When wheat prices and protein premiums/discounts are high, there is renewed grower interest in late N applications to enhance wheat protein. Following is an old recipe we have recently evaluated in on-farm-tests and small plot studies.
- Apply 30 lb N/ac, which is 10 US gallons of UAN solution (28-0-0) diluted with 10 gallons water
- Apply with flat fan nozzles
- Apply 7-10 days following anthesis (so about 7-10 days after your fusarium head blight fungicide)
- Apply in morning or evening when temperatures are less than 20o C. Avoid heat of the day.
Under such treatments we have observed leaf burn of 8-15% of the leaf area without detrimental impact on yield. The one instance sprayed at mid day in high temperatures reduced yields by 6 bu/ac with 31% leaf damage . Protein increase ranged from 0-1.5% and averages are reported in Table 1.
Table 1. Effect of post anthesis N (PAN) on wheat class yield and protein (2015-16).
| CNHR (6 sites) | CWRS (7 sites) | CPS (2 sites) | |
| Yield bu/ac | |||
| Base N | 80 | 68 | 69 |
| Base N & PAN | 78 | 68 | 65 |
| Protein % | |||
| Base N | 13.0 | 14.2 | 13.8 |
| Base N & PAN | 13.6 | 14.6 | 14.1 |
In most cases, the farmer’s base rate of N was high at 150-200 lb N/ac (soil N plus fertilizer), so the extra N was not required for high protein.
The full on-farm-test report is available from the Manitoba Wheat and Barley Growers Association at: http://www.mbwheatandbarley.ca/wp-content/uploads/2014/11/OFT-summary-2017-FINAL.pdf
If attempting such a practice, leave a check strip – not so much for yield determination, but to gauge the success in protein increase.