Short term nitrogen availability following overwinter cereal/grass and legume cover crop monocultures and mixtures in South Coastal British Columbia
Bibliographic record
Abstract
This 1995 to 1996 study was conducted to determine the effects of cereal/grass and legume cover crop monocultures and mixtures on short term N availability. Cover crop treatments included winter wheat (Triticum aestivum L.), fall rye (Secale cereale L.), annual ryegrass (Lolium multiflorum L.) planted in monoculture and in mixtures with crimson clover (Trifolium incarnatum L.), crimson clover, winter wheat + hairy vetch (Vicia villosa) and bare control. Incubation studies using the cover crop residues were set up for a sixteen week incubation period under field conditions using the in situ resin core method. At the end of the incubation period, total net N release by winter wheat, fall rye, and annual ryegrass ranged from 48 to 80 kg N ha−1 in 1995 and 41 to 92 kg N ha−1 in 1996. Crimson clover mixtures with winter wheat, fall rye, or annual ryegrass had total net N released ranging between 42 to 106 kg N ha−1 in 1995 and 83 to 104 kg N ha−1 in 1996. In contrast, total net N released by winter wheat + hairy vetch was 160 kg N ha−1 in 1995 and 170 kg N ha−1 in 1996. Total net N released by crimson clover was 158 kg N ha−1 in 1995 and 41 kg N ha−1 in 1996. Critical N concentration above which N mineralization occurred was determined as 14.1 g kg−1 and this corresponded to a critical C:N ratio of 31.7. Winter wheat + hairy vetch mixture seems to be more reliable than cereal/grass + crimson clover mixtures in terms of N contribution on decomposition, and legumes in mixtures may reduce the potential for short term N immobilization.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 source (direct Gemma or distilled Codex), 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".