Corncob bits instead of chemicals for weed control? Sounds like an interesting, if not slightly odd possibility, doesn’t it?
U.S. Department of Agriculture research agronomist Frank Forcella has been using an air compressor to spray gritty material like corncob bits on both sides of a crop to kill young weeds without harming corn or soybeans. His method utilizing the new technology is gaining attention from organic farmers who don’t use chemicals to control weeds in their fields.
“It obliterates the weed, especially if it’s a small broad-leaved weed like Lamb’s quarters or pigweed that’s one to 3 inches high,” Forcella said. “The corn plants growing next to them are taller and thicker and can withstand the grit blast, but the weeds just disappear.”
Food companies who have been forced by consumer demand to provide snacks and staples that don’t have agrichemicals are interested, too.
Forcella admits the device still needs more testing, but that it obliterates weeds, especially if they are “small broad-leaved weeds like Lamb’ quarters or pigweed that’s one to 3-inches high.”
The device relies on the strength and maturity of desirable crops like corn to withstand the blast while the user demolishes unwanted weeds.
“The corn plants growing next to them are taller and thicker and can withstand the grit blast, but the weeds just disappear.”
Aside from corncob bits, the weed blaster can use other gritty material like ground walnut hulls or soybean meal. Forcella and others have been working on organically certified plots owned by the University of Minnesota at its West Central Research and Outreach Center in Morris to test the technology.
“In our initial work [with tomatoes], we were able to reduce the density of weeds by about 75 percent with just one application,” he said. “And the weeds that we didn’t kill we were able to reduce the overall height so that they wouldn’t become competitive with the crop.”
At first, the blaster was mounted on an all-terrain vehicle and used an air compressor, but this meant that each row had to be weeded by hand. Now, with the help of an engineer, the device has been mounted on a tractor that can blast four rows at a time. High-speed particles of grit shred the weeds at 100 pounds per square inch of compressed air.
Forcella’s technique requires that he hit the fields with his air compressor twice – once when the weeds are about four inches high, and again later when the plants are more mature.
“We’ve been getting season-long weed control of about 80 to 90 percent, which isn’t perfect, but most organic farmers would be happy with that amount of weed control,” Forcella said.
Furthermore, the technology could eventually be combined with fertilization so that the desired plants would be nourished with granular, nitrogen-rich food as the weeds are eradicated.
The device isn’t ready for wide-scale use, but the results thus far look promising. Who knew that corncob bits or fungi could repel weeds naturally?
Featured image source: Sustainable Mycology