Contributions of carbonates to soil CO2 emissions
Bibliographic record
Abstract
Ramnarine, R., Wagner-Riddle, C., Dunfield, K. E. and Voroney, R. P. 2012. Contributions of carbonates to soil CO 2 emissions. Can. J. Soil Sci. 92: 599-607. Carbon dioxide (CO2) is released in soil as a by-product of microbial and root respiration, but soil carbonates may also be a source of CO2 emissions in calcareous soils. Global estimates of inorganic carbon range from 700 to 900 Pg as carbonates stored in soils, representing a significant potential source of CO2 to the atmosphere. While previous studies have focused on the total CO2 efflux from the soil, our goal was to identify the various sources and their contribution to total CO2 emissions, by measuring the isotopic signature of the CO2 emitted from the soil. Calcareous Luvisolic silt loam soil samples were obtained from conventional tillage (CT) and no-tillage (NT) plots in southern Ontario, Canada. Soil samples (root- and residue-free) were laboratory-incubated for 14 d and the isotopic signature of the CO2 (δ13CCO2) released was analyzed using isotope ratio mass spectrometry. Isotopic measurement was essential in quantifying the abiotic CO2 production from carbonates, due to the unique δ13C signature of carbonates and soil organic matter. A two-end member mixing model was used to estimate the proportion of CO2 evolved from soil carbonates and soil organic matter decomposition. Analysis of emitted CO2 collected after the 14-d incubation indicate that the proportion of CO2 originating from soil inorganic carbon was 62 to 74% for CT soil samples, and 64 to 80% for NT soil samples. Further work is recommended in the quantification of CO2 emissions from calcareous soils, and to determine the transferability of laboratory results to field 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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| 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 | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".