Objective:                   

To evaluate nitrogen use response of spring wheat varieties on yield and quality.

Methods:                    

Eight spring wheat cultivars, including four soft white and four hard red, were grown under five nitrogen (N) levels as a split plot, randomized complete block design with four replications. The N levels represent the whole plot factor and the eight spring wheat varieties were the sub plot factor. The five N treatments included an unfertilized check, 40, 80, 120, and 160 lbs/A added N. The check had an initial 98 lbs/A soil N. The resulting total N of the five treatments were 98 (check), 138, 178, 218, and 258 total lbs N per acre. Supplemental irrigation was applied to keep soil moisture from falling below 50% of the plant available water. Total irrigation applied was 5.7”.

Summary:

N treatment was significant for protein and recorded a maximum protein response at 138 total N/A (Figure 1). Protein ranged from 10.45 percent for UI-Stone to 16.30 percent for Egan (Figure2, Table 2). All other agronomic traits showed no significant difference for N treatment (Table 2). Note that the check (no added N) had high initial N content.  Yield and other traits were significant for the variety main effect. On average, yield of soft whites were higher than hard reds (Figure 3). Within hard red market class, Egan yield was significantly depressed from McNeal, but equivalent with Solano and Vida. Egan consistently had high protein. Refer to Table 3 for yield response - bushels produced per lb of N.

 

Table 1: Material and Methods   
Seeding Date: 4/21/2016 Herbicide:  5/17/2016
Julian Date: 112 Huskie 11 fl oz/A + Axial 16. fl oz/A
Seeding Rate: 25 plnts/sqft Fungicide:  6/23/2016
Previous Crop: Alfalfa 8.2 fl oz/A Prosaro
Tillage: Conventional Insecticide:  6/27/2016
Irrigation: Yes 1.92 fl oz/A Warrior II
Soil Type: Fine sandy loam Harvest Date: 8/25/2016
Soil Test: 57-10-95 Julian Date:  238 
Fertilizer: (_)-63-148

 

 

A bar graph showing the mean protein response of irrigated wheat with total nitrogen on an irrigated fine sandy loam soil.

Figure 1.

Mean protein response of irrigated wheat with total nitrogen (N) on an irrigated fine sandy loam soil. Same letter assignment denotes nonsignificance at α =0.05.

 

Bar graph showing the mean variety protein response of soft white spring wheat and hard red spring wheat

Figure 2.

Mean variety protein response of soft white spring wheat (SWSW) and hard red spring wheat (HRSW). Same letter assignment denotes nonsignificance at α = 0.05.

 

Bar graph showing the mean yield response of soft white spring wheat and hard red spring wheat

Figure 3.

Mean yield response of soft white spring wheat (SWSW) and hard red spring wheat (HRSW). Same letter assignment denotes nonsignificance at α = 0.05.

 

