Relationship between Phosphorus and Nitrogen Concentrations in Spring Wheat
Bibliographic record
Abstract
Efficient management of P in crop production requires the development of tools to quantify the P status of plants. Our objectives were to establish the relationship between P and N concentrations of spring milling wheat ( Triticum aestivum L.) during the growing season and, in particular, to determine the critical P concentration required to diagnose P deficiency. Shoot biomass and P and N concentrations were determined weekly and grain yield was measured at harvest in an experiment with four to six N rates conducted over 2 yr (2004 and 2005) at three sites with adequate soil P for growth each year. Both shoot P and N concentrations decreased with time as shoot biomass increased during the growing season. They also increased with N fertilization, suggesting that they are closely related. The relationship between shoot P and N concentrations under nonlimiting N conditions is described by a linear function ( P = 0.94 + 0.107 N, R 2 = 0.59, P < 0.001; n = 76) in which concentrations are expressed in g kg −1 dry matter (DM). Under limiting N conditions (relative grain yield <0.80), the relationship was different ( P = 1.70 + 0.092 N ( R 2 = 0.48; P < 0.001; n = 19) with greater P concentrations for a given N concentration. These relationships approximate the critical P concentration under both nonlimiting and severely limiting N conditions. This critical P concentration can then be used to quantify the degree of P deficiency during the current growing season.
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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 | 0.000 | 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) | 0.000 | 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".