Investigation\nof Soil Legacy Phosphorus Transformation\nin Long-Term Agricultural Fields Using Sequential Fractionation, P\nK‑edge XANES and Solution P NMR Spectroscopy
Bibliographic record
Abstract
Understanding legacy phosphorus (P)\nbuild-up and draw-down from\nlong-term fertilization is essential for effective P management. Using\nreplicated plots from Saskatchewan, Canada, with P fertilization from\n1967 to 1995 followed by either P fertilization or P cessation (1995–2010),\nsoil P was characterized in surface and subsurface layers using sequential\nfractionation, P K-edge X-ray absorption near-edge structure (XANES)\nand solution 31P nuclear magnetic resonance (P NMR) spectroscopy.\nLegacy P from a 28-year build-up was sufficient for 15 years of wheat\ncultivation, resulting in no significant differences in crop yield\nin 2010. In surface soils, soil test (Olsen) P decreased significantly\nin unfertilized plots compared with 1995, which was reflected in declining\naluminum (hydr)oxide-associated inorganic P by fractionation and XANES.\nFurthermore, XANES analysis revealed a decrease of calcium-associated\nP in 2010-unfertilized soils at both depths and an increase of Fe\n(hydr)oxides-associated P in the 2010-fertilized and -unfertilized\nsurface soils relative to the 1995 soils. Increased total organic\nP and orthophosphate diesters by P NMR and accumulated inositol hexaphosphate\nby XANES were observed in surface soils with P fertilization cessation.\nIn subsurface soils, few legacy P transformations were detected. These\nresults provide important information about legacy P to improve agricultural\nsustainability while mitigating water quality deterioration.
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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) | 0.000 | 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".