Table 2. Nitrogen effects on irrigated spring wheat agronomic performance         
 Cultivar HT LOD YLD PRO TWT TKW FN PM MC
in % bu/A % lb/bu g sec days %
98 lbs/A Nitrogen (no added fertilizer)        
Alpowa 35.0 7.5 137.9 11.15 64.3 43.5 377 100 10.9
Alturas 36.8 5.0 155.8 10.75 63.4 42.7 295 103 10.9
Penewawa 35.5 2.5 133.1 10.95 63.6 42.1 331 99 10.8
UI-Stone 34.5 0.0 143.8 10.45 63.2 42.3 308 100 11.0
Egan 37.8 0.0 125.2 15.38 62.5 43.0 489 99 10.5
McNeal 37.3 0.0 121.8 14.08 63.3 45.7 487 102 10.7
Solano 28.3 0.0 127.6 15.15 63.8 39.3 398 102 10.9
Vida 34.0 1.3 131.1 14.13 63.1 42.2 355 103 11.1
138 lbs/A Nitrogen        
Alpowa 35.0 25.0 128.1 11.55 64.0 43.3 341 102 11.2
Alturas 38.0 0.0 139.4 10.98 63.1 41.5 289 103 11.0
Penewawa 35.0 7.5 128.6 11.30 63.2 41.2 329 100 10.9
UI-Stone 34.0 20.0 141.8 10.85 62.8 41.9 255 102 11.1
Egan 35.8 10.0 121.9 16.30 62.2 42.1 478 101 10.7
McNeal 39.0 12.5 131.6 14.48 63.4 45.7 464 102 10.9
Solano 30.0 0.0 127.9 15.35 63.6 44.9 407 103 11.4
Vida 36.0 7.5 123.8 14.33 62.8 42.3 347 104 11.9
178 lbs/A Nitrogen        
Alpowa 35.8 2.5 131.8 11.90 64.2 43.8 357 101 11.0
Alturas 37.3 5.0 139.3 11.00 63.3 41.8 277 103 11.1
Penewawa 35.0 10.0 130.8 11.40 63.5 41.5 307 102 10.9
UI-Stone 33.5 25.0 146.9 10.85 63.0 41.0 291 101 11.4
Egan 36.8 0.0 109.5 16.40 62.4 42.0 491 101 10.7
McNeal 37.0 1.3 130.1 14.83 63.3 45.0 492 102 10.8
Solano 28.5 0.0 113.7 15.85 63.6 46.0 400 103 10.9
Vida 34.5 1.3 127.0 14.83 62.9 42.3 346 102 11.5
218 lbs/A Nitrogen        
Alpowa 34.5 17.5 133.6 11.68 64.2 44.1 360 100 10.9
Alturas 37.0 12.5 140.0 10.85 63.2 42.0 282 102 11.1
Penewawa 33.5 5.0 118.0 11.20 63.2 42.7 328 101 10.8
UI-Stone 34.5 1.3 141.7 10.65 62.9 42.0 301 99 10.8
Egan 38.8 0.0 127.0 16.28 62.4 42.0 477 100 10.6
McNeal 39.3 0.0 128.1 14.73 63.3 46.1 440 102 10.9
Solano 29.3 0.0 127.0 15.50 63.6 45.5 396 102 11.4
Vida 35.0 0.0 138.3 14.53 62.8 41.6 344 104 11.9
258 lbs/A Nitrogen        
Alpowa 35.5 5.0 123.5 11.83 64.1 45.2 346 102 11.2
Alturas 37.5 10.0 137.2 11.10 63.3 42.6 274 103 11.1
Penewawa 34.5 27.5 133.5 11.50 63.0 42.8 299 101 11.0
UI-Stone 34.3 17.5 120.2 10.70 62.9 39.6 291 101 11.1
Egan 37.0 2.5 127.5 16.28 62.4 40.0 461 101 10.7
McNeal 37.8 2.5 135.5 14.95 63.3 46.4 473 103 11.2
Solano 29.8 0.0 119.7 15.73 63.3 44.7 383 105 11.6
Vida 34.3 25.0 124.5 13.70 62.4 41.5 348 105 11.9
LSD ns ns ns 0.50 ns ns ns ns ns
Pr>F(0.05) - N 0.8506 0.6023 0.6953 0.0441 0.3877 0.8374 0.3642 0.6523 0.1937
Pr>F(0.05) - Var <.0001 0.0266 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001 <.0001
Pr>F(0.05) - N x Var 0.6691 0.2489 0.1062 0.7361 0.8687 0.0041 0.2922 0.4980 0.0853
HT: height, LOD: lodging, MC: moisture content, PM: physiological maturity, YLD: yield, PRO: protein, TWT: test weight, TKW: thousand kernel weight, FN: falling number, V: variety.         

 

Table 2. Nitrogen productivity (Bushels per lb N) of irrigated soft white spring wheat (SWSW) and hard red spring wheat (HRSW)     
Variety  98 138 178 218 258
 Total N (lbs/A)   
SWSW   
Alpowa 1.34 0.95 0.74 0.60 0.51
Alturas 1.45 1.03 0.80 0.65 0.55
Penewawa 1.31 0.93 0.72 0.59 0.50
UI-Stone 1.42 1.01 0.78 0.64 0.54
Average 1.38 0.98 0.76 0.62 0.52
HRSW   
Egan 1.25 0.89 0.69 0.56 0.47
McNeal 1.32 0.94 0.73 0.59 0.50
Solano 1.26 0.89 0.69 0.57 0.48
Vida 1.32 0.93 0.72 0.59 0.50
Average 1.29 0.91 0.71 0.58 0.49