Sulfur Species Formed in the Seed Row of Sulfur‐Fertilized Soils as Revealed by K‐Edge X‐ray Absorption Near‐Edge Structure Spectroscopy
Bibliographic record
Abstract
Core Ideas Knowledge of the S fertilizer reaction products is important for understanding the behavior and efficacy of S fertilizers in soils. Sulfur K‐edge X‐ray absorption near‐edge structure spectroscopy is a useful tool for identifying the soil S species formed following application of different fertilizer forms under field conditions. Knowledge of S fertilizer reaction products following application is needed to predict the ability of different fertilizer forms to provide sufficient plant‐available S to crops. K‐edge X‐ray absorption near‐edge structure (XANES) spectroscopy and wet chemical analysis techniques were used to identify the soil S species formed week to months after fertilization in the field on Brown Chernozem and Black Chernozem soils in Saskatchewan, Canada. The S fertilizer forms were ammonium sulfate, liquid ammonium thiosulfate, gypsum, elemental S, and a zero‐S control treatment. Treatments were applied at seeding at 20 kg S ha −1 . Sulfur as ammonium sulfate, ammonium thiosulfate, and gypsum increased the extractable SO 4 –S in the seed row 1 wk after application; thereafter, it decreased through plant uptake and runoff. For all fertilizers, total S concentration in the seed row increased after application and decreased over time. The XANES results showed that the highly oxidized sulfate form of S was dominant (45–55%) in ammonium sulfate‐ and gypsum‐treated soils 1 wk following application. Thereafter, the proportion as sulfate decreased over time while the reduced and intermediate S forms increased. The proportion of reduced S was highest in the elemental S and ammonium thiosulfate treatments and the proportion in oxidized forms increased from Week 1 to Week 8. Overall, the highly oxidized fertilizer S forms applied (sulfates) transformed to intermediate and reduced S species via immobilization and reduction processes, whereas the highly reduced forms (e.g., elemental S) underwent some oxidation as reduced S decreased and highly oxidized sulfate increased.
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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".