Late-summer fire and follow-up herbicide treatments in tallgrass prairie.

Abstract

Research on fire in tallgrass prairie focuses almost exclusively on dormant season fires, primarily in winter and spring. Relatively little is known about the response of tallgrass prairie vegetation to growing-season fires or follow-up management. We evaluated vegetation response of grazed, high-seral tallgrass prairies to herbicides after late-summer burning. Dry matter yields of little bluestem [Schizachyrium scoparium (Michx.) Nash], other perennial grasses, total perennial grasses, and total herbage were significantly reduced by late-summer burning. Tallgrass and annual grass standing crop did not differ between burn treatments. Forb standing crop on burned plots averaged about twice that of unburned plots. Follow-up treatment with 2,4-D[(2,4-dichlorophenoxy)-acetic acid] significantly reduced forb standing crop compared to atrazine [6-chloro-N-ethyl-N'-(1-methylethyl) 1,3,5-triazine-2,4-diamine]. Standing crop of tallgrasses and total perennial grasses was greater on plots treated with 2,4-D than on plots treated with no herbicide or with atrazine. Because late-summer burning did not severely reduce herbage production nor drastically alter community composition for more than 1 year, late-summer burning may be a viable alternative for brush control and for improving wildlife habitat in high-seral tallgrass prairie. If management objectives require reduced forb production and increased perennial grass production following late-summer burning, application of 2,4-D would be an appropriate management practice.