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Introduction of Little Bluestem (Schizachyrium scoparium) into Dense KR Bluestem (Bothriochloa ischaemum var. songarica)

by Bob Harms  email-here
To try to determine whether little bluestem could be successfully introduced into dense KR with subsequent penetration of the KR, in fall 2003 I dug out the KR plants from three narrow plots, roughly 1 1/2 x 6 feet. I then transplanted one small little bluestem clump into one end of the plot and also placed culms with mature little bluestem inflorescences of that fall (assumed to have seeds) along the plot. I watered the plots once at that time, but gave them no other care. The following summer (2004) all three plots had little bluestem seedlings but few KR seedlings. I didn't inspect the plots closely during 2005 and the drought of 2006, fearing the worst. If they had bloomed, I would have noticed. But in July 2007, a wet summer overall, all three plots showed well-developed new grasses, preparing to bloom in early August, with only minimal incursion of KR into the plots. In plots 2 and 3 little bluestem culms can be seen emerging in the Aug. 11 photos..

One unexpected side effect of this project was the appearance of strongly rhizomatous sideoats grama (Bouteloua curtipendula) in plots 1 and 3, unexpected because I had introduced only one little bluestem plant in each plus culms with seeds, and it is not otherwise present in the adjacent area. The most likely answer is that the seeds were already present in the soil, and germinated when the soil was disturbed in removing the KR. In plot 1 the sideoats grama has spread throughout the entire plot, perhaps blocking development of little bluestem. I can't rule out the possibility that either seeds or rhizomes were present in the soil introduced with the little bluestem transplants, but this does not seem likely since the transplants were taken from different areas.

The photos were taken in August, 2007. The brighter green plants in the center are little bluestem and sideoats grama — otherwise the two are difficult to distinguish in the photos.

Plot 1, area never mown, with sideoats grama.
Sideoats culm shown on left is from area with red outline.

Plot 2, an area mown until recently.
Little bluestem culm shown on left is from area with red outline.

Plot 3, in 1988 burn area