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Free your fields: Plant LibertyLink

With weed resistance quietly developing throughout Minnesota and the Dakotas, LibertyLink soybeans are becoming more popular as a rotational tool.

Many farmers have moved to a high, if not 100%, glyphosate-resistance weed control program. It is easy to understand that if problem weeds do slip through, dirty fields will soon follow. When just five resistant weeds remain per acre, they can potentially produce up to 400 plants per acre the following year. By year three, there is the potential of 32,000 plants per acre producing resistant seed.

We have watched the weed resistance problem gain momentum as it has moved from Missouri and Arkansas through the Midwest and now into our part of the world. Common ragweed, giant ragweed, waterhemp and common lambsquarters have all been identified in our region as resistant to glyphosate.

So far, the problem has been in isolated areas and is not widespread yet. But it will not take long for weeds to spread if they are not controlled.

There is some good news. A full lineup of LibertyLink soybeans across maturities is now available. These varieties are able to compete with any of the Roundup Ready varieties on the market and have the agronomic traits to handle our variable soil conditions. Most of the current varieties have great iron deficiency chlorosis tolerance and soybean cyst nematode resistance as well.

Ignite herbicide for LibertyLink soybeans is the only alternative on the market to glyphosate for complete weed control. I have used Ignite (formerly called Liberty) since it became available in the early 1990s in Bt corn hybrids. But Ignite really fits better with soybeans because we are spraying in warmer conditions. There are also tankmix options for grass control.

By planting LibertyLink soybeans, you also have a way to control volunteer Roundup Ready crops, including corn and canola, from the previous year. We saw excellent volunteer control this year in the fields we examined. Even with the wet weather and the several applications made by air, excellent weed control was achieved.

Don’t get me wrong, though. LibertyLink soybeans are not the only answer to weed resistance. Another management strategy we need to embrace is the use of preemerge herbicides in both corn and soybean fields. This practice is becoming essential because:

Early weeds do the most damage to yield.

A preemerge gives timing flexibility with post-applied herbicides.

University data has shown increased yields by including preemerge chemicals in your weed control program.

Another management strategy to look at is tank mixing other herbicides with glyphosate in post-applied applications. There has been more research on this lately, and chemical companies have some very good options. Talk to your local chemical supplier for recommendations.

Spelhaug is an agronomist with Peterson Farms Seed, Harwood, N.D. For more information, contact him at 866-481-7333 or adam@peterson
farmsseed.com,
or visit www.petersonfarmsseed.com.

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This article published in the December, 2011 edition of DAKOTA FARMER.

All rights reserved. Copyright Farm Progress Cos. 2011.