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YIELD OBSERVATIONS WHEN SHIFTING TO EARLIER MATURITY GROUP SOYBEANS - 2021
TRIAL OBJECTIVE
We continue to see a growing trend of growers planting early soybeans and managing them at a higher level with seed treatments and foliar applications of fungicide and insecticide. This shift to earlier soybean maturity groups is becoming increasingly important in some locations. There are many benefits of planting early soybeans including, but not limited to, earlier harvest timing, earlier cover crop seeding and risk management benefits.
OBJECTIVE:
Determine the yield impact of soybean product selection against the normal maturity group products for the location.
RESEARCH SITE DETAILS

SITE NOTES:
- The trial was divided into 2 sets – North & South
- A total of 4 trial locations with 2 North locations and 2 south locations
- North Set – Storm Lake and Marble Rock, Iowa
- South Set – Atlantic and Victor, Iowa
- Each maturity group set consisted of 3 Kruger Seeds™ brand soybean products.
- Three early maturity group (MG) soybean products:
- North Set – 1.5 to 2.0 MG (K1501XF brand, K1804XF brand, K2084XF brand)
- South Set – 2.2 to 2.6 MG (K2294XF brand, K2391XF brand, K2604XF brand)
- Three normal maturity group soybean products:
- North Set – 2.2 to 2.5 MG (K2294XF brand, K2391XF brand, K2594XF brand)
- South Set – 3.0 to 3.5 MG (K3003XF brand, K3305XF brand, K3593XF brand)
- Three early maturity group (MG) soybean products:
- Plot size, replications, and row spacings varied depending on location.
- Storm Lake (2 replications)—6 rows at 20-inch spacing
- Atlantic (3 replications)—8 rows at 30-inch spacing
- Marble Rock (3 replications)—6 rows at 30 -inch spacing
- Victor (2 replications)—8 rows at 30-inch spacing
- Rainfall in 2021 was timely and arrived during the soybean reproductive stages across all locations.
UNDERSTANDING THE RESULTS
With earlier planting dates in 2021 and rainfall events from late June through September, the effects of maturity group on soybean yield potential pointed to a clear yield advantage for the normal maturity group set at all locations.
The north locations normal MG set had a 7 bushel/acre advantage over the early MG set (Figure 1) and in the southern locations, the normal MG set had a 9 bushel/acre advantage over the early MG set (Figure 2).


WHAT DOES THIS MEAN FOR YOUR FARM?
In this study, the early MG soybean products averaged 7 to 9 bu/acre less than the normal MG soybean products with a range of 2 to 13 bu/acre less than normal MG products.
Late season rainfall in 2021 was ideal, providing ample moisture during reproductive stages to maximize yield potential especially for the normal MG soybean products varieties at all locations.
More research needs to be done in the genetic pipeline to better understand which soybean products will move south.
- It should be noted that shifting to an earlier MG group may not be for every operation and that benefits could be defined in terms other than yield such as early harvest and establishment of cover crop.
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Yield Observations When Shifting to Earlier Relative Maturity Soybeans - 2020
TRIAL OBJECTIVE
We continue to see a growing trend for soybean growers to plant “early” soybean products and manage them at a higher level with seed treatments and foliar applications of fungicide and insecticide. This phenomenon, dubbed “relative maturity (RM) shift” is becoming increasingly important in some locations.
There are many benefits of planting “early” soybeans including, but not limited to, earlier harvest timing, earlier cover crop seeding, and risk management benefits.
The objective of this study was to determine the yield impact of planting “early” RM soybean products compared to planting normal RM products for the location.
RESEARCH SITE DETAILS

SITE NOTES:
- The trial consisted of two sets – North and South.
- There were five locations planted:
- North Set – Storm Lake, and Marble Rock
- South set – Huxley, Atlantic, and Victor
- Each set consisted of three unique soybean products.
- Three soybean products were considered early RM for the location:
- North set – 1.6 to 1.8 RM
- South set – 2.0 to 2.6 RM
- Three soybean products were considered normal RM for the location:
- North set – 2.0 to 2.6 RM
- South set – 3.3 to 3.6 RM
- The 2.0 to 2.6 RM group consisted of the same nine soybean products for both the North and South sets.
- Three soybean products were considered early RM for the location:
- The trial included a mix of plot sizes, replications (reps), and row spacings:
- Storm Lake (2 reps): six row strips with 20-inch row spacing
- Atlantic (2 reps) and Marble Rock (3 reps): four row strips with 30-inch row spacing
- Huxley (2 reps): six row strips with 30-inch row spacing
- Victor (1 rep): eight row strips with 30-inch row spacing
- Average rainfall during the growing season was very low compared to long term averages with 3 to 15 inches less rainfall, depending on location.
- Marble Rock was impacted the least with 3 inches less and Atlantic the most with 15 inches less total rainfall.
UNDERSTANDING THE RESULTS
With earlier planting dates in 2020 and rainfall events in September, the effects of RM selection on average soybean yield pointed to a clear yield advantage for the normal RM group.
The North set with the normal RM group had a 9 bu/acre advantage over the early RM group (Figure 1) and the South set with the normal RM group had a 12 bu/acre advantage over the early RM group (Figure 2).


