Performance Story: Increasing wheat protein with post-emergent applications of UAN vs. dissolved urea
In 2019 and 2020, trials were established at 8 AgriARM locations across Saskatchewan to demonstrate the potential of increasing either wheat yield or grain protein with late-season applications of N in the form of UAN or dissolved urea. All late-season applications of UAN were applied at 30 lb N/ac to a base rate of 70 lb N/ac of side-banded urea. Applications of dissolved urea were only applied at 25 lb N/ac due to a calculation error. Earlier dribble band applications of UAN at the boot stage caused less flag leaf burn compared to post-anthesis applications. Using less concentrated forms of UAN was not necessary to reduce leaf burn when dribble banding at either stage. When applying post-anthesis, dribble banding UAN caused significantly less flag leaf burn compared to a broadcast spray which caused the most damage of any treatment. Leaf injury from broadcast spraying was substantially reduced when using dissolved urea instead of UAN. While this phenomenon is supported by the past study, the lower rate of N with the dissolved urea in this study would also contribute to greater crop safety.
In general, split applications of N were able to raise the grain protein relative to applying all the N at seeding but they also tended to result in less yield. An increase in protein content with the reduction in yield was less pronounced with the boot stage timing compared to the post-anthesis timing. Economically, split applications did not prove to be economical because the value of the protein increases was negated by the associated yield losses even when assuming a healthy protein spread of $0.6/%/bu. This was true whether considering all site/years combined, the top 8 yielding sites combined, or the lowest 8 yielding sites combined. In other words, the benefit of split applications was not more economical for a high-yielding crop compared to a low yield crop when assuming the same protein spread.
Results from this study were also presented by Mike Hall in YouTube videos, and links are provided below.
· SaskWheat Youtube:
o Getting the Most Out of Nitrogen (94 views) (https://www.youtube.com/watch?v=dxYlADUsZUE)
· ECRF/Parkland College Youtube:
o Virtual tour: In-season applications of UAN vs dissolved urea for increasing wheat protein (132 views) https://www.youtube.com/watch?v=8wfGDz2E5aw
o Getting the Most out of Nitrogen (328 views) https://www.youtube.com/watch?v=GYLLviErfFM&t=1s
o UAN vs Dissolved Urea for Increasing Wheat Grain Protein (Video was released March 8, 2021 https://www.youtube.com/watch?v=tpD9DiRi5yI
· WARC- Crop Opportunity Seminar (March 3rd 2021-144 in attendance)
o Video for this presentation was released on the ECRF/Parkland College Youtube site March 8, 2021 https://www.youtube.com/watch?v=yWeQ8ckoKEY
o Video may also be available from the WARC site.