A study was undertaken on the Livestock and Range Research Station near Miles City, eastern Montana (USA), to evaluate the effects of autumn and spring prescribed burning on three important forage species (western wheatgrass Agropyron smithii, blue grama Bouteloua gracilis and threadleaf sedge Carex filifolia) in mixed grass prairie.
The study was conducted on three prairie sites comprising plant communities of relatively uniform, pure stands of each study species.
One of four treatments was randomly assigned to 3 x 3 m plots (10 replications of each treatment) at each site: autumn (end of October, i.e. post growing season, 1978) burn; spring burn; autumn clip; and a control. Threadleaf sedge plots were burned on 3 April, blue grama plots on 9 April and western wheatgrass plots on 17 April.
Yield measurements of the study species were made throughout the 1979 growing season at 2-week intervals. Measurements of vegetation cover and soil moisture were also made.
Spring burning stimulated blue grama production, peaking on 18 June (spring burn 950 kg/ha; clipped 880 kg/ha; autumn burn 730 kg/ha; control 710 kg/ha). Western wheatgrass production was also a little higher on 18 June than other treatments but peaked in early July when little difference was apparent between treatments (1,500-1,600 kg/ha). Autumn burning stimulated yield slightly.
Threadleaf sedge yield was little affected by treatment (all treatments slightly less than 600 kg/ha at the peak on 18 June). It was reduced a slightly by autumn burning (c. 450 kg/ha vs. 500 kg/ha in other treatments).
Burning and clipping substantially reduced litter cover and increased bare soil in the western wheatgrass (control litter = 67% vs. 22-33%; control bare soil = 5% vs. 43-48%) and threadleaf sedge (control litter = 65% vs. 26-40%; control bare soil = 9% vs. 30-49%) communities.
In the blue grama community, there was a slight increase in litter cover on the burned and clipped plots (45-47% and 51% respectively) compared to the control (39%). There was also a slight increase in bare soil (3-9% in treatments plots vs. control 3%)
No significant differences in soil moisture were observed between spring and autumn burns.
The authors conclude that spring or autumn burning has beneficial management effects on Northern Great Plains rangelands dominated by western wheatgrass, blue grama or threadleaf sedge.
Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at: