Nitrogen fertilization of trembling aspen seedlings grown on soils of different pH
Bibliographic record
Abstract
Seedlings from three open-pollinated aspen (Populus tremuloides Michx.) families were grown in a greenhouse with four nitrogen (N) sources, each at two N levels and three pH levels. Nitrogen sources were ammonium sulfate ((NH4)2SO4), calcium nitrate (Ca(NO3)2), ammonium nitrate (NH4NO3), and urea ((NH2)2CO); N levels were 50 and 200 mg·L1 (100-mL aliquots three times per week); and pH levels were 5, 6, and 7. Shoot dry mass and leaf area increased with pH in (NH4)2SO4 and (NH2)2CO treatments, but were greatest at pH 6 in the NH4NO3 and Ca(NO3)2 treatments as a result of a pH × N source interaction. N level was directly related to growth, net assimilation, water-use efficiency, and leaf carbon isotope ratio, while N source had no effect on these parameters. Seedlings from families 2 and 3 grew larger than seedlings from family 1, which allocated relatively more dry matter to roots. Growth of the three families interacted with soil pH so that family 1 was largest at pH 7, but families 2 and 3 were largest at pH 6. Seedling boron (B) uptake was reduced by increasing pH and by the Ca(NO3)2 fertilizer. These results were interpreted to show that although the three families seemed well adapted to all the N and pH conditions to which they were exposed, growth could be increased by selection of a fertilizer most suitable to the pH and availability of other nutrients in the soil.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 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".