Effects of organic compounds, water content and clay on the water repellency of a model sandy soil
Bibliographic record
Abstract
Abstract Soil water repellency is related to organic matter and clay, and varies non-linearly with soil water content. The purpose of this study is to assess the combined effects of organic compounds, water content and clays on water repellency of a model sandy soil under wetting and drying processes. Hydrophobic stearic acid and hydrophilic glucomannan were used as the organic compounds, and kaolinite or montmorillonite was used as the clay conditioner. Water repellency was estimated using the water drop penetration time test. Repellency did not appear in samples free of stearic acid. Samples containing both stearic acid and glucomannan showed higher repellency compared with samples containing stearic acid alone during the wetting process. Glucomannan with stearic acid increased the critical water content and widened the range of water content at which soils showed slight repellency. During the wetting process, the repellency of most samples increased with increasing water content under relative humidity conditions ranging from 33 to 94%. During the drying process, repellency appeared, reached a maximum and then decreased in samples containing stearic acid. Maximum repellency was observed not at oven-dried but at air-dried water content. Repellency was highly sensitive to water content at around air-dried condition. The effects of organic compounds and clay on the water repellency of sandy soils were negligible in oven-dried condition. Repellency tended to increase with the addition of a small amount of clay (1–2%) as a dry mix during the wetting process. Once wetted, repellency disappeared with the addition of montmorillonite, but not with kaolinite. The higher the kaolinite content, the higher the critical water content.
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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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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".