Enhanced Efficiency Urea Sources and Placement Effects on Nitrous Oxide Emissions
Bibliographic record
Abstract
The effects of band placement of enhanced efficiency fertilizers (EEF) on nitrous oxide (N 2 O) emissions are uncertain. Placement and EEF on N 2 O emissions from spring wheat ( Triticum aestivum L.) at two locations in Manitoba, in 2011 and 2012 were examined. Treatments were a no N control and 80 kg N ha −1 at planting of five combinations of placement and granular N source: broadcast‐incorporated urea (Urea I ) and, subsurface side‐banded urea (Urea S ; each row side‐banded), midrow‐banded urea (Urea M ; placement between every other set of rows), midrow‐banded environmentally smart nitrogen (ESN, Agrium, Inc.) (ESN M ), and midrow‐banded SuperU (Koch Industries Inc.) (SuperU M ). Planting in 2011 was delayed 40 d compared to 2012. Planting coincided with higher soil temperature and moisture resulting in three‐ to sevenfold more growing season N 2 O emissions (∑N 2 O) in 2011 than 2012. In 2011, SuperU M and ESN M reduced ∑N 2 O, emission factor (EF) scaled by N‐applied EF, and yield‐scaled N 2 O emission intensity (EI) by 47, 67, and 55%, respectively, compared with Urea I . In 2011, increasing placement concentration of N in order broadcast‐incorporation, side‐banding, and midrow‐banding tended to decrease ∑N 2 O, EF, and EI of granular urea, but not statistically significant. The ∑N 2 O and nitrate exposure (NE), were significantly correlated over the site‐years, indicating N availability from treatments in part determined emissions. Grain yield and crop N uptake were unaffected by sources and placement. These results suggest for early season wet and warm conditions, EEF N sources can reduce emissions compared with granular urea. Further studies are required to clarify placement effects on N 2 O emissions.
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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".