Ammonium-N persistence and root nitrogen content of annual crops and perennial forage grasses following pig manure application
Bibliographic record
Abstract
Studies have shown that significant amounts of nitrate-N is leached beyond root zones of annual crops while small amounts of nitrate-N is leached beyond the root zones of perennial forage grasses. This study investigated short-term ammonium-N persistence and root nitrogen content of annual crop and perennial forage grasses following application of pig manure to a sandy loam soil at Carman, Manitoba. Results showed that ammonium-N in liquid pig manure (LPM) amended treatment peaked four days after manure application (DAM) in perennial cropping system (PCS; 50 - 74 kg ha-1) and annual cropping system (ACS; 18 - 29 kg ha-1) in 2014 and 2015. Ammonium-N persisted up to 7 DAM in LPM amended PCS, but did not persist beyond 4 DAM in LPM amended ACS. Ammonium-N measured in solid pig manure (SPM) amended ACS and PCS was low throughout the sampling days in both years. There was a greater percentage increase in accumulation of nitrate-N at 15 - 30 cm soil depth of LPM and SPM amended ACS than PCS. In both years, dry weight below-ground plant biomass ranged from 5,258 to 9,627 kg ha-1 at 0 - 60 cm depth in PCS while that of ACS ranged from 1,088 to 1,456 kg ha-1. Also, root N content in PCS ranged from 43 to 118 kg N ha-1 in both years while that of ACS ranged from 9 to 20 kg N ha-1. In conclusion, ammonium-N persisted longer in PCS than ACS in the short-term and total plant N was greater in PCS than ACS. Greater total plant N in PCS than ACS was mainly due to its greater root N content rather than above-ground N uptake. The order of magnitude of the difference in root N content (34 to 98 kg N ha-1) between ACS and PCS was sufficient to account for the 20 to 60 kg N/ha of nitrate-N leached in ACS in previous study at the same site.
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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".