Location: Global Change and Photosynthesis Research
2021 Annual Report
Objectives
Objective 1: Develop control measures for weeds in vegetables, fruits, and specialty crops. [NP304, C2, PS 2A]
Objective 2: Determine herbicide residues in harvested product. [NP 304, C2, PS 2A]
Approach
Candidate herbicides for use in minor crops will be identified. Herbicides alone or in combination with other tactics will be evaluated under field conditions and crop and/or weed responses will be determined.
Progress Report
This is the first report for this new project which just began in July 2020 and continues research from the previous project, 0500-00007-107-00D, “Minor Use Weed Management”. Please see the report for the previous project for additional information.
In support of Objective 1, significant progress has been made on developing control measures for weeds in vegetables crops. A genotyped snap bean diversity panel has been used to determine tolerance to pyroxasulfone and sulfentrazone in multiple field environments. Preliminary analyses of existing data identified several candidate genes conferring tolerance to a specific soil-active both herbicides. A manuscript is being prepared. Additional follow-up studies (lab and greenhouse) are being developed to identify the extent to which tolerance is conferred to both similar and different herbicidal sites of action. The diversity panel is also being used to understand crop competitiveness with weeds, including the role of biological nitrogen fixation and any crop competitive advantage in low synthetic-nitrogen-fertilizer environments. In previous work, field experiments found an early-terminated cereal rye cover crop worked well for weed management in edamame but not lima bean or snap bean. Data were analyzed, a manuscript was written, and the work is now published. Additional ongoing cover crop research includes: 1) developing a grower-oriented web application to predict cereal rye phenology that will be useful in determining cover crop termination dates, and 2) examining interactions between s-metolachlor and cereal rye residues on shattercane, velvetleaf, and waterhemp emergence and seedling growth. A field experiment was conducted to determine the role of postharvest weed seed control in reducing weed seedbank inputs following sweet corn harvest. Seed production dynamics of velvetleaf, waterhemp, and wild-proso millet are being characterized in multiple planting environments. Currently weed seed samples are being processed.
No progress was made on Objective 2 since quantifying herbicide residues in harvested product was of low priority or inappropriate for experiments developed for Objective 1, which were centered on crop tolerance, crop competitiveness, cover crops for weed suppression, and harvest weed seed control.
Accomplishments
1. Cereal rye cover crop plays important role in edamame weed management. Vegetable legumes grown for processing (i.e. edamame, lima bean, snap bean) contribute to a healthy diet; however, weeds are a major production problem with few tools to manage them economically. ARS researchers at Urbana, Illinois, examined the role of early-terminated cereal rye cover crop on weed suppression and crop yield. While the cover crop system harmed lima bean and snap bean emergence and growth, researchers found the system selectively enhanced weed control in edamame comparable to handweeding. The research offers a new, economically viable solution to weed management in edamame while being the first to reduce reliance on chemical weed control. Grown almost entirely outside the United States a decade ago, the research facilitates the development of a competitive, sustainable domestic edamame industry to feed the growing interest among American consumers.
