Senior Lecturer Soil Science
Overview
Dr McLaren graduated in 2009 with a Bachelor of Rural Science (Honours) from the University of New England, Armidale (NSW), Australia. He then completed a doctorate in soil science and cropping systems in 2013 (main supervisor, Associate Professor Dr Christopher Guppy) at the University of New England, followed by a three year postdoctoral research fellowship in soil science and grazing systems (main supervisor, Associate Professor Dr Ronald Smernik) at the University of Adelaide. From 2015 to 2021, Dr McLaren was a 'Senior Scientist' in the Group of Plant Nutrition under Professor Dr Emmanuel Frossard, at the Swiss Federal Institute of Technology (ETH) Zurich, Switzerland. In 2021, Dr McLaren returned to Australia and was appointed as a 'Senior Lecturer in Soil Science' at the University of Queensland.
The overall goal of Dr McLaren's work is to provide new insight on the biogeochemistry of nutrients that will lead to improved outcomes for agricultural and environmental contexts. In particular, he is interested in identifying the diversity of inorganic and organic forms of nutrients, and understanding the processes governing their flux in soil-plant systems. An important part of Dr McLaren's work has been the characterisation of organic matter, and understanding the processes governing the accumulation and depletion of nutrients within soil organic matter. In addition, Dr McLaren has gained much experience on understanding the fate of fertiliser in agroecosystems, and assessing different agronomic strategies to improve plant growth and fertiliser use efficiency, and decrease nutrient transfer to aquatic/marine ecosystems.
Dr McLaren's work has primarily focused on phosphorus, but also included sulfur, nitrogen, and carbon. It has involved a wide variety of analytical approaches, including radiotracers (P-33, S-35), stable isotopes (N-15), spectroscopy (NMR, PXRF, XANES), chromatography (size-exclusion), and 'wet' chemistry (e.g. sequential chemical fractionation and hypobromite oxidation). Research has involved laboratory, glasshouse, and field based experiments, a diversity of soil types, and various ecosystem contexts (e.g. cropping, pasture, and forests). Lastly, Dr McLaren has often worked in colloboration with a variety of stakeholders (e.g. primary producers, agronomists, and industry), and formed international colloborations with applied and fundamental scientists.
Research Interests
- Understanding the processes governing the release and stabilisation of nutrients in soil.
- Characterising soil organic matter.
- Understanding the fate of fertiliser in terrestrial ecosystems, including that of manures and organic wastes.
- Assessing agronomic management strategies to improve plant growth and fertiliser use efficiency.
- Developing analytical approaches for soil-plant-fertiliser matrices.
- Assessing soil tests for predicting 'plant-available' nutrients.
Qualifications
- Bachelor of Rural Science (Honours), University of New England
- Doctor of Philosophy, University of New England
Publications
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Journal Article: Phosphorus speciation along a soil to kettle hole transect: sequential P fractionation, P XANES, and 31P NMR spectroscopy
Prüter, Julia, McLaren, Timothy I., Pätzig, Marlene, Hu, Yongfeng and Leinweber, Peter (2023). Phosphorus speciation along a soil to kettle hole transect: sequential P fractionation, P XANES, and 31P NMR spectroscopy. Geoderma, 429 116215, 1-13. doi: 10.1016/j.geoderma.2022.116215
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Journal Article: Phosphorus species in sequentially extracted soil organic matter fractions
Reusser, Jolanda E., Piccolo, Alessandro, Vinci, Giovanni, Savarese, Claudia, Cangemi, Silvana, Cozzolino, Vincenza, Verel, René, Frossard, Emmanuel and McLaren, Timothy I. (2023). Phosphorus species in sequentially extracted soil organic matter fractions. Geoderma, 429 116227, 1-12. doi: 10.1016/j.geoderma.2022.116227
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Book Chapter: The use of radioactive isotopes to study soil pools and processes
McLaren, Timothy I. (2023). The use of radioactive isotopes to study soil pools and processes. Reference Module in Earth Systems and Environmental Sciences. (pp. 96-106) Elsevier. doi: 10.1016/b978-0-12-822974-3.00258-5
Grants
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Quantifying fertiliser phosphorus use efficiency in Vertosols across the Northern Region
(2023–2027) Grains Research & Development Corporation
