Carbon and Microbial Community Dynamics in Saskatchewan Cropland Buried Surface Horizons
Bibliographic record
Abstract
To understand the potential implications of climate change on soil C, it is important to understand the nature of C at depth in the soil profile. Buried surface horizons are formed when soil eroding from hill-tops (e.g., due to intensive tillage) transports and eventually buries the original A horizon in the lower slopes of hills. There is limited research on the nature of C-rich buried surface horizons in Saskatchewan which could hold valuable insights into the stabilization mechanisms and permanence of sub-soil C. The objective of this study was to identify potential microbial and soil organic matter biomarkers that contribute to C stability in buried surface horizons across different cropland soil zones and textures. Soils were collected at footslope positions in five different sites across the Brown, Dark Brown, Black, and Dark Gray soil zones in Saskatchewan, and were determined to have a substantial concentration of organic C in the buried surface horizon. The organic C in the buried surface horizon at all five sites was significantly more resistant to mineralization than the corresponding surface horizon during a 100-day C mineralization incubation experiment. A closer examination of the nature of the organic C using organic matter fractionation found that a decreased proportion of organic C was stored as particulate organic matter in buried surface horizons. Further analyses of the microbial community using PLFA profiling found a less abundant, but unique microbial community in the buried surface horizon compared to the corresponding surface horizon.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.010 | 0.002 |
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".