XANES Speciation of Phosphorus in Organically Amended and Fertilized Vertisol and Mollisol
Bibliographic record
Abstract
Knowledge of the dominant P species present in the soil following the application of organic amendments and fertilizer is important in understanding the fate of P in the environment. This study was performed to identify P species in two calcareous soils, an Osborne series (Typic Humicryert) and a Lakeland series (Typic Calciudoll), treated with organic amendments (biosolids and hog and dairy cattle manure) and fertilizer (monoammonium phosphate, MAP). Phosphorus 1s x‐ray absorption near‐edge structure (XANES) spectroscopy was used to speciate P compounds in these amended soils. The result showed that “adsorbed P” was the dominant P species in both soils. For the Osborne soil, the unamended soil (control) and those amended with biosolids and MAP contained an appreciable amount of hydroxyapatite (HAP), the most thermodynamically favored Ca phosphate. In addition, soils amended with biosolids or hog or dairy manures contain β‐tricalcium phosphate (TRICAL), a more soluble form of Ca phosphate than HAP. The amended Lakeland soils contained a variety of species in addition to the dominant “adsorbed P.” While TRICAL was found in all the amended soils except in that amended with hog manure, HAP was present in appreciable amount only in the unamended soil. Overall, the adsorbed P, most likely through inner‐sphere complexation, in these amended soils may not be readily available as a source of P into the environment. In addition, the HAP and TRICAL will have limited solubility, and thus, are probably only a very minor source of P in the environment.
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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".