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ARS Home » Midwest Area » Morris, Minnesota » Soil Management Research » Research » Publications at this Location » Publication #339876
Title: Spent coffee grounds as air-propelled abrasive grit for weed control

Author
item Forcella, Frank

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2017
Publication Date: 9/1/2017
Publication URL: http://handle.nal.usda.gov/10113/5922756
Citation: Forcella, F. 2017. Spent coffee grounds as air-propelled abrasive grit for weed control. Weed Technology. 31(5):769-772. https://doi.org/10.1017/wet.2017.42.

Interpretive Summary: Thousands of tons of spent coffee grounds are generated daily in the USA, and this waste material can be a problem for landfills. Adding value to this residue may be beneficial environmentally and economically. Spent coffee grounds have a gritty texture. Other gritty agricultural residues, such as corncob grit, recently have been employed as abrasive air-propelled agents for weed control in organically certified crops. Consequently, in greenhouse experiments we compared the efficacy of spent coffee grounds with that of corn cob grit for injury to two weeds important in the Upper Midwest: waterhemp and velvetleaf. Waterhemp seedlings, which are small and delicate, were controlled easily with as little as 0.5 g of coffee grit at an air pressure of 100 psi. Velvetleaf seedlings, which are much sturdier, better tolerated abrasion, but still were damaged appreciably by just 1 to 2 g of grit. Coffee grit was at least as effective for killing weed seedlings as corncob grit, whose value for this purpose in organic crops has been shown previously. These results will be of interest to organic growers as well as extension educators and agronomists who participate in organic farming research.

Technical Abstract: Spent coffee grounds (SCG) represent a significant food waste residue. Value-added uses for this material would be beneficial. Gritty agricultural residues, such as corncob grit, can be employed as abrasive air-propelled agents for organically-compatible postemergence shredding of weed seedlings selectively within established organic crops. SCG were tested and compared with corncob grit for their ability to injure seedlings of two important weeds: waterhemp and velvetleaf. Waterhemp seedlings were controlled completely with as little as 0.5 g of SCG at an air pressure of 690 kPa. Velvetleaf seedlings were much larger than those of waterhemp, better tolerated SCG abrasion, but still were damaged appreciably by 1 to 2 g of grit. SCG was at least as effective for abrading weed seedlings as corncob grit, whose value for this purpose in organic crops was demonstrated previously.