The contamination of ground water resources represents a serious problem and a prominent threat to the health of our society. This study focuses on the leaching of inorganic anions as a function of agricultural practices under natural field conditions. In order to enhance the understanding of such leaching processes, this thesis evaluates the spatial variability of the leaching characteristics of a site, the factors controlling percolation, and the use of a cereal rye cover crop to reduce nitrate leaching. Thirty-two Passive Capillary Wick Samplers (PCAPS) and 32 suction cups were installed at a depth of 120 cm under row crop produced in a Woodburn Variant loam (fine-loamy mixed mesic Aquultic Argixeroll). Significant correlation for the water flux was seen at the 2.0 m distance, beyond which values were uncorrelated. No spatial correlation was seen in hydrodynamic dispersion coefficients. Percolation was independent of field saturated hydraulic conductivity, while the quantity of incident water was strongly correlated with percolation. The occurrence of preferential flow affected the leaching process as documented by solute breakthrough ahead of the main solute peak. Rates of nitrogen fertilizer application were proportional to observed nitrate leaching losses. The cover crop significantly reduced the amount of nitrate leaching at all N fertilizer application rates. At the recommended rate, nitrate-N concentrations were lowered on average from 22.2 to 9.9 mg/l; cumulative N mass losses were cut by 62% due to plant uptake by the cover crop. The study demonstrated the importance of conducting long-term field experiments under natural conditions to accurately assess leaching processes. / Graduation date: 1996

This study was designed to provide a physical and ecological analysis of paired watersheds in the semi-arid western juniper (Juniperus occidentalis) woodlands of Central Oregon. Instrumentation and monitoring was accomplished in Jensen and Mays watersheds as the preliminary portion of a longer term project. Instrumentation was designed to address changes in the erosional processes, hydrology, and vegetation on a watershed scale. Instrumentation was setup to assist in the comparison and calibration of water flow out of the watersheds. This information will be used in the long-term study in conjunction with the treatment of the western juniper overstory on one of the watersheds. Determination of the study area in each watershed required extensive reconnaissance with the assistance of aerial photos, topographic maps, and Geographic Information Systems (GIS). Mapping of the study areas was accomplished with GIS and Global Positioning Systems (GPS). Watersheds were paired according to specific characteristics that influence treatment effects. Flume types were chosen with respect to precipitation intensity and frequency with placement being more a function of watershed topography and channel morphology. Upland sedimentation and erosion measurement required intense acknowledgement of both abiotic as well as biotic characteristics. Analysis showed the watersheds to be similar in size, percent juniper, grass and bare soil cover, topography, and precipitation frequency and intensity. Differences were obtained relative to erosional processes, area of different soil types and channel discharge. Further monitoring and calibration should provide greater insight into the comparison of these components of the study. / Graduation date: 1996

A total of 44 intermittent sand filter-septic systems, in five counties of Western Oregon, were sampled over a three-month period during the summer of 1995. The sand filter systems varied in age from 36 months up to 167 months (3 to 13.9 years). Liquid samples were taken from the septic tank and distribution box. In addition, soil samples were taken adjacent to the disposal trench and away from the disposal field area (control). All samples were analyzed for Total Kjeldahl Nitrogen (TKN) and nitrate and nitrite. Nitrite was not detected in any of the samples. The average removal of total nitrogen (TKN + nitrate) through the filter was found to be 43%. Nitrate was determined to be the dominant form of nitrogen in the sand filter effluent making up 94% of the total nitrogen. The age of the system was found not to be a predictor of the system's performance. Once the effluent entered the disposal field, little if any transformation of nitrogen occurred at an average depth of 30 inches (76.2 cm). / Graduation date: 1996

The objectives of this research were to 1) evaluate the establishment and peak standing crop of Berber Orchardgrass (Dactylis glomerata var. "Berber"), Palestine Orchardgrass (Dactylis glomerata var. "Palestine"), and Sheep Fescue (Festuca ovina var. "Covar") ; 2) to assess establishment and production changes resulting from environmental gradients (elevation, slope, aspect, soil texture, precipitation, and resident annual community) across the foothill landscape; 3) develop a mathematical model that predicts site potential for restoration; and 4) evaluate the utility of Geographic Information Systems for creation and analysis of spatial data which identify site production potential. Sixteen sites were chosen which reflect the general character of the foothill rangelands in southwestern Oregon. A Randomized Complete Block design was used to select treatment arrangement on each site. Seeded treatments received both chemical (Glyphosate, Hoelon, and 2,4-D) and mechanical (residue removal) disturbance. Test species were seeded into three replications at each site. Each replication also included a non-treatment control. Standing crop data for test species and resident exotics were collected after three growing seasons. Berber orchardgrass did not establish at most sites and where establishment did take place production was less than 132 kgDM/ha. Palestine orchardgrass established on on a majority of the study sites and produced most aboveground phytomass at mid-elevations where coarser soil textures and deeper soil depths were common. Sheep fescue was the most successful of the three test species and did best on low elevation high clay sites. There was significantly (P=0.001) more phytomass produced by annual exotics on seeded plots than on undisturbed controls at most sites. Both Palestine orchardgrass and sheep fescue treatments significantly suppressed the annual exotics when compared to the Berber treatments. Generally, "Covar" sheep fescue can establish and successfully compete with exotics on heavier textured soils at low elevations. "Palestine orchardgrass is adapted to mid-elevation coarser soils. / Graduation date: 1995

