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Corn+Soybean Digest

Roundup Ready Soybean System Simply Works

"You plant. You spray. You don't worry." That's how Bud Motsinger, crop management specialist at Consumers Oil Co., Braymer, MO, sums up soybean production using Roundup Ready beans and Roundup Ultra herbicide. It's almost too simple to be true, says Motsinger.

Roundup Ready soybean acreage has grown from a million in 1996, to roughly 8 million in 1997, to an amazing 25 million-plus this year. That's more than one-third of all soybean acres planted. In some areas, 80% of the soybeans are Roundup Ready varieties. Predictions are for even more growth in 1999.

The reason for the Roundup Ready system's popularity is simple.

"It's as close to 100% control as you can get," says Jim Spahr, Seward, NE. "We make a single application with 32 oz of Roundup Ultra 30 to 35 days after planting. You have to be able to deal with fields that are weedy to look at. But you end up with clean fields. Clean of weeds and clean of chemical residue."

Need more benefits? Spahr adds, "With Roundup Ready soybeans you don't lose yield due to herbicide burn, and soil type doesn't make any difference."

"Roundup was already a household name and with the simplicity of the system, farmers have quickly adopted the technology," says Trent Leopold, soybean product manager for Asgrow Seed Co. "For a lot of guys, it's an unbelievable system."

The only rap against Roundup Ready beans has been that some varieties didn't yield as well as their conventional counterparts. Industry experts agree some were brought to the market too soon. Also, they say, some growers planted Roundup Ready varieties not suited to their conditions.

Farmers were more disciplined about seed selection in 1998.

"Last year, the guys just wanted the beans; they didn't care about variety," says Jon Kruse, senior crop management advisor for Blue Valley Co-op, Tamora, NE. "This year they were a lot pickier. They asked a lot more questions about yield potential."

The bigger question farmers face: "Is one application of Roundup enough?" In many cases the answer is yes.

"In general, Roundup by itself is looking pretty darn good," says Alan York, North Carolina State University weed specialist. "If your timing is good, you shouldn't need to use any other herbicides.

"A single application of 1 qt of Roundup works particularly well in drilled beans where you get a quick canopy," York states. "That's worth a bunch when you don't have a residual herbicide."

However, an inexpensive soil-applied herbicide can be awfully cheap insurance, points out Clemson University extension agronomist Jim Palmer.

"Weather and other crops that put soybeans in the backseat put a real strain on weed control," says Palmer. "If you have early weed pressure in the first four weeks after planting, you may have already lost yield."

Many university weed control trials, however, indicate that, assuming a clean-ground start, there is no yield loss due to newly emerged weed pressure in the first four weeks.

"Our biggest control concern is morningglory," Palmer adds. "We have some morningglories that are pretty doggone tolerant to Roundup."

The concern over morningglory control is shared by growers wherever that weed is a problem. Nightshade and dayflower also appear to have a natural tolerance for Roundup.

There is some logic to not relying strictly on a single application of Roundup for weed control, believes Bob Hartzler, Iowa State University weed specialist.

"I think it takes more than one tactic to get maximum yield and maximum weed control," he says. "That might mean a PPI or pre-emerge herbicide, two applications of Roundup or a cultivation. For growers with large acreages, there's less risk if they use a PPI or pre-emerge herbicide."

What about the possibility of weeds developing resistance to continued Roundup use?

It's certainly possible, agree scientists, but some think it's bound to happen eventually. Nevertheless, after more than 20 years of use worldwide, there is no known case of it occurring.

Hartzler, however, feels it's inevitable that weeds will develop resistance to Roundup.

"They've adapted to every other herbicide," he points out. "And on this many acres, it will happen faster. Morningglory, nutsedge and velvetleaf are likely candidates to develop tolerance first. I think we'll also start to see more late-emergers like waterhemp and fall panicum."

Kent and Jeff Templeton, Polo, MO, believe the simplicity of Roundup Ready soybeans out-weighs any concerns.

"This is so simple. We used to go to chemical company meetings and at each one we'd hear about a witch's brew of products to use for weed control," says Kent. "With Roundup, you've got a bigger window to be timely. With other herbicides, if you're late, you're in trouble."

The Templetons no-tilled 90 acres of Roundup Ready soybeans in 1996, took a plunge in 1997 with 2,000 acres and no-till-drilled even more in 1998.

"We stepped out on a limb," says Jeff.

They aren't married to Roundup, though.

"We put down quite a bit of Steel for burndown. You get some residual control with it," says Kent. "We come back with a quart of Roundup, depending on weed size rather than the calendar."

Like many growers, the Templetons were surprised when other chemical companies dropped prices this year, as much as 70%, to compete with the Roundup Ready system.

"I'm glad to see they're going to be competitive. It's never good for us when somebody has the whole basket of eggs."

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