Sulfur Availability on Lodgepole Pine Sites in British Columbia
Bibliographic record
Abstract
Growth response of lodgepole pine ( Pinus contorta Dougl.ex. Loud var. latifolia Engelm.ex S. wats.) to N fertilization is limited by insufficient S on certain sites in British Columbia. This study was conducted to document differences in soil and foliar S fractions between sites with either adequate or insufficient S as determined by foliar nutrient data and growth response information obtained from previously established fertilization research trials with N and N + S application, and to examine relationships among soil S fractions, foliar S status, and growth response to N fertilization. Mineral soil total S concentrations were very low (∼65 mg kg −1 ) at both S‐sufficient and S‐deficient sites, and were not different between the sites. Soluble inorganic SO 4 concentration was significantly greater in B horizon soil at the S‐sufficient sites than at the S‐deficient sites. Soluble inorganic SO 4 was significantly and positively correlated with organic SO 4 ( r 2 = 0.24; P = 0.03) and organic C ( r 2 = 0.76; P < 0.001). Foliar SO 4 ‐S was significantly greater at the S‐sufficient sites, and was significantly and positively correlated with B‐horizon soluble inorganic SO 4 ( r 2 = 0.84; P < 0.001), organic SO 4 ( r 2 = 0.46; P = 0.032), and organic C ( r 2 = 0.72; P = 0.002). The highest R 2 for a regression model between soil or foliar properties and response to N fertilization was for a model containing foliar N, foliar SO 4 ‐S, and B horizon organic C ( R 2 = 0.81; P = 0.004). Cycling of soluble inorganic SO 4 through organic SO 4 in mineral soil appears to be the process limiting S availability on S‐deficient sites. Organic SO 4 and soluble inorganic SO 4 concentrations at the S‐sufficient sites are maintaining foliar SO 4 ‐S at levels required for response to N fertilization.
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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 | 0.001 | 0.002 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".