Browsing by Subject "Integrated Weed Management"

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    Emergence Modeling and Economics of Managing Herbicide-Resistant Giant Ragweed (Ambrosia trifida) with Crop Rotation
    (2017-03) Goplen, Jared
    Herbicide-resistant biotypes of giant ragweed are becoming widespread, making control with herbicides increasingly difficult. To improve control of giant ragweed and prevent the proliferation of resistant biotypes, it is necessary to use integrated methods of weed control. This research evaluated the economic performance and weed control potential of several crop rotations and spring pre-plant tillage dates. The prediction accuracy of previously developed giant ragweed emergence models was evaluated in various crop rotations and spring tillage dates to determine the giant ragweed emergence model most effective at predicting emergence. Total and temporal patterns of giant ragweed emergence were evaluated in various spring tillage dates to determine the best timing of spring tillage for giant ragweed control. Finally, the economic performance of various crop rotations was determined in the presence of herbicide-resistant giant ragweed. This research provides a valuable assessment of the crop rotations, tillage dates, and emergence models that are most effective in improving herbicide-resistant giant ragweed control.
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    Integrated weed management in soybean
    (2013-10) Flipp, Amanda Marie
    Studies were conducted in 2011 and 2012 at two sites at the Southern Research and Outreach Center in Waseca, MN to evaluate different combinations of row spacing, soybean varieties, and early season weed control treatments on giant ragweed, common lambsquarters, and tall waterhemp density, biomass, and seed production. The early season weed control treatments consisted of a pre-emergence herbicide, winter rye cover, and radish/pennycress cover mixture. Overall, a flumioxazin, acetochlor, or winter rye treatment were the most effective in reducing weed density, biomass, and seed production. These two treatments generally resulted in at least a 50% reduction in total weed density compared to the control. A flumioxazin or winter rye treatment resulted in no weed seed production of common lambsquarters at Site 1 in 2011, compared to 2018 seeds m-2 in the control. Results demonstrate the importance of early season weed control as part of a comprehensive weed management plan. Soybean row spacing and variety were not as effective in reducing weed density, biomass, and seed production. However, they were important as part of an integrated weed management strategy when used in combination with the winter rye cover crop and flumioxazin or acetochlor in controlling weeds in soybeans. A fully integrated approach is needed to control weeds, either to prevent herbicide resistant weeds or to manage herbicide resistant weeds.