Responses of Acer saccharum canopy trees and saplings to P, K and lime additions under high N deposition
Bibliographic record
Abstract
Heavy atmospheric nitrogen (N) deposition has been associated with altered nutrient cycling, and even N saturation, in forest ecosystems previously thought to be N-limited. This observation has prompted application to such forests of non-N mineral nutrients as a mitigation measure. We examined leaf gas-exchange, leaf chemistry and leaf and shoot morphological responses of Acer saccharum Marsh. saplings and mature trees to experimental additions of non-nitrogenous mineral nutrients (dolomitic lime, phosphorus + potassium (P + K) and lime plus P + K) over 2 years in the Haliburton region of central Ontario, which receives some of the largest annual N inputs in North America. Nutrients were adsorbed in the mineral soil and taken up by A. saccharum trees within 1 year of fertilizer application; however, contrary to expectation, liming had no effect on soil P availability. Saplings and canopy trees showed significant responses to both P + K fertilization and liming, including increased foliar nutrient concentration, leaf size and shoot extension growth; however, no treatment effects on leaf gas-exchange parameters were detected. Increases in shoot extension preceded increases in diameter growth in saplings and canopy trees. Vector analysis of shoot extension growth and nutrient content was consistent with sufficiency of N but marked limitation of P, with co-limitation by calcium (Ca) in saplings and by Ca, Mg and K in canopy trees.
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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) | 0.001 | 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".