Broccoli residue-derived nitrogen immobilization following amendments of organic carbon: An incubation study
Bibliographic record
Abstract
Congreves, K. A., Voroney, R. P., O'Halloran, I. P. and Van Eerd, L. L. 2013. Broccoli residue-derived nitrogen immobilization following amendments of organic carbon: An incubation study. Can. J. Soil Sci. 93: 23–31. Cole crops, compared with many other crops, can pose a high risk of N losses after harvest due to substantial quantities of readily mineralizable N in crop residues. Organic C amendments (OCA) may reduce N losses via immobilization; however, the synchrony of OCA decomposition and cole crop residue N mineralization is crucial. A soil incubation study evaluated net N and C mineralization of broccoli residue-derived N or fertilizer-derived N with three OCAs: wheat straw, yard waste, or used cooking oil, to predict N immobilization and the potential to mitigate post-harvest N losses. By the 56th d of incubation, broccoli residue mineralized 67.0 mg N kg−1. In the broccoli residue-derived N treatments, wheat straw, yard waste, and used cooking oil significantly reduced the quantity of net N mineralization by 16.9, 12.3, and 86.0 mg N kg−1, respectively. The net N mineralization data were fitted to a first-order exponential model, and the overall trend of OCA was negative, indicating immobilization, whether N was derived from broccoli residue or fertilizer. The order of effect from OCAs on N immobilization corresponded to the order of effect on net C mineralization, where wheat straw and yard waste were lower than used cooking oil. In broccoli residue treatments, compared with fertilizer, higher N immobilization occurred for used cooking oil, and higher net C mineralization occurred for used cooking oil and yard waste. The higher N immobilization and net C mineralization suggest that broccoli residue produced a synergistic effect on the decomposition of used cooking oil. Additionally, both broccoli residue and used cooking oil treatments had synchronous peaks of net C mineralization at 4 d. This study provides evidence to warrant field studies to confirm that the application of organic C, especially used cooking oil, after cole crop harvest may be a beneficial management practice to minimize soil N losses.
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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 | 0.001 |
| 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".