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Proximal and remote sensing for low-cost soil carbon stock estimation
(2023–2025) Commonwealth Department of Industry, Science, Energy and Resources
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(2022–2025) Cotton Research & Development Corporation
Supervision
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A mechanistic view of how phosphorus and carbon is sequestered in soil organic matter
Doctor Philosophy
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The chemical composition and dynamics of organic amendments to supply phosphorus for improved crop production
Doctor Philosophy
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Contrasting the phosphorus responsiveness of winter pulses and cereals - the role of nitrogen and crop phenology
Doctor Philosophy
Publications
Book Chapter
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The use of radioactive isotopes to study soil pools and processes
McLaren, Timothy I. (2023). The use of radioactive isotopes to study soil pools and processes. Reference Module in Earth Systems and Environmental Sciences. (pp. 96-106) Elsevier. doi: 10.1016/b978-0-12-822974-3.00258-5
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McLaren, Timothy I., Smernik, Ronald J., McLaughlin, Michael J., Doolette, Ashlea L., Richardson, Alan E. and Frossard, Emmanuel (2020). The chemical nature of soil organic phosphorus: a critical review and global compilation of quantitative data. Advances in agronomy. (pp. 51-124) edited by Donald L. Sparks. Cambridge, MA, United States: Academic Press. doi: 10.1016/bs.agron.2019.10.001
Journal Article
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Prüter, Julia, McLaren, Timothy I., Pätzig, Marlene, Hu, Yongfeng and Leinweber, Peter (2023). Phosphorus speciation along a soil to kettle hole transect: sequential P fractionation, P XANES, and 31P NMR spectroscopy. Geoderma, 429 116215, 1-13. doi: 10.1016/j.geoderma.2022.116215
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Phosphorus species in sequentially extracted soil organic matter fractions
Reusser, Jolanda E., Piccolo, Alessandro, Vinci, Giovanni, Savarese, Claudia, Cangemi, Silvana, Cozzolino, Vincenza, Verel, René, Frossard, Emmanuel and McLaren, Timothy I. (2023). Phosphorus species in sequentially extracted soil organic matter fractions. Geoderma, 429 116227, 1-12. doi: 10.1016/j.geoderma.2022.116227
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The molecular size continuum of soil organic phosphorus and its chemical associations
Reusser, Jolanda E., Tamburini, Federica, Neal, Andrew L., Verel, René, Frossard, Emmanuel and McLaren, Timothy I. (2022). The molecular size continuum of soil organic phosphorus and its chemical associations. Geoderma, 412 115716, 115716. doi: 10.1016/j.geoderma.2022.115716
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Soil phosphomonoesters in large molecular weight material comprise of multiple components
McLaren, Timothy I., Verel, René and Frossard, Emmanuel (2022). Soil phosphomonoesters in large molecular weight material comprise of multiple components. Soil Science Society of America Journal, 86 (2), 345-357. doi: 10.1002/saj2.20347
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Neal, Andrew L., McLaren, Timothy, Campolino, Mariana Lourenco, Hughes, David, Coelho, Antonio Marcos, de Paula Lana, Ubiraci Gomes, Gomes, Eliane Aparecida and de Sousa, Sylvia Morais (2021). Crop type exerts greater influence upon rhizosphere phosphohydrolase gene abundance and phylogenetic diversity than phosphorus fertilization. FEMS Microbiology Ecology, 97 (4) fiab033. doi: 10.1093/femsec/fiab033
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Alewell, Christine, Huang, Jen-How, McLaren, Timothy, Huber, Lea and Bunemann, Else K. (2021). Phosphorus retention in constructed wetlands enhanced by zeolite- and clinopyroxene-dominated lava sand. Hydrological Processes, 35 (2) e14040. doi: 10.1002/hyp.14040
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Reusser, Jolanda E., Verel, René, Zindel, Daniel, Frossard, Emmanuel and McLaren, Timothy I. (2020). Identification of lower-order inositol phosphates (IP5 and IP4) in soil extracts as determined by hypobromite oxidation and solution 31P NMR spectroscopy. Biogeosciences, 17 (20), 5079-5095. doi: 10.5194/bg-17-5079-2020
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Reusser, Jolanda E., Verel, René, Frossard, Emmanuel and McLaren, Timothy I. (2020). Quantitative measures of: Myo-IP6 in soil using solution 31P NMR spectroscopy and spectral deconvolution fitting including a broad signal. Environmental Science: Processes and Impacts, 22 (4), 1084-1094. doi: 10.1039/c9em00485h
