Canola needs 0.6 to 0.8 pounds of sulphur per bushel of yield — or 30 to 40 pounds for a 50-bushel crop. To make up for high variability of soil sulphur reserves across a field, growers will often apply 20 pounds or so of actual sulphur for canola each year.
Sulphur does not provide a pop up effect, so seed-row placement is not necessary. Some sulphur could go in the seed row, but pay attention to safe seed-placed rates. Ammonium sulphate can have a damaging effect on the seedlings, both from the nitrogen and sulphur components. You’re likely also applying ammonium phosphate in the seed row, so note the limit on how much nitrogen can be safely added to the seed row blend.
Know the analysis of the seed-placed sulphur product. Are you applying enough sulphur while also being mindful of seed-placed fertilizer rates? If you are using elemental sulphur in the seed row, this component may not break down in time to be useful to the crop in the year of application. Elemental sulphur applied on a regular basis will contribute to sulphur reserves and eventually increase soil reserves of available sulphur.
Short sulphur supply? Some reports suggest sulphur fertilizer supplies may be limited in some areas this spring. If growers have trouble getting all the sulphur they need prior to seeding, divide what you have across all your canola acres, then top up with an in-crop application of ammonium sulphate.