Pigweed persists as farmers seek answers
Strong cotton prices are a carrot for producers who are spending more, but gaining ground, on one of their toughest foes: herbicide-resistant pigweed.
The economic impact of herbicide-resistant pigweed is different for every field and crop. Most farmers indicate they are spending $30 more per acre on weed control in soybeans, of which there more than 3 million acres in Arkansas. Cotton growers are spending an average of $75 more per acre in a year where farmers are expected to harvest 640,000 acres, according to the National Agricultural Statistics Service. These dollar figures don't include hits from increased harvesting costs or reduced yields.
Here's one measure of how economically important the pigweed problem is. When Extension Weed Scientist Ken Smith was asked what weed situations would be shown at the Eastern Clay County Field Day demonstrations, he said: "I don't have but one situation in my life now. We were talking about managing pigweed and soil seed banks."
Smith has a dual Extension and research appointment for the University of Arkansas Division of Agriculture.
The effectiveness of new pigweed control techniques in corn, cotton and soybeans were displayed at the 2011 Eastern Clay County Field Day, held July 27 at the Henderson, Palmer and Cagle farms. About 75 producers and other farm industry workers attended the field day, "and they came to learn."
Fields such as the ones shown at the field day are living laboratories, testing theories developed by Smith and others, to combat herbicide-resistant weeds. These weeds are fast-moving targets, and that puts pressure on researchers such as Smith to find new control methods quickly and be right the first time.
"Back when I started with Extension, our role was to wait until the researchers get three years of data and summarize and give us the data to pass on to producers," Smith said.
Like other businesses that have to adapt to rapidly changing conditions, farmers want just-in-time answers ASAP.
Years ago, farmers would've been upset if you changed a recommended practice. "Today, the farmer does want answers now, and we might have to come back and change a recommendation in six months or a year."
What's working now in pigweed management is a three-step approach:
--Use overlapping residual herbicides.
--Manage the soil seed bank.
Because the pigweeds can produce millions of seeds per acre, and because there are no chemical controls after reaching a certain maturity level, it's important to keep the seeds from forming, if possible.
"They're spending a lot of money taking the weeds out of the crops," said Smith said.
"One guy told me, 'I had a budget this year when I went into this. I was going to spend $50,000 on hand-hoeing,'" he said. "'I've already gone over that. I can't quit now. I'm not going to quit now.'
"Fortunately, producers are making this effort when cotton and bean prices are up," Smith said. "If prices go back down, they cannot spend the levels for weed control that they are now. But by doing what they're doing now, by the time the prices go back down, we hope they'll be able to back off the expenses a little bit."
A fact sheet, "Prevention and control of glyphosate-resistant pigweed in soybean and cotton," FSA2152, is available online at www.uaex.edu/Other_Areas/publications/PDF/FSA-2152.pdf.