Influence of formulation of elemental S fertilizer on yield, quality and S uptake of canola seed
Bibliographic record
Abstract
The rate of S oxidation in elemental S fertilizers to plant-available sulphate-S depends on factors that affect microbial activity, such as soil moisture, temperature, aeration and size of fertilizer granules. Three field experiments were conducted on S-deficient Gray and Dark Gray Luvisol soils (Typic Cryoboralf) during 2000 and 2001 in Saskatchewan (exp. 1 at Porcupine Plain and exp. 3 at Canwood) and Alberta (exp. 2 at Legal) to determine the effects of formulation of elemental S fertilizers on yield, oil, protein and S concentration, S uptake, percent recovery of applied S and N uptake in seed of canola (Brassica napus L. ‘A4573’ at Porcupine Plain and ‘Invigor 2663’ at Legal and Canwood). In exp. 1 (2000 and 2001) and exp. 2 (2000), treatments included five elemental S fertilizers (granular ES-99, ES-95, ES-90 and Biosul-90; and Biosul-50 suspension), granular potassium sulphate and zero-S control. In exp. 3, treatments included eight elemental S fertilizers (granular ES-99, ES-95, ES-90 and Biosul-90; powder Lab fine ES-99.5, ES Settle-47 and ES SPB571-85.8; and Biosul-50 suspension), 21.7% elemental S plus 18.7% sulphate-S (Agrium Plus), blend of granular ES-90 and ammonium sulphate (1:1), granular ammonium sulphate and zero-S control. The S fertilizers were surface-broadcast or sprayed at 15 and 30 kg S ha-1 rates within 2–3 d after sowing in spring. Canola plants in the zero-S treatment showed S deficiency in the growing season, and seed yield increased with sulphate-S fertilizer by 21.8, 1.4, and 3.6 times in exps. 1, 2, and 3, respectively. There was little effect of S fertilizer on protein concentration in seed. Biosul-50 suspension in all experiments and powder forms of elemental S fertilizers, used only in exp. 3, were almost as effective as sulphate-S fertilizers. In all experiments, granular elemental S fertilizers had no or only a very small effect on yield, S uptake, percent recovery of applied S, N uptake, oil concentration, S concentration and protein concentration of canola seed in the first year of application. In the second year of exp. 1, granular elemental S fertilizers tended to increase yield, S uptake, N uptake, oil concentration, and S concentration of canola seed, but none of them produced seed yield or improved other parameters of canola seed comparable with the sulphate-S and elemental S powder or suspension fertilizers. In summary, granular elemental S fertilizers were not effective in increasing canola seed yield and S uptake on S-deficient soils in the first year of application. After the second annual application, most granular elemental S fertilizers tended to correct deficiency of S in canola plants, but improvements in yield and other parameters of seed were still less than the sulphate-S and suspension or powder forms of elemental S fertilizers. Key words: Canola, elemental and sulphate S fertilizers, granular, suspension, oil and protein content, seed yield, S uptake
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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 | 0.001 |
| 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 | 0.001 | 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".