Nitrogen fertilizer placement for fall and spring seeded <i>Brassica napus</i> canola
Bibliographic record
Abstract
Brassica napus L. canola seeded in the fall (dormant) just prior to freeze-up, or in the early spring as soon as fields are passable, can improve productivity in semiarid regions on the Canadian prairies. The objective of this study was to assess N fertilizer placement options for alternative canola seeding dates. Herbicide-tolerant B. napus canola (cv. Quest) seedling density, phenological development, seed yield, seed weight, oil concentration, and protein concentration were assessed for four N (urea) placement options [banded prior to fall seeding date (only Melfort), broadcast in early-spring, side banded, and seed placed] and three seeding dates (late October, mid- to late April, and mid-May) at Scott and Melfort, SK, Canada. Nitrogen fertilizer placed with the seed often reduced seedling density. At Melfort, seed placed N fertilizer reduced the seed yield (10%), seed oil concentration (4%) and increased protein concentration (5%) of fall and mid-May seeded canola. The other N fertilizer placement options consistently maintained the highest level of canola production for all seeding dates. At Scott, seeding canola in fall or April generally maintained adequate plant stands, and often increased seed yield (43%), seed weight (18%), and oil concentration (5%) , when compared with the mid-May seeding date. Our results indicate that N fertilizer placement considerations used for the more traditional mid-May seeding date should be similar for canola dormant or April seeded. Current N fertilizer placement options, such as side banding, pre-plant banding or early-spring broadcasting, are options that resulted in equivalent crop yield responses. Given the variability in crop yield response measured with seed placement of N, we recommend that this practice should be a voided. Key words: Seeding date, dormant, direct seeding, alternative cropping practice, N fertilizer management
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.000 |
| Open science | 0.001 | 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".