Long‐Term Changes in Soil Carbon under Different Fertilizer, Manure, and Rotation
Bibliographic record
Abstract
Soil C contents can be raised by land use practices in which rates of C input exceed those of C oxidation. Rates of C inputs to soil can be raised by continuous cropping, especially with perennial legumes, and by soil amendments, especially manure. We have summarized our understanding of the processes by which changes in soil C content are determined by rates of soil C input in the mathematical model ecosys We compared model output for changes in soil C with those measured in a Gray Luvisol (Typic Cryoboralf) at Breton, Alberta, during 70 yr of a 2‐yr wheat ( Triticum aestivum L.)–fallow rotation vs. a 5‐yr wheat–oat ( Avena sativa L.)–barley ( Hordeum vulgare L.)–forage–forage rotation with unamended, fertilized, and manured treatments. Model results indicated that rates of C input in the 2‐yr rotation were inadequate to maintain soil C in the upper 0.15 m of the soil profile unless manure was added, but that those in the 5‐yr rotation were more than adequate. Consequent changes of soil C in the model were corroborated by declines of 14 and 7 g C m −2 yr −1 measured in the control and fertilized treatments of the 2‐yr rotation; by gains of 7 g C m −2 yr −1 measured in the manured treatment of the 2‐yr rotation; and by gains of 4, 14, and 28 g C m −2 yr −1 measured in the control, fertilized, and manured treatments of the 5‐yr rotation. Model results indicated that soil C below 0.15 m declined in all treatments of both rotations, but more so in the 2‐yr than in the 5‐yr rotation. These declines were corroborated by lower soil C contents measured between 0.15 and 0.40 m after 70 yr in the 2‐ vs. 5‐yr rotation. Land use practices that favor C storage appear to interact positively with each other, so that gains in soil C under one such practice are greater when it is combined with other such practices.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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".