The form and fate of stubble phosphorus in cropping soils

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dc.contributor.authorNoack, S.
dc.contributor.authorMcLaughlin, M.
dc.contributor.authorSmernik, R.
dc.contributor.authorMcBeath, T.
dc.contributor.authorArmstrong, R.
dc.contributor.conference16th Agronomy Conference 2012: Capturing Opportunities and Overcoming Obstacles in Australian Agronomy (14 Oct 2012 - 18 Oct 2012 : Armidale, NSW)
dc.contributor.editorYunusa, I.
dc.date.issued2012
dc.description.abstractPhosphorus (P) within stubble can be released directly to soil as soluble P or assimilated by microorganisms and subsequently released back into the soil through mineralisation. The chemical composition of P in crop stubble may play an important role in the rate of stubble P release. Crop stubble sampled after grain maturity in 2010/11 and 2011/12 contained 1-5 kg P/ha. Nuclear magnetic resonance (NMR) spectroscopy was used to determine the different forms of P present in the stubble. On average 50% of the total stubble P was orthophosphate which is water soluble and readily available to plants and microorganisms. The remaining P forms were identified as phospholipids, ribonucleic acid (RNA) and pyrophosphate. The majority (65-90%) of P in the major stubble component (stems) was water-soluble, and most of this was detected as orthophosphate. However, this includes organic P forms that may have been hydrolysed during the water extraction. Results from a field leaching experiment show between 0 and 7.5% of stubble P was released from 52 mm (collected after 11 mm and 41.4 mm) of summer rainfall. That indicated crop stubbles in the field release some P into soil solution which could be readily accessed by plant roots. However, the slower release of stubble P in the field compared to the laboratory suggests that residues potentially play a more important role as a long term P supply to subsequent crops. Subsequent experimentation will measure the contribution of surface applied and incorporated stubble P to crop plant P nutrition using 33P isotopic techniques.
dc.description.statementofresponsibilitySarah Noack, Mike McLaughlin, Ronald Smernik, Therese McBeath, and Roger Armstrong
dc.identifier.citationProceedings of 16th Australian Agronomy Conference 2012, 2012 / Yunusa, I. (ed./s), pp.1-6
dc.identifier.orcidMcLaughlin, M. [0000-0001-6796-4144]
dc.identifier.urihttp://hdl.handle.net/2440/94944
dc.language.isoen
dc.publisherRegional Institute Online Publishing
dc.rightsCopyright status unknown
dc.source.urihttp://www.regional.org.au/au/asa/2012/nutrition/8326_noacksr.htm
dc.subjectCrop residues
dc.subjectspeciation
dc.subjectnutrient cycling
dc.titleThe form and fate of stubble phosphorus in cropping soils
dc.typeConference paper
pubs.publication-statusPublished

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