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<title>UTas ePrints - Nitrogen isotope fractionation in the fodder tree tagasaste (Chamaecytisus proliferus) and assessment of N2 fixation inputs in deep sandy soils of Western Australia</title>
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<meta content="Unkovich, M J" name="eprints.creators_name" />
<meta content="Pate, J S" name="eprints.creators_name" />
<meta content="Lefroy, E.C." name="eprints.creators_name" />
<meta content="Arthur, D" name="eprints.creators_name" />
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<meta content="Ted.Lefroy@utas.edu.au" name="eprints.creators_id" />
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<meta content="2008-01-20 22:05:38" name="eprints.datestamp" />
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<meta content=" Nitrogen isotope fractionation in the fodder tree tagasaste (Chamaecytisus proliferus) and assessment of N2 fixation inputs in deep sandy soils of Western Australia" name="eprints.title" />
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<meta content="Nitrogen (N) isotope fractionation and symbiotic N fixation were investigated in the shrub legume tagasaste, growing in the glasshouse and field. In a pot study of effectively nodulated plants supplied with 0, 1, 5 and 10 mM nitrate [stable isotope 15N (δ15N) of 3.45‰], the δ15N of dry matter N of fully symbiotic cultures indicated a greater isotope fractionation during distribution of N between nodules, stems, leaves and roots than for N2 fixation itself, with whole-plant δ15N being near zero (–0.46 to 0.42‰). Regardless of whether plants were field-grown, pot-cultured, fixing N2 or utilising mineral N, woody stems were depleted in 15N relative to all other plant parts. The similar orders of ranking of δ15N for plant components of the nitrate-treated and fully symbiotic plants, and a general increase in δ15N as plants were exposed to increasing concentrations of nitrate, indicated that N isotope fractionation can be accounted for, and thus not undermine 15N natural abundance as means of measuring N2 fixation inputs in tagasaste trees. In pot culture the percentage of plant N derived from the atmosphere (%Ndfa) by symbiotic N2 fixation fell from 85 to 37% when the nitrate supply was increased from 1 to 10 mM, with evidence of nitrate N being preferentially allocated to roots. δ15N natural abundance assessments of N2 fixation of 4-year-old trees of field-grown tagasaste in alley (550 trees ha-1) or plantation (2330 trees ha-1) spacing were undertaken at a study site at Moora, Western Australia, over a 2-year period of shoot regrowth (coppicing). Cumulative N yields and %Ndfa were similar for trees of alley and plantation spacing, with much less coppice N accumulation in the first compared to the second year after cutting. Scaling values from a tree to plot area basis, and using a mean %Ndfa value of 83% for all trees at the site, inputs of fixed N into current biomass plus fallen litter over the 2 years of coppicing were calculated to be 83 kg N ha-1 year-1 for the alley and 390 kg N ha-1 year-1 for the plantation spacing. Although the plantation tagasaste fixed 587 kg N ha-1 in the second year, close to the maximum value reported in the literature for any N2-fixing system, this should not be seen as typical where the trees are used for animal production, since grazing and cutting management will substantially reduce productivity and N2 fixation input." name="eprints.abstract" />
<meta content="1999-09-07" name="eprints.date" />
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<meta content="Unkovich, M J and Pate, J S and Lefroy, E.C. and Arthur, D (1999) Nitrogen isotope fractionation in the fodder tree tagasaste (Chamaecytisus proliferus) and assessment of N2 fixation inputs in deep sandy soils of Western Australia. Australian Journal of Plant Physiology, 27 (10). pp. 921-929. ISSN 1445-4408" name="eprints.citation" />
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<meta content=" Nitrogen isotope fractionation in the fodder tree tagasaste (Chamaecytisus proliferus) and assessment of N2 fixation inputs in deep sandy soils of Western Australia" name="DC.title" />
<meta content="Unkovich, M J" name="DC.creator" />
<meta content="Pate, J S" name="DC.creator" />
<meta content="Lefroy, E.C." name="DC.creator" />
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<meta content="Nitrogen (N) isotope fractionation and symbiotic N fixation were investigated in the shrub legume tagasaste, growing in the glasshouse and field. In a pot study of effectively nodulated plants supplied with 0, 1, 5 and 10 mM nitrate [stable isotope 15N (δ15N) of 3.45‰], the δ15N of dry matter N of fully symbiotic cultures indicated a greater isotope fractionation during distribution of N between nodules, stems, leaves and roots than for N2 fixation itself, with whole-plant δ15N being near zero (–0.46 to 0.42‰). Regardless of whether plants were field-grown, pot-cultured, fixing N2 or utilising mineral N, woody stems were depleted in 15N relative to all other plant parts. The similar orders of ranking of δ15N for plant components of the nitrate-treated and fully symbiotic plants, and a general increase in δ15N as plants were exposed to increasing concentrations of nitrate, indicated that N isotope fractionation can be accounted for, and thus not undermine 15N natural abundance as means of measuring N2 fixation inputs in tagasaste trees. In pot culture the percentage of plant N derived from the atmosphere (%Ndfa) by symbiotic N2 fixation fell from 85 to 37% when the nitrate supply was increased from 1 to 10 mM, with evidence of nitrate N being preferentially allocated to roots. δ15N natural abundance assessments of N2 fixation of 