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dubius) and field bindweed (Convolvulus arvensis) were also present at the Aquarius sites. <br />Within these study sites we also evaluated herbicide treatment effects on desirable grass and forb <br />species. Treatments were applied to 10 x 30 ft plots with four replications for each treatment, <br />arranged in a randomized complete block design. Eight herbicide treatments were applied before <br />(PRE) and after (POST) downy brome emergence in December 2016 and March 2017. Due to <br />the limited moisture in fall 2016, very few germinated downy brome seedlings were observed in <br />the December timing. For this reason, the treatment was conducted as a pre -emergent timing and <br />glyphosate was not added to control any germinated seedlings. Perennial grasses and forbs were <br />dormant at the time of application. In March 2016 cool season grasses were coming out of <br />dormancy so although downy brome had begun to germinate, glyphosate was not added to the <br />treatments to avoid injury to the native species. All treatments were applied with a CO2 <br />pressurized backpack sprayer at 207 kPa using 11002LP flat fan nozzles at 187 L•ha 1. Percent <br />cover estimates of perennial grass and forbs were determined by conducting visual evaluations <br />across each entire plot (18 m2 plot area) in July 2017 at all three sites. In winter 2017, a <br />prescribed burn was conducted at Aquarius Open Space and included burning through the study <br />sites, therefore in 2018 cover estimates were only collected at the Davidson Mesa site. In 2019, <br />cover estimates were again collected at all three sites. Downy brome, perennial grass and forb <br />biomass was also collected from the Davidson Mesa study site in July 2018 and 2019. This study <br />was designed to be conducted for 2-3 years and one more year of evaluations will be collected in <br />2019. <br />Davidson Mesa Downy Brome Protocol (2 Application Timings) <br />Trt No. <br />Treatment <br />Rate <br />Rate Unit <br />Volume/Plot <br />Growth <br />1 <br />Esplanade <br />3.5 <br />OZ/A <br />0.02 oz <br />December 2016 <br />NIS <br />0.25 <br />% V/V <br />December 2016 <br />2 <br />Esplanade <br />5 <br />OZ/A <br />0.03 oz <br />December 2016 <br />NIS <br />0.25 <br />% V/V <br />December 2016 <br />3 <br />Esplanade <br />7 <br />OZ/A <br />0.05 oz <br />December 2016 <br />NIS <br />0.25 <br />% V/V <br />December 2016 <br />4 <br />Plateau <br />7 <br />OZ/A <br />0.05 oz <br />December 2016 <br />Accord XRT II <br />24 <br />OZ/A <br />0.17 oz <br />December 2016 <br />NIS <br />0.25 <br />% V/V <br />December 2016 <br />Esplanade <br />3.5 <br />OZ/A <br />0.02 oz <br />March 2017 <br />NIS <br />0.25 <br />% V/V <br />March 2017 <br />6 Esplanade <br />5 <br />OZ/A <br />0.03 oz <br />March 2017 <br />NIS <br />0.25 <br />% V/V <br />March 2017 <br />Esplanade <br />7 <br />OZ/A <br />0.05 oz <br />March 2017 <br />NIS <br />0.25 <br />% V/V <br />March 2017 <br />8 Plateau <br />7 <br />OZ/A <br />0.05 oz <br />March 2017 <br />NIS <br />0.25 <br />% V/V <br />March 2017 <br />Non -treated <br />Statistical Analysis <br />To test the effect of herbicide treatment on percent cover estimates and biomass all data were <br />subjected to analysis of variance and treatment means separated using Fisher's LSD. All <br />response variables (weed, grass, and forb cover estimates, and downy brome, perennial grass and <br />forb biomass) were evaluated for significant main effects by performing an analysis of variance <br />15 <br />