Response of trembling and hybrid aspens to phosphorus and sulfur fertilization in a Gray Luvisol: growth and nutrient uptake
Bibliographic record
Abstract
A greenhouse experiment was conducted to investigate the effects of P and S fertilization on the growth and nutrition of two aspens, a clonal aspen (Populus tremuloides Michx.) and a hybrid aspen (a mixture of Populus tremu loides × P. tremula L. and Populus tremula × P. tremuloides), grown in a Gray Luvisol fertilized with N. Phosphorus application significantly increased basal diameter (BD) increment and most other growth parameters for both clonal and hybrid aspens, whereas S application increased BD increment only for the hybrid aspen. Diameter increment, leaf area, and seedling biomass were generally increased by P application, regardless of S levels, but they responded to S application only if P was also applied. Phosphorus application significantly increased foliar P concentrations and foliar N and P contents and their uptake for the clonal aspen. For the hybrid aspen, P application increased foliar N, P, and S concentrations, contents, and uptake. Sulfur application significantly increased foliar S concentration, content, and uptake for the hybrid aspen but not foliar N concentration, content, and uptake for the clonal aspen. Except for height increment, growth parameters were significantly related to foliar percent P and N/P ratios and percent S and N/S ratios. It can be concluded that both P and S were deficient, but P was more limiting after potential N limitation was removed.
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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".