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RESEARCH ARTICLE

Soil carbon is only higher in the surface soil under minimum tillage in Vertosols and Chromosols of New South Wales North-West Slopes and Plains, Australia

M. K. McLeod A C , G. D. Schwenke A , A. L. Cowie B and S. Harden A
+ Author Affiliations
- Author Affiliations

A NSW Department of Primary Industries Tamworth Agricultural Institute, 4 Marsden Park Road, Calala, NSW 2340, Australia.

B Rural Climate Solutions, University of New England, Armidale, NSW 2351, Australia.

C Corresponding author. Email: malem.mcleod@dpi.nsw.gov.au

Soil Research 51(8) 680-694 https://doi.org/10.1071/SR13032
Submitted: 25 January 2013  Accepted: 4 June 2013   Published: 20 December 2013

Abstract

Reduced carbon stock levels in Australian soil due to cropping provide a significant opportunity for carbon sequestration, and the recent initiative to consider soil carbon in domestic emissions trading requires a scientific assessment of soil carbon levels under a range of cropping soil management practices. Some of the previous research in southern and western New South Wales (NSW) showed that the rate of carbon decline in cropping soils is slowed under minimum tillage when the stubble is also retained. However, such comparison is rare in the NSW North-West Slopes and Plains region, particularly on the red soils (Chromosols) which are one of the major soil types in the region. We surveyed 50 dryland Chromosols, 72 dryland Vertosols, and 25 irrigated Vertosols on commercial farms across this region to examine the effects of conventional tillage, minimum tillage, and irrigation on total soil organic carbon. Samples of 0.1 m segments to 0.3 m depth were analysed for total organic carbon and other soil properties. Mid-infrared scans were used to predict the particulate, humus, and resistant soil organic carbon fractions. Bulk density was used to calculate total organic carbon stock for each segment, and equivalent soil mass (ESM) for 0–0.3 m.

In Vertosols, for 0–0.3 m ESM, total organic carbon and particulate organic carbon were not different between management practices, whereas humic organic carbon and resistant organic carbon were consistently lower under conventional tillage. However, in 0–0.1 m, total organic carbon was greater under minimum tillage (15.2 Mg ha–1) than conventional tillage (11.9 Mg ha–1) or irrigation (12.0 Mg ha–1), reflecting less soil surface disturbance under minimum tillage. In Chromosols, only total organic carbon was higher under minimum tillage than conventional tillage in the 0–0.3 m ESM (39.8 v. 33.5 Mg ha–1) and in 0–0.1 m (19.7 v. 16.9 Mg ha–1).

The strong influences of rainfall, temperature, bulk density, texture, and management history on soil carbon stocks suggested that these environmental and management factors require further consideration when gauging soil carbon sequestration potential under current and novel tillage practices in key regional locations.

Additional keywords: carbon accounting, conservation tillage, soil carbon sequestration.


References

ABS (2011) Land Management and Farming in Australia, 2009–10: Land Management and Farming in New South Wales–2009–10. Australian Bureau of Statistics, Canberra, ACT. Available at: www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/4627.02009-10?OpenDocument

Baker JM, Ochsner TE, Venterea RT, Griffis TJ (2007) Tillage and soil carbon sequestration—What do we really know? Agriculture, Ecosystems & Environment 118, 1–5.
Tillage and soil carbon sequestration—What do we really know?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xht1CnsL3F&md5=a6b157e5bc0456333b8bcca00a57bd2eCAS |

Baldock J, Skjemstad JO (1999) Soil organic carbon/soil organic matter. In ‘Soil analysis: an interpretation manual’. (Eds KI Peverill, LA Sparrow, DJ Reuter) pp. 159–170. (CSIRO Publishing: Melbourne)

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 |

Blackburn G, Mcleod S (1983) Salinity of atmospheric precipitation in the Murray-Darling drainage division, Australia. Soil Research 21, 411–434.
Salinity of atmospheric precipitation in the Murray-Darling drainage division, Australia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2cXhtVOjsLg%3D&md5=76b5b076eafeb78a79bd6a55f0cf4c14CAS |

Blair N, Crocker GJ (2000) Crop rotation effects on soil carbon and physical fertility of two Australian soils. Australian Journal of Soil Research 38, 71–84.
Crop rotation effects on soil carbon and physical fertility of two Australian soils.Crossref | GoogleScholarGoogle Scholar |

Blanco-Canqui H, Lal R (2008) No-Tillage and Soil-Profile Carbon Sequestration: An On-Farm Assessment. Soil Science Society of America Journal 72, 693–701.
No-Tillage and Soil-Profile Carbon Sequestration: An On-Farm Assessment.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXmtlans7s%3D&md5=b8f682a0bbc2e8e150a95eaf1bf07f4fCAS |

Butler DG, Cullia BR, Gilmour AR, Gogel BJ (2009) ASReml-R Reference Manual Release-3 Technical Report. Queensland Department of Primary Industries, Brisbane.

