Profits, best practices threatened as weed challenges increase
"The Roundup Ready® technology was just awesome when it came out,” recalls Malcolm Haigwood of Newport, Ark. “It’s had a big impact on the way we farm.”
It simplified weed control, was cost-effective and fit well with the reduced- and no-till practices he, his father and his brothers had put in place to conserve soil and lower equipment costs on the thousands of bottomland acres where they grow corn, soybeans, cotton, rice, wheat and sorghum. But as Haigwood and growers across the Mid-South, Southeast and now the Midwest are having to turn to an arsenal of alternative methods to fight difficult and glyphosateresistant weeds, their costs are increasing, and those valuable benefits are at risk.
Growers value benefits of glyphosate-tolerant cropping system
When crops that tolerate the broad-spectrum herbicide glyphosate came on the scene 12 years ago and in the years since, the new cropping system was quickly adopted, bringing positive change and tangible benefits.
Growers in a recent market research study1 ranked the importance of those benefits to their operations. All participants farm more than 250 acres and either presently use the glyphosate-tolerant cropping system or have used it in the past.
Economic consequences of weed pressure, changes in practices
From his perspective as both a grower and a custom applicator running White River Ag, Haigwood sees firsthand what’s at stake as the number of glyphosate-resistant and hard-to-control weeds increases. It’s become much more complicated, expensive and time-consuming to fight weeds like Palmer amaranth and horseweed that glyphosate used to control, he says, but it’s crucial to do so. In addition, this also applies to weeds that have never been completely controlled by glyphosate.
“I’ve seen fields completely lost because of the weed pressure,” Haigwood says. “You can’t just spray more Roundup.”
Iowa State University Professor of Agronomy Mike Owen says growers are already seeing economic consequences from the proliferation of the glyphosate-resistant and difficult-to-control weeds. He cites a 2008 study of 400 corn, soybean and cotton producers in 17 states in which growers estimated their costs increased by $14 to $16 an acre due to glyphosate-resistant weeds.
The diverse programs of multiple pre- and post-emergent treatments and even spring tillage needed to keep fields as clean as possible can come at a high cost. For example, some products are more expensive to spray and use more water, which adds to input costs and decreases the number of acres Haigwood can spray with a tankload.
“We had to get larger sprayers and more of them,” he says. “We’re running three now versus one -- that’s an added cost.” He adds that timing becomes even more crucial, too. “You can’t just wait until Monday to spray.”
Looking to the future -- how to save soil, profits while fighting weeds
“One of the things that we feel is potentially a problem, is that growers are likely to return to tillage as a strategy to manage specific weeds,” Owen said. And that comes with an “economic cost, a significant cost of time utilization and also has an environmental cost, with more potential for erosion.”
No one wants to see U.S. farmers take a step backward when it comes to conserving soil and water. Years of conservation tillage have enabled growers to reduce their inventory of tractors and tillage equipment -- the cost of gearing back up for conventional tillage could be prohibitive. In addition, tillage that reduces or removes residue from fields could mean those fields being out of compliance with conservation plans, putting farm program participation at risk.
Owen and Haigwood both stress the importance of maintaining and making use of all management tactics to control weeds, whether they are resistant or not -- adding in different herbicides, using different products at different times, even isolating problem fields to prevent the spread of glyphosate-resistant weed seed with tillage and harvest equipment.
“The good news is that there are many strategies that can be used to maintain the effectiveness of glyphosate and sustain the glyphosate-tolerant crop cultivars in corn and soybeans,” Owen says.
In the market research study,1 a full 93 percent of grower respondents said they would be open to a weed-control system that works with and improves the glyphosate system by adding new modes of action and traits. Combined with more diverse crop management practices, such new systems hold out hope for continued effective weed control in glyphosate-tolerant crops.
1: Successful Farming Ag Advisor Market Research Survey of corn, soybean and cotton
growers, conducted June 2010
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