WHAT DOES THIS MEAN FOR YOUR FARM?
In 2020, early RM soybean products yielded, on average, 9 to 12 bu/acre less than normal RM soybean products and ranged between 2 to 17 bu/acre less than normal RM soybean products for both locations.
In 2020, late season rainfall was less than ideal. The lack of adequate rainfall in July and August quickly finished off the early RM group, while the early September rains helped the normal RM group maximize pod fill.
More research should be conducted in the genetic pipeline to better understand which soybean products can be grown south of their typical production area.
It should be noted that a RM shift may not be applicable for every operation and any potential benefits can be defined in terms other than yield.
Yield Observations When Shifting To Earlier Maturity Group Soybean Products - 2019
TRIAL OBJECTIVE
A growing trend for soybean growers is to plant “early” soybean products (south of their normal adaptation) earlier in the season and managing them at a higher level with seed treatments and foliar applications of fungicide and insecticide. This phenomenon, dubbed “relative maturity (RM) shift” is becoming increasingly important in some locations.
There are many benefits of planting “early” soybean products including:
- Earlier harvest
- Earlier cover crop seeding
- Risk management benefits
- Earlier harvest
The objective of this study was to determine the yield impact of planting “early” (for the location) RM soybean products compared to planting normal RM products for the location.
RESEARCH SITE DETAILS

- The trial consisted of two sets – North and South.
- Each set had three Iowa locations:
- North Set – Storm Lake, Marble Rock, and Huxley
- South Set – Huxley, Atlantic, and Victor
- Each RM group consisted of three unique Kruger Seeds™ brand soybean products.
- Three products were considered early RM for the location:
- North Set – 1.3 to 1.8 RM
- South Set – 2.0 to 2.6 RM
- Three products were considered normal RM for the location:
- North Set – 2.0 to 2.6 RM
- South Set – 3.3 to 3.6 RM
- The 2.0 to 2.3 RM group consisted of the same three products for both the North and South sets.
- Three products were considered early RM for the location:
- The trial was a mix of plot sizes, replications (reps), and row spacings:
- Storm Lake (4 reps)—six row strips, 20-inch spacing
- Atlantic (2 reps) and Marble Rock (4 reps)—four row strips, 30-inch spacing
- Huxley (3 reps)—six row strips, 30-inch spacing
- Victor (2 reps)—eight row strips, 30-inch spacing
- During the growing season, all sites recorded 20+ inches of rainfall with Atlantic receiving 32 inches total.
- The Marble Rock site received several heavy rainfall events.
UNDERSTANDING THE RESULT
Delayed planting dates in the spring and late rains in the fall favored the normal RM group at the sites tested in 2019.
At the North locations, the normal RM group had a 3.0 bu/acre advantage over the early RM group (Figure 1) and at the South locations, the normal RM group had a 9.0 bu/acre advantage over the early RM group (Figure 2).


KEY LEARNINGS
In 2019, the early RM products yielded, on average, 6.0 bu/acre less than the normal RM products and yields ranged between 1 to 13 bu/acre less than the normal RM products.
In 2019, rainfall was plentiful with Marble Rock receiving the heaviest one-time event, and with Atlantic receiving over 32 inches total.
The 2019 growing season favored the normal RM products, especially with a few delayed planting dates and excessive late-season rainfall that the normal RM group was able to utilize.
More research needs to be conducted in the genetic pipeline to better understand which soybean products can be grown south of their main area of adaptability.
- It should be noted that a RM shift may not be for every operation and that its benefits could be defined in terms other than yield.
3011_R11
Yield Observations When Shifting To Earlier Maturity Group Soybean - 2018
TRIAL OBJECTIVE
We continue to see a trend of growers planting earlier maturity group (MG) soybeans for the region and managing them at a higher level with seed treatments and foliar applications of fungicide and insecticide. This phenomenon, dubbed “MG shift”, is becoming increasingly important in some locations.
- There are many benefits of planting early MG soybeans including, but not limited to, earlier harvest timing, earlier cover crop seeding, and risk management benefits.
- The objective of this trial was to determine the yield impact of early MG soybean product selection against the normal MG products for the location.
RESEARCH SITE DETAILS

- This trial was broken into two sets, North and South Iowa, with a total of eight locations – four locations in the north set and four locations in the south set:
- North Set – Fonda, Storm Lake, Marble Rock North, and Marble Rock South
- South Set – Huxley, Atlantic, Shenandoah, and Victor
- Each set consisted of 18 unique soybean products:
- Nine products are considered early MG
- North Set – 1.1 MG to 1.8 MG
- South Set – 2.0 MG to 2.4 MG
- Nine products are considered normal MG
- North Set – 2.0 MG to 2.4 MG
- South Set – 2.9 MG to 3.5 MG
- The nine 2.0 to 2.4 MG products were the same products for both the north and south sets.
- Nine products are considered early MG
- The plots consisted of four, 15-ft-long rows in 30-in row spacing with three replications.
- The Shenandoah site exhibited above average levels of frogeye leaf spot and insect feeding.
- Above average levels of sudden death syndrome were observed at the Victor site.
- The Marble Rock North site was impacted with hail on August 28th.
Understanding the Results
- The effect of maturity group on soybean yield was variable and highly dependent on the location. For example, Victor saw an 8 bu/acre yield advantage with early MG products, whereas Huxley realized a 7 bu/acre advantage with normal MG products.
- In general, three locations (Atlantic, Victor, and Storm Late) saw some level of yield advantage with early MG soybean products versus the other locations where normal MG products gained some yield advantage. However, average site performance across all locations was nearly similar at 58 bu/acre.
What Does This Mean for Your Farm?

- In general, early MG soybean products yield close to late MG products, especially when conditions are favorable.
- In this trial, there were some unfavorable growing conditions (listed below) in the locations where the normal MGs succeeded:
- Excessive rain, wind, and hail
- Weathered/delayed harvest
- Lower management (no R3 growth stage fungicide/insecticide application)
- Finding the proper genetic package for a maturity group is still critical when considering planting early soybeans.
- More research needs to be done in the genetic pipeline to better understand which soybean products will move south.
- It should be noted that an MG shift may not be right for every operation and that its benefits could be defined in terms other than yield.
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