A USDA agronomist in Minnesota has invented an air-powered device that shoots out farm residues — “from seed meals to nut shells, fruit pits, and corn cob grits” — at weeds and pulverizes them while leaving corn shoots standing tall, reports Modern Farmer. Dried chicken manure is a current favorite to target the pesky plants. “We can weed and feed at the same time,” Frank Forcella told the magazine.
Forcella, a hobby farmer, came up with the idea when he was researching what to do with fruit pits. He found that the pits were used for sand blasting, so he decided to try them out on weeds. “[The idea] sounded too silly initially,” Forcella told the magazine. But he and a colleague, Dean Peterson, at the USDA North Central Soil Conservation Research Laboratory in Morris, Minnesota, kept batting it around. “Eventually, we bought a cheapo sand blaster and started some simple experiments in a greenhouse.”
“Their initial work involved growing weeds next to a corn plant; when the corn was about six inches tall and the weed was about one to three inches tall, the researchers blasted both with a split-second application of grit,” Modern Farmer writes. “It turned out that only the weeds got hurt. In fact, they vanished, while the corn plant was fine. This prompted a field experiment in 2012 with a bigger sand blaster mounted on an ATV. While Peterson drove, Forcella followed, crouched over with the sand blaster nozzle, blasting pigweed and other pesky sprouts.”
Modern Farmer says Forcella then nabbed a Sustainable Agriculture Research and Education grant for an “Air-Propelled Abrasive Grit Management” system. The machine, dubbed PAGMan, has four pairs of nozzles and shreds weeds up to two inches high, but it leaves corn plants four inches or taller intact. Two applications—at corn’s three- and five-leaf stages—provide about 80 percent season-long weed control, Forcella told Modern Farmer.
A second model, the Veggie Blaster, for vegetable crops is overseen by an assistant professor at the University of Nebraska.
“Interest in the method, known as ‘abrasive weeding,’ keeps growing,” Modern Farmer said. “A two-year field study at the University of Illinois Sustainable Student Farm found the technique may reduce the need for tillage and hand-weeding; and in Spain, a group of collaborators at the University of Seville are developing their version of the Veggie Blaster, which can sense a weed and only turns on when needed.”