2011 Field Research Shows Little Yield Effect from Soybean Seed Treatments - UNL CropWatch, 2011

2011 Field Research Shows Little Yield Effect from Soybean Seed Treatments - UNL CropWatch, 2011

January 12, 2012

A seed treatment trial was conducted at four locations in Nebraska in 2011 to determine its effect on stand, disease control, and yield. The sites, part of the Soybean Management Field Days, were near Bancroft (northeast Nebraska), Clay Center (south central), Cortland (southeast), and Elba (central).

Researchers found that seed treatments did not cause any yield differences at any of the sites. There were differences in stand counts at Clay Center and Elba in the spring, and at Clay Center in the fall; however these differences did not influence yield.

How the Trial was Conducted

The study included 10 treatments and an untreated control.

  • Plot size: 4 rows wide by 17 feet long.
  • Planting: 140,000 seeds/ac at a depth of 2.5 inches to promote disease development. Syngenta NK S25-T8 soybean seed was used for all sites.
  • Weed control: Warrant (acetochlor) and Round up (glyphosate).
  • Treatments were arranged in a randomized complete block design and were replicated four times at each site.

Seed treatments were applied using a slurry sufficient for 2 lb of seed for each treatment. Uniform coverage to the seed was accomplished in a resealable plastic bag. Stand counts were taken twice in the spring and once in the fall prior to harvest. Plant populations were determined by counting plants between two flags placed 10 ft apart in the center two rows of each plot. The stand count flags remained in place for the entire season so that the same area was counted at each stand count assessment. Stand count data was converted into plants per acre. Prior to harvest, the ends of each plot were cut to minimize edge effects on yield. All yields were adjusted to 13% moisture. Additional site details are given in the table headers below.

Findings

Weather conditions from planting until mid-June were cool and wet across much of the state. These conditions combined with deep seed placement resulted in slow and uneven emergence. In some cases soybeans were still emerging 21 to 35 days after planting (DAP).

Seed treatments did not cause any yield differences at any of the sites. There were differences in stand counts at Clay Center and Elba in the spring.. In the fall, Clay Center had differences in stand counts but none of the treatments were different from the untreated control. These differences did not influence yield.

Loren Giesler
Extension Plant Pathologist, Lincoln
Travis Gustafson
Technologist, Department of Agronomy and Horticulture

Table 1:  Effects of seed treatments on soybean stand and yield at Bancroft.  Site was planted on May 4 and harvested on October 10.  Herbicides for weed control were applied on May 18.
 
Population (plants/ac)
 
 
6/1/2011
6/14/2011
10/5/2011
 
Treatment and Rate/Ac
28 DAP*
41 DAP
154 DAP
Yield (bu/ac
Untreated
121,750
117,394
105,197
60.4
ApronMaxx RTA 5 fl oz/cwt
117,394
113,909
104,980
60.2
ApronMaxx RTA 5 fl oz/cwt + Apron XL 0.32 fl oz/cwt
114,345
120,879
103,891
58.6
Cruiser Maxx Plus 3.2 fl oz/cwt
122,621
121,097
106,504
59.7
Trilex 2000 1 fl oz/cwt
122,404
122,621
104,108
63.2
Trilex 2000 1 fl oz/cwt + Poncho Votivo 0.13 mg ai/seed
120,661
118,265
107,158
61.3
Acceleron Disease
123,275
122,186
99,099
63.3
Acceleron Disease + Insect
117,830
123,275
104,326
58.8
Cruiser Maxx Plus 3.2 fl oz/cwt + N-Hibit 0.25 oz/cwt
118,483
122,839
109,336
60.2
Inovate System
124,364
122,621
109,118
60.5
LSD (α=0.1)
NS
NS
NS
NS
*Days after planting
 
Table 2: Effects of seed treatments on soybean stand and yield at Clay Center.  Site was planted on May 3 and harvested on October 14.  Herbicides for weed control were applied on May 17.
 
