With warm soils, good stand establishment and generally good moisture in many canola growing areas in Western Canada, growers may wonder if they’ve applied enough fertilizer to meet the yield potential of the crop. Nitrogen and sulphur are effectively applied as a top-dress. The best method is to dribble on fertilizer in a concentrated band rather than as a spray mist. Tank mixing with the herbicide, while it may be possible if the herbicide manufacturer approves, will not allow high enough rates to make any useful difference to the crop. The fine mist may also damage the crop.
In some cases, a little ammonium sulphate can correct antagonism cause by hard water ions in spray water and improve herbicide results, but the rate of ammonium sulphate will have a minimal fertility benefit.
We will talk more about fertilizer top-dress timing, rates and techniques next week. In the meantime, if you do plan to top-dress, this may be a good time to order product and get the top-dress equipment ready to go.