Initial responses of phosphorus biogeochemistry to calcium addition in a northern hardwood forest ecosystem
Bibliographic record
Abstract
We measured changes in P pools and cycling 1 year after a Ca fertilization treatment at the Hubbard Brook Experimental Forest in central New Hampshire. We hypothesized that by increasing soil pH and available Ca, the treatment would change the amount of readily available P in the forest floor and the biogeochemical cycling of P in the forest ecosystem. One year after the Ca addition, significant increases occurred in soil pH (one pH unit), resin-sorbed P (2- to over 10-fold), and the microbial respiratory quotient (27%) in the Oe horizon of the treated watershed compared with a reference watershed. Additionally, we observed significant increases in foliar P concentrations (20133% across six species) and in P retranslocation in the treated watershed between pre- and post-Ca-addition years (p < 0.05). Foliar P was strongly correlated (r = 0.74) with resin-sorbed P. Microbial biomass P, microbial C to P ratios, and available organic and inorganic P fractions were lower in the Oe horizon of the treatment watershed than in the reference watershed, but no differences were observed in soil solution or fine root P concentration. Apparently, by changing soil pH, Ca addition increased rates of P cycling in forest floor horizons at Hubbard Brook Experimental Forest.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 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".