Cadmium Accumulation in Wheat and Potato from Phosphate and Waste-Derived Zinc Fertilizers
Bibliographic record
Abstract
Phosphate and zinc fertilizer sources greatly vary in cadmium concentration, depending on the fertilizer raw material source and processing. Washington state has adopted Canadian guidelines for maximum allowable metal loading rates from fertilizers. Fertilizer screening rates are application rates established to determine potential metal loading rates in WA. Screening rates of 196 kg P 2 O 5 /ha and 8.4 kg Zn/ha were defined by 1998 Fertilizer Regulation Act. A 2-y field experiment was conducted to determine effects of some P and Zn fertilizers, applied at and above WA fertilizer screening rates, on wheat and potato Cd. An irrigated sandy soil was treated with 4 P sources, ranging from 49 to 780 mg Cd/kg P, and 1 waste derived Zn source. All sources applied at the WA screening rate maintained Cd levels at or below 0.05 mg Cd/kg fw for potato tubers and 0.1 mg Cd/kg dw for wheat grain. However, excessive triple super phosphate (TSP) applications over two years (1568 and 3156 kg P 2 O 5 /ha) exceeded 0.01 mg Cd/kg in wheat grain. In potato, 784 and 1568 kg P 2 O 5 /ha rates of TSP in both years and Western diammonium phosphate (WDAP) applied at 392 kg P 2 O 5 /ha over two years approached or exceeded 0.05 mg Cd/kg fw tuber. Overall, the current WA regulations on fertilizer Cd loading appear to be adequate at the established screening rates. Growers should be advised to adhere to agronomic rates to minimize metal loading.
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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".