils according to soil organic matter content.Crossref | GoogleScholarGoogle Scholar |

Simpson RJ, Stefanski A, Marshall DJ, Moore AD, Richardson AE (2015) Management of soil phosphorus fertility determines the phosphorus budget of a temperate grazing system and is the key to improving phosphorus efficiency. Agriculture, Ecosystems & Environment 212, 263–277.
Management of soil phosphorus fertility determines the phosphorus budget of a temperate grazing system and is the key to improving phosphorus efficiency.Crossref | GoogleScholarGoogle Scholar |

Skjemstad JO, Swift RS, McGowan JA (2006) Comparison of the particulate organic carbon and permanganate oxidation methods for estimating labile soil organic carbon. Soil Research 44, 255–263.
Comparison of the particulate organic carbon and permanganate oxidation methods for estimating labile soil organic carbon.Crossref | GoogleScholarGoogle Scholar |

Sleeman JR (1979) Soils of the Ginninderra experiment station, ACT. CSIRO Division of Soils, Canberra, ACT. 10.25919/5c7038bed0f0410.25919/5c7038bed0f04

Sollins P, Homann P, Caldwell BA (1996) Stabilization and destabilization of soil organic matter: mechanisms and controls. Geoderma 74, 65–105.
Stabilization and destabilization of soil organic matter: mechanisms and controls.Crossref | GoogleScholarGoogle Scholar |

Spycher G, Sollins P, Rose S (1983) Carbon and nitrogen in the light fraction of a forest soil: vertical distribution and seasonal patterns. Soil Science 135, 79–87.
Carbon and nitrogen in the light fraction of a forest soil: vertical distribution and seasonal patterns.Crossref | GoogleScholarGoogle Scholar |

Tisdall JM, Oades JM (1982) Organic matter and water-stable aggregates in soils. Journal of Soil Science 33, 141–163.
Organic matter and water-stable aggregates in soils.Crossref | GoogleScholarGoogle Scholar |

Trumbore SE, Vogel J, Southon J (1989) AMS 14C measurements of fractionated soil organic matter: an approach to deciphering the soil carbon cycle. Radiocarbon 31, 644–654.
AMS 14C measurements of fractionated soil organic matter: an approach to deciphering the soil carbon cycle.Crossref | GoogleScholarGoogle Scholar |

US Department of Agriculture (USDA) (1999) ‘Soil taxonomy, a basic system of soil classification for making and interpreting soil surveys. Agriculture Handbook No. 436.’ (Natural Resources Conservation Service: Washington, DC)

US Environmental Protection Agency (USEPA) (1998) Method 3051A, microwave assisted acid digest of sediments, sludges, soils and oils. In ‘USEPA methods for evaluating solid waste, physical/chemical methods (SW-846)’. (US Environmental Protection Agency: Boston, MA)

Vance ED, Brookes PC, Jenkinson DS (1987) An extraction method for measuring soil microbial biomass C. Soil Biology & Biochemistry 19, 703–707.
An extraction method for measuring soil microbial biomass C.Crossref | GoogleScholarGoogle Scholar |

Williams C, Donald C (1957) Changes in organic matter and pH in a podzolic soil as influenced by subterranean clover and superphosphate. Australian Journal of Agricultural Research 8, 179–189.
Changes in organic matter and pH in a podzolic soil as influenced by subterranean clover and superphosphate.Crossref | GoogleScholarGoogle Scholar |

Wynn JG, Bird MI (2008) Environmental controls on the stable carbon isotopic composition of soil organic carbon: Implications for modelling the distribution of C3 and C4 plants, Australia. Tellus. Series B, Chemical and Physical Meteorology 60, 604–621.
Environmental controls on the stable carbon isotopic composition of soil organic carbon: Implications for modelling the distribution of C3 and C4 plants, Australia.Crossref | GoogleScholarGoogle Scholar |

Young R, Cowie A, Harden S, McLeod R (2016) Soil carbon and inferred net primary production in high- and low-intensity grazing systems on the New England Tableland, eastern Australia. Soil Research 54, 824–839.
Soil carbon and inferred net primary production in high- and low-intensity grazing systems on the New England Tableland, eastern Australia.Crossref | GoogleScholarGoogle Scholar |