Assessment of N<sub>2</sub> fixation by understorey acacias in recurrently burnt eucalypt forests of subtropical Australia using <sup>15</sup>N isotope dilution techniques
Bibliographic record
Abstract
The N2 fixation by understorey acacias in repeatedly burnt dry and wet sclerophyll forest sites in subtropical Australia was assessed using 15N isotope dilution techniques. In the first study, aboveground parts of established acacias and nonlegume reference plants at the two sites were collected from plots subjected to varying fire frequencies for measurements of 15N natural abundance (<$Q150E00000010446D80BFFEFF88A45505A9A1C8282ADCC6210090483DA6ED4F658F80>15N). The <$Q150E00000010446D80BFFEFF88A45505A9A1C8282ADCC6210090483DA6ED4F658F80>15N values of acacias and nonlegumes were similar, and substantial variation in these <$Q150E00000010446D80BFFEFF88A45505A9A1C8282ADCC6210090483DA6ED4F658F80>15N values precluded any evaluation of N2 fixation. In the second study, 15N enrichment method was used to examine N2 fixation of acacia seedlings grown for 5 months in glasshouse pots of top 10-cm soils collected from the fire plots at the two sites. In Acacia leiocalyx (Domin) Pedley at the dry site, whole plant percent N derived from the atmosphere (%Ndfa) was 25% in unburnt soil, 66% in periodically burnt soil, and 42% in annually burnt soil (referenceAlphitonia excelsa (Cunn. ex Fenzl) Reisseck ex Benth.), compared with 33, 69, and 66%, respectively (reference Corymbia variegata (Hook.) K.D. Hill & L.A.S. Johnson). In Acacia oshanesii F. Muell. & Maiden at the wet site, whole plant %Ndfa was 9% in unburnt soil, 41% in quadrennially burnt soil, and 50% in biennially burnt soil (reference Dodonaea triquetra Andr.), compared with -4, 26, and 55%, respectively (reference Eucalyptus pilularis Sm.).
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".