However, fires occurring more frequently than every 2 years will probably lower biomass production. Postburn herbage production indicates that the season of burning, the amount of annual precipitation the area receives, and site conditions greatly influence big bluestem's response to burning. Response is somewhat variable though, and dependent upon site characteristics. 42.4 43.4 2.0 15.1 23.0 Fires that occur during the summer cause the most harm to big bluestem. Measurements taken the following August showed that productivity was within the seasonal normal range.
Late spring is the best time to burn big bluestem stands.
The later in the spring burning occurs, just prior to the emergence of new growth, the greater the postburn herbage production will be. Regardless of season of burn, however, soil moisture content is consistently lower in burned areas than in unburned areas. Thus in drought years, in areas of low precipitation, or in areas where soil moisture is limiting, big bluestem will probably not show the high postburn biomass increases generally reported for tallgrass prairie sites. Late spring burning can be used to increase grass productivity and improve cattle use. Late spring burning can be used to increase big bluestem and other warm season grass composition in warm season pastures or rangelands infested with undesirable cool season grasses such as Kentucky bluegrass.