4-year-old trees of field-grown tagasaste in alley (550 trees ha-1) or plantation (2330 trees ha-1) spacing were undertaken at a study site at Moora, Western Australia, over a 2-year period of shoot regrowth (coppicing). Cumulative N yields and %Ndfa were similar for trees of alley and plantation spacing, with much less coppice N accumulation in the first compared to the second year after cutting. Scaling values from a tree to plot area basis, and using a mean %Ndfa value of 83% for all trees at the site, inputs of fixed N into current biomass plus fallen litter over the 2 years of coppicing were calculated to be 83 kg N ha-1 year-1 for the alley and 390 kg N ha-1 year-1 for the plantation spacing. Although the plantation tagasaste fixed 587 kg N ha-1 in the second year, close to the maximum value reported in the literature for any N2-fixing system, this should not be seen as typical where the trees are used for animal production, since grazing and cutting management will substantially reduce productivity and N2 fixation input." name="DC.description" />
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<h1 class="ep_tm_pagetitle">Nitrogen isotope fractionation in the fodder tree tagasaste (Chamaecytisus proliferus) and assessment of N2 fixation inputs in deep sandy soils of Western Australia</h1>
<p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Unkovich, M J</span> and <span class="person_name">Pate, J S</span> and <span class="person_name">Lefroy, E.C.</span> and <span class="person_name">Arthur, D</span> (1999) <xhtml:em>Nitrogen isotope fractionation in the fodder tree tagasaste (Chamaecytisus proliferus) and assessment of N2 fixation inputs in deep sandy soils of Western Australia.</xhtml:em> Australian Journal of Plant Physiology, 27 (10). pp. 921-929. ISSN 1445-4408</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/2718/1/Nitrogen_isotope_fraction.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" border="0" class="ep_doc_icon" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/2718/1/Nitrogen_isotope_fraction.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />141Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input value="3594" name="docid" accept-charset="utf-8" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://www.publish.csiro.au/nid/102/paper/PP99201.htm">http://www.publish.csiro.au/nid/102/paper/PP99201.htm</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">Nitrogen (N) isotope fractionation and symbiotic N fixation were investigated in the shrub legume tagasaste, growing in the glasshouse and field. In a pot study of effectively nodulated plants supplied with 0, 1, 5 and 10 mM nitrate [stable isotope 15N (δ15N) of 3.45‰], the δ15N of dry matter N of fully symbiotic cultures indicated a greater isotope fractionation during distribution of N between nodules, stems, leaves and roots than for N2 fixation itself, with whole-plant δ15N being near zero (–0.46 to 0.42‰). Regardless of whether plants were field-grown, pot-cultured, fixing N2 or utilising mineral N, woody stems were depleted in 15N relative to all other plant parts. The similar orders of ranking of δ15N for plant components of the nitrate-treated and fully symbiotic plants, and a general increase in δ15N as plants were exposed to increasing concentrations of nitrate, indicated that N isotope fractionation can be accounted for, and thus not undermine 15N natural abundance as means of measuring N2 fixation inputs in tagasaste trees. In pot culture the percentage of plant N derived from the atmosphere (%Ndfa) by symbiotic N2 fixation fell from 85 to 37% when the nitrate supply was increased from 1 to 10 mM, with evidence of nitrate N being preferentially allocated to roots. δ15N natural abundance assessments of N2 fixation of 4-year-old trees of field-grown tagasaste in alley (550 trees ha-1) or plantation (2330 trees ha-1) spacing were undertaken at a study site at Moora, Western Australia, over a 2-year period of shoot regrowth (coppicing). Cumulative N yields and %Ndfa were similar for trees of alley and plantation spacing, with much less coppice N accumulation in the first compared to the second year after cutting. Scaling values from a tree to plot area basis, and using a mean %Ndfa value of 83% for all trees at the site, inputs of fixed N into current biomass plus fallen litter over the 2 years of coppicing were calculated to be 83 kg N ha-1 year-1 for the alley and 390 kg N ha-1 year-1 for the plantation spacing. Although the plantation tagasaste fixed 587 kg N ha-1 in the second year, close to the maximum value reported in the literature for any N2-fixing system, this should not be seen as typical where the trees are used for animal production, since grazing and cutting management will substantially reduce productivity and N2 fixation input.</p></div><table style="margin-bottom: 1em" border="0" cellpadding="3" class="not_ep_block"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">agroforestry, soil N cycling, nitrate, 15N natural abundance</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/300800.html">300000 Agricultural, Veterinary and Environmental Sciences > 300800 Environmental Sciences</a></td></tr><tr><th valign="top" class="ep_row">Collections:</th><td valign="top" class="ep_row">UNSPECIFIED</td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">2718</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Ms Mignon J Jolly</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">21 Jan 2008 09:05</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">23 Jan 2008 15:55</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=2718;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=2718">item control page</a></p>
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