Evidence of the need for crop-specific N2O emission factors
Bibliographic record
Abstract
Crop residues are an important source of N for subsequent crops and contribute to cropping system nitrous oxide (N 2 O) emissions. Oilseed residues, particularly canola ( Brassica napus L.), can instigate higher N 2 O emissions compared to pulse and wheat crop residues but the reason for this disproportionate emission response is unknown. To determine the quantity and source of N 2 O emissions, we conducted an incubation experiment (84 d) using 15 N and 13 C labelled residues of canola, wheat, flax, pea and investigated key N-cycling gene abundances, microbial abundance and community structure using PLFA and soil C and N dynamics. Residue addition of all types significantly increased microbial abundance and abundances of denitrification and nitrification genes. Canola residue resulted in significantly greater nosZI abundance. Lower incorporation of canola residue 13 C into PLFA and higher 13 CO 2 emissions suggests that canola residue C was used less efficiently (i.e., less for growth and more for respiration), depleting O 2 and stimulating denitrification. The magnitude of N 2 O emission from residue-amended soils was significantly higher ( p < 0.05) than the unamended control soil and differed with residue type: canola > pea = wheat > flax > control. The canola residue emission factor was 1.56% of residue N – significantly higher than that of wheat (0.99%), pea (0.95%) and flax (0.18%). This higher canola emission factor resulted from greater residue-derived (1.47%) N 2 O as well as residue-induced (0.65%) soil emissions. The combined use of stable isotope tracing of 15 N 2 O and 13 CO 2 and microbial characterization quantified differences in residue-derived N 2 O emissions from common crops that were linked to differences in microbial abundance, community structure and activity. • Carbon and nitrogen in crop residues are important substrates for microbial metabolism. • Canola, pea, wheat and flax residues shape microbial abundance and activity differently. • Crop residue N is a source of N 2 O and can stimulate N 2 O emission from soil N pools. • Enhanced N 2 O emissions from canola related to microbial activity more than community structure. • Soil N 2 O emission highest in canola and lowest in flax (1.6–0.2 % of residue N).
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".