Establishment of the Critical Limit of Soil-Available Phosphorous for Maize Production in Low Acidic Ultisols of West Africa
Bibliographic record
Abstract
The relationship between yields and the Bray I–extractable phosphorous (P) was studied on a 21-year-old experiment with maize (Zea mays) in an acid Ultisol of West Africa. Chemical fertilizer alone decreased soil organic carbon and increased soil acidity. The applications of cattle manure maintained the highest level of soil organic carbon, and soil acidity did not decrease. The extractable P varied from 4 mg kg–1 (original soil) to 25 mg P ha–1 in fertilized treatments. A linear correlation (P < 0.01; r = 0.85) was found between soil extractable P and maize yields. Each unit increase in soil extractable P tallied with 16% of yield increase. A critical limit of soil extractable P of 15.6 mg P kg–1 was identified. Below this limit, maize produced less than 2500 kg ha–1, 80% of the maximum yield. Responses to P fertilizer were not expected above this limit.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.003 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".