The Rangeland Journal The Rangeland Journal Society
Rangeland ecology and management
RESEARCH ARTICLE

Impacts of fire on soil organic carbon stocks in a grazed semi-arid tropical Australian savanna: accounting for landscape variability

D. E. Allen A E , P. M. Bloesch A , R. A. Cowley B , T. G. Orton A C , J. E. Payne A D and R. C. Dalal A
+ Author Affiliations
- Author Affiliations

A Landscape Sciences (ESP), Department of Science, Information Technology, Innovation and the Arts, Queensland State Government, GPO Box 5078, Brisbane, Qld 4001, Australia.

B Northern Territory Department of Primary Industry and Fisheries, PO Box 1346, Katherine, NT 0851, Australia.

C Faculty of Agriculture and Environment, The University of Sydney, 1 Central Avenue, Australia Technology Park, Eveleigh, NSW 2015, Australia.

D Soils & Landscapes, Landcare Research, PO Box 69040, Lincoln 7640 New Zealand.

E Corresponding author. Email: Diane.Allen@dsitia.qld.gov.au

The Rangeland Journal 36(4) 359-369 https://doi.org/10.1071/RJ14044
Submitted: 1 April 2014  Accepted: 21 August 2014   Published: 24 September 2014

Abstract

Fire and grazing are commonplace in Australian tropical savannas and the effects of these management practices on soil organic carbon stocks (SOC) is not well understood. A long-term (20 years) experiment studying the effects of fire on a grazed semi-arid tropical savanna was used to increase this understanding. Treatments, including frequency of fire (every 2, 4 and 6 years), season of fire [early (June) vs late (October) dry season] and unburnt control plots, were imposed on Vertosol grassland and Calcarosol woodland sites, which were grazed. Additionally long-term enclosures [unburnt (except the Calcarosol in 2001) and ungrazed since 1973] on each soil type adjacent to each site were sampled, although not included in statistical analyses. SOC stocks were measured to a soil depth of 0.3 m using a wet oxidation method (to avoid interference by carbonates) and compared on an equivalent soil mass basis. Significant treatment differences in SOC stocks were tested for, while accounting for spatial background variation within each site. SOC stocks (0–0.3 m soil depth) ranged between 10.1 and 28.9 t ha–1 (Vertosol site) and 20.7 and 54.9 t ha–1 (Calcarosol site). There were no consistent effects of frequency or season of fire on SOC stocks, possibly reflecting the limited statistical power of the study and inherent spatial variability observed. Differences in the response to frequency and season of fire observed between these soils may have been due to differences in clay type, plant species composition and/or preferential grazing activity associated with fire management. There may also have been differences in C input between treatments and sites due to differences in the herbage mass and post-fire grazing activity on both sites and changed pasture composition, higher herbage fuel load, and a reduction in woody cover on the Vertosol site. This study demonstrated the importance of accounting for background spatial variability and treatment replication (in the absence of baseline values) when assessing SOC stocks in relation to management practices. Given the absence of baseline SOC values and the potentially long period required to obtain changes in SOC in rangelands, modelling of turnover of SOC in relation to background spatial variability would enable management scenarios to be considered in relation to landscape variation that may be unrelated to management. These considerations are important for reducing uncertainty in C-flux accounting and to provide accurate and cost-effective methods for land managers considering participation in the C economy.

Additional keywords: bulk density, calcareous, fire, grazing, organic matter, soil organic carbon.


References

Allen, D. E., Pringle, M. J., Page, K. L., and Dalal, R. C. (2010). A review of sampling designs for the measurement of soil organic carbon in Australian grazing lands. The Rangeland Journal 32, 227–246.
A review of sampling designs for the measurement of soil organic carbon in Australian grazing lands.CrossRef |

Allen, D. E., Pringle, M. J., Bray, S., Hall, T. J., O’Reagain, P. O., Phelps, D., Cobon, D. H., Bloesch, P. M., and Dalal, R. C. (2013). What determines soil organic carbon stocks in the grazing lands of north-eastern Australia? Soil Research 51, 695–706.
What determines soil organic carbon stocks in the grazing lands of north-eastern Australia?CrossRef | 1:CAS:528:DC%2BC3sXhvF2ktbbM&md5=3e269a4d310387c68e86c4090a04df61CAS |

