Timing and rates of nitrogen fertiliser application on seed yield, quality and nitrogen-use efficiency of canola
Why this work is in the frame
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Bibliographic record
Abstract
Effective management strategies for nitrogen (N) fertiliser are important to ensure optimum seed yields and seed quality of canola (Brassica napus L.) crop production. A field experiment was conducted for 3 years in Ontario, Canada to determine the (i) impact of different rates and timing of application of N fertiliser on canola yield and quality; and (ii) fertiliser-N economy, including agronomic N-use efficiency (aNUE), N-uptake efficiency (NupE), N-utilisation efficiency, partial N balance and N harvest index. Treatments included factorial combinations of six (2011) or eight (2012 and 2013) rates of N as urea (46% N) and timing of application (pre-plant only or preplant plus side-dressed applications at the 6-leaf stage). Side-dressed N application resulted in significant improvements in seed yield and protein concentrations (up to 16%) over equivalent preplant-only applications. The highest seed yield (2700 kg ha–1 in 2011 and 3500 kg ha–1 in 2013) was produced by the treatments including side-dressing: 50 + 50 kg N ha–1 or 50 + 100 kg N ha–1 (preplant + side-dressing). Seed protein concentrations varied from 21% to 23% in 2011 and 2013 and up to 28% in 2012. On average, the sum of protein and oil concentrations was 65–68%. Oil yield increased with increasing N rates in 2011 and 2013, but significant increases were recorded only when N was side-dressed at the 6-leaf stage. Drought conditions in 2012 negated responses to N fertiliser regardless of when it was applied. In general, aNUE and N-utilisation efficiency were decreased with increasing N fertiliser rates, but NupE varied among environments with increasing preplant and side-dressed N application. Side-dressed N applications after preplant application resulted in higher partial N balance, aNUE and/or higher NupE than comparative preplant-only N applications. Overall, side-dressed N application led to improved crop N uptake and better N economy of canola production in eastern Canada.
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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 | 0.001 |
| 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 it