Cavanagh P, Koppi A, Mcbratney A (1991) Corrigenda – The effects of minimum cultivation after three years on some physical and chemical properties of a red-brown earth at Forbes, NSW. Soil Research 29, 263–270.

Chan KY (1997) Consequences of changes in particulate organic carbon in Vertisols under pasture and cropping. Soil Science Society of America Journal 61, 1376–1382.
Consequences of changes in particulate organic carbon in Vertisols under pasture and cropping.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXmvV2gt7s%3D&md5=4e5a1bb125b3c53e6784946f865465b5CAS |

Chan K, Mead J (1988) Surface physical properties of a sandy loam soil under different tillage practices. Soil Research 26, 549–559.
Surface physical properties of a sandy loam soil under different tillage practices.Crossref | GoogleScholarGoogle Scholar |

Chan K, Mead J (1992) Tillage-induced differences in the growth and distribution of wheat-roots. Australian Journal of Agricultural Research 43, 19–28.
Tillage-induced differences in the growth and distribution of wheat-roots.Crossref | GoogleScholarGoogle Scholar |

Chan K, Bellotti W, Roberts W (1988) Changes in surface soil properties of vertisols under dryland cropping in a semiarid environment. Soil Research 26, 509–518.
Changes in surface soil properties of vertisols under dryland cropping in a semiarid environment.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXjvVaisw%3D%3D&md5=0efe174e500cf1ff8f75e4e0f23e7cebCAS |

Chan KY, Heenan DP, So HB (2003) Sequestration of carbon and changes in soil quality under conservation tillage on light-textured soils in Australia: a review. Australian Journal of Experimental Agriculture 43, 325–334.
Sequestration of carbon and changes in soil quality under conservation tillage on light-textured soils in Australia: a review.Crossref | GoogleScholarGoogle Scholar |

Chan KY, Oates A, Liu DL, Li GD, Prangnell R, Polie G, Conyers MK (2010) ‘A farmer’s guide to increasing soil organic carbon under pastures.’ (Industry & Investment NSW: Wagga Wagga, NSW)

Chivenge PP, Murwira HK, Giller KE, Mapfumo P, Six J (2007) Long-term impact of reduced tillage and residue management on soil carbon stabilization: Implications for conservation agriculture on contrasting soils. Soil & Tillage Research 94, 328–337.
Long-term impact of reduced tillage and residue management on soil carbon stabilization: Implications for conservation agriculture on contrasting soils.Crossref | GoogleScholarGoogle Scholar |

Christopher SF, Lal R, Mishra U (2009) Regional study of no-till effects on carbon sequestration in the Midwestern United States. Soil Science Society of America Journal 73, 207–216.
Regional study of no-till effects on carbon sequestration in the Midwestern United States.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXitVarsLg%3D&md5=998986834c97c7b5d4cae994f5b37a42CAS |

Chung H, Grove JH, Six J (2008) Indications for soil carbon saturation in a temperate agroecosystem. Soil Science Society of America Journal 72, 1132–1139.
Indications for soil carbon saturation in a temperate agroecosystem.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXos1Gqu7Y%3D&md5=5b41ee14f2d3a8055d0249dc36ad686fCAS |

Conteh A, Blair GJ, Rochester IJ (1998) Soil organic carbon fractions in a Vertisol under irrigated cotton production as affected by burning and incorporating cotton stubble. Soil Research 36, 655–668.
Soil organic carbon fractions in a Vertisol under irrigated cotton production as affected by burning and incorporating cotton stubble.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXks1Kitro%3D&md5=72d971b7ee6e2aab0fbe9dd5fca56b54CAS |

Coughlan KJ (1984) The structure of vertisols. In ‘The properties and utilization of cracking clay soil’. 24–28 August 1981, Armidale, NSW. (Eds JW McGarity, EH Hoult, HB So) pp. 87–96. (University of New England: Armidale, NSW)