Population (plants/ac)
 
 
5/17/2011
5/31/2011
10/3/2011
Treatment and Rate/Ac
14 DAP*
28 DAP
153 DAP
Yield (bu/ac)

Untreated
86,902
109,771
93,654
63.2
ApronMaxx RTA 5 fl oz/cwt
81,675
114,781
102,802
63.2
ApronMaxx RTA 5 fl oz/cwt + Apron XL 0.32 fl oz/cwt
76,012
117,612
103,019
68.0
Cruiser Maxx Plus 3.2 fl oz/cwt
76,012
109,336
89,080
64.5
Trilex 2000 1 fl oz/cwt
89,951
118,048
96,268
66.0
Trilex 2000 1 fl oz/cwt + Poncho Votivo 0.13 mg ai/seed
90,387
128,284
97,357
64.2
Acceleron Disease
81,239
117,830
102,584
69.3
Acceleron Disease + Insect
79,497
117,830
104,108
66.9
Cruiser Maxx Plus 3.2 fl oz/cwt + N-Hibit 0.25 oz/cwt
79,715
119,790
103,455
64.2
Inovate System
101,713
126,977
107,811
64.1
LSD (α=0.1)
NS
9,851
8,011
NS
*Days after planting
 
Table 3:  Effects of seed treatments on soybean stand and yield at Cortland.  Site was planted on May 2 and harvested on October 12.  Herbicides for weed control were applied on May 16.
  Population (plants/ac)  
 
5/23/2011
6/6/2011
9/20/2011
Treatment and Rate/Ac
21 DAP*
35 DAP
141 DAP
Yield (bu/ac)

Untreated
106,722
114,998
98,881
64.2
ApronMaxx RTA 5 fl oz/cwt
107,375
124,799
98,446
68.4
ApronMaxx RTA 5 fl oz/cwt + Apron XL 0.32 fl oz/cwt
103,891
117,612
101,277
66.8
Cruiser Maxx Plus 3.2 fl oz/cwt
103,019
119,790
90,823
62.7
Trilex 2000 1 fl oz/cwt
95,832
107,593
95,614
67.4
Trilex 2000 1 fl oz/cwt + Poncho Votivo 0.13 mg ai/seed
107,593
118,048
99,099
62.4
Acceleron Disease
107,375
120,008
95,396
68.2
Acceleron Disease + Insect
108,247
119,354
95,614
67.0
Cruiser Maxx Plus 3.2 fl oz/cwt + N-Hibit 0.25 oz/cwt
112,820
122,404
96,268
64.6
Inovate System
103,019
126,760
104,762
64.7
LSD (α=0.1)
NS
NS
NS
NS
*  Days after planting
 
Table 4:  Effects of seed treatments on soybean stand and yield at Elba.  Site was planted on May 5 and harvested on October 21.
 
Population (plants/ac)
 
 
6/2/2011
6/14/2011
10/6/2011
 
Treatment and Rate/Ac
28 DAP*
40 DAP
154 DAP
Yield (bu/ac)

Untreated
102,584
99,317
90,387
61.5
ApronMaxx RTA 5 fl oz/cwt
111,296
114,127
93,654
68.7
ApronMaxx RTA 5 fl oz/cwt + Apron XL 0.32 fl oz/cwt
116,523
114,998
99,317
61.3
Cruiser Maxx Plus 3.2 fl oz/cwt
114,563
113,909
102,148
61.8
Trilex 2000 1 fl oz/cwt
117,830
117,176
97,792
62.8
Trilex 2000 1 fl oz/cwt + Poncho Votivo 0.13 mg ai/seed
99,317
100,406
88,645
56.4
Acceleron Disease
113,474
108,682
98,663
61.7
Acceleron Disease + Insect
122,186
113,474
92,129
60.4
Cruiser Maxx Plus 3.2 fl oz/cwt + N-Hibit 0.25 oz/cwt
113,909
115,870
88,645
59.4
Inovate System
126,542
127,413
100,406
60.4
LSD (α=0.1)
14,161
14,198
NS
NS
*Days after planting