Effect of fertilizer nitrogen management on N<sub>2</sub>O emissions in commercial corn fields
Bibliographic record
Abstract
This study examined the effect of rate and time of fertilizer N application to corn on N 2 O emissions in 2 yr on commercial corn fields. All treatments received starter fertilizer at 45 and 59 kg N ha -1 in 2004 and 2005, respectively, similar to grower practice. Treatments included a control, with no additional fertilizer N application, 75 or 150 kg N ha -1 banded at sidedress or 150 kg N ha -1 broadcast at emergence. There was no significant effect of N fertility treatment on corn grain or silage yield, indicating that all N applications were at or in excess of crop N requirement. Delay of fertilizer application to sidedress and reduced fertil izer N application were effective in reducing nitrate intensity, an index of soil nitrate availability calculated as the summation of daily soil NO 3 − -N concentration for the 0- to 15-cm depth. However, there was no significant effect of N fertility treatment on cumulative N 2 O emissions, and nitrate intensity explained a small proportion of the variation in cumulative N 2 O emissions. This study provides evidence that improved fertilizer N management may not result in reduced N 2 O emissions under some conditions. Key words: Zea mays, nitrate, denitrification, carbon availability, soil aeration
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| 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".