Bibliographic record
Abstract
A soil chronosequence near Cox Bay, on the west coast of Vancouver Island, British Columbia, was investigated and verified. Soils in the sequence are developed in sandy beach deposits, which were found to aggrade toward the ocean at a rate of 0.26 m per year. Dendrochronology and geomorphic evidence established surface ages for seven selected pedons (sites 1 to 7) across these deposits, that ranged from 127 years at site 1 to 550 years at site 7. Soil classification ranged from an Orthic Dystric Brunisol (Typic Udipsamment) to an Orthic Humo-Ferric Podzol (Aquic Haplorthod) in thes sites, respectively. A variety of soil weathering characteristics, identified by wet-chemical, physical and optical techniques, were used to demonstrate that the soils along this transect have developed in a manner which is compatible with the presumed genesis of Podzols (Spodosols). A 0.17% increase in B horizon, oxalate extractable Al and a 0.22 meq/100 g decrease in C horizon, exchangeable Mg along this transect were plotted with site age to exemplify soil weathering chronofunctions. Soxhlet procedures were developed to artificially weather Cox Bay chronosequence soil materials, in the laboratory. Site 1, C3 horizon soil samples were leached with distilled water in soxhlets containing O₂, N₂, CO₂ and air atmospheres. The CO₂-water system clearly produced allitic weathering trends, whereas, a total elemental balance approach and more intense leaching were required to further interpret the weathering characteristies created by the other atmospheres. Problems of sample erosion and leachate contamination indicated a need for alterations in the design of the commercially available soxhlet. Modifications made, by reducing the height (A) or completely removing (B) the soxhlet siphon tube, rectified these problems and showed promise in simulating pedogenic processes. Acetic acid (0.3 M) was used to leach 220 g samples of the site 1, C3 horizon soil in A-modified soxhlets. High (4.3 litres per day) and low (2.2 litres per day) leaching rates produced 13 106 and 4 750 mg of precipitate, respectively, which accumulated in the leachates during an eight week experiment. Rates of removal of elements from the soil samples were in the order of Ca > Mg > Fe > K > Al > Na > Si for the low leaching rate and Ca > K > Mg > Al > Fe > Na > Si for the high leaching rate. These results are compatible with a podzolic weathering process. Acetic acid and both A- and B-modified soxhlets were used to weather chronosequence soil samples over 4, 8, 12, 20 and 24 week periods. Chemical changes in the resultant weathered products were evaluated. Ca and Mg decreases in the samples from both types of soxhlet were plotted against weathering time and statistically-derived, exponential functions were used to explain the resultant curves. The similarity between these laboratory chronofunctions and the field chronofunctions, derived earlier, was noted. Calcium-bound phosphate (PCa) and Ca chronofunctions from both field and soxhlet weathered soils were compared mathematically. By comparing the slopes of statistically-generated equations, both the A- a B-modified soxhlets were calibrated to pedogenic time. B-modified soxhlets closely simulated the chronosequence weathering and produced consistent calibration results. Statistically-based chronofunctions predicted that 100 years of pedogenic weathering of PCa required 7.4 weeks of B-modified soxhlet weathering. This compared well with the 5.5 weeks predicted for a similar loss of Ca. A- and B-modified soxhlets were presented as valuable pedologic tools for simulating soil weathering in the Cox Bay soil chronosequence.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| 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 | 0.000 | 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 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".