Winter wheat response to nitrogen fertilizer form and placement in southern Alberta
Bibliographic record
Abstract
The recommended method for N fertilization to winter wheat (Triticum aestivum L.) on the Canadian prairies has been to broadcast ammonium nitrate (AN) during early spring. In the Chinook region of southern Alberta, considerable interest exists in alternative formulations (particularly urea), times of application and placements. To determine the effect of alternative N fertilizer practices on winter wheat in southern Alberta, two field experiments were conducted over 2 consecutive years (1998-1999 and 1999-2000) at three locations. In the first experiment, fall applications of urea or coated urea, seed-placed or banded, were compared to the standard practice of spring-broadcast AN. At five of six sites, there was no difference between fall-banded urea and coated urea in plant stand, grain yield or protein concentrations when compared to spring-broadcast AN. In 1998-1999, fall-banded urea reduced grain yield by 13% at the site in the Brown soil. Seed-placed N was only safe for urea at 30 kg N ha-1 and for coated urea at rates up to 60 kg N ha-1. In the second experiment, urea and coated urea were broadcast in spring for comparison with AN. Coated urea was ineffective in dry years due to poor N release. Urea was equally effective as AN in this study, possibly due to the cool, dry conditions at the time of application and the relatively low surface soil pH levels at these reduced tillage sites. Further research will be required to confirm the effectiveness of this practice for this region. Key words: Ammonium nitrate, urea, coated urea, nitrogen fertilizer placement, nitrogen timing, grain protein
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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 | 0.000 | 0.000 |
| 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".