Long‐term Movement of a Chloride Tracer under Transient, Semi‐Arid Conditions
Bibliographic record
Abstract
Understanding the magnitude and variability of water and solute fluxes in the vadose zone is required to assess the risk of potential contamination of ground water resources. In this study, the long‐term (>30 yr) movement of a Cl tracer applied to the soil surface is quantified. In 1966, granular KCl was applied to the surface of nine 6 by 90 m plots at a field site near Saskatoon, Saskatchewan. Additional KCl was applied to two of the plots in 1970. Application rates varied between 0.11 to 2.24 kg KCl m −2 Moment analysis was used to calculate the mean travel depth ( E [ z ]) and variance ( V [ z ]) of depth breakthrough curves compiled from soil samples taken 1, 2, 3, 4, 28, and 34 yr after the initial KCl application from the 2.24‐kg KCl m −2 plot. Spatial variability of Cl transport was assessed on 51 cores taken along a 10‐m transect, 34 yr after application. Initial movement of the tracer through the root zone was relatively quick ( E [ z ] = 1.34 m, 4 yr after application), followed by slow movement ( E [ z ] = 1.68 m, 34 yr after application). The change in E [ z ] between 4 and 34 yr after application was used to calculate a velocity below the root zone of 11 mm yr −1 and a deep drainage estimate of 3 mm yr −1 (θ = 0.3) which is within the range of other estimates for the Canadian Prairies. Variability in E [ z ] along the 10‐m transect, after 34 yr of transport was low (coefficient of variation [CV] = 4%), suggesting relatively uniform deep drainage. This contrasts sharply with the high variation in convective fluxes measured in other steady‐state high‐flow field‐tracer experiments.
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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 | 0.001 | 0.003 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".