C : N ratios and carbon distribution profile across rooting zones in oilseed and pulse crops
Bibliographic record
Abstract
Knowledge on the C : N ratio of crop residues is of great importance for modelling carbon (C) and nitrogen (N) dynamics of agricultural systems. This study determined (i) the C : N ratios in the seed, straw, and roots of selected broadleaf crops and (ii) the root C and N distribution in the 0–100 cm rooting zone. Three oilseed (Brassica napus canola, Brassica juncea mustard, Linum usitatissimum flax), three pulse crops (Cicer arietinum chickpea, Pisum sativum dry pea, Lens culinaris lentil), and spring wheat (Triticum aestivum L.) were grown under field conditions with low- (rainfall only) and high-water (rainfall plus irrigation) availability. Root C mass decreased substantially with rooting depth, with ~58% of root C mass in the top 20 cm of the soil, 78% in the top 40 cm, and 94% in the top 60 cm. Significant differences in root C mass between crop species occurred in the top 20 cm with canola, mustard, and wheat allocating 66% of their root C total, compared with 55% for dry pea, lentil, and flax, and 41% for chickpea. Root N mass followed a similar response to root C. Seed C : N ratios ranged between 6 and 17, whereas straw C : N ranged between 14 and 55, and root C : N between 17 and 75. Under low-water conditions, canola and mustard had a straw C : N of 33, lower than that of flax (38) and wheat (41). Under higher-water availability, however, mustard and wheat had straw C : N ratios at 55, greater than canola, mustard and flax (47). Three pulses had an average straw C : N ratio of 17, significantly lower than 41 for the oilseeds and 32 for wheat. On average, canola, mustard and wheat had greater root C : N ratios (44) than chickpea (33) and lentil (29), with dry pea having a smallest root C : N ratio (18). Root C : N ratios did not change with soil depth. These detailed measurements on the vertical distribution of root C and N as well as C : N ratios for various crops will assist in improving estimates of inputs for C and N cycling studies.
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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 | 0.000 | 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 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".