NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

September 24, 1998

Desiccation of Weeds in Some Soybean Fields Recommended

Farmers can't control the actions of Mother Nature, but sometimes they can trump one of her moves. Soybean producers with heavy weed infestations have just such an opportunity, says a crop specialist with the North Dakota State University Extension Service.

"I've seen a lot of weedy soybean fields," says Duane Berglund, extension agronomist at NDSU. "It's probably a good idea for some soybean producers to desiccate before harvest to prevent weed interference during combing.

The herbicides labeled for desiccation or preharvest weed control in North Dakota are these: Gramoxone Extra (paraquat), Drexel Defol (sodium chlorate), Roundup Ultra and Roundup Ultra RT. The preharvest interval for all these herbicides is seven days.

The rate for aerial application of the Roundup products for preharvest weed control in soybean is no more than 1 quart per acre. Rates for ground applications can be up to 6 quarts per acre. Berglund cautions producers that soybean fields receiving a preharvest treatment with either Roundup product should not be used for seed because the herbicides could affect seedling vigor.

The Roundup products require that the soybean crop be fully mature—all pods free of any green color. The label for Gramoxone Extra says at least 65 percent of the seed pods must display a mature brown color (or the seed moisture is 30 percent or less) before application can occur.

Berglund says producers should check the herbicide label or consult the NDSU Extension Service's "1998 North Dakota Weed Control Guide" for further details. The guide is available via the World Wide Web at http://www.ext.nodak.edu/extnews/weedpro/.

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Source: Duane Berglund (701) 231-8135

Editor: Dean Hulse (701) 231-6136