Dalal RC, Chan KY (2001a) Soil organic matter in rainfed cropping systems of the Australian cereal belt. Australian Journal of Soil Research 39, 435–464.
Soil organic matter in rainfed cropping systems of the Australian cereal belt.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXks1Kqt7c%3D&md5=a0808765b25458ef717e39818258119cCAS |

Dalal RC, Chan KY (2001b) Soil organic matter in rainfed cropping systems of the Australian cereal belt. Soil Research 39, 435–464.
Soil organic matter in rainfed cropping systems of the Australian cereal belt.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXks1Kqt7c%3D&md5=a0808765b25458ef717e39818258119cCAS |

Dalal R, Mayer R (1986) Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. II. Total organic carbon and its rate of loss from the soil profile. Soil Research 24, 281–292.
Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. II. Total organic carbon and its rate of loss from the soil profile.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL28XkvFKmsLw%3D&md5=a5054bec44ec9ebf5e5109c3f6e2c1c4CAS |

Dalal RC, Allen DE, Wang WJ, Reeves S, Gibson I (2011) Organic carbon and total nitrogen stocks in a Vertisol following 40 years of no-tillage, crop residue retention and nitrogen fertilisation. Soil & Tillage Research 112, 133–139.
Organic carbon and total nitrogen stocks in a Vertisol following 40 years of no-tillage, crop residue retention and nitrogen fertilisation.Crossref | GoogleScholarGoogle Scholar |

Daniells IG (1995) Benchmark values for soil nitrogen and carbon in soils of the northern wheat-belt of NSW. NSW Agriculture, Final Report for GRDC Project DAN 240NR.

Ellert BH, Bettany JR (1995) Calculation of organic matter and nutrients stored in soils under contrasting management regimes. Canadian Journal of Soil Science 75, 529–538.
Calculation of organic matter and nutrients stored in soils under contrasting management regimes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XhslKlsbo%3D&md5=2c31928b3873b1fbb2727b449836b997CAS |

Fernandes M, Krull E (2008) How does acid treatment to remove carbonates affect the isotopic and elemental composition of soils and sediments? Environmental Chemistry 5, 33–39.
How does acid treatment to remove carbonates affect the isotopic and elemental composition of soils and sediments?Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXitlagsbk%3D&md5=53a31ce81e14df170f79d934befe3f5aCAS |

Fettell N, Gill H (1995) Long-term effects of tillage, stubble, and nitrogen management on properties of a red-brown earth. Australian Journal of Experimental Agriculture 35, 923–928.
Long-term effects of tillage, stubble, and nitrogen management on properties of a red-brown earth.Crossref | GoogleScholarGoogle Scholar |

Follett RF (2001) Soil management concepts and carbon sequestration in cropland soils. Soil & Tillage Research 61, 77–92.
Soil management concepts and carbon sequestration in cropland soils.Crossref | GoogleScholarGoogle Scholar |

Gupta VVSR, Roget D, Davoren CW, Llewellyn R, Whitbread A (2008) Farming system impacts on microbial activity and soil organic matter dynamics in southern Australian Mallee soils. In ‘Global issues, paddock action. Proceedings 14th Australian Agronomy Conference’. 21–25 Sept. 2008, Adelaide, S. Aust. (Ed. M Unkovich) (Australian Society of Agronomy/The Regional Institute Ltd: Gosford, NSW)

Hallsworth E, Gibbons F, Lemerle T (1954) The nutrient status and cultivation practices of the soils of the North-West wheat belt of NSW. Australian Journal of Agricultural Research 5, 422–447.
The nutrient status and cultivation practices of the soils of the North-West wheat belt of NSW.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaG2cXotVSrtQ%3D%3D&md5=e72467291b951fadbce729260154bb4cCAS |

Harte AJ (1984) Effect of tillage on the stability of three red soils of the northern wheat belt. Journal of Soil Conservation Service NSW 40, 94–101.

