Influence of Temperature on Water‐Extractable Organic Matter and Ammonium Production in Mineral Soils
Bibliographic record
Abstract
Cold (room temperature) and hot water (70–80°C) extraction methods have been used to assess the availability of organic matter and N in soil; however, the influence of temperature on their extractability is largely unknown. Twenty‐one mineral soils from New Zealand and eastern Canada were incubated for 16 h in water (1:6 soil/water ratio) at temperatures ranging from 20 to 80°C. After centrifugation and removal of the supernatant solution, the soil residue was extracted with 2 mol L −1 KCl to recover NH 4 –N released during incubation. In all cases, water‐extractable organic C (WEOC) and N (WEON) increased exponentially with temperature. The temperature dependence of organic matter solubility differed considerably among the soils (estimated increase in WEOC and WEON: 1.1–5.3% °C −1 ). These differences were not explained by management history or soil physicochemical properties, although there was evidence that organic matter extractability in some clay soils was less sensitive to temperature. Ammonium N was released in significant amounts at all temperatures. Peak NH 4 –N release typically occurred at 50°C, where NH 4 –N comprised an average of 49% of the total recovered N (WEON plus NH 4 –N). Factors that may account for NH 4 –N production during the 16‐h incubation include mineralization at the lower temperatures and abiotic processes (e.g., release of clay‐fixed NH 4 and thermal degradation of organic N) at higher temperatures. The possibility that mineralization made a significant contribution to NH 4 –N production at temperatures as high as 50°C warrants further investigation.
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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 | 0.001 | 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".