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Effects Of Irrigation And Mowing On Species Diversity Of Grass And Wildflower Mixtures For The Intermountain West, Daniel W. Dewey, Paul G. Johnson, Roger Kjelgren

Plants, Soils, and Climate Faculty Publications

Grass and wildflower mixtures can be aesthetically appealing, water-conserving, low-maintenance alternatives to conventional turfgrass. One problem with these mixtures is loss of species diversity over time. We examined the effects of irrigation and mowing on the species diversity of 3 grass and wild-flower mixtures. The nonirrigated and non-mowed treatment combination maintained diversity most effectively whereas the irrigated and mowed treatment combination was least effective. Generally, when the irrigation treatment was significant (P < 0.05), irrigated plots contained more wildflowers. When the mowing treatment was significant (P < 0.05), mowed plots contained more common yarrow (Achillea millefolium L. [Asteraceae]) and strawberry clover (Trifolium fragiferum L. [Fabaceae]) and fewer Pacific aster (Symphyotrichum chilense (Nees) Nesom [Asteraceae]). Height measurements on non-mowed plots showed that irrigated plots had taller canopies than nonirrigated plots. Common yarrow was the most competitive wildflower, followed by strawberry clover and Pacific aster. Mixture 3 containing crested wheatgrass (Agropyron cristatum (L.) Gaertn. [Poaceae]) and thickspike wheatgrass (Elymus lanceolatus (Scribn. & J.G. Sm.) Gould ssp. lanceolatus [Poaceae]) maintained species diversity for the longest duration under nonirrigated and non-mowed conditions.