A review of sulphur fertilizer management for optimum yield and quality of canola in the Canadian Great Plains
Bibliographic record
Abstract
In the Parkland region of the Canadian prairies, Canola (Brassica napus L. or Brassica rapa L.) is an important cash crop. Canola has a high requirement for sulphur (S). However, many soils in this region are deficient or potentially deficient in plant-available S for optimum canola seed yield. Application of sulphate-S at about 15–30 kg S ha-1 is usually sufficient to prevent S deficiency in canola on most of the S-deficient soils. Application of sulphate-S to canola at seeding time gives the highest increase in yield and S uptake. Deficiencies of S in canola plants can be prevented and/or corrected and seed yield improved with the use of sulphate-S fertilizers in the growing season. Application of sulphate-S at bolting can substantially restore seed yield, while an application at early flowering can moderately correct S deficiency damage. Side-banding is the most effective way to apply sulphate-S fertilizers to produce maximum seed yield and to prevent any damage to canola seedlings from seed-row placement. In relatively moist areas, broadcast-incorporation methods can produce seed yield similar to side-banding in most years. Elemental S fertilizers were not effective in increasing seed yield in the year of application, and were generally less effective than sulphate-S fertilizer even after multiyear annual applications, especially when applied in spring. Autumn-applied elemental S was more effective than spring-applied elemental S. Banding delayed availability of elemental S as compared to broadcast application. Use of granular elemental S products is not reliable for optimum seed yield of canola under Canadian prairie conditions on S-deficient soils, particularly in the initial year and with spring application or band placement. Elemental S fertilizers may have a role to maintain or build-up sulphate-S levels in soils marginally low in S where residual benefits are desirable, but management decisions should consider both immediate and long-term effects of S fertilizer on seed yield, seed quality and economics. The findings suggest the need of future research to increase dispersion and distribution of S particles from granules for faster oxidation of elemental S in soil, and to develop elemental S fertilizer products/formulations that can be used on a commercial scale to prevent and/or correct S deficiency in the growing season to optimize seed yield and quality of canola. Research is also required to determine the long-term effects of balanced application of S with other nutrients on soil quality, accumulation and distribution of nitrate-N, sulphate-S and other nutrients in the soil profile, efficiency of nutrient, water and energy use, and crop diseases. More research should be conducted in relation to soil/plant tissue testing issues for optimum seed yield and quality of canola. Key words: Balanced fertilization, canola, elemental S fertilizers, method of application, rate of S, seed quality, seed yield, sulphate-S fertilizers
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.005 | 0.007 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".