ROW CONFIGURATIONS IN SOYBEANS
Introduction
Testing was done to demonstrate the impact of
different row spacing configurations on soybean
yield potential under various growing conditions,
such as the unusual drought and heat stress
conditions of 2012.
Materials and
Methods
A demonstration trial was established in 2012 at
the Monsanto Learning Center near Gothenburg,
NE to evaluate the effect of row spacing on
soybean yield potential.
A Genuity® Roundup Ready 2 Yield® soybean
product with relative maturity (RM) of 2.4 was
planted on May 7, 2012 in 7.5-inch (drilled),
15- and- 30-inch row, and 30-inch twin row
systems. In all row widths, the planted population
was 140,000 seeds per acre.
The trial consisted of 16 plots (four row widths,
one soybean product, four replications), which
were conventionally tilled on April 2, 2012. The
plots were planted into previous corn ground.
Temperature (oF)
Twin row planting has been shown to have
several potential benefits including maximizing
light interception and allowing for greater plant
root growth and development, which increases
water and nutrient uptake.
120
1.9
1.7
1.5
1.3
1.1
0.9
0.7
0.5
0.3
0.1
100
80
60
40
20
0
2012 Rainfall
2012 Max Temp
2011 Max Temp
2011 Rainfall
Figure 1. Average maximum temperature and rainfall from May 1 to
October 31 for 2011 and 2012.
94
92
92
Yield (bu/acre)
Narrow row spacing (less than 30-inch) has been
expanding rapidly in the past 20 years. Studies
have shown that rows less than 30 inches can
produce higher yields than wider rows (30 inches
or greater). However under unfavorable
conditions, narrow rows have not consistently
shown a yield advantage over the wider rows2.
Rainfall (mm)
The combination of optimum genetics and good agronomic practices along with favorable environmental conditions are required to
help increase yield potential. Proper soybean row spacing is considered more important than tillage or optimum plant population for
maximizing yield potential1.
90
88
86
86
86
84
82
82
80
78
76
7.5‐inch 15‐inch (drilled) single
30‐inch single
30‐inch twin
Figure 2. Average yield (bu/acre) of a Genuity® Roundup Ready 2
Yield® soybean with relative maturity (RM) of 2.4 to row spacing
configurations for trial conducted in 2012.
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ROW CONFIGURATIONS IN SOYBEANS
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Yield Loss (bu/acre)
Enlite® (2.8 fl oz/acre), Roundup PowerMAX®
(28 fl oz/acre), and Sharpen® (2 fl oz/acre)
herbicides were applied pre-plant on April 23,
2012. In addition, Roundup PowerMAX® (28 fl
oz/acre) and Warrant® Herbicide (2 pints/acre)
were applied on July 2, 2012. Between June 1
and September 10, 2012 approximately 16
inches of irrigation were applied to all plots at
a rate of one inch/acre on weekly intervals. All
plots were harvested on September 25, 2012.
Other agronomic practices were in alignment
with local standards.
10
10
8
6
6
6
4
2
Weather conditions during the 2012 growing
season were considered to be abnormal for
the area with low rainfall and unusual high
temperatures (Figure 1). Generally, May,
June, and July temperatures were 9, 11, and 7
degrees, respectively, higher than 2011. There
were days in late June and early July 2012
that daytime temperature was at or above
100o F; June 26 temperature recorded 111o F.
Figure 3. Average yield loss of a Genuity® Roundup Ready 2 Yield®
soybean with relative maturity (RM) of 2.4 planted in three row
spacing configurations compared to drilled (7.5-inch) single row for
trial conducted in 2012.
In 2011, only two days in late July when
daytime high temperatures were 100o F, while
16 days of temperature at or above 100o F
was recorded in 2012.
Figure 3 shows the 7.5-inch row configuration had a 12% and 7% average yield
increase over the 30-inch row and both the 15-inch row and the 30-inch twin rows,
respectively. These values equate to 10 and 6 bu/acre yield reductions for the 30inch and both the 15-inch and the 30-inch rows, respectively.
The rainfall in 2012 was below the 2011 level.
Only 11 inches of rainfall was received from
May to the end of October compared to 26
inches at the same time period in 2011.
Canopy closure in the 7.5-inch drilled soybeans may have occurred earlier than in
the 30-inch row configuration. Testing in Iowa showed a 4.5 bu/acre yield
advantage for 15-inch over 30-inch row spacing1. Testing in Nebraska showed a
2.2 bu/acre yield advantage for 20-inch over the 30-inch row spacing2.
Results &
Discussion
Due to earlier canopy closure, narrow rows can have a larger yield advantage
when the soybean planting date is delayed into June. Canopy closure is needed
by the start of pod set (R3) for maximum pod formation and seed filling2.
Results showed that out of the four planting
configurations, the drilled 7.5-inch row
outperformed the 30-inch rows. The 7.5-inch
row produced an average 92 bu/acre, while
the 30-inch row yielded the lowest (82 bu/
acre). The average yield of the 30-inch twin
row and 15-inch row systems were similar (86
bu/acre) (Figure 2).
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15‐inch single 30‐inch single
30‐inch twin
In general, narrow rows decrease the time to canopy closure, which can help
leaves intercept more light throughout the season. Additionally, the time to canopy
closure can have a significant impact on soil moisture loss, ability to control
emerging weeds, and especially on crop growth rate.
The overall minimal yield difference across row spacing configurations might be
due to several factors. The unusual drought in 2012 combined with disease
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ROW CONFIGURATIONS IN SOYBEANS
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pressure, late rain, and high temperatures ● Average yield from 15-inch and twin rows were similar.
during the critical growth stages may have
negatively impacted soybean yields. ● The average yield differences between row space configurations in 2012 might be
due in part to the unfavorable environmental conditions of drought and unusually
Additionally, previous factors might have
high temperatures during critical growth stages.
negated the benefits of the different
configuration systems that were implemented in
● Always consider proper soybean product selection, seedling population, row
this study.
spacing, and fungicide application strategies to help reduce stress and help
In a similar study conducted in 2011, drilled
optimize soybean yield potential.
soybeans produced the highest yields. On
average, the 7.5-inch drilled soybeans had a 20 ● The extended period of high temperatures and low rainfall during the growing
-35% increase in yield over the 15, 30, 36-inch
season contributed to the below average yields recorded for soybean in 2012.
and the twin row configurations. The 30-inch
row yielded less than the drilled soybeans but Additional testing is needed to better understand the effects of row spacing under
relatively similar yields to 15- and-36-inch row different field environmental conditions.
and the twin row configurations.
Sources: 1Pedersen, P. 2008. Row spacing is important to maximize your yield. Soybean Production
Summary Comments
● The 7.5-inch row drilled soybeans produced
the highest average yield (92 bu/acre) while
the 30-inch row produced the lowest yield
(82 bu/acre).
Fact Sheet 3/12/2008. Iowa State University Extension. http://extension.agron.iastate.edu (10/18/12).
2
Elmore, R.W. et al. 1990. Narrow-row soybeans. University of Nebraska-Lincoln Cooperative
Extension. NebGuide G90-963 issued November 1990.
3
Monsanto National Research Summary. 2009. Interaction of plant population, row spacing and variety
selection on soybean yield. Monsanto Technology Development.
4
Plant Health Initiative. 2009. Soybean row spacing. http://www.planthealth.info (10/10/12).
The information discussed in this report is from a single site, non-replicated, one-year
demonstration. This informational piece is designed to report the results of this demonstration and
is not intended to infer any confirmed trends. Please use this information accordingly.
Figure 4. Soybean V3 (L) and
V4 (R) growth stages.
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