Planting Date and Nitrogen Effects on Grain Yield and Protein Content of Spring Wheat
Bibliographic record
Abstract
ABSTRACT High grain yield with adequate protein concentration is an important goal for spring wheat (Triticum aestivum L.) production. A field experiment conducted at two sites representing sandy loam and clay loam soils in Ottawa during 2003 and 2004 examined the effects of planting date and nitrogen (N) management on grain yield and grain protein concentration (GPC) in spring wheat. Cultivar AC Brio was planted at three dates at about 10 d intervals starting from the last week of April. Five N treatments were 0, 60, and 100 kg N ha−1 applied as preplant, 60+40 (preplant + topdress at boot stage), and 60 + 40 kg N ha−1 (preplant + foliar spray at boot stage). Both planting date and N had significant effects on grain yield and GPC. When planting was delayed beyond mid‐May, grain yield was reduced by 15 to 45% in three out of four site‐years. However, GPC increased by 6 to 17% in all late planting dates than the early plantings. Grain yields were increased with N application, but there was no benefit due to split N application as topdress or foliar spray than a single application at 100 kg N ha−1 Regardless of application method, GPC was greater with 100 kg N ha−1 than with 0 or 60 kg ha−1, and GPC was more responsive to applied N in a sandy loam soil than in the clay loam soil. Results of this study suggest that it is likely to achieve the target GPC in spring wheat without a significant reduction in grain yield if wheat is planted before the middle of May, especially in clay loam soil.
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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 | 0.000 | 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".