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
Objective:
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.
Approach:
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.
