On‐Farm Assessment of the Amount and Timing of Nitrogen Fertilizer on Ammonia Volatilization
Why this work is in the frame
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Bibliographic record
Abstract
Ammonia (NH 3 ) volatilization is one of the main pathways through which applied N enters the environment undesirably. A seven site‐year on‐farm field experiment was performed for 3 yr at Ottawa, ON, and 2 yr at Guelph, ON, and Saint‐Valentin, QC, Canada. Our objectives were to (i) quantify the flux and the amount of NH 3 volatilization as affected by the rate and time of N fertilizer; (ii) assess the impact of rainfall and soil temperatures on NH 3 volatilization; and (iii) determine the threshold level of N fertilizer at which large NH 3 volatilization losses occur. Using the static chamber method, NH 3 volatilization was monitored after preplant or sidedress N application. Rate of NH 3 volatilization peaked at 3 to 7 d and then dropped sharply within next 7 d before leveling off in the following weeks. The amount of NH 3 volatilization increased with increasing N levels applied preplant or sidedress at all site‐years. Peak NH 3 volatilization ranged from 40 to 8000 g N ha −1 d −1 after preplant fertilization and from about 100 to 2100 g N ha −1 d −1 after sidedress, resulting in NH 3 losses of 0.1 to 47 kg N ha −1 and 0.6 to 20 kg N ha −1 , respectively, equivalent to 0.1 to 38% and 0.3 to 13% of fertilizer‐induced emission (FIE) within 28 d after preplant or sidedress N fertilization. Our data clearly indicate that sidedress applications enable reduction in N fertilizer for economic crop yields, and may reduce losses simply due to lower total N rates.
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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 | 0.000 |
| 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 it