HRS Wheat Variety Response to N Application Timing and Seeding Rate

Greg Endres, Blaine G. Schatz, and Richard Maine


Text Box: A study was conducted at the Carrington Research Extension Center in 2005 to evaluate agronomic performance of selected hard red spring (HRS) wheat varieties with nitrogen (N) fertilizer application timings and seeding rates. The dryland trial was established with 'Briggs' and ‘Granite’ seeded at 1 and 1.75 million pure live seeds (PLS)/acre (A) on April 28. Both varieties have high-yield potential, but ‘Briggs’ is more susceptible to lodging and has greater tillering potential compared to ‘Granite’.  Soil N level at the 0-2 ft depth was 53 lbs./acre. Nitrogen treatments included: 1) 100 lbs./acre as PPI urea on April 27, 2) 50 lbs./acre as PPI urea on April 27 and 50 lbs./acre as POST UAN (28% liquid N) applied by steam nozzles on June 11at 4-leaf stage, and 3) 100 lbs./acre as POST UAN applied by steam nozzles on June 11 at 4-leaf stage. A total of 0.79 inches of rain was received within three days of  application of the POST N. Folicur at 4 fl oz/A + NIS (Induce) at 0.125% v/v was applied to flowering wheat.


N application timing did not impact seed yield or quality, except protein with PPI N which was 0.5 percentage points higher than POST N (Table 1). Across varieties, established plant stands were 1,190,000 and 1,687,000 plants/A with seeding rates of 1.0 and 1.75 million PLS/acre, respectively (Table 2). Minimal plant lodging occurred in the trial and did not differ between seeding rates.  Grain yield increased 2.7 bu/acre (4.5%) and test weight increased 0.4 lb/bu with the higher seeding rate. However, yield and quality were similar between seeding rates for each variety (data not shown). Variety yield and protein response was similar among N timings but ‘Granite’ test weight improved with PPI or PPI/POST N compared to POST N (Table 3). n