Evaluation of Soybean Populations on Yield and Economics
in South Central Nebraska
J.M. Rees*, J.W. Schneider, B.S. VanDeWalle, and G.L. Zoubek,
Extension Educators, University of Nebraska-Lincoln Extension.
ABSTRACT: RESULTS:
Rising input costs have producers examining ways to reduce
costs of production. In 2006 and 2007, producers involved Table 2. 2006 Soy Pop Yield Results (bu/acre)
with the Greater Quad County On-farm Research Group
tested four different soybean populations to determine yield Loc/Var/Rep 90 K 120 K 150 K 180 K Avg.
and economic impact on the cost of production. Seeding
Fillmore
rates were 90,000; 120,000; 150,000; and 180,000
seeds/acre. Stand counts and yield were taken both years Pio. 93M11 65.9 66.2 68.4 68.6 67.3
and pod counts were also taken in 2007. Yield data were 3 Reps
analyzed using the mixed procedure in SAS 9.1. In 2006 at Seward
two locations, there was a significant population effect NC+ 2A98 65.2 65.9 65.3 66.3 65.7
(p=0.0151) and no significant location effect (p=0.1222).
3 Reps
There was no location by population significant interaction
(p=0.0734). Significant population differences in 2006 Avg. 65.5 66.1 66.9 67.4 66.5
occurred between 90,000 vs. 150,000 seeds/acre (p=0.0255);
90,000 vs. 180,000 seeds/acre (p=0.0032) and 120,000 vs. •Both locations on 30 inch rows.
180,000 seeds/acre (p=0.0214). The average yield was •No significant location by population interactions
65.52 bushels/acre at 90K vs. 67.43 bushels/acre at 180K (p=0.0734).
even though significant statistical yield differences occurred •No significant location effect (p=0.1222).
between populations. In 2007 (five locations), there were no •Significant population effect (p=0.0151).
location by population significant interactions (p=0.9328) and •Significant at:
1 2
no significant population interactions (p=0.6279). There were
90 vs. 150K (p=0.0255).
significant location differences (p=<0.0001) due to hail in a
few locations. Average 2007 yield differed from 59.42
90 vs. 180K (p=0.0032).
bushels/acre at 90K vs. 60.17 bushels/acre at 180K. This 120 vs. 180K (p=0.0214).
research shows that producers typically averaging 160,000
seeds/acre could reduce their populations to 120,000
seeds/acre with no significant yield loss. Reducing these Table 3. 2007 Soy Pop Yield Results (bu/acre)
populations on the estimated 270,000 soybean acres planted
in these four counties in 2007 would have resulted in a
Loc/Var/Rep 90 K 120 K 150 K 180 K Avg.
$9.00/acre seed savings, equivalent to saving $2.5 million!
Hamilton *
Kruger 315SCN 52.8 51.8 51.4 52.9 52.2
MATERIALS/METHODS: Stand Counts 3 Reps
Clay
Hogemeyer 316 61.5 60.9 61.1 61.7 61.3
4 Reps
York
NK S28G1 61.4 61.9 62.2 62.5 62.0
3 Reps
Fillmore*
3 4
Pio. 93M11 56.5 57.5 58.0 58.9 57.7
Figures 1-4: Lower planted populations of 90K (Fig. 1) and 120K (Fig. 2) compensated for reduced 3 Reps
plants by increased branching, flowering, and pod set, regardless of typical variety architecture. Pods Seward
Table 1. 2006 & 2007 Actual vs. Planted Pops were also observed closer to the ground in these lower planted populations. Producers typically plant AG3001 63.1 63.9 62.8 63.4 63.3
Location 90 K 120 K 150 K 180 K between 150K (Fig. 3) and 180K (Fig. 4) in South Central Nebraska (30” rows). Plants at these 4 Reps
2006 Fillmore 89,000 105,750 140,167 158,333 populations were observed having a more erect architecture with reduced branching compared to the
lower populations. Average 59.4 59.6 59.4 60.2 59.7
Seward - - - -
2007 Hamilton 88,667 114,333 143,333 171,667
•All locations on 30 inch rows.
Clay 88,950 112,450 142,500 167,200 CONCLUSIONS: •*Denotes some hail. Significant location
York 94,333* 119,833 153,667* 155,833
The average yield between 90K and 180K in 2006 was 1.91 bu/acre and 0.75 bu/acre in 2007. differences (p=<0.0001) due to hail.
Fillmore 82,167 97,417 134,500 160,500
Based on these results, the minimal yield differences obtained do not justify the additional •No significant location by population interactions
Seward 72,625 102,000 126,000 159,375 seeding expense of planting 180K. (p=0.9328).
Average 85,957 108,631 140,028 162,151 Producers in South Central Nebraska can safely reduce their seeding rate by 40,000 •No significant population interactions (p=0.6279).
% Stand 96% 91% 93% 90% seeds/acre (assuming 160K planted avg.). At a $9/acre seed cost over 270,000 soybean acres
*Planted at 95K and 151K planted in 2007, this would have resulted in savings equivalent to $2.5 million!