Belowground to aboveground biomass ratio and vertical root distribution responses of mature<i>Pinus radiata</i>stands to phosphorus fertilization at planting
Bibliographic record
Abstract
We compared the belowground biomass (BGB)/aboveground biomass (AGB) ratio and the vertical root distribution of 40-year-old Pinus radiata D. Don fertilized with 0 or 90 kg P·ha1at planting. Root biomass was determined by a combination of coring (fine roots, ϕ < 2 mm; small roots, 2 ≤ ϕ < 15 mm) and excavation (coarse roots, ϕ ≥ 5 mm). Stand-level AGB and coarse root biomass (CRB) were estimated with the use of allometric relations. After 40 years, AGB and CRB of P-fertilized trees were 4.5 times those of unfertilized trees, indicating that CRB scaled isometrically with AGB independently of P supply. By contrast, P fertilization increased the fine and small root biomass (FSRB) pool by only 50%. As a result, the scaling of FSRB to AGB was dependent on P supply. The differential response of the FSRB to P fertilization caused the overall BGB/AGB ratio to decrease from 0.29 in control plots to 0.20 in P-fertilized plots. Phosphorus fertilization also altered the vertical distribution of fine root biomass (FRB). For example, the proportion of FRB in the top 15 cm increased from 41% to 52% with P fertilization. Collectively, the results showed that P added early in the growth phase had a persistent effect on the BGB/AGB ratio in P. radiata. This was primarily brought about by altered biomass partitioning to the nutrient-acquiring FSRB pool.
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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".