Prediction equations were developed for estimating the flow regime at ungaged stream locations in the Oregon coastal range. Principal components analysis was used to screen the initial data set of physiographic and meteorological parameters. The final regression equations for predicting mean monthly flow had standard errors of estimate ranging from 3 to 42 percent, with an average standard error of 13.5 percent. A linear prediction equation was found to give the best results for drainage basins larger than 150 square miles, while a logarithmic equation gave best results for basins of less than 150 square miles in area. A simple linear relationship was also established between mean monthly flow and the standard deviation of monthly flow. A test on an independent sample indicated that the monthly estimates of standard deviation made using the simple linear relations were comparable to those reported by others using equations containing physiographic and meteorological parameters. Equations were also developed to forecast monthly streamflow for Oregon coastal streams. When observed rainfall for the current month was used, the average standard error of the forecast equations was 18 percent. The use of the National Weather Service's 30-day precipitation outlooks in forecasting monthly streamflow was also investigated. The results showed that the forecasts based upon the 30-day outlook precipitation were worse than those based upon median historical precipitation. It was suggested that the monthly streamflow forecast equations could best be applied on a probability basis. / Graduation date: 1974

The purpose of this case study was to explore the perceptions of school district administrators and members of the community about the influence of school-based activities had on voter behavior. The case study focused on a school district in the Willamette Valley of Oregon. Interviews were held with the school district administrators and taxpayers in the community. The surveyed taxpayers were prominent, influential and well informed about the school district and the community. Three questions were addressed to both the school administrators and taxpayers. (1.) What are the perceptions of the interviewee on the influence of school site activities on voter behavior? (2.) What activities would the interviewee perceive to be most effective in gaining/keeping community support? (3.) Does the interviewee perceive anything unusual about the community in its participation in school site activities and/or non-school activities? It was found that attracting the people to the school site can be a positive influence, provided that the schoolsite is in good order. The activities most effective in gaining/keeping community support were those activities that pulled the widest range of community members to the school site. The administrators perceived the large attendance at school activities as support for the school system rather than the family members supporting the children. Administrators were also aware of a large segment of the community without school-age children, yet no active budgeted plans to reach them had been made. Furthermore, community members felt that the district should live within their budget even though there was large community support for school based activities. The change in demographic characteristics, increased enrollment, and increased property evaluations have caused the community's perception of the school district to become more fiscally conservative. Due to the lack of trust by the taxpayers, the school district needs to be sensitive to the community by furnishing timely information about the how and why public monies are being spent. / Graduation date: 1994

Graduation date: 1995

The thesis is a case study of two traditional family farms that were settled in Oregon in 1850 and 1915. The study embraces the theory that material culture reflects customs and values. The material culture indicators within the study are the architectural structures of the Oregon farms. The study filters the architecture through theoretical and historical data of both Oregon and the Upland South. The farms are recorded with oral history, photographs, architectural descriptions, and evolutionary settlement patterns. The filtering process results in two constructs that correlate the commonalities of both the Oregon farms and the Upland South architecture. The results point out that, with the disappearance of vernacular architecture on family farms, it follows that historic traditional cultures vanish. / Graduation date: 1993

Thesis (doctoral)--Oregon State University. / Bibliography: p. 127-132. Also available via the World Wide Web.

The relationship between population and residential property taxes is not well understood. This study is an attempt to discern the relationship. The basic questions examined are: How does population affect tax bills? What are the short-run and long-run relationships between population and taxes? What reasons lie behind the answers to the first two questions? Nearly all of a typical residential property tax bill is paid to the three units of local government, counties, cities, and school districts. The equation for determining the tax bill is the same for each unit of government: Total Expenditures minus other non-property tax revenues equals the Levy which divided by the total value of all property in the district equals the tax rate which multiplied by the value of a residence gives that residence's tax bill. The relationships between each of the above variables and population are examined to facilitate understanding of the tax-population relationship. The model chapter provides a logical link between each variable and population and corresponding estimating equations to assess long-run and short-run relationships and the relative effect of population on the separate tax variables. For long-run relationships both simple linear and quadratic functions are used with population as the explanatory variable. For short-run equations, first difference estimates are computed. Elasticities are computed for comparing the relative effect of population on the tax variables. The results obtained show that despite high R2 values the large confidence intervals about the regression lines imply that substantial variation is left unexplained by population variables. Generally, levies appear to be more responsive to population than does the value of all property as a whole resulting in a rate of growth in the levies which exceeds that of property values. Hence, tax rates tend to increase slightly with increases in population. Higher residential property taxes are associated with larger populations. This appears to be due in part to the relatively more elastic response of residential values to population than all property values as a whole. Taxes appear to be shifting toward residential property owners. Finally, short-run changes in taxes and variables composing the tax equation do not appear to be related to short-run changes in population. / Graduation date: 1979