LATE-SUMMER FIRE AND FOLLOW-UP HERBICIDE TREATMENTS IN TALLGRASS PRAIRIE

Research on fire in tallgrass prairie focuses almost exclusively on do rmant 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 respons e of grazed, high-seral tallgrass prairies to herbicides after late-su mmer burning. Dry matter yields of little bluestem [Schizachyrium scop arium (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 th at of unburned plots. Follow-up treatment with 2,4-D[(2,4-dichlorophen oxy)acetic acid] significantly reduced forb standing crop compared to atrazine yl-N'-(l-methylethyl)-l,3,5-triazine-2,4-diamine]. Standing c rop of tallgrasses and total perennial grasses was greater on plots tr eated with 2,4-D than on plots treated with no herbicide or with atraz ine. Because late-summer burning did not severely reduce herbage produ ction nor drastically alter community composition for more than 1 year , late-summer burning may be a viable alternative for brush control an d for improving wildlife habitat in high-seral tallgrass prairie. If m anagement objectives require reduced forb production and increased per ennial grass production following late-summer burning, application of 2,4-D would be an appropriate management practice.