Baldock, J. A., Sanderman, J., Macdonald, L. M., Puccini, A., Hawke, B., Szarvas, S., and McGowan, J. (2013). Quantifying the allocation of soil organic carbon to biologically significant fractions. Soil Research 51, 561–576.
Quantifying the allocation of soil organic carbon to biologically significant fractions.CrossRef | 1:CAS:528:DC%2BC3sXhvF2ktbbL&md5=088c03fa20589d5dbaae824c0b4ae352CAS |

Bird, M. I., Veenendaal, E. M., Moyo, C., Lloyd, J., and Frost, P. (2000). Effect of fire and soil texture on soil carbon in a sub-humid savanna (Matopos, Zimbabwe). Geoderma 94, 71–90.
Effect of fire and soil texture on soil carbon in a sub-humid savanna (Matopos, Zimbabwe).CrossRef | 1:CAS:528:DC%2BD3cXmtVGrtw%3D%3D&md5=51ae9873c66bd05d61224df577fa51beCAS |

Bradshaw, C. J. A., Bowman, D. M. J. S., Bond, N. R., Murphy, B. P., Moore, A. D., Fordham, D. A., Thackway, R., Lawes, M. J., McCallum, H., Gregory, S., Dalal, R. C., Boer, M. M., Lynch, A. J. J., Bradstock, R. A., Brook, B. W., Henry, B. K., Hunt, L. P., Fisher, D. O., Hunter, D., Johnson, C. N., Keith, D. A., Lefroy, E. C., Penman, T. D., Meyer, W. S., Thomson, J. R., Thornton, C. M., VanDerWal, J., Williams, R. J., Keniger, L., and Specht, A. (2013). Brave new green world – consequences of a carbon economy for the conservation of Australian biodiversity. Biological Conservation 161, 71–90.
Brave new green world – consequences of a carbon economy for the conservation of Australian biodiversity.CrossRef |

Brus, D. J., de Gruijter, J. J., Walvoort, D. J. J., de Vries, F., Bronswijk, J. J. B., Römkens, P. F. A. M., and de Vries, W. (2002). Mapping the probability of exceeding critical thresholds for cadmium concentrations in soils in the Netherlands. Journal of Environmental Quality 31, 1875–1884.
Mapping the probability of exceeding critical thresholds for cadmium concentrations in soils in the Netherlands.CrossRef | 1:CAS:528:DC%2BD38Xptlaht7s%3D&md5=84bd7cbdddd9f9e2068b86be5db52a28CAS | 12469837PubMed |

Burrows, W. H., Henry, B. K., Back, P. V., Hoffmann, M. B., Tait, L. J., Anderson, E. R., Menke, N., Danaher, T., Carter, J. O., and McKeon, G. M. (2002). Growth and carbon stock change in eucalypt woodlands in north-east Australia: ecological and greenhouse sink implications. Global Change Biology 8, 769–784.
Growth and carbon stock change in eucalypt woodlands in north-east Australia: ecological and greenhouse sink implications.CrossRef |

Chen, X., Hutley, L. B., and Eamus, D. (2005). Soil organic carbon content at a range of north Australian tropical savannas with contrasting site histories. Plant and Soil 268, 161–171.
Soil organic carbon content at a range of north Australian tropical savannas with contrasting site histories.CrossRef | 1:CAS:528:DC%2BD2MXks1ers7k%3D&md5=9949d97b614efcf35e2f352549e4af63CAS |

Cheng, C.-H., Chen, Y.-S., Huang, Y.-H., Chiou, C.-R., Lin, C.-C., and Menyailo, O. V. (2013). Effects of repeated fires on ecosystem C and N stocks along a fire-induced forest/grassland gradient. Journal of Geophysical Research: Biogeosciences 118, 215–225.
Effects of repeated fires on ecosystem C and N stocks along a fire-induced forest/grassland gradient.CrossRef | 1:CAS:528:DC%2BC3sXhtVKrsrbJ&md5=988140747d359dd315de2c2e39028367CAS |

Cobiac, M. (2006). Predicting native pasture growth in the Victoria River District of the Northern Territory. PhD Thesis, The University of Adelaide, Australia.

Commonwealth of Australia (2012). ‘The pasture type and management affect soil carbon stocks in grazing lands of northern Australia.’ Climate Change Research Program: Soil Carbon Research Program Final Report. (The Department of Agriculture, Forestry and Fisheries, Commonwealth of Australia: Canberra, ACT.) Available at: www.csiro.au/en/Organisation-Structure/Flagships/Sustainable-Agriculture-Flagship/Soil-Carbon-Research-Program/SCaRP-Projects-Overview.aspx (accessed 6 July 2014).

