We’re coming to the end of flowering in canola and nearing an opportunity to add yield with foliar nitrogen. Producers in the UK apply liquid urea at the early pod stage to generate higher oil content and yield. The results have been mixed but in some cases they’ve found a 7 to 9 bu/ac yield increase from a 25 lb/N/ac application using liquid urea solution. I think a quick tissue test for nitrogen at the end of flowering could show you whether nitrogen is limiting in the plant. If there is adequate moisture in the soil profile, a liquid top dress of urea might be a new avenue to explore in our canola production systems.
The majority of producers are using liquid urea instead of liquid UAN (28-0-0) for its lower cost, increased uptake efficiency and reduction in leaf burn. That’s not to say that liquid urea doesn’t burn because it will under high light intensity or temperatures above 18 degrees C. The key to reducing scorch is water volume.
Here's a list of tips used by my UK friend Nick Ward to give you some ideas.
And I've added a couple of points of my own:
Steve's quick math
Let's see what this nitrogen boost could pay back.
25 lbs/ac × $0.69 lb/N: $17.25 ac + $3.50 application = $20.75/ac
50 bu/ac canola yield × 8% × $10.00 bu = $40.00/ac
ROI: 2 to1
In theory, if we were to see the same response as some have in the UK, the additional $20.75 ac investment in top dress nitrogen may net you a 100% return on your investment. I believe there is value in spreading out your nitrogen applications in canola and this might be a way to generate better nitrogen use efficiency rather than applying all of our nitrogen up front which by now is almost 90 days ago. Even a 5% yield increase at today's prices makes this option viable. SL
Chris Decker - 2015-03-16
I agree a very good idea. not to apply all N up front.
Randy Saskiw - 2015-07-19
Tried it for three years in field trials and one trial out of 25 had a positive economic response. Conclusion: W. Canada growing season isn't long enough to see the benefit consistently.