By Tim Landis, The (Springfield) State Journal-Register Researchers at the University of Illinois are blasting away at noxious weeds. Fields test are expected to begin this summer of Star Wars sounding "weed blaster" technology that fires, concentrated organic grit from a high-pressure nozzle at Mach 1 -- more than 760 mph -- to obliterate vulnerable weed seedlings. Early field tests of hand-held air compressors used in conjunction with traditional control methods reduced weed waste in vegetable plots by 67 to 97 percent, according to early results.
"It's another non-chemical, weed-management approach," said Sam Wortman, a researcher on the project and an assistant professor at U of I. "We're looking at some of the higher-value vegetable crops." Wortman said field tests of hand-held models began in 2012 at greenhouses and on small vegetable plots. He said the automated model to be tested this summer requires only a tractor and an operator. Organic grit used to blast weed stems -- soybean meal, walnut shells, corncobs and green sand -- doubles as fertilizer. Commercial use likely is years away, said Wortman. But he said refinements should continue to lower costs compared with traditional organic weed-control methods such as cover crops, bioplastic, mulch and old-fashioned weeding by hand. Field tests also have reduced unintended damage to crops by targeting weeds at early growth stages of less than three inches. "We're still fairly early in working out the mechanics," said Wortman. Organic farming has grown in Illinois along with consumer and supermarket demand for pesticide-free, locally grown foods, according to a U.S. Department of Agriculture survey. Sales of organic commodities in Illinois totaled $52.7 million from 249 certified producers in 2014 compared with $25.2 million in sales from 229 farms in 2008. The industry remains tiny compared with the state's major grain crops. Illinois grain farmers in 2015 harvested 2.01 billion bushels of corn from 11.5 million acres and 544 million bushels of soybeans from 9.72 million acres, according to USDA. "It's increasing, but it's still a relatively small industry," said John Fulton, director of the U of I Extension office for Logan, Menard and Sangamon counties. Fulton said interest in chemical-free farming has grown with backyard gardeners, as well as commercial growers who often sell through farmers' markets and local food cooperatives. Obtaining the certified organic label from USDA can be time-consuming, he added. "There are a lot of hoops you have to jump through to get certified," said Fulton. PrairieErth Farm near the Logan County community of Atlanta was among test sites for the U of I weed blaster. The approximately 300-acre vegetable, egg and meat farm has been in Dave Bishop's family for three decades. "I think it has great possibilities," Bishop said of the weed blasting. "It's a good concept that needs work." He said the farm relies on traditional organic weed-control techniques such as cover crops, mulching and manual tillers, but that the weed blaster eventually could be an additional tool. "It's experimental. We're just trying to get the bugs out," said Bishop. Wortman said the U of I research has been aided by the work of Frank Forcella, a USDA research agronomist in Minnesota who has been experimenting with high-pressure corn-cob grit to control weeds in corn and soybeans. In addition to a variety of organic abrasives, Wortman said field tests helped to refine factors such as nozzle pressure, angle and the best time to hit young weeds. "We're basically aiming right at where the stem meets the soil," said Wortman. "If you have a crop that is six inches tall, and the weeds that are less than three inches, that's a nice differential." The organic grit is the biggest expense, so maximum efficiency is key to commercial use, said Wortman. "We hope we can work out the kinks," he said, "and make it a well-packaged technology that's ready for the market.