Conyers, M. K., Poile, G. J., Oates, A. A., Waters, D., and Chan, K. Y. (2011). Comparison of three carbon determination methods on naturally occurring substrates and the implication for the quantification of ‘soil carbon’. Soil Research 49, 27–33.
Comparison of three carbon determination methods on naturally occurring substrates and the implication for the quantification of ‘soil carbon’.CrossRef | 1:CAS:528:DC%2BC3MXit1Wgu78%3D&md5=6def2bf2a651af7a75599a3f19f111a3CAS |

Cook, G. D., Williams, R. J., Stokes, C. J., Hutley, L. B., Ash, A. J., and Richards, A. E. (2010). Managing sources and sinks of greenhouse gasses in Australia’s rangelands and tropical savannas. Rangeland Ecology and Management 63, 137–146.
Managing sources and sinks of greenhouse gasses in Australia’s rangelands and tropical savannas.CrossRef |

Cowley, R. A., Hearnden, M. H., Joyce, K. E., Tovar-Valencia, M., Cowley, T. M., Pettit, C. L., and Dyer, R. M. (2014). How Hot? How Often? Getting the fire frequency and timing right for optimal management of woody cover and pasture composition in northern Australian grazed tropical savannas. Kidman Springs Fire Experiment 1993–2013. The Rangeland Journal 36, 323–345.

Dai, X., Boutton, T. W., Hailemichael, M., Ansley, R. J., and Jessup, K. E. (2006). Soil carbon and nitrogen storage in response to fire in a temperate mixed-grass savanna. Journal of Environmental Quality 35, 1620–1628.
Soil carbon and nitrogen storage in response to fire in a temperate mixed-grass savanna.CrossRef | 1:CAS:528:DC%2BD28Xns1Cku7g%3D&md5=96a994f355b33ccd87df3bfd3a8adc22CAS | 16825482PubMed |

De Gruijter, J. J., Brus, D. J., Bierkens, M. F. P., and Knotters, M. (2006). ‘Sampling for Natural Resource Monitoring.’ (Springer: Amsterdam, The Netherlands.)

Dean, C., Roxburgh, S. H., Harper, R. J., Eldridge, D. J., Watson, I. W., and Wardell-Johnson, G. W. (2012a). Accounting for space and time in soil carbon dynamics in timbered rangelands. Ecological Engineering 38, 51–64.
Accounting for space and time in soil carbon dynamics in timbered rangelands.CrossRef |

Dean, C., Wardell-Johnson, G. W., and Harper, R. J. (2012b). Carbon management of commercial rangelands in Australia: major pools and fluxes. Agriculture, Ecosystems & Environment 148, 44–64.
Carbon management of commercial rangelands in Australia: major pools and fluxes.CrossRef |

Douglass, L. L., Possingham, H. P., Carwardine, J., Klein, C. J., Roxburgh, S. H., Russell-Smith, J., and Wilson, K. A. (2011). The effect of carbon credits on savanna land management and priorities for biodiversity conservation. PLoS ONE 6, e23843.
The effect of carbon credits on savanna land management and priorities for biodiversity conservation.CrossRef | 1:CAS:528:DC%2BC3MXht1OmsrzN&md5=18c82af4d88d6190708df6e873191cc3CAS | 21935363PubMed |

Fynn, R. W. S., Haynes, R. J., and O’Connor, T. G. (2003). Burning causes long-term changes in soil organic matter content of a South African grassland. Soil Biology & Biochemistry 35, 677–687.
Burning causes long-term changes in soil organic matter content of a South African grassland.CrossRef | 1:CAS:528:DC%2BD3sXjt1GqsL0%3D&md5=edb4aa740e2d5a955af756312e0609d7CAS |

Fynn, A. J., Alvarez, P., Brown, J. R., George, M. R., Kustin, C., Laca, E. A., Oldfield, J. T., Schohr, T., Neely, C. L., and Wong, C. P. (2009). ‘Soil Carbon Sequestration in U.S. Rangelands: Issues paper for Protocol Development.’ (Environmental Defence Fund: New York.)

Garnaut, R. (2011). ‘The Garnaut Review 2011: Australia in the Global Response to Climate Change.’ (Cambridge University Press: Canberra, ACT.)

