Roundup Ready crops: How have they changed things?
By Robert Wilson
University of Nebraska Panhandle Research and Extension Center, Weed Specialist
The adoption rate of Roundup Ready crops in the United States has been one of the major changes in agriculture in the last 20 years. More than 155 million acres of cropland were treated with Roundup (glyphosate) during the 2008 growing season.
The use of Roundup Ready crops has changed farming practices throughout the country. No-till or reduced-tillage practices have increased dramatically and are closely associated with adoption of Roundup Ready crops. During the first 10 years of growing Roundup Ready crops, growers have relied heavily on glyphosate as the only herbicide used for weed management. With the development of glyphosate-resistant weeds in the cotton and corn belts, the glyphosate use patterns are starting to change, and herbicides with different modes of action are being incorporated into weed management programs.
Are producers concerned about glyphosate-resistant weeds? If growers have had a problem controlling a specific weed, you generally have their undivided attention. However, when glyphosate is working well, it is only human nature to resist change as long as possible. Some growers are not worried about anything but surviving next year and are not thinking about change. To get growers who do not have a glyphosate-resistant weed problem to change to a prevention mode requires looking past the next year and making decisions that will have a long-term payoff.
Growers in western Nebraska overwhelmingly adopted Roundup Ready sugar beets in 2008. The technology has resulted in increased yields, improved weed control, and renewed enthusiasm for growing sugar beets. Growers who previously were planting only Roundup Ready corn can now use glyphosate in two crops: corn and sugar beets.
After waiting 10 years for Roundup Ready sugar beets, let's hope growers don't ask themselves the question "Why did I drive Roundup Ready technology off the cliff before I changed?" Growers in western Nebraska still have the opportunity to make weed-control changes to keep the best technology they have ever seen viable on their farms. However, you cannot keep putting it off until next year.
In corn, growers can add a pre-emergence herbicide at planting and then tank-mix an additional herbicide with glyphosate postemergence. Yes, the additional herbicides will increase production costs $20 to $30 per acre, but will improve weed control and reduce the chances for developing glyphosate-resistant weeds.
Growing crops in your rotation that do not utilize glyphosate for weed control also reduces the chances of resistance, especially if good weed control is obtained in the rotational crop. Utilizing herbicides other than glyphosate in sugar beets, especially when weeds that are difficult to control with glyphosate are prevalent, will pay dividends in crop yield and further reduce resistant weed development.
Making these weed control changes now will help preserve the opportunity of using this technology in the future.