Torching tough-to-control weeds
An innovative tool that utilizes a propane-fueled flame system is seeing encouraging results in helping farmers battle herbicide resistant weeds.
Historically tailored toward smaller-scale, organic farm operations, interest in flame weeding from conventional farmers is gaining traction as companies offering the product ramp up speed and coverage capabilities.
Sustainability and environmentally-friendly attributes also are making flame weeding a more attractive option for farmers in the Midwest.
Mike Newland, director of agricultural business development with the Propane Education Research Council (PERC), said farmers are taking notice as the product is being further developed.
“Everybody’s first impression is we’re just throwing fire out there across the ground and scorching the earth,” said Newland. “But this is a highly-engineered product, efficient and effective.
“I think it can be a solution for larger acres than what we’ve been able to touch. Folks struggling with weed resistance, this could be a possible solution, another tool in the toolbox.”
That’s positive news for farmers tackling new and difficult weeds with a variety of control methods beyond herbicides, including weed seed destructors that pulverize weed seeds, blue light technology to zap the seeds, or with the use of cover crops to suppress weed growth.
“We are seeing more and more traditional Midwest chemistry guys who are looking for a way to more effectively treat problem acres due to herbicide-resistant weed populations,” said Newland. “Flame weeding is one of the options.”
Flame Engineering of LaCrosse, Kansas, was one of the first companies to test the market, offering its handheld Red Dragon torches back in the 1950s for spot control of weeds without herbicides. Fast forward a few decades, and the opportunity for weed torches in the hardware, nursery and lawn care businesses also has expanded. The firm also began manufacturing agricultural equipment.
“Flaming weeds is such an easy and effective process … and since the torches are powered by clean burning propane, the effect to the environment is minimal, if any,” said Mel Limon, executive director of sales for Flame Engineering. “There are virtually no limitations on what crops can be flamed while green and growing conditions exist.”
Additionally, in the early 2000s, George Gogos, professor of Mechanical and Materials Engineering at the University of Nebraska-Lincoln, and Stefan Knezevic, UNL Department of Agronomy professor, collaborated on flame weeding research, funded by PERC as well as the USDA and other partners.
Their research focused on everything from design and testing of torches and ignition systems to mobile propane tanks and efficacy in controlling weeds without damaging crops. Field testing and experiments were conducted on university fields.
“After two seasons of field testing with corn, we realized that we had built an agricultural implement that was safe and superior to anything that was available for flame weeding in the United States or anywhere in the world,” Gogos said.
The startup Agricultural Flaming Innovations (AFI) was founded, offering flame weeding solutions for crops across the globe.
In its simplest form, flame weeding introduces heat to a weed, killing it.
How it works
“Essentially, it’s disrupting the internal cells of the weed, rendering it unable to grow anymore,” explained Newland. “We’re super heating the water inside that cell, and that’s how the plant dies.”
Gogos said the high temperature of the flame destroys the membrane of the cells and they leak water. “As a result, the weeds wilt and lose most of their height,” he said. “The broadleaves die, whereas the grasses recover over the next 3 to 4 days.”
Experts suggest the process can be done twice per year — pre-plant and post-harvest, as well as carefully in-row during the season if needed. Results show a better than 90% weed control efficacy rate.
“It doesn’t matter if that weed is a conventional weed or it’s resistant to a certain herbicide, we’re still going to be able to control it at 90% effectiveness,” said Newland.
The apparatus is mounted on the toolbar, and currently is offered in an 8-row, and newer 12-row and 16-row, setups.
Gogos said organic farmers who have been relying on hoeing and cultivation have found the flaming process ideal, and are seeing yield increases especially when removing the weeds within a row that compete for nutrients with crops. “Two flamings can provide season control of weeds,” he said.
Economically it makes sense, too, he said. Utilizing anywhere from 10 to 20 gallons of fuel per acre, depending on how much flaming is needed, the cost to control weeds using flame weeding is less than the cost of herbicides.
The size of the unit has prevented conventional farmers from fully adopting flame weeding, but it is becoming more popular, especially to treat spot areas, on organic farms or in smaller fields, Gogos said.
Newland said the process provides a different mode of action to clean up very thick weed populations.
“If you have farms that have incredibly thick, resistant weed populations, I think this is a very real and possible solution for you,” Newland said. “It may have a pretty broad application for crops.”
Going forward, the industry will look at ways to speed up the units, which currently travel from 3 to 5 mph. While safe and sound, the technology is limiting in the fact that it’s unlikely to expand to encompass more crop rows.
“It’s a slower process,” Newland admitted. “Guys that jump in that sprayer, unfold the 90 or 120-foot booms and blow across the field aren’t going to like the speed of this unit.
“But it takes time to heat the weed up to kill it. It’s not a fast process. You won’t get across every acre with this tool every year.”
Yet both Newland and Gogos see likely growth in usage. “We’re looking at ways to speed the units up,” Newland said. “If we can overcome that to an extent, I think that really opens up a lot of different acres for us.”
Added Gogos, “The technology has a great future due to the resistance that has been developed by major weeds to the herbicides used, and due to an increasing consumption of organic food.”
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