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United States Department of Agriculture

Agricultural Research Service

Title: Decline of Weed Densities in Sunflower As Affected by Multiple Tactics in A3-Crop Rotation

Authors
item Ries, Ronald - USDA-ARS, RETIRED
item Tanaka, Donald
item Anderson, Randal

Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: December 15, 2001
Publication Date: January 17, 2002
Citation: Ries, R.E., Tanaka, D.L., Anderson, R.L. 2002. Decline of weed densities in sunflower as affected by multiple tactics in a3-crop rotation. Proceedings Sunflower Research Workshop.

Interpretive Summary: Cultural weed control is generally ineffective when only one practice is used. However, combining several practices into a cultural system can synergistically improve crop competitiveness with weeds. A spring wheat- winter wheat-sunflower rotation, established in 1984, was extremely weedy by 1996. This provided us with an opportunity to assess impact of combining multiple tactics on weed changes over time. Several cultural practices were changed to favor crop growth over weeds; changes included banding N fertilizer by the seed, growing crops in narrower rows, and delaying planting to control early season weeds. The new management system drastically limited seed production by weeds; within three years, weeds were almost eliminated. This study demonstrates that producers can greatly improve a crop's ability to compete with weeds. Competitive crops may help producers in reducing rate and/or use of herbicides.

Technical Abstract: Producers are seeking to reduce the use of herbicides, with the goal of reducing input costs as well as avoid the development of herbicide resistant weeds. A long-term rotation established in 1984 had become heavily infested with weeds by 1996. To improve weed management, we changed several cultural practices with the goal of improving crop competitiveness. Changes included narrower rows, N placement, and delayed planting to control early season weeds. The new management system almost eliminated seed production by weeds; within three years, weeds were reduced dramatically. Our study demonstrates that producers can greatly improve a crop's ability to compete with weeds. Competitive crops may help producers in reducing the rate and/or use of herbicides.

Last Modified: 12/18/2014
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