Doublecrop Soybeans Allow Resistant Weeds Clean Up
As glyphosate-resistant weeds continue to spread, this year’s soybean market could be a godsend for farmers to invest in crippling the spread of such weeds, especially in areas of doublecrop soybean production.
Chris Kale, owner and manager of Farmers Supply Company at Marvell in east-central Arkansas, reports more wheat acres than normal in his area, and he said nearly 100 percent of those acres will be doublecropped with soybeans this year. The typical doublecrop production method in the Marvell area is to cut the wheat, burn the field off and till one time to allow planting into fairly weed-free soil.
“The problem we run into during June when we are planting beans is that soil moisture is minimal. We don’t get a lot of rain typically at that time; so, residual herbicides stand a good chance of not getting activated from rainfall,” Kale noted.
Therefore, Kale is convinced the best option is postemergence herbicide use, but not glyphosate because of all the glyphosate-resistant weeds. “So, in my opinion, the best shot we have is planting LibertyLink soybeans and Ignite herbicide applied twice,” he said.
Kale said farmers have had good success using residual herbicides with early-season planted Roundup Ready soybeans, but not at doublecrop timing. More often than not, residuals have failed.
“Last year nearly all our wheat beans had weeds, the weeds just took over the fi elds, and farmers spent a lot more money than two Ignite applications trying to reclaim them, and we were not successful. Using the LibertyLink system is just going to be a better opportunity for a grower to make a clean bean crop,” Kale said.
A little farther north of Kale’s region in central to southern Missouri, much of the doublecrop soybeans are planted no-till, but that doesn’t mean the basics for having a clean bean field are much different, noted Doug Tinnes, Bayer CropScience technical sales consultant, who assists ag retailers throughout most of eastern Missouri and southeast Iowa.
For no-till doublecropping, instead of burning and tilling before planting, the main recommendation here is for a burndown herbicide application after wheat harvest. That is followed up with a post-emerge herbicide application in season. But because of glyphosate-resistant weeds, such as marestail, again the weed control needs to be done with something other than glyphosate.
In Missouri and Arkansas, a common burndown recommendation has been the old Gramoxone, but during the past two years, use of Ignite has become common. The planting of LibertyLink soybeans allows the application of Ignite over the top of the soybean plants during the growing season.
Tinnes is convinced that reducing the glyphosate-resistant weeds in a fi eld calls for eliminating the use of glyphosate throughout one growing season. He said, “If a grower has any worry about resistant weeds, LibertyLink soybeans and Ignite herbicide will clean up the fi eld and help to break the cycle of resistant weeds spreading.”
Of course, nothing competes with glyphosate in price, but resistant weeds aren’t inexpensive to control. “When the market was low for beans, then farmers treated doublecrop beans like a cheap crop. Now that beans are more valuable, this is the year for farmers to plan a weed control program that reduces glyphosate-resistant weeds, rather than doing like most years in the past and trying to get by with the lowest-cost weed control possible,” Tinnes said.
Kale echoed Tinnes’ point of view and also said, “If we don’t allow weeds to go to seed, we are lowering the seed bank or carryover weed seed dramatically for next year. One year is not going to solve the problem, but it is going to really help.”
For more information about weed control in doublecrop soybeans, Tinnes can be reached at firstname.lastname@example.org.