Researchers test a three-row flamer in the evening so they can better see the flame patterns.
Researchers test a three-row flamer in the evening so they can better see the flame patterns.

Organic growers have very few chemical herbicides from which to choose, so many instead resort to hand weeding and cultivation.

As a result, interest has increased in flame weeding, which uses direct heat to kill weeds, according to a news release.

The technique isn't new, having been used at least since the early 1950s.

What is new is the research into flame weeding being conducted at the University of Nebraska-Lincoln's Haskell Agricultural Laboratory near Concord.

Flame weeding involves a propane-fueled torch that shoots flames at weeds.

The flame, which can reach temperatures up to 2,500 degrees Fahrenheit, heats the water within cells, causing them to expand and eventually break the cell walls.

Moisture leaks from the plant, causing it to wilt and eventually die.

Flaming costs between $8 and $15 per acre, much less than hand weeding, according to the release.

One of the drawbacks is that commercial flaming machinery is limited in size.

Stevan Knezevic, an Extension weeds specialist, and mechanical engineering professor George Gogos have worked to design a better flame-weeding machine.

Their latest, a four-row machine, is patented.

Randy Fendrich, an organic grower near Abie and David City, Neb., has been a cooperator in their research.

"With the flamer, we can get a total kill," Fendrich said in the release. "With the rotary hoe and harrow, we'll miss some of them and we won't get a total kill.

Nevertheless, Fendrich still uses a rotary hoe and harrow because certain methods control specific weeds better.

Knezevic and Gogos have tested their machine on 20 weed species among seven agronomic crops, including sweet corn.

Along with student assistants, they're compiling the research results and plan to publish a kind of how-to manual on flaming equipment and best management practices.

The manual is under going review and should be available later this year.