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Soil phosphorus pools with addition of fertiliser phosphorus in a long-term grazing experiment
McLaren, Timothy I., Smernik, Ronald J., McLaughlin, Michael J., McBeath, Therese M., McCaskill, Malcolm R., Robertson, Fiona A. and Simpson, Richard J. (2020). Soil phosphorus pools with addition of fertiliser phosphorus in a long-term grazing experiment. Nutrient Cycling in Agroecosystems, 116 (2), 151-164. doi: 10.1007/s10705-019-10035-y
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Phosphorus desorption and isotope exchange kinetics in agricultural soils
Braun, Sabina, McLaren, Timothy I., Frossard, Emmanuel, Tuyishime, J. R. Marius, Börjesson, Gunnar and Gustafsson, Jon Petter (2020). Phosphorus desorption and isotope exchange kinetics in agricultural soils. Soil Use and Management, 38 (1) sum.12674, 1-13. doi: 10.1111/sum.12674
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van der Bom, F. J.T., McLaren, T. I., Doolette, A. L., Magid, J., Frossard, E., Oberson, A. and Jensen, L. S. (2019). Influence of long-term phosphorus fertilisation history on the availability and chemical nature of soil phosphorus. Geoderma, 355 113909, 1-12. doi: 10.1016/j.geoderma.2019.113909
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McLaren, Timothy I., Verel, René and Frossard, Emmanuel (2019). The structural composition of soil phosphomonoesters as determined by solution 31P NMR spectroscopy and transverse relaxation (T2) experiments. Geoderma, 345, 31-37. doi: 10.1016/j.geoderma.2019.03.015
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Glæsner, Nadia, van der Bom, Frederik, Bruun, Sander, McLaren, Timothy, Larsen, Flemming Hofmann and Magid, Jakob (2019). Phosphorus characterization and plant availability in soil profiles after long-term urban waste application. Geoderma, 338, 136-144. doi: 10.1016/j.geoderma.2018.11.046
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Transformation of calcium phosphates in alkaline Vertisols by acidified incubation
Andersson, Karl O., Tighe, Matthew K., Guppy, Christopher N., Milham, Paul J., McLaren, Timothy I., Schefe, Cassandra R., Lombi, Enzo, Lisle, Leanne M. and Klysubun, Wantana (2019). Transformation of calcium phosphates in alkaline Vertisols by acidified incubation. Environmental Science and Technology, 53 (17), 10131-10138. doi: 10.1021/acs.est.9b01565
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George, T. S., Giles, C. D., Menezes-Blackburn, D., Condron, L. M., Gama-Rodrigues, A. C., Jaisi, D., Lang, F., Neal, A. L., Stutter, M. I., Almeida, D. S., Bol, R., Cabugao, K. G., Celi, L., Cotner, J. B., Feng, G., Goll, D. S., Hallama, M., Krueger, J., Plassard, C., Rosling, A., Darch, T., Fraser, T., Giesler, R., Richardson, A. E., Tamburini, F., Shand, C. A., Lumsdon, D. G., Zhang, H., Blackwell, M. S.A. ... Haygarth, P. M. (2018). Correction to: Organic phosphorus in the terrestrial environment: a perspective on the state of the art and future priorities (Plant and Soil, (2018), 427, 1-2, (191-208), 10.1007/s11104-017-3391-x). Plant and Soil, 427 (1-2), 209-211. doi: 10.1007/s11104-017-3488-2
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George, T. S., Giles, C. D., Menezes-Blackburn, D., Condron, L. M., Gama-Rodrigues, A. C., Jaisi, D., Lang, F., Neal, A. L., Stutter, M. I., Almeida, D. S., Bol, R., Cabugao, K. G., Celi, L., Cotner, J. B., Feng, G., Goll, D. S., Hallama, M., Krueger, J., Plassard, C., Rosling, A., Darch, T., Fraser, T., Giesler, R., Richardson, A. E., Tamburini, F., Shand, C. A., Lumsdon, D. G., Zhang, H., Blackwell, M. S.A. ... Haygarth, P. M. (2018). Organic phosphorus in the terrestrial environment: a perspective on the state of the art and future priorities. Plant and Soil, 427 (1-2), 191-208. doi: 10.1007/s11104-017-3391-x
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Phosphorus dynamics in a tropical forest soil restored after strip mining
Spain, Alister V., Tibbett, Mark, Ridd, Michael and McLaren, Timothy I. (2018). Phosphorus dynamics in a tropical forest soil restored after strip mining. Plant and Soil, 427 (1-2), 105-123. doi: 10.1007/s11104-018-3668-8
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Helfenstein, Julian, Jegminat, Jannes, McLaren, Timothy I. and Frossard, Emmanuel (2018). Soil solution phosphorus turnover: derivation, interpretation, and insights from a global compilation of isotope exchange kinetic studies. Biogeosciences, 15 (1), 105-114. doi: 10.5194/bg-15-105-2018
