Modified rothamsted carbon model for andosols and its validation: changing humus decomposition rate constant with pyrophosphate-extractable Al
Bibliographic record
Abstract
We modified the Rothamsted carbon model (RothC) to adopt it to Andosols. We changed the decomposition rate constant of the humus (HUM) pool because the presence of Al-humus complexes in Andosols gives HUM strong stability. In addition, the inert organic matter (IOM) pool was set at zero, because the soil did not contain carbon when it was formed from fresh volcanic ash. H(f) was defined as the factor required to divide the decomposition rate constant of the HUM pool so that the modelled soil organic carbon (SOC) level matched the measured level. H(f) was calculated for 32 Japanese Andosols, and the relationships between H(f) and soil properties such as contents of acid-oxalate-extractable Al, Fe, and Si (Mo, Feo, and Sio) or pyrophosphate-extractable Al (Alp) were analysed. The equation H(f) =1.20 + 2,50Alp(% ), (r 2 = 0.518) was selected to divide the decomposition rate constant of HUM. The modified model was tested for four long-term experimental data sets on Andosols under various climatic conditions, soil textures, and management techniques from north to south across Japan. We obtained considerably improved fits between the contents of modelled and measured SOC by using the modified RothC instead of the original model. Use of this modified model may contribute to the improvement of the performance of existing SOC2 models in modelling Andosols. It can be used for estimating CO2 emission from soils, as well as for planning suitable organic matter management in Japanese Andosols.
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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 | 0.002 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.003 | 0.000 |
| Research integrity | 0.002 | 0.001 |
| 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".