Rapid redistribution of P to deeper soil layers in P saturated acid sandy soils
Bibliographic record
Abstract
Abstract Problems of excessive soil phosphorus (P) levels as a result of intensive agriculture are found in many regions in Western Europe, USA, Canada and New Zealand. This may lead to phosphorus leaching in soils with low P binding capacity. However, little is known about the changes in P saturation degree (PSD) of such soils with time. Between 1995 and 2005, an intensive inventory of the PSD status of acid sandy soils in Flanders was conducted, the results of which were used to enforce strict rules on P fertilizer inputs on P saturated soils. A new smaller survey on a selection of these fields was undertaken in 2009 and 2010. Comparison of the survey results shows that the mean PSD increased significantly from 46 to 59% over this period. We found evidence for a strong shift of the PSD from the upper to lower layers. The PSD level in the top layer (0–30 cm) generally increased significantly ( P < 0.01) from 83 to 91%. The average increase in the PSD level of the 30–60 and 60–90 cm layers was even greater, from 33 to 55% and from 14 to 25%, respectively ( P < 0.01). Current limits on P fertilizer application have not yet resulted in P mining in these soils and will thus need to be further restricted. The very clear increase in PSD movement in deeper layers from both increased P ox , and reduced Fe ox concentrations show that these high PSD soils pose a very serious and direct threat to groundwater quality.
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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 | 0.000 | 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".