Speciation of Phosphorus from Agricultural Muck Soils to Stream and Lake Sediments
Bibliographic record
Abstract
The nature and management of agricultural soils can influence the forms of legacy P present in affected sediments; however, few studies have specifically characterized P in sediments affected by polder agriculture. In this study, the speciation of P as it flows from the muck soils of the Holland Marsh to the sediments of the West Holland River and Lake Simcoe, Ontario, Canada, was investigated. The distribution of P fractions and the characterization of organic P were analyzed by the sequential fractionation method and solution 31P nuclear magnetic resonance spectroscopy, respectively. Organic P was the predominant P form (∼58% of total P) in muck soils, whereas the redox‐sensitive P fraction was predominant in surface stream sediments rich in organic matter (∼41–48% of total P), despite these sediments exhibiting near‐neutral pH and high concentrations of both Ca and P. The proportion of relatively recalcitrant organic P forms was much greater in the muck soils than that exhibited by both stream and lake sediments. The decreasing proportion of recalcitrant organic P forms in sediments downstream from the Holland Marsh indicated the potential for faster organic P cycling. Our findings support the notion that diesters and pyrophosphate should be monitored, in addition to loosely bound inorganic P, due to their potential impact on water quality. The unique environment of the streams and lake area is considered to be particularly vulnerable to excessive fertilizer P use in adjacent croplands. Core Ideas The predominant P fraction in muck soil was recalcitrant organic P. The predominant P fraction in organic matter‐rich sediments was redox‐sensitive P. The predominant form of organic P in sediments was labile orthophosphate diesters. Organic P cycles faster in stream sediments than that in muck soils.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| 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".