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Weed Strategies for Corn and Soybean Rotations

July 8, 2019
This agronomic image shows soybean rows.

A strong soybean program cleans the field for the following season’s corn planting.

Different crops produce different conditions for the weeds that compete with them. Planting the same crop again and again on any given field creates a pattern of conditions. Weeds can adapt to patterns and become more resistant with each growing season.

The key to getting the most benefit from crop rotation is the use of herbicide programs with multiple effective sites of action (SOAs) and overlapping residuals. A strong corn program doesn’t just protect your yields this year; it also keeps the field clean for next season’s soybeans. After rotation, a strong soybean program cleans the field for the following season’s corn planting.

This cycle of crop rotation and herbicide applications with multiple effective SOAs fights tough weeds and helps prevent resistance over the long-term. Weeds never have a chance to adapt to the patterns created around either crop or usage of single SOAs.

Even though crop rotation and a good corn program can help boost a good soybean program, you shouldn’t use less than the full labelled rate on herbicides. For instance, don’t reduce the herbicide rate applied for corn, thinking that the full rate for soybeans will make up the difference, or vice versa. This strategy and good land stewardship both depend on the consistency and quality of all the products used to keep your fields clean, year after year.

For your soybean herbicide program, we recommend a preemergence application of Boundary® 6.5 EC or BroadAxe® XC herbicides, both of which contain 2 effective SOAs. Those can be followed by Tavium® Plus VaporGrip® Technology herbicide, the market’s first premix residual dicamba herbicide. Tavium is a formulation of dicamba and S-metolachlor, making it convenient for managing key ALS-, PPO- and glyphosate-resistant broadleaf and grass weeds in Roundup Ready 2 Xtend® Soybeans.

For corn, we recommend Acuron® corn herbicide, which combines 4 active ingredients (AIs) and 3 effective SOAs. Acuron also offers flexible application from 28 days preplant up to 12” corn. The atrazine-free counterpart of Acuron, Acuron Flexi , has 3 AIs, 2 effective SOAs, and provides the same safety and performance from 28 days preplant up to 30” corn. Acuron Flexi also allows for the flexibility to add atrazine or glyphosate based on farming practice.

Both Acuron and Acuron Flexi can be followed by Halex® GT corn herbicide plus either an atrazine or dicamba herbicide for season-long control of annual grass and broadleaf weeds. Halex GT provides a more convenient alternative to other post-emergence, glyphosate corn herbicide programs.

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