PS 32-190 - Germination and growth of cheatgrass and blue grama in burned and unburned soils

Tuesday, August 9, 2011
Exhibit Hall 3, Austin Convention Center
Timothy N. Terry, Biology Department, Regis University, Denver, CO and Catherine Kleier, Biology, Regis University, Denver, CO
Background/Question/Methods

We wanted to see how different grasses reacted to burned soils compared to unburned soils.  We collected soil from the Flatirons Vista trailhead in Boulder Colorado. We planted cheatgrass (Bromus tectorum), an invasive species of grass, as well as blue grama (Bouteloua graciliss) a native Colorado grass, in both burned and unburned soils  within the environmental growth chambers at Regis University Lowell campus.  We ran  dry weight analysis on the roots as well as the shoots and also compared the root to shoot ratio. There was a significant increase in root growth in the burned soils.  This study is important to help us better manage an invasive species as well as see the impact fire has on the grassland community.

Results/Conclusions

An ANOVA showed no statistical differences between species or burn treatments for shoot growth (F=1.319, p = 0.273) and no statistical differences between species or burn treatments for root to shoot ratio (F=0.732, p=0.536).  For root growth, ANOVA detected differences among all treatments (F=1.319, p<0.001).  An LSD post-hoc analysis showed that unburned cheatgrass had higher root grass than all other treatments (p,0.01) and that unburned cheatgrass had greater root growth than unburned blue grama (p=0.031).  Burning had a significant impact on the growth of cheatgrass roots, but did not change the growth of blue grama roots.

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