Glyphosate [N-(phosphonomethyl)glycine] is a non-selective 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 1980's 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% of the soybean acres in the US are planted with glyphosate-tolerant varieties. Production practices have therefore changed significantly. Weed control today is approximately half per acre what it was prior using glyphosate-resistant soybean cultivars, even when the greater cost for seed of most glyphosate-resistant cultivars is considered. This translates to increased profits if yields from glyphosate-resistant cultivars are equal or nearly equal to those from conventional cultivars. Non-glyphosate pre-emergence 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 or other topics related to soybean production, contact your state extension specialist or your local extension educator/agent.”

The following is the link to the soybean extension specialists: state extension soybean specialist