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McLaren, Timothy I., McBeath, Therese M., Simpson, Richard J., Richardson, Alan E., Stefanski, Adam, Guppy, Christopher N., Smernik, Ronald J., Rivers, Colin, Johnston, Caroline and McLaughlin, Michael J. (2017). Direct recovery of 33P-labelled fertiliser phosphorus in subterranean clover (Trifolium subterraneum) pastures under field conditions – the role of agronomic management. Agriculture, Ecosystems and Environment, 246, 144-156. doi: 10.1016/j.agee.2017.05.029
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McLaren, Timothy I., Smernik, Ronald J., Simpson, Richard J., McLaughlin, Michael J., McBeath, Therese M., Guppy, Christopher N. and Richardson, Alan E. (2017). The chemical nature of organic phosphorus that accumulates in fertilized soils of a temperate pasture as determined by solution 31P NMR spectroscopy. Journal of Plant Nutrition and Soil Science, 180 (1), 27-38. doi: 10.1002/jpln.201600076
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Doolette, Ashlea L., Smernik, Ronald J. and McLaren, Timothy I. (2017). The composition of organic phosphorus in soils of the Snowy Mountains region of south-eastern Australia. Soil Research, 55 (1), 10-18. doi: 10.1071/SR16058
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Andersson, Karl O., Tighe, Matthew K., Guppy, Christopher N., Milham, Paul J., McLaren, Timothy I., Schefe, Cassandra R. and Lombi, Enzo (2016). XANES demonstrates the release of calcium phosphates from alkaline vertisols to moderately acidified solution. Environmental Science and Technology, 50 (8), 4229-4237. doi: 10.1021/acs.est.5b04814
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McLaren, Timothy I., McLaughlin, Michael J., McBeath, Therese M., Simpson, Richard J., Smernik, Ronald J., Guppy, Christopher N. and Richardson, Alan E. (2016). The fate of fertiliser P in soil under pasture and uptake by subterraneum clover – a field study using 33P-labelled single superphosphate. Plant and Soil, 401 (1-2), 23-38. doi: 10.1007/s11104-015-2610-6
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The release of phosphorus in alkaline vertic soils as influenced by pH and by anion and cation sinks
Andersson, Karl O., Tighe, Matthew K., Guppy, Christopher N., Milham, Paul J. and McLaren, Timothy I. (2016). The release of phosphorus in alkaline vertic soils as influenced by pH and by anion and cation sinks. Geoderma, 264, 17-27. doi: 10.1016/j.geoderma.2015.10.001
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Incremental acidification reveals phosphorus release dynamics in alkaline vertic soils
Andersson, Karl O., Tighe, Matthew K., Guppy, Christopher N., Milham, Paul J. and McLaren, Timothy I. (2015). Incremental acidification reveals phosphorus release dynamics in alkaline vertic soils. Geoderma, 259-260, 35-44. doi: 10.1016/j.geoderma.2015.05.001
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McLaren, Timothy I., Smernik, Ronald J., Simpson, Richard J., McLaughlin, Michael J., McBeath, Therese M., Guppy, Christopher N. and Richardson, Alan E. (2015). Spectral sensitivity of solution 31P NMR spectroscopy is improved by narrowing the soil to solution ratio to 1:4 for pasture soils of low organic P content. Geoderma, 257-258, 48-57. doi: 10.1016/j.geoderma.2015.02.004
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Complex forms of soil organic phosphorus-a major component of soil phosphorus
McLaren, Timothy I., Smernik, Ronald J., McLaughlin, Mike J., McBeath, Therese M., Kirby, Jason K., Simpson, Richard J., Guppy, Christopher N., Doolette, Ashlea L. and Richardson, Alan E. (2015). Complex forms of soil organic phosphorus-a major component of soil phosphorus. Environmental Science and Technology, 49 (22), 13238-13245. doi: 10.1021/acs.est.5b02948
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Mclaren, Timothy I., Simpson, Richard J., Mclaughlin, Michael J., Smernik, Ronald J., Mcbeath, Therese M., Guppy, Christopher N. and Richardson, Alan E. (2015). An assessment of various measures of soil phosphorus and the net accumulation of phosphorus in fertilized soils under pasture. Journal of Plant Nutrition and Soil Science, 178 (4), 543-554. doi: 10.1002/jpln.201400657
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McLaren, T. I., Guppy, C. N., Tighe, M. K., Schefe, C. R., Flavel, R. J., Cowie, B. C.C. and Tadich, A. (2015). Validation of soil phosphate removal by alkaline and acidic reagents in a vertosol soil using XANES spectroscopy. Communications in Soil Science and Plant Analysis, 46 (16), 1998-2017. doi: 10.1080/00103624.2015.1048252
