Allometry, nitrogen status, and carbon stable isotope composition of<i>Pinus ponderosa</i>seedlings in two growing media with contrasting nursery irrigation regimes
Bibliographic record
Abstract
Nursery irrigation regimes that recharged container capacity when target volumetric water content reached 72%, 58%, and 44% (by volume) influenced Pinus ponderosa Douglas ex Lawson & C. Lawson growth more than either a 1:1 (by volume) Sphagnum peat – vermiculite (PV) or a 7:3 (by volume) Sphagnum peat – sawdust (PS) medium. Exponential fertilization avoided confounding irrigation and fertilization. Temporary nitrogen (N) immobilization in PS caused transient allometric differences prior to hardening. Subsequent release of immobilized N during the onset of hardening, when daily N flux decreased from 4.2% to 1.6%, allowed PS seedlings to avoid foliar N dilution experienced by PV seedlings. Media yielded seedlings with similar final morphological characteristics, although PS seedlings had improved N status. At onset, particle density and volumetric water content were similar for both media, but PS held about 10% more water than PV at all water potentials at experiment conclusion. Exposure to the driest water content (44%) decreased seedling growth and root N status compared with cohorts that were provided ample moisture (72%). Despite maximum tissue heterogeneity within samples and regardless of irrigation regime, seedlings became 1.3‰ more depleted of13C as the growing season progressed. Refinement of sampling procedures, with focus on ontogenetics, may improve subsequent use of stable carbon isotopes in nursery research.
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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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".