Thesis (M.S.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references (leaves 132-140). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 291-317). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2002. / Typescript. Vita. Includes bibliographical references (leaves 291-317). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 36-40). Also available via the Internet.

Thesis (M.S.)--Montana State University--Bozeman, 2006. / Typescript. Chairperson, Graduate Committee: Cliff Montagne. Includes bibliographical references (leaves 63-70).

Thesis (Ph. D.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on July 31, 2007) Includes bibliographical references.

Grasslands throughout the world including those in British Columbia have been severely reduced and altered by agricultural production and inappropriate livestock grazing practices. Ongoing degradation of rangelands is a worldwide problem, currently affecting about 680 million hectares of rangelands. Studies on development and application of criteria and indicators for forests and grasslands are often lacking, or have been done on a limited number of sites with relatively narrow ranges of climate and soil type. This study aims to (i) quantify the relationships among soil/vegetation properties known to be affected by grazing to easily-assessed indicators, used in the existing health assessment systems, that do not require laboratory analyses or time consuming measurement, and (ii) to evaluate impacts of grazing on soil aggregate stability on the rough fescue grasslands of the southern interior of British Columbia. During the growing seasons of 2006 and 2007, soil and vegetation properties were measured on nine open grassland sites with a potential natural plant community dominated by rough fescue (Festuca campestris Rydb.) in the southern interior of British Columbia. Each site had at least one area excluded from grazing and all units were classified into different seral stages according to the amount of rough fescue present on the land. Rough fescue cover was found to be a useful indicator of the presence of functioning recovery mechanisms. Percent exposed mineral soil was found to be a sensitive indicator of the degree of soil stability and watershed function, as well as an indicator of the integrity of nutrient cycles and energy flows in rough fescue grasslands. Percent Junegrass cover was not as sensitive an indicator as percent exposed mineral soil, but has general overall strength with many health measures.. Only the 1-2 mm aggregate size class was closely related to most soil and vegetation properties, showing that it is more sensitive than the other aggregate stability parameters to soil and vegetation properties. The results from this study can help rangeland managers and ranchers in determining the rangeland health in their area as well as help researchers understand that only a certain number of parameters need to be assessed. / Land and Food Systems, Faculty of / Graduate

Rhizoctonia zeae is a common pathogen of tall fescue and other turfgrasses in various regions of the United States. Disease caused by R. zeae typically occurs during hot, humid summer months when conditions are ideal for growth of the fungus but less than ideal for growth of tall fescue. While R. zeae has been reported on turfgrasses in several Mid-Atlantic states, there are no records of this pathogen being present in Virginia. Rhizoctonia isolates were obtained from samples of various turfgrasses exhibiting typical Rhizoctonia disease symptoms in Virginia. Additional isolates were obtained from several other states. All were characterized with respect to species characteristics as well as pathogenicity and virulence on two common cultivars of tall fescue. All isolates were pathogenic on tall fescue but there was some variability in virulence. There was consistently slightly less disease present on Crossfire II than on Kentucky 31. Experiments were also conducted to determine the impact of prior exposure to high air temperatures on the severity of disease. Preliminary data showed that one week of exposure to higher air temperatures caused an initial increase in overall turf quality, but as length of exposure increased the quality of turfgrass declined. Tall fescue plants were subjected to 0, 7, and 35 days of heat stress prior to inoculation with several isolates of R. zeae. No relationship was found between predisposing heat stress and disease severity. / Master of Science