Gill, R. A., and Burke, R. C. (1999). Ecosystem consequences of plant life form changes at three sites in the semi-arid United States. Oecologia 121, 551–563.
Ecosystem consequences of plant life form changes at three sites in the semi-arid United States.CrossRef |

Grace, J., San José, J., Meir, P., Miranda, H. S., and Montes, R. A. (2006). Productivity and carbon fluxes of tropical savannas. Journal of Biogeography 33, 387–400.
Productivity and carbon fluxes of tropical savannas.CrossRef |

Heanes, D. L. (1984). Determination of total organic-C in soils by an improved chromic acid digestion and spectrophotometric procedure. Communications in Soil Science and Plant Analysis 15, 1191–1213.
Determination of total organic-C in soils by an improved chromic acid digestion and spectrophotometric procedure.CrossRef | 1:CAS:528:DyaL2cXmt12itL8%3D&md5=c686e9df053c20409dedd587a23d0bf4CAS |

IPCC (2006). ‘2006 IPCC Guidelines for National Greenhouse Gas Inventories. Vol 4: Agriculture, Forestry and Other Land Use.’ (Eds S. Eggleston, L. Buendia, K. Miwa, T. Ngara and K. Tanabe.) (IGES: Tokyo, Japan.)

Jackson, R. B., Banner, J. L., Esteban, G. J., Pockman, W. T., and Wall, D. H. (2002). Ecosystem carbon loss with woody plant invasion of grasslands. Nature 418, 623–626.
Ecosystem carbon loss with woody plant invasion of grasslands.CrossRef | 1:CAS:528:DC%2BD38XlvVylt7c%3D&md5=8e98af245bf56f5e98d488e1ec53ed44CAS | 12167857PubMed |

Jandl, R., Rodeghiero, M., Martinez, C., Cotrufo, M. F., Bampa, F., van Wesemael, B., Harrison, R. B., Guerrini, I. A., deB Richter, D. Jr., Rustad, L., Lorenz, K., Chabbi, A., and Miglietta, F. (2014). Current status, uncertainty and future needs in soil organic carbon monitoring. The Science of the Total Environment 468–469, 376–383.
Current status, uncertainty and future needs in soil organic carbon monitoring.CrossRef | 24041605PubMed |

Kanniah, K. D., Beringer, J., and Hutley, L. B. (2010). The comparative role of key environmental factors in determining savanna productivity and carbon fluxes: a review, with special reference to northern Australia. Progress in Physical Geography 34, 459–490.
The comparative role of key environmental factors in determining savanna productivity and carbon fluxes: a review, with special reference to northern Australia.CrossRef |

Liu, F., Wu, X. B., Bai, E., Boutton, T. W., and Archer, S. R. (2011). Quantifying soil organic carbon in complex landscapes: an example of grassland undergoing encroachment of woody plants. Global Change Biology 17, 1119–1129.
Quantifying soil organic carbon in complex landscapes: an example of grassland undergoing encroachment of woody plants.CrossRef |

Malone, B. P., McBratney, A. B., Minasny, B., and Laslett, G. (2009). Mapping continuous depth functions of soil carbon storage and available water capacity. Geoderma 154, 138–152.
Mapping continuous depth functions of soil carbon storage and available water capacity.CrossRef | 1:CAS:528:DC%2BD1MXhsVCrs7rM&md5=dcfcd1111bf90320dd399214f1997d1eCAS |

Murphy, B. P., Lehmann, C. E. R., Russell-Smith, J., and Lawes, M. J. (2014). Fire regimes and woody biomass dynamics in Australian savannas. Journal of Biogeography 41, 133–144.
Fire regimes and woody biomass dynamics in Australian savannas.CrossRef |

Napier, D. E., and Hill, J. V. (2012). ‘Land resources of the Victoria River District.’ Technical Report No. 19/2012. (Rangelands Division, Department of Land Resource Management: Palmerston, NT.)

Olson, K. R. (2013). Soil organic carbon sequestration, storage, retention and loss in U.S. croplands: issues paper for protocol development. Geoderma 195–196, 201–206.
Soil organic carbon sequestration, storage, retention and loss in U.S. croplands: issues paper for protocol development.CrossRef |

Pringle, M. J., Allen, D. E., Dalal, R. C., Payne, J. E., Mayer, D. G., O’Reagain, P. O., and Marchant, B. P. (2011). Soil carbon stock in the tropical rangelands of Australia: effects of soil type and grazing pressure, and determination of sampling requirement. Geoderma 167–168, 267–273.

