If you're interested in harvesting top yields with Roundup Ready no-till corn and soybeans, it’s likely that you’ll have to add residual herbicides to the weed-control mix.

Mike Moss, the head of biological research and development for Syngenta Crop Protection, says a key concern when using glyphosate materials in a single no-till application is deciding on the best time to make the application.

He says one option for superior no-till weed control might be to apply Bicep or Magnum during the third week of April to no-till corn ground, apply a glyphosate material in June and come back in July with an application of Callisto.

“If you are going after top yields, you have to use residual herbicides with any glyphosate products such as Touchdown,” says Moss. “With multiple weed flushes and more broadleaf weeds, there’s normally a need for both a burndown and a residual herbicide with continuous no-till weed control.”

Little On-Farm Data

Bryan Young says one problem is that most no-tillers don’t have on-farm data indicating the amount of yield losses due to a lack of early season weed control.

The weed scientist at Southern Illinois University in Carbondale, Ill., says early-season herbicide applications should be made when no-tilled corn is 2 to 4 inches tall and no-till soybeans are 6 to 8 inches tall.

Speaking about no-till weed control at next January’s 11th annual National No-Tillage Conference in Indianapolis, Young says weed height at the time of herbicide application is critical. While early-season weed control in…