Hassink J (1997) The capacity of soils to preserve organic C and N by their association with clay and silt particles. Plant and Soil 191, 77–87.
The capacity of soils to preserve organic C and N by their association with clay and silt particles.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2sXltVKju7g%3D&md5=2f9c63c5ae6ca1899be1596470253a7aCAS |

Hayman P, Daniells I (1997) Benchmarking rotation management and soil fertility in the NW NSW Wheat Belt – Two Decades On. In ‘Proceedings of the Farming Systems Conference’. 8 April 1997, Moree, NSW. (Ed. J Edward)

Heenan D, McGhie W, Thomson F, Chan K (1995) Decline in soil organic carbon and total nitrogen in relation to tillage, stubble management, and rotation. Australian Journal of Experimental Agriculture 35, 877–884.
Decline in soil organic carbon and total nitrogen in relation to tillage, stubble management, and rotation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28Xhs1yiu7Y%3D&md5=27a962c6421ea8d93c8e308a76abbbc7CAS |

Heenan DP, Chan KY, Knight PG (2004) Long-term impact of rotation, tillage and stubble management on the loss of soil organic carbon and nitrogen from a Chromic Luvisol. Soil & Tillage Research 76, 59–68.
Long-term impact of rotation, tillage and stubble management on the loss of soil organic carbon and nitrogen from a Chromic Luvisol.Crossref | GoogleScholarGoogle Scholar |

Holford I (1990) Effects of eight year rotations of grain sorghum with lucerne, annual legume, wheat and long fallow on nitrogen and organic carbon in two contrasting soils. Soil Research 28, 277–291.
Effects of eight year rotations of grain sorghum with lucerne, annual legume, wheat and long fallow on nitrogen and organic carbon in two contrasting soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK3cXmtFSks7s%3D&md5=b4991131d719d64de5c217e40e3ddf2aCAS |

Hulugalle NR, Weaver TB, Finlay LA (2012) Carbon inputs by wheat and vetch roots to an irrigated Vertosol. Soil Research 50, 177–187.
Carbon inputs by wheat and vetch roots to an irrigated Vertosol.Crossref | GoogleScholarGoogle Scholar |

IPPC (2006) ‘2006 IPCC Guidelines for National Greenhouse Gas Inventories. Vol. 4 Agriculture, forestry and other land use.’ (IPCC: Geneva)

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

Janik LJ, Skjemstad JO, Shepherd KD, Spouncer LR (2007) The prediction of soil carbon fractions using mid-infrared-partial least square analysis. Soil Research 45, 73–81.
The prediction of soil carbon fractions using mid-infrared-partial least square analysis.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXjsFygurk%3D&md5=46cbb15b7ca591ae54ccfe50e4b25d57CAS |

Krull ES, Baldock JA, Skjemstad JO (2003) Importance of mechanisms and processes of the stabilisation of soil organic matter for modelling carbon turnover. Functional Plant Biology 30, 207–222.
Importance of mechanisms and processes of the stabilisation of soil organic matter for modelling carbon turnover.Crossref | GoogleScholarGoogle Scholar |

Lal R (2004) Soil carbon sequestration impacts on global climate change and food security. Science 304, 1623–1627.
Soil carbon sequestration impacts on global climate change and food security.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXks1Cgsrk%3D&md5=6e52d72e77364b0e7dfe5e70954cac54CAS | 15192216PubMed |

Lal R, Follett RF, Kimble JM (2003) Achieving soil carbon sequestration in the United States: A challenge to the policy makers. Soil Science 168, 827–845.
Achieving soil carbon sequestration in the United States: A challenge to the policy makers.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXpslCgsr4%3D&md5=9e3de01375861a9d0bffb495849b8ce9CAS |

Lodge GM, King KL (2006) Soil microbial biomass, labile and total carbon levels of grazed sown and native pastures in northern New South Wales. Australian Journal of Agricultural Research 57, 837–845.
Soil microbial biomass, labile and total carbon levels of grazed sown and native pastures in northern New South Wales.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XnvVylur4%3D&md5=79614bfee4f0e1ac0498f15a9d4eb73aCAS |

Luo Z, Wang E, Sun OJ (2010a) Soil carbon change and its responses to agricultural practices in Australian agro-ecosystems: A review and synthesis. Geoderma 155, 211–223.
Soil carbon change and its responses to agricultural practices in Australian agro-ecosystems: A review and synthesis.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXitlWgtb0%3D&md5=d5dd038210f1cd57e58d00e7c583a487CAS |

Luo Z, Wang E, Sun OJ (2010b) Can no-tillage stimulate carbon sequestration in agricultural soils? A meta-analysis of paired experiments. Agriculture, Ecosystems & Environment 139, 224–231.
Can no-tillage stimulate carbon sequestration in agricultural soils? A meta-analysis of paired experiments.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXht1Krt73I&md5=69c6ee261da1d09074108f2755bb3065CAS |

Marcellos H, Felton W (1992) Cropping systems of the temperate summer rainfall region. In ‘6th Australian Agronomy Conference’. pp. 48–53. (Agronomy Society of Australia)

