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Selected Publication:
MCNEILL, AM; HOOD, RC; WOOD, M.
(1994):
DIRECT MEASUREMENT OF NITROGEN-FIXATION BY TRIFOLIUM-REPENS L AND ALNUS-GLUTINOSA L USING N-15(2)
J EXP BOT. 1994; 45(275): 749-755.
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- Abstract:
- A closed-system flow-through enclosure apparatus was used to measure symbiotic nitrogen fixation directly. A legume-based system comprising 6-week-old Trifolium repens L. (white clover cv. Blanca) growing with Lolium perenne L. (perennial ryegrass cv. Trani) in an agricultural soil was incubated for 19 d in a N-15-enriched atmosphere (mean value 3.663 atom%). An actinorhizal-based system comprising 1-year-old Alnus glutinosa L. (alder) saplings growing with Festuca rubra L. (red fescue) in open-cast coal spoil was incubated for 21 d in a N-15-enriched atmosphere (mean value 3.265 atom%). Indirect estimates of N-2 fixation were carried out concurrently using N difference and N-15 isotope dilution techniques. The theory underlying the three techniques and modifications which were adopted for comparative purposes are discussed. The direct measurements of N-2 fixation were then compared with the indirect estimates using P-inc, the proportion of the N increment during the measurement period that was derived from fixation. The simple N difference method gave similar values for P-inc (0.94 and 0.97) as those derived from more complicated isotope methodologies, both indirect (0.91) and direct (0.90). Values for alder were far more variable, ranging from 0.16 to 0.92; this was due largely to variability within the trees and a very small N increment during the measurement period.
- Authors BOKU Wien:
- Hood-Nowotny Rebecca
- Find related publications in this database (Keywords)
- N-2 FIXATION
- N-15(2)
- WHITE CLOVER
- ALDER
- ENCLOSURE APPARATUS
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