January 12, 2021
TRIAL OBJECTIVE
- The Roundup Ready® Xtend Crop System with XtendFlex® soybeans provides growers with soybean products that have herbicide tolerance to glufosinate, glyphosate, and dicamba.
- In 2020, two herbicide tolerant soybean platforms launched Enlist E3® soybeans and LibertyLink® GT27™ soybeans.
- Enlist E3® soybeans confer tolerance to 2,4-D choline, glyphosate, and glufosinate that allows growers to use Enlist Duo® herbicide or Enlist One® herbicide to control weeds.
- LibertyLink GT27 soybeans have a tolerance to glyphosate, glufosinate, and isoxaflutole. To date, Alite 27® is the only group 27 herbicide product registered for use on GT27™ soybeans.
- The objective of the trial was to evaluate the three soybean systems: Roundup Ready® Xtend Crop System with XtendFlex soybeans, the Enlist™ weed control system with Enlist E3 soybeans, and the GT27™ Soybean Performance with LibertyLink G27 soybeans.
RESEARCH SITE DETAILS
Location | Salina, KS Gothenburg, NE | ||
Soil Type | Silt loam | ||
Previous Crop | Corn | ||
Tillage Type | Conventional Strip tillage |
Planting Date | 5/20/20 5/8/205 | ||
Harvest Date | 10/5/20 10/20/20 | ||
Potential Yield (bu/acre) | 50 | ||
Seeding Rate (seeds/acre) | 160,000 |
- Single replication demonstrations were planted on sites with very high Palmer amaranth pressure.
- Plot size was 10 by 243 feet at Salina, KS and 10 by 250 feet at Gothenburg, NE.
- Three soybean products for each weed control platform were used. The maturity groups ranged from 3.6 to 4.2 at Salina and 2.5 to 3.0 at Gothenburg.
- Herbicide application dates
- Salina
- Pre-emergence (PRE): May 20
- Early Post (EPOST): June 9
- Late Post (LPOST): July 6
- Gothenburg
- PRE: May 8
- EPOST: June 18
- LPOST: July 2
- Salina
Herbicide treatments included in Tables 1, 2, and 3.



- Weed control efficacy ratings were taken on a scale of 0 to 100% with 0 indicating no control and 100% indicating compete control of the evaluated weed species.
- Weed control efficacy ratings for each system were averaged across the three soybean products for each system for each rating date.
- Yields were low at both sites due to late season moisture stress and were not reported.
UNDERSTANDING THE RESULTS
- The early POST (EPOST) applications were applied to soybeans at the V4 growth stage when Palmer amaranth plants were approximately 4.5 inches tall.
- The late POST (LPOST) applications were applied to all soybeans prior the R1 growth stage when Palmer amaranth plants were approximately 2-12 inches tall. A disparity in weed height was observed in this trial because the EPOST Roundup Ready® Xtend Crop System with XtendFlex® soybeans treatment performed better than the other two EPOST systems.


KEY LEARNINGS
- Early season weed control efficacy initially appeared to be similar between the three weed control systems at both sites with a small advantage for the Roundup Ready® Xtend Crop System with XtendFlex® soybeans platform.
- Differences in weed efficacy became more apparent as the growing season continued with the XtendFlex® platform showing better weed control efficacy at both the mid-season and pre-harvest observations.
- Palmer amaranth is a difficult weed for farmers to control effectively. A system like the Roundup Ready® Xtend Crop System with XtendFlex® soybeans that can help provide season-long control by layering residuals is one way to help achieve effective weed control.
- Farmers should visit with their local Bayer Crop Science Sales Representative about the possible benefits the Roundup Ready® Xtend Crop System with XtendFlex® soybeans platform can bring to their operation.
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