Researcher Studies Abrasive Weeding

Researcher Studies Abrasive Weeding CROPS Miscellaneous FARM SHOW editors first heard about “blasting weeds” with corn grit when we published a story about the idea 2 years ago Vol 38 No 5 Now we’ve learned about research being done at the Universtiy of Illinois by agroecologist Samuel Wortman using a variety of products for abrasive weeding In Wortman’s U of Ill study grit made from walnut shells granulated corn cobs green sand and soybean meal was blasted onto nuisance weeds in growing vegetables Wortman says the grit was applied through a handheld siphon-fed sandblaster attached to a gas powered air compressor The compressor was on a cart pulled between rows by a self-propelled walk-behind garden tractor Wortman says grit blows out the nozzle at supersonic speeds and is directed at growing weeds to completely shred their leaves He found that particle size or type didn’t have a bearing on how well the blasting worked because the force of the material always did extensive damage to weed leaves He did advise that the process works best on transplanted crops where the good plant is larger and more mature than the small weeds around it His test results showed that yields on the “blasted” crops were about 33 to 44 percent better than those in the non-weeded control plots The weed control in the abrasive plots ranged from 69 to 97 percent effective Wortman says another benefit of pressurized weeding is that granulated fertilizers could be used as the abrasive which would supply added nutrients to the growing crop He says growers also like the idea of fertilizing and killing weeds in one pass saving time and money His research suggests that using poly mulch or a biodegradeable plastic mulch greatly improves the effectiveness of abrasive blasting when compared to straw mulch and bare soil Additional tests will be done on other crops including kale and broccoli Wortman adds that growers can try abrasive weeding without a lot of up front costs If they don’t own a portable air compressor renting one along with a sandblasting pump is one route to go The unit could be pulled through a garden with a small tractor and wagon Eye protection should always be used with abrasive blasting because small particles easily richochet Contact: FARM SHOW Followup Samuel Wortman Assistant Professor University of Illinois 1011 Plant Sciences Laboratory 1201 S Dorner Drive Urbana Ill 61801 swortman@illinois edu

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