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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Research Project #443243

Research Project: Climate-adaptive Strategies for Overcoming Barriers to Establishment of Diverse CRP Plantings in Drylands - Miles City

Location: Livestock and Range Research Laboratory

Project Number: 3030-21500-001-004-I
Project Type: Interagency Reimbursable Agreement

Start Date: Sep 1, 2022
End Date: Aug 31, 2027

To test the hypothesis that benefits of herbicides (reduced weed competition) to seeded forbs outweigh disadvantages (herbicide damage to forbs) when weed abundances are high.

We will study 30 CRP fields that are seeded by managers over three years (10 fields per year × 3 years) in Colorado and Montana. Within each field, we will measure weed and seeded species densities shortly after they emerge in the first growing season. Then we will establish 12 plots [3 replications × (1 untreated control + 3 herbicide treatments)] and apply three herbicide treatments. The treatments will be two imidazolinone herbicides (imazethapyr, imazapic) and one grass-specific herbicide (fluazifop). Two weeks after applying herbicides, we will measure weed control and herbicide damage to seeded species. In the fifth and final growing season of the study, we will measure cover of all weeds and seeded plants by species.