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Browsing by Author "Redente, Edward F., advisor"

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    Canada thistle (Cirsium arvense [L.] Scop.) response to mowing, herbicide, competitive grasses, and soil amendments on wetland, upland, and mesic sites
    (Colorado State University. Libraries, 2009) Knudson, Julie A., author; Redente, Edward F., advisor; Meiman, Paul J., advisor
    Canada thistle (Cirsium arvense [L.] Scop.) is one of the most problematic weeds of temperate regions and is found throughout North America, Europe, Africa, and across central Asia. Canada thistle's ability to spread quickly and recover from many control methods makes managing Canada thistle a significant challenge for land managers. Herbicide application can be effective, but mixed results, toxicity concerns, and the need for re-application demand new, more efficient strategies that reduce herbicide use. A greenhouse study tested effectiveness of clipping and grass seeding for Canada thistle control. Grasses used included two natives (western wheatgrass [Pascopyrum smithii {Rydb.} A. Löve], streambank wheatgrass [Elymus lanceolatus {Scribn. & J.G. Sm.} Gould ssp. lanceolatus]) and one sterile hybrid (common wheat [Triticum aestivum L.] x tall wheatgrass [Thinopyrum ponticum {Podp.} Z.W. Liu & R.C. Wang]) called Regreen™. Grasses were seeded alone or in combination (Regreen+western wheatgrass) in pots with Canada thistle. Field Study I tested combinations of mowing, herbicide, and grass seeding across two habitats (wetland, upland) and three different local climatic regimes for control of Canada thistle. Grass treatments involved seeding western wheatgrass (upland sites) or prairie cordgrass (Spartina pectinata Bosc ex Link) (wetland sites) alone or in combination with Regreen (upland and wetland sites). Six sites (three wetland, three upland) were paired geographically across Colorado with each wetland site in close proximity to an upland site. Field Study II tested combinations of mowing, herbicide, soil amendment addition (organic matter, manganese), and grass seeding (western wheatgrass, intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] on a Colorado mesic site. In greenhouse trials, clipping inhibited Canada thistle growth, while grass seeding did not. In Field Study I, herbicide application produced effective control. In Field Study II, tilling enhanced herbicide effectiveness. Organic matter or manganese alone did not reduce Canada thistle growth. Manganese addition reduced herbicide effectiveness. In both field studies, neither mowing nor grass seeding enhanced herbicide effectiveness, and tilling did not increase Canada thistle biomass. Future research should address restoration of infested wetland sites, the importance of irrigation during drought for restoration, and the mechanism through which manganese sulfate inhibits herbicide effectiveness.
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    ItemOpen Access
    The application of ecological principles to accelerate reclamation of well pad sites
    (Colorado State University. Libraries, 2009) Eldridge, Joshua David, author; Redente, Edward F., advisor; Barbarick, Kenneth A., committee member; Paschke, Mark W., committee member
    Western Colorado is experiencing a boom in natural gas development. However, the semi-arid ecosystems of this area have difficulty recovering from energy related disturbances. The purpose of this study was to improve reclamation techniques of natural gas well pads on the Western Slope of Colorado to establish viable native plant populations. The reclamation techniques studied are intended to repair damaged ecological processes and help guide the trajectory of natural plant succession toward a more desired plant community. The study examined the effects and interactions of seedbed preparation, soil amendments, seed mixtures, and seeding methods. The experiment was conducted in pinyon-juniper and sagebrush steppe/salt desert scrub plant communities on five natural gas well pads near Parachute, Colorado. Soil and plant cover data were collected to assess the effectiveness of 16 different treatment combinations. The data were analyzed by using a generalized linear mixed model. There was a significant difference in precipitation between 2007 and 2008, with 2007 receiving only 53% of average precipitation while 2008 was slightly above the average precipitation of 300 mm. After two growing seasons, the data show that the use of wood chips as a soil amendment increased organic matter content and reduced non-native species. Rough seedbed preparation increased the establishment of native species, especially during years of below average precipitation. Island broadcasting resulted in an increase of noxious plant cover in 2008. Additional monitoring over time is still needed before more conclusive statements can be made about the effects of the different seed mixtures. Soil testing revealed that soil salinity will need to be ameliorated in some areas for successful reclamation to occur.