Martin R, McMillan M, Cook J (1988) Survey of farm management practices of the northern wheat belt of New South Wales. Australian Journal of Experimental Agriculture 28, 499–509.
Survey of farm management practices of the northern wheat belt of New South Wales.Crossref | GoogleScholarGoogle Scholar |

Miklos M, Short MG, McBratney AB, Minasny B (2010) Mapping and comparing the distribution of soil carbon under cropping and grazing management practices in Narrabri, north-west New South Wales. Soil Research 48, 248–257.
Mapping and comparing the distribution of soil carbon under cropping and grazing management practices in Narrabri, north-west New South Wales.Crossref | GoogleScholarGoogle Scholar |

Murphy B, Rawson A, Ravenscroft L, Rankin M, Millard R (2003) Paired site sampling for soil carbon estimation––New South Wales. National Carbon Accounting System. Technical Report No. 34.

Murphy B, Packer IJ, Cowie AL, Singh BP (2011) Tillage and crop stubble management and soil health in a changing climate. In ‘Soil health and climate change’. (Eds BP Singh, AL Cowie, KY Chan) (Springer: New York)

Ogle SM, Breidt FJ, Paustian K (2005) Agricultural management impacts on soil organic carbon storage under moist and dry climatic conditions of temperate and tropical regions. Biogeochemistry 72, 87–121.
Agricultural management impacts on soil organic carbon storage under moist and dry climatic conditions of temperate and tropical regions.Crossref | GoogleScholarGoogle Scholar |

Ogle SM, Swan A, Paustian K (2012) No-till management impacts on crop productivity, carbon input and soil carbon sequestration. Agriculture, Ecosystems & Environment 149, 37–49.
No-till management impacts on crop productivity, carbon input and soil carbon sequestration.Crossref | GoogleScholarGoogle Scholar |

Packer IJ, Hamilton GJ, White I (1984) Tillage practices to conserve soil and improve soil conditions. Journal of Soil and Water Conservation NSW 40, 78–87.

Packer I, Hamilton G, Koen T (1992) Runoff, soil loss and soil physical property changes of light textured surface soils from long term tillage treatments. Soil Research 30, 789–806.
Runoff, soil loss and soil physical property changes of light textured surface soils from long term tillage treatments.Crossref | GoogleScholarGoogle Scholar |

Page KL, Dalal RC, Pringle MJ, Bell M, Dang YP, Radford B, Bailey K (2013) Organic carbon stocks in cropping soils of Queensland, Australia, as affected by tillage management, climate and soil characteristics. Soil Research 51, 596–607.

Parton WJ, Schimel DS, Cole CV, Ojima DS (1987) Analysis of factors controlling soil organic matter levels in Great Plains Grasslands. Soil Science Society of America Journal 51, 1173–1179.
Analysis of factors controlling soil organic matter levels in Great Plains Grasslands.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL2sXmtlGnsbw%3D&md5=650c5c970a9b9482f61bd93eaaa183e1CAS |

Peterson GA, Lyon DJ, Fenster CR (2012) Valuing long-term field experiments: Quantifying the scientific contribution of a long-term tillage experiment. Soil Science Society of America Journal 76, 757–765.
Valuing long-term field experiments: Quantifying the scientific contribution of a long-term tillage experiment.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XosFejtb4%3D&md5=3b5f7872cd380b4b377e1c541e290accCAS |

Rayment GE, Lyons DJ (2011) ‘Soil chemical methods – Australasia.’ (CSIRO Publishing: Melbourne)

Sanderman J, Farquharson R, Baldock J (2010) Soil Carbon Sequestration Potential: A review for Australian agriculture. A report prepared for Department of Climate Change and Energy Efficiency. CSIRO Land and Water, Urrbrae, S. Aust.

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, Urrbrae, S. Aust.

Schwenke GD, Felton W, Herridge DF, Khan DF, Peoples MB (2002) Relating particulate organic matter-nitrogen (POM-N) and non-POM-N with pulse crop residues, residue management and cereal N uptake. Agronomie 22, 777–787.
Relating particulate organic matter-nitrogen (POM-N) and non-POM-N with pulse crop residues, residue management and cereal N uptake.Crossref | GoogleScholarGoogle Scholar |

Shrestha R, Ladha J, Lefroy R (2002) Carbon management for sustainability of an intensively managed rice-based cropping system. Biology and Fertility of Soils 36, 215–223.
Carbon management for sustainability of an intensively managed rice-based cropping system.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XntlOmtLw%3D&md5=a8847501d5f12fbcbcc015c366ef46b7CAS |

