Copper, zinc, and cadmium accumulation in two prairie soils and crops as influenced by repeated applications of manure
Bibliographic record
Abstract
Abstract A study was conducted to determine the effect of repeated (5–7 y) annual application of liquid swine or solid cattle manure on the plant availability of copper (Cu), zinc (Zn), and cadmium (Cd) at two field sites in the W‐central and E‐central agricultural regions of Saskatchewan, Canada. Soil samples, plant‐straw and grain samples from the 2003 growing season were collected and analyzed for total Cu, Zn, and Cd concentrations using nitric acid microwave digestion followed by atomic‐absorption spectroscopy. An ammonium bicarbonate diethylenetriaminepentaacetic acid (AB‐DTPA) extraction was performed on the soil samples as a measure of the plant‐available fraction. Crop plants that were tested included wheat ( Triticum aestivum L.) and barley ( Hordeum vulgare L.). The results of this study indicated that long‐term repeated applications of manure fertilizer sometimes resulted in increased plant availability of Cu, Zn, and Cd, as reflected in increased concentrations of the plant‐available metal observed both in the soil and plant tissue. In the case of Cu and Zn, these increases were related to the rate of application, as the manure is a source of Cu and Zn. Changes in soil conditions from repeated manure application, including a decrease in pH and stimulated plant‐root growth can explain the effect that both manure and urea‐fertilizer application had on increasing the Cd concentration in the plant. Overall, there does not appear to be any concern about soil metal loading and plant accumulation in these soils after 5–7 y of manure application, as soil and plant concentrations were well below the allowable limits.
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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".