Strategies to Convert Exotic Grass Pastures to Tall Grass Prairie Communities1

Abstract

Exotic cool- and warm-season grasses have been used throughout the eastern United States as an improved forage in pastures and for wildlife habitat and erosion control. Several of these grasses, including tall fescue are invasive and diminish native grassland biodiversity. This article presents three strategies for reconstructing or rehabilitating native grasslands using herbicides. A variety of herbicides including glyphosate, imazapic, and clethodim, alone or in combination, are effective in killing tall fescue. Imazapic and clethodim show promise for removing tall fescue from native grasslands. Imazapic is more effective when applied with a surfactant and when tall fescue is burned before herbicide application. A standard recommendation for converting tall fescue to native warm-season grasses (NWSG) is to burn tall fescue in late winter, followed by application of 0.2 kg ai/ha imazapic with surfactant and a small amount of nitrogen a month later. The native grasses are seeded directly into the dying and dead sod with a no-till drill. An alternative method is to apply 2.2 kg ai/ha glyphosate to kill the fescue and use 0.067 kg ai/ha imazapic at seeding for weed control. NWSG can be effectively established using conventional tillage by preparing a firm seedbed, drilling or broadcasting the seed directly into the seedbed, and applying 0.067 kg ai/ha imazapic for weed control.Nomenclature: Clethodim; glyphosate; imazapic; tall fescue, Festuca arundinacea Schreb. #3 668 FESAR.Additional index words: Bahiagrass, bermudagrass, fescue conversion, herbicides, native warm-season grasses, quackgrass.Abbreviation: NWSG, native warm-season grasses.