Author
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Forcella, Frank |
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Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/18/2013 Publication Date: 8/15/2013 Publication URL: http://handle.nal.usda.gov/10113/57398 Citation: Forcella, F. 2013. Soybean seedlings tolerate abrasion from air-propelled grit. Weed Technology. 27:631-635. Interpretive Summary: New tools for controlling weeds would be useful for soybean production in organic systems. Air-propelled abrasive grit is one such tool that performs well for in-row weed control in corn, but crop safety in soybean is unknown. We examined responses to abrasion by corn-cob grit of soybean seedlings at several development stages (emergence, VE; cotyledon, VC; unifoliate, VU; first trifoliate, V1; and send trifoliate, V2) and combinations of these growth stages in both greenhouse and field settings. Seedling leaf areas and dry weights in greenhouse experiments were reduced by treatments that included abrasion at VC, with the primary effect expressed through reductions in the size of the unifoliate leaf. In the field, soybean stand also was reduced by grit applications at VC, especially if followed by a second application at VU or V1. However, soybean yield was not reduced by grit applied at any soybean stage of growth. End-of-season weed dry weights did not differ from hand-weeded checks and did not impact soybean yields. Thus, abrasive grit for in-row weed control can be applied at least twice at VE through V2 growth stages without reducing soybean yield, but applications at VC probably should be avoided. These results will benefit organic growers and their crop advisors who seek information on when and how to control weeds in soybean. Technical Abstract: New tools for controlling weeds would be useful for soybean production in organic systems. Air-propelled abrasive grit is one such tool that performs well for in-row weed control in corn, but crop safety in soybean is unknown. We examined responses to abrasion by corn-cob grit of soybean seedlings at VE, VC, VU, V1, V2, and combinations of these growth stages in both greenhouse and field settings. Seedling leaf areas and dry weights in greenhouse experiments were reduced by treatments that included abrasion at VC, with the primary effect expressed through reductions in the size of the unifoliate leaf. In the field, soybean stand also was reduced by grit applications at VC, especially if followed by a second application at VU or V1. However, soybean yield was not reduced by grit applied at any soybean stage of growth. End-of-season weed dry weights did not differ from hand-weeded checks and did not impact soybean yields. Thus, abrasive grit for in-row weed control can be applied at least twice at VE through V2 growth stages without lowering soybean yield, but applications at VC probably should be avoided. |
