Post Anthesis Nitrogen for Wheat Protein

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.

  1. Apply 30 lb N/ac, which is 10 US gallons of UAN solution (28-0-0) diluted with 10 gallons water
  2. Apply with flat fan nozzles
  3. Apply 7-10 days following anthesis (so about 7-10 days after your fusarium head blight fungicide)
  4. 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.

 

 

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