Improved integrated vegetation management strategies for Indiana roadsides

Jamie Mariah Herold, Purdue University

Abstract

With over 90,000 miles of road in Indiana, it is important that adjoining vegetation be maintained for safety, road structure maintenance and aesthetics. An understanding of vegetation management tools, the disturbance they cause and the effect of that disturbance on the plant community are important when designing an integrated vegetation management (IVM) program. In this study, I examine multiple components of an IVM plan for the Indiana Department of Transportation (INDOT), including mowing regimes, selective broadleaf control, plant growth regulators and native species plantings. The first portion of this study examines the use of herbicide and mowing at six sites throughout the state of Indiana. Two mowing treatments, six herbicide treatments, and an untreated control were compared for their ability to decrease dicot species cover and maintain grass height. Mowing treatments included a one-cycle mowing treatment consisting of an early growing season mow (late May to early June 2011) and a two-cycle mowing treatment consisting of both an early (late May to early June 2011) and late growing season mow(August 2011). Herbicide treatments were foliar applied in May2001 and included tank mixes consisting of 2,4-dichlorophenoxyacetic acid (2,4-D®), aminopyralid (Milestone ®), and metsulfuron methyl (Escort®), imazapic (Plateau®),and aminocclopyrachlor (Perspective®, Viewpoint® and Streamline®). We found that dicot cover in all herbicide treatments was reduced rapidly and remained low into the second growing season. Herbicide treatments also regulated grass growth, keeping grass under 15 inches for three months after application. In comparison, mowing treatments provided no decrease in dicot cover and the early season mowing provide little control over grass height. For the second portion of the study, four native seed mixes (western wheatgrass, short grass, tall grass and short grass with forbs) were analyzed for use alternatives to traditional non-native roadside vegetation. Determination of successful planting was based on density of planted species at 90 days and one year after planting at six sites throughout the state of Indiana. Drought and persistent weeds at study sites resulted in a sparse covering of native species during the year after planting; however, this is not uncommon for native roadside planting studies since many native grass species require two to three growing seasons to establish.

Degree

M.S.

Advisors

Dukes, Purdue University.

Subject Area

Ecology|Land Use Planning

COinS