Six J, Elliott ET, Paustian K (2000) Soil macroaggregate turnover and microaggregate formation: a mechanism for C sequestration under no-tillage agriculture. Soil Biology & Biochemistry 32, 2099–2103.
Soil macroaggregate turnover and microaggregate formation: a mechanism for C sequestration under no-tillage agriculture.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXpvFWg&md5=50a83eb613fefd07598b245f66379a9bCAS |

Six J, Conant RT, Paul EA, Paustian K (2002) Stabilization mechanisms of soil organic matter: Implications for C-saturation of soils. Plant and Soil 241, 155–176.
Stabilization mechanisms of soil organic matter: Implications for C-saturation of soils.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XltV2jsbo%3D&md5=3f33136cdd70b1fe36e6a0aec34d506eCAS |

Skjemstad JO, Janik LJ, Head MJ, McClure SG (1993) High energy ultraviolet photo-oxidation: a novel technique for studying physically protected organic matter in clay- and silt-sized aggregates. Journal of Soil Science 44, 485–499.
High energy ultraviolet photo-oxidation: a novel technique for studying physically protected organic matter in clay- and silt-sized aggregates.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK2cXktlCjt7g%3D&md5=2e83ab92e221882369032b6ea19b6e90CAS |

Smith P, Martino D, Cai Z, Gwary D, Janzen H, Kumar P, McCarl B, Ogle S, O’Mara F, Rice C, Scholes B, Sirotenko O, Howden M, McAllister T, Pan G, Romanenkov V, Schneider U, Towprayoon S, Wattenbach M, Smith J (2008) Greenhouse gas mitigation in agriculture. Philosophical Transactions of the Royal Society B. Biological Sciences 363, 789–813.
Greenhouse gas mitigation in agriculture.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXislGgtb8%3D&md5=f7e1f920702078bcf7fc95719ae862a1CAS |

Speight JG (2009) Landform. In ‘Australian soil and land survey field handbook’. 3rd edn. (CSIRO Publishing: Melbourne)

Surapaneni A, Slattery W (2002) Effect of soil management practices on the sequestration of carbon in duplex soils of southeastern Australia. In ‘Agriculture practices and policies for carbon sequestration in soil’. (CRC Press: Boca Raton, FL)

Timms W, Acworth RI, Berhane D (2001) Shallow groundwater dynamics in smectite dominated clay on the Liverpool Plains of New South Wales. Soil Research 39, 203–218.
Shallow groundwater dynamics in smectite dominated clay on the Liverpool Plains of New South Wales.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 | 1:CAS:528:DyaL38XlsVels7w%3D&md5=9142cdf9ff083d2487f79bbffcc6c90dCAS |

Valzano F, Murphy B, Koen T (2005) The impact of tillage on changes in soil carbon density with special emphasis on Australian conditions. National Carbon Accounting System Report No. 43. Australian Greenhouse Office, Canberra, ACT.

West TO, Post WM (2002) Soil Organic Carbon Sequestration Rates by Tillage and Crop Rotation. Soil Science Society of America Journal 66, 1930–1946.
Soil Organic Carbon Sequestration Rates by Tillage and Crop Rotation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XoslKhsbk%3D&md5=d110698b668f04c45b9f2a95ec63523eCAS |

Whitbread AM, Lefroy RDB, Blair GJ (1998) A survey of the impact of cropping on soil physical and chemical properties in north-western New South Wales. Soil Research 36, 669–682.
A survey of the impact of cropping on soil physical and chemical properties in north-western New South Wales.Crossref | GoogleScholarGoogle Scholar |

Young R, Wilson BR, McLeod M, Alston C (2005) Carbon storage in the soils and vegetation of contrasting land uses in northern New South Wales, Australia. Soil Research 43, 21–31.
Carbon storage in the soils and vegetation of contrasting land uses in northern New South Wales, Australia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtl2ku7c%3D&md5=da9b0a5300736072f35989e42380a978CAS |

Young RR, Wilson B, Harden S, Bernardi A (2009) Accumulation of soil carbon under zero tillage cropping and perennial vegetation on the Liverpool Plains, eastern Australia. Soil Research 47, 273–285.
Accumulation of soil carbon under zero tillage cropping and perennial vegetation on the Liverpool Plains, eastern Australia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXmtlWrtbY%3D&md5=007d3833e7eff336abf40f5b29ecb532CAS |