Season Foliar N Application Effects on Grain Yield Parameters of Hard Red Winter Wheat Varieties (16796).

A. Bly, H. Woodard, and D. Winther

Introduction:

Applications of foliar N on wheat have been shown to increase grain protein. However increases in grain protein are not consistent. Individual winter wheat varieties may respond differently to a foliar application of N. The objective of this experiment was to investigate the effect of a late season foliar N application on grain test weight, protein, and yield of hard red winter wheat (HRWW) varieties.

Methods:

An experiment site was selected at the Crop Improvement Association farm at Aurora SD.  Plot dimensions were 5' wide and 35' long and no
till planted into alfalfa sod at a seeding rate of 1.2 million pure live seeds/a on September 14, 1995.  At planting, 50 Ibs/a P205 as 0
0 was applied with the seed.  Composite soil samples were taken throughout the Fall and Spring for monitoring N levels.  Nitrogen from the desiccated and decaying alfalfa sod had a good potential for supplying adequate levels of N for wheat growth and yield.  No soil N was applied due to soil test results which showed adequate levels of N for a 50 bu/a yield.  The treatment comparisons were a control with no foliar N, and foliar N applied at post anthesis (Feeke's stage 10.53).  The foliar N application consisted of 30 Ibs/a N which was applied as a 1:1 solution of 28
0 (UAN):water and sprayed at a rate of 20 gpa with a commercial sprayer protected with a hood to prevent drift. Treatment plots were replicated four times for each HRWW variety and randomized within replications.  A tankmix of Hoelon (2.66 pts/a), Buctril (1 pt/a), and MCP Ester (1.25 oz/a) was applied on June 4, 1996 to control grass and broadleaf weeds.  The post anthesis foliar application was applied June 28, 1996.  Plots were harvested on August 9, 1996 with a small plot combine.  Grain samples were used to measure test weight, protein, and yield.  Treatments were statistically compared by SAS.

Results and Discussion:

ANOVA indicated a significant variety and foliar N treatment effect on grain test weight, protein, and yield (Table 1).  The variety and treatment interaction significantly influenced only grain yield.  Grain test weight and protein was not influenced by variety and treatment interaction.  Grain test weight, protein, and yield variety differences are expected due to genetic differences between the varieties.  Application of foliar N significantly increased grain test weight and protein when averaged over all varieties.  Foliar N did reduce overall grain yield but not significantly.

Due to the influence of varieties to the response of a foliar N application a second ANOVA was performed for each variety.  Most varieties showed a significant grain protein response to foliar N application (Table 2). Longhorn and Dawn varieties did not show significant grain protein increases, but were very close to the Pr>F at .10 level which was chosen to indicate significance. Grain protein increase was quite different between the varieties. The largest increase was from Rose at 1.0 percent and the smallest from Thunderbird at 0.3 percent (Table 2).  Overall grain yields were very good due to excellent
growing conditions.  However, significant grain yield reduction to applied foliar N occurred with Thunderbird and Q
549 varieties, and a significant grain yield increase with Sage (Table 2).  All other varieties showed no significant yield influence from application of foliar N but were variable.  Some yields increased when others were decreased.
 

Conclusions:


Table 1.  ANOVA and foliar nitrogen treatment means of grain test weight, protein, and yield of fifteen varieties of hard red winter wheat near Brookings, SD in 1996 (project no.16796).
 
    Dependant Variables
    Grain
Class variable:   Test wt.   Protein   Yield
    ------------------------------------Pr > F---------------------------------
variety (V)   0.001   0.001   0.007
treatment (T)A    0.013   0.003   0.070
V * T   0.086   0.174   0.009
--------------------------------------------------------------------------------------------------------------------------------
                   
Variety: Relative HeadingB  lbs/bu   %   bu/a
Rose Medium Late 5 62.8 g   12.5 fg   60.6 cde
Redland Medium Early 3 58.1 a   10.9 a   61.0 cde
Siouxland Medium Early 3 59.4 cd   11.8 bc   61.0 cde
Arapahoe Medium Early 3 59.1 bc   11.7 bc   60.0 cd
Norstar Late 7 61.1 f   10.8 a   59.0 bcd
Abilene Early 2 60.7 ef   11.7 bc   61.4 de
Thunderbird Medium 4 59.1 bc   12.6 g   55.6 abc
Longhorn Medium 3 59.1 bc   12.4 fg   50.9 a
Vista Early 2 58.8 b   11.9 cde   57.4 bcd
Seward Medium Late 5 60.4 e   10.7 a   65.6 e
Dawn Medium 5 60.4 e   11.4 b   61.1 cde
Sage Early 2 59.7 d   12.2 efg   53.5 ab
TAM 107 Early 0 57.9 a   11.4 b   57.7 bcd
Q-549 Medium Early 3 59.2 bc   11.8 cd   62.6 de
Roughrider Medium Late 6 60.6 e   12.1 def   58.6 bcd
LSD (.05)    0.5   0.4   5.6
                   
TreatmentA                   
No foliar N   59.6   11.2   59.6
foliar N   59.9   12.2   58.6
LSD (.05)    0.2   0.2   NS
A  Foliar nitrogen at 30 lbs/a applied as 1:1 (H2O/28-0-0) dilution at Feekes 10.54
B  Relative Heading scale 0-7, 0=early and 7=late.
LSD - Least Significant Difference test between two mean comparisons.  Means with
similar lower case letter within a comparison column are not different.
 
 

Table 2. Foliar nitrogen treatment means of grain protein and yield of fifteen varieties of hard red winter wheat near Brookings, SD in 1996 (project no. 16796).
  Dependant Variable
  Grain Protein Grain Yield
    Foliar NA        Foliar NA   
Variety ANOVAB  no yes LSD (.05)    ANOVAB  no yes LSD (.05) 
  Pr>F -------------%-------------   Pr>F ------------bu/a------------
                   
Rose 0.036 11.9 13.0 1.0   0.380 59.5 61.6 NS
                   
Redland 0.001 10.3 11.6 0.4   0.613 61.6 60.3 NS
                   
Siouxland 0.007 11.2 12.3 0.5   0.304 62.1 59.8 NS
                   
Arapahoe 0.004 11.1 12.3 0.5   0.406 58.6 61.4 NS
                   
Norstar 0.004 10.3 11.4 0.4   0.163 60.1 58.0 NS
                   
Abilene 0.020 11.2 12.2 0.7   0.853 61.7 61.2 NS
                   
Thunderbird 0.002 12.1 13.1 0.3   0.005 58.3 53.0 2.3
                   
Longhorn 0.106 12.1 12.7 NS   0.446 50.1 51.6 NS
                   
Vista 0.051 11.5 12.4 0.9   0.421 57.8 56.9 NS
                   
Seward 0.049 10.3 11.0 0.6   0.115 68.4 62.9 NS
                   
Dawn 0.101 11.1 11.7 NS   0.312 59.8 62.3 NS
                   
Sage 0.001 11.7 12.8 0.1   0.048 50.7 56.3 5.5
                   
TAM 107 0.009 10.9 11.9 0.6   0.62 57.0 58.4 NS
                   
Q-549 0.012 11.2 12.4 0.7   0.030 65.9 59.4 5.3
                   
Roughrider 0.019 11.6 12.7 0.8   0.517 59.3 57.9 NS
A  Foliar nitrogen at 30 lbs/a applied as 1:1 (H2O/28-0-0) dilution at Feekes 10.54
B  ANOVA analysis by variety.
LSD - Least Significant Difference test between two mean comparisons.

Last Updated on 5/28/98
By Howard J. Woodard
Email: woodardh@mg.sdstate.edu