Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2015
Publication Date: 9/1/2015
Citation: Williams II, M.M. 2015. Managing weeds in commercial edamame production: current options and their outcomes. Weed Science. 63:954-961.
Interpretive Summary: Lack of effective weed management systems is a major barrier to producing edamame domestically in the U.S., the world’s leading producer of grain-type soybean that also imports most of its edamame. This work developed and compared 10 weed management systems in edamame. The systems included cultural and mechanical tactics, as well as herbicides that have become registered for use on the crop in recent years or may become registered in the near future. The impact of this work is that it identifies currently available weed management systems which are most effective. It also demonstrates specific weed-related issues requiring future research, including the use of crop traits that improve competitive ability against weeds. Overall, this research will likely reduce reliance on handweeding and improve competitiveness of U.S.-grown edamame.
Technical Abstract: Edamame, a specialty food-grade soybean popular among health-conscious consumers, is growing in popularity worldwide. Despite a well-developed soybean industry, nearly all edamame consumed in the U.S. is imported from Asia. Considerable interest exists to grow edamame domestically; however, weed interference is a major problem, and until recently, only a single herbicide was registered for use on the crop. The objectives of this work were to 1) compare effectiveness of weed management systems that utilize herbicides currently registered for use on edamame or that may be registered in the near future, 2) determine the significance of edamame cultivar on performance of these systems, and 3) identify relationships among population density, plant biomass, and yield of the weed/crop community. Ten different weed management systems were tested in three edamame cultivars over a three-year period. All weed management systems increased marketable pod yield relative to the nontreated control, but only systems with metolachlor or saflufenacil were comparable to the handweeded weed-free treatment. Of the systems studied, metolachlor followed by imazamox was among the highest yielding, lowest weed density and biomass, and did not reduce crop population density. Also, cultivars differed in their weed suppressive ability. Path analysis indicated certain relationships were consistent across cultivars, such as weed population density having a direct negative association with crop biomass; however, other edamame-weed interactions were not identical across cultivars. Although more improvements are needed, the vegetable industry now has viable weed management tools in edamame, which will likely reduce reliance on handweeding and result in crop production costs that are more competitive in the global market.