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The organic P composition of vertisols as determined by 31P NMR spectroscopy
McLaren, Timothy I., Smernik, Ronald J., Guppy, Christopher N., Bell, Mike J. and Tighe, Matthew K. (2014). The organic P composition of vertisols as determined by 31P NMR spectroscopy. Soil Science Society of America Journal, 78 (6), 1893-1902. doi: 10.2136/sssaj2014.04.0139
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Stanley, John N., Baqir, Hussein Ali and Mclaren, Timothy I. (2014). Effect on larval growth of adding finely ground silicon-bearing minerals (wollastonite or olivine) to artificial diets for Helicoverpa spp. (Lepidoptera: Noctuidae). Austral Entomology, 53 (4), 436-443. doi: 10.1111/aen.12086
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McLaren, Timothy, Bell, Michael, Rochester, Ian, Guppy, Christopher, Tighe, Matthew and Flavel, Richard (2013). Growth and phosphorus uptake of faba bean and cotton are related to Colwell-P concentrations in the subsoil of Vertosols. Crop and Pasture Science, 64 (8), 825-833. doi: 10.1071/CP13025
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A rapid and nondestructive plant nutrient analysis using portable X-ray fluorescence
McLaren, Timothy I., Guppy, Christopher N. and Tighe, Matthew K. (2012). A rapid and nondestructive plant nutrient analysis using portable X-ray fluorescence. Soil Science Society of America Journal, 76 (4), 1446-1453. doi: 10.2136/sssaj2011.0355
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Rapid, nondestructive total elemental analysis of vertisol soils using portable X-ray fluorescence
McLaren, Timothy I., Guppy, Christopher N., Tighe, Matthew K., Forster, Nicola, Grave, Peter, Lisle, Leanne M. and Bennett, John W. (2012). Rapid, nondestructive total elemental analysis of vertisol soils using portable X-ray fluorescence. Soil Science Society of America Journal, 76 (4), 1436-1445. doi: 10.2136/sssaj2011.0354
Conference Publication
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Schefe, Cassandra R., Barlow, Kirsten M., Robinson, Nathan J., Crawford, Douglas M., McLaren, Timothy I., Smernik, Ronald J., Croatto, George, Walsh, Ronald D. and Kitching, Matt (2015). 100 Years of superphosphate addition to pasture in an acid soil - Current nutrient status and future management. International Workshop on Soil Change Matters, Bendigo, VIC, Australia, 24-27 March 2014. Clayton, VIC, Australia: CSIRO Publishing. doi: 10.1071/SR14241
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McLaren, Timothy I., Guppy, Christopher N., Tighe, Matthew K., Moody, Phil and Bell, Mike (2013). Dilute acid extraction is a useful indicator of the supply of slowly available phosphorus in Vertisols. Madison, WI, United States: Soil Science Society of America. doi: 10.2136/sssaj2013.05.0188
Grants (Administered at UQ)
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Quantifying fertiliser phosphorus use efficiency in Vertosols across the Northern Region
(2023–2027) Grains Research & Development Corporation
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Proximal and remote sensing for low-cost soil carbon stock estimation
(2023–2025) Commonwealth Department of Industry, Science, Energy and Resources
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(2022–2025) Cotton Research & Development Corporation
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Assessment of organic phosphorus sources
(2022–2025) Grains Research & Development Corporation
PhD and MPhil Supervision
Current Supervision
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A mechanistic view of how phosphorus and carbon is sequestered in soil organic matter
Doctor Philosophy — Principal Advisor
Other advisors:
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The chemical composition and dynamics of organic amendments to supply phosphorus for improved crop production
Doctor Philosophy — Principal Advisor
Other advisors:
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Contrasting the phosphorus responsiveness of winter pulses and cereals - the role of nitrogen and crop phenology
Doctor Philosophy — Principal Advisor
Other advisors:
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Wheat responses to different sources of nitrogen as affected by phosphorus in the northern grain region of eastern Australia
Doctor Philosophy — Associate Advisor
Other advisors:
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Minimising the impacts of land use on microbially mediated soil ecosystem services
Doctor Philosophy — Associate Advisor