R Core Team (2013). ‘R: A Language and Environment for Statistical Computing.’ (R Foundation for Statistical Computing: Vienna, Austria.) Available at: www.R-project.org/ (accessed 7 August 2014)

Rayment, G. E., and Higginson, F. R. (1992). ‘Australian Laboratory Handbook of Soil and Water Chemical Methods.’ (Inkata Press: Melbourne, Vic.)

Richards, A. E., Cook, G. D., and Lynch, B. T. (2011). Optimal fire regimes for soil carbon storage in tropical savannas of northern Australia. Ecosystems 14, 503–518.
Optimal fire regimes for soil carbon storage in tropical savannas of northern Australia.CrossRef | 1:CAS:528:DC%2BC3MXktVSgsbg%3D&md5=f8d28624210cd5e9ce199ceb7f135652CAS |

Saidy, A. R., Smernik, J. J., Baldock, J. A., Kaiser, K., Sanderman, J., and Macdonald, L. M. (2012). Effects of clay mineralogy and hydrous iron oxides on labile organic carbon stabilization. Geoderma 173–174, 104–110.
Effects of clay mineralogy and hydrous iron oxides on labile organic carbon stabilization.CrossRef |

Saiz, G., Bird, M. I., Domingues, T., Schrodt, F., Schwarz, M., Feldpausch, T. R., Veenendaal, E., Djagbletey, G., Hien, F., Compaore, H., Diallo, A., and Lloyd, J. (2012). Variation in soil carbon stocks and their determinants across a precipitation gradient in West Africa. Global Change Biology 18, 1670–1683.
Variation in soil carbon stocks and their determinants across a precipitation gradient in West Africa.CrossRef |

Scharlemann, J. P. W., Tanner, E. V. J., Hiederer, R., and Kapos, V. (2014). Global soil carbon: understanding and managing the largest terrestrial carbon pool. Carbon Management 5, 81–91.
Global soil carbon: understanding and managing the largest terrestrial carbon pool.CrossRef | 1:CAS:528:DC%2BC2cXht1emtrw%3D&md5=ec0eced3e8eb3c6cce54304e76afdb71CAS |

Schmidt, M. W., Torn, M. S., Abiven, S., Dittmar, T., Guggenberger, G., Janssens, I. A., Kleber, M., Kögel-Knabner, I., Lehmann, J., Manning, D. A. C., Nannipieri, P., Rasse, D. P., Weiner, S., and Trumbore, S. E. (2011). Persistence of soil organic matter as an ecosystem property. Nature 478, 49–56.
Persistence of soil organic matter as an ecosystem property.CrossRef | 1:CAS:528:DC%2BC3MXht1yltrnF&md5=1c850ecd65b6458d761676c7bd3c3232CAS | 21979045PubMed |

Schmidt, A., Smernik, R. J., and McBeath, T. M. (2012). Measuring organic carbon in Calcarosols: understanding the pitfalls and complications. Soil Research 50, 397–405.
Measuring organic carbon in Calcarosols: understanding the pitfalls and complications.CrossRef | 1:CAS:528:DC%2BC38Xht1Smu7nO&md5=760aa58d1a7a30f4c342a7aab3b10dbdCAS |

Stewart, G. A., Perry, R. A., Paterson, S. J., Sleeman, J. R., and Traves, D. M. (1970). Land systems of the Ord-Victoria Area. In: ‘Lands of the Ord-Victoria Area, Western Australia and Northern Territory’. Land Research Series No. 28. pp. 11–61. (Division of Land Research and Regional Survey, CSIRO: Melbourne, Vic.)

van Putten, B., Knippers, T., and Buurman, P. (2010). On design and statistical analysis in soil treatment experiments. Soil Science 175, 519–529.
On design and statistical analysis in soil treatment experiments.CrossRef | 1:CAS:528:DC%2BC3cXhtl2ju7rK&md5=6903a67b227015f28aad336a3ef1426dCAS |

Viscarra Rossel, R. A., Webster, R., Bui, E. N., and Baldock, J. A. (2014). Baseline map of organic carbon in Australian soil to support national carbon accounting and monitoring under climate change. Global Change Biology 20, 2953–2970.
Baseline map of organic carbon in Australian soil to support national carbon accounting and monitoring under climate change.CrossRef | 24599716PubMed |

Webster, R., and Oliver, M. A. (2001). ‘Geostatistics for Environmental Scientists.’ (John Wiley & Sons: Chichester, UK.)



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