An Agri‐Environmental Phosphorus Saturation Index for Acid Coarse‐Textured Soils
Bibliographic record
Abstract
Abstract Potato (Solanum tuberosum L.) is a high P demanding crop contributing to P saturation of acid coarse‐textured soils. The P status is commonly assessed agronomically by soil testing of P (STP) and environmentally by soil P saturation or P solubility indexes. The aim of this work was to develop a P fertilizer recommendation model integrating P environmental risk and crop response probability, using P and Al extracted by the Mehlich‐III soil testing method (mg P or Al L−1 of soil) and expressed as (P/Al)M‐III percentage. The environmentally critical (P/Al)M‐III percentage was 15%, corresponding to the critical degree of phosphate saturation (DPS) value of 25% (oxalate extraction procedure) proposed in the Netherlands. Using the Cate‐Nelson procedure, the critical (P/Al)M‐III percentage across 78 field experiments was 8.2% as determined by inductively coupled‐argon plasma (ICP). Probability of potato response to P was close to 100% even above the critical STP values as shown by power tests on relative yields. The P recommendation model was computed from conditional expectations of 50 and 80% within each fertility group below 15% as (P/Al)M‐III. Above 15%, the model recommended 21 kg P ha−1, the amount of P exported by a tuber harvest of approximately 42 Mg ha−1. Using conversion equations with 114 soil samples for STP methods, fertility groups built for Quebec acid coarse‐textured soils were found to be comparable with those currently used in the Netherlands and Lower Saxony (Germany). The (P/Al)M‐III percentage provided a reliable and unifying criterion for making environmentally acceptable and agronomically efficient P recommendations for sustainable potato production.
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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 | 0.001 | 0.001 |
| 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".