Cheatgrass competition and establishment of desert needlegrass seedlings

Published source details Rafferty D. & Young J.A. (2002) Cheatgrass competition and establishment of desert needlegrass seedlings. Journal of Range Management, 55, 70-72.
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Summary

In semi-arid regions of the US Great Basin, where habitat is disturbed by construction, contractors are required to attempt to revegetate such areas using native plants. Revegetation often fails due to competition (primarily for moisture) from an invasive annual, cheatgrass (drooping brome) Bromus tectorum. In very dry areas, the perennial desert needlegrass Achnatherum speciosum has potential for use in restoration projects.In a greenhouse study in Reno (Nevada, southwest USA), the effect of cheatgrasscompetition on desert needlegrassseedling establishment was assessed.

Desert needlegrass was grown in a greenhouse with five different densities of cheatgrass (four replicates of each); densities were derived from field sampling at a site in the Dog Skin Mountains (35 km north of Reno) where needlegrass establishment was desired along a pipeline route.

Seed was sown in cylinders (95 cm deep x 30 cm diameter) filled with soil from the pipeline at the following densities: 1) 100% of field conditions (283 seeds/cylinder); 2) 75% of field density (212 seeds); 3) 25% of field density (71 seeds); and 4) no cheatgrass (control).

The soil was saturated prior to sowing and the surface soil kept moist until seedling emergence. No more watering took place until week 7 when seedlings of both grasses exhibited severe moisture stress. Needlegrass height was recorded weekly for 12 weeks following emergence.

During weeks 1 to 4 there were no statistically significant differences in average needlegrass seedling height among the five treatments. Subsequently, from week 5 to 12, there was a highly significant difference in needlegrass height between the controls (week 5, 9.9 cm; week 12, 13.9 cm) and those sown with cheatgrass at all densities (tallest seedlings were in 25% cheat grass density: week 5, 7.5 cm; week 12, 6.3 cm). However, even at the lowest cheatgrass grass density (equivalent to 25% of field density) needlegrass seedlings were prevented from establishing. Thus to allow desert needlegrass to establish in the field, some form of cheatgrass control is probably required where cheatgrass is present.

Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at: https://www.uair.arizona.edu/holdings/journal/issue?r=http://jrm.library.arizona.edu/Volume55/Number1/