Weather Delays Increase Potential for Top Dressing

Late seeding in many parts of the Prairies this year has more canola growers considering a top dressing application as a way to boost fertility before bolting.

“In order to get crops seeded this year, many growers did not get the chance to use as much fertilizer as they wanted or needed at planting, particularly in Manitoba and parts of eastern Saskatchewan, ” says Canola Council senior agronomy specialist John Mayko.

“If thinking about adding fertility now, a plant tissue test can help identify nutrient deficiencies, as long as samples are collected according to the test lab’s protocols. If a field is well established at or before the 4- to 6 -leaf stage and looks like it has good yield potential, it may be a good candidate for top dressing.”

In Manitoba, the weather over the next few weeks will determine the extent to which denitrification will occur since this process is accelerated with very wet field conditions.

Mayko offers further advice for growers who have identified nutrient deficiencies or good crop potential.

For nitrogen, he advises using dribble-band liquid urea-ammonium nitrate or broadcast granular urea or ammonium sulphate. A nitrogen stabilizer such as Agrotain or N-Serve can reduce volatilization losses, especially with broadcast urea.

For sulphur, Mayko recommends ammonium sulphate or liquid ammonium thio-sulphate.  “Make sure the application equipment is right for the product. For example, fertilizer fines require fixed-boom fertilizer broadcasters rather than spinner-type spreaders.”

Growers are advised to adjust rates based on the nitrogen or sulphur they may have applied this spring, keeping in mind available soil test levels relative to desired yield targets, and the proper balance of available nitrogen to sulphur required by the canola plants, which is a ratio of about 5:1.

For more information, contact:

John Mayko, Senior Agronomy Specialist

780-764-2593

Canola Council