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Research Project: Enhancing Cropping System Sustainability Through New Crops and Management Strategies

Location: Soil Management Research

Title: Propelled abrasive grit for weed control in organic silage corn

Author
item Erazo-barradas, Mauricio - South Dakota State University
item Forcella, Frank
item Humburg, Daniel - South Dakota State University
item Clay, Sharon - South Dakota State University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2017
Publication Date: 3/1/2018
Citation: Erazo-Barradas, M., Forcella, F., Humburg, D., Clay, S. 2018. Propelled abrasive grit for weed control in organic silage corn. Agronomy Journal. 110:632-637. https://doi.org/10.2134/agronj2017.08.0454.

Interpretive Summary: Many agricultural residues, like corn cobs, can be processed into abrasive grits that can be used for sandblasting. These same grits propelled at high air pressures can be employed for the selective in-row control of weed seedlings in corn. However, the timing of corn cob grit application to simultaneously maximize weed control and corn yield was unknown. Consequently, a two-year field experiment in certified organic silage corn was implemented to rank grit applications at the following corn growth stages: V1, V3, V5, and V7. Single grit applications were made as were double and triple combinations at these growth stages (for example, V1+V3, or V1+V3+V5). For between-row weed control, cultivation or flaming was used at the time of the final grit application. Grit applications could achieve greater than 80% season-long weed control and increase silage corn yields by 250% over those of weed-infested plots. The most successful treatments were those initiated at the V1 and V3 stages of corn growth. If initiated at later stages, weed competition affected corn yields. Both cultivation and flaming aided with between-row weed control. These results will be of interest to organic growers, the organic dairy industry, weed scientists, and extension educators responsible for organic agriculture.

Technical Abstract: Weed management in organic farming requires many strategies to accomplish acceptable control and maintain crop yields. This two-year field study used air propelled abrasive grit for in-row weed control in a silage corn system. Corncob grit was applied as a single application at corn vegetative growth stages of V1, V3, or V5 (2013) and V3, V5, and V7 (2014) and in double and triple combinations. Between-row weed control was accomplished by flame-weeding or cultivation after the last grit application. Grit effects on weed efficacy and silage corn yield were quantified and compared with hand-weeded and season-long weedy treatments. Grit applications decreased in-row weed biomass by >80% and increased yield up to 250% when compared with the weedy check. Single early applications (V1 and V3) increased yield, with additional treatments decreasing end-of-season weed density and biomass. Single late grit applications (V5 and V7) also decreased weed biomass, but corn yields were reduced compared with hand-weeded and early treatments.