Glyphosate (N-(phosphonomethyl)glycine) is a nonselective herbicide that kills both annual and perennial grass and broadleaf weeds, as well as woody species. The development of glyphosate-tolerant crops was pursued in the early 1980s, and glyphosate-resistant soybean was one of the first major applications of genetic engineering. The first glyphosate-resistant soybean cultivars were released in 1996 and today more than 95 percent of the soybean acres in the United States are planted with glyphosate-tolerant varieties.

Production practices have, therefore, changed significantly. Glyphosate applied to glyphosate-resistant soybeans does not injure the crop but will control most weeds. Nonglyphosate preemergence herbicides do not adversely affect glyphosate-resistant soybean. Thus, residual herbicides can be used when planting glyphosate-resistant cultivars to prevent early season weed competition in situations where a timely application of glyphosate is not possible.

For more information on this and other topics related to soybean production, contact your state extension specialist or your local extension educator/agent.

Following is the link to the soybean extension specialists: state extension soybean specialist.