Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2011
Publication Date: 1/1/2012
Citation: Forcella, F. 2012. Air-propelled abrasive grit for postemergence in-row weed control in field corn. Weed Technology. 26:161-164.
Interpretive Summary: Weed control remains the most critical agronomic issue faced by organic growers. Although many organically-approved techniques for weed control exist, more are needed to help solve weed-related problems in organic crops. A technique was developed at the USDA-ARS laboratory in Morris, Minnesota, that uses the concept of sand-blasting for selective postemergence control of weed seedlings in corn, except that corn cob grit is used in place of sand. Season-long, in-row weed control is achieved if the corn cob grit is propelled at weed seedlings growing in the corn row when the corn is at the 1-leaf, 3-leaf, and 5-leaf stages of development. No weed-related corn yield losses occur and the corn is not damaged by applications of grit at these times. Although much additional research will be needed to refine this new technique, it likely will be of interest to organic growers to control weeds without herbicides, agricultural engineers to design novel machinery, and implement manufacturers to produce new products to manage weeds.
Technical Abstract: Organic growers need additional tools for weed control. A new technique involving abrasive grit propelled by compressed air was tested in field plots. Grit derived from corn cobs was directed at seedlings of summer annual weeds growing at the bases of corn plants when the corn was at differing early stages of leaf development. Season-long, in-row, weed control exceeded 90% when two or three abrasion events were coupled with interrow cultivation. Timing of weed abrasion was critical, with highest levels of control corresponding to the 1- and 5-leaf stages or the 1-, 3-, and 5-leaf stages of corn development. Corn yields associated with these treatments were equivalent to those of hand-weeded checks in which no abrasive grit was applied. Thus, air-propelled abrasive grit applications at the 1-, 3-, and 5-leaf stages of corn controlled weeds sufficiently to prevent weed-induced reduction of corn grain, and these applications were not harmful to corn plants. Because no synthetic herbicides are needed with this new concept for weed control, it may be of interest to organic crop managers.