Work still needs to be done to raise yields, but there's no doubt about the value of Roundup Ready soybeans as a weed control tool.

"Right now," says Cooperative Extension Service weed scientist Dr. Ford Baldwin, "our weed control research is ahead of variety development, but with all the good plant breeders working on Roundup Ready soybeans, that will change."

Supported by checkoff funds granted by the Arkansas Soybean Promotion Board, Baldwin and University of Arkansas research weed scientist Dr. Dick Oliver are studying the effects of Roundup and other herbicides on Roundup Ready soybeans.

"During the past several years, Dr. Oliver and I have looked at Roundup alone and in program approaches with other herbicides in just about every weed situation you can look at," said Baldwin.

"Dick does a lot of individual weed species work. His students plant the seeds of just about every weed we can get our hands on, then he looks at how Roundup does on each plant. I look at the use of Roundup in as many field situations as I can--conventional tillage versus no till program, row versus drilled soybeans, and so on."

Baldwin's work includes field studies of the effect of Roundup on red rice, Palmer pigweed, sicklepod, cocklebur, johnsongrass, morningglories and yellow nutsedge.

"Dick and I together look at Roundup in as many situations as we can and then compare the results to our best available standards," said Baldwin.

Both agree that Roundup is a step up in herbicide technology. Baldwin said, "It gives much better control of Palmer pigweed, which is our biggest weed problem in soybeans, and sicklepod, which is rapidly getting worse.

"If you look at the response ratings in MP 44, Extension's weed control publication, you'll see that there are very few weeds in there that Roundup doesn't give at least 70 percent control of. It's very broad spectrum."

Baldwin feels there's a place for other herbicides in a Roundup Ready soybean program. "For instance, Dr. Oliver and I have been evaluating an FMC compound called Authority. It's outstanding as a preemerge herbicide on morningglories and nutsedge, and those are two weeds that Roundup tends to be weak on.

"The problem now is that by the time farmers have paid the additional cost for the Roundup Ready seed and Monsanto's technology fee, and then bought the Roundup, they may feel they've already invested too much to use the Authority preemerge.

"The market has a way of working those things out."

As the work to improve weed control continues, so do the efforts to increase Roundup Ready soybean yields. Don Dombek, UofA research associate for variety testing, says the university conducted eight commercial variety tests at five locations, irrigated and non-irrigated, during 1996.

"We evaluated about 140 varieties and about 60 advanced, unreleased strains around the state," said Dombek. "We're trying to find the best adapted varieties for particular environments."

Dombek said the potential for Roundup Ready soybeans is tremendous. "They're not a panacea, but I think they're going to be an important management tool."