Repository logo

Theses and Dissertations

Permanent URI for this collection

https://hdl.handle.net/10217/100454

Browse

Browsing Theses and Dissertations by Author "Andales, Allan A., committee member"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Changes in golf course fairway soils under effluent water irrigation
    (Colorado State University. Libraries, 2010) Skiles, David John, author; Qian, Yaling, advisor; Andales, Allan A., committee member; Koski, Tony, committee member
    As the use of effluent irrigation increases, salinity and sodicity issues associated with its use continue to be of great concern to the golf course industry. The purpose of our research was to (i) observe salinity accumulation patterns on 4 fairways of two effluent water irrigated golf courses using 2 different types of sensors and to (ii) determine long-term changes in soil chemistry in soils under effluent water irrigation on golf course fairways. Temporal and spatial accumulation patterns were measured using a network of in-situ soil sensors located at two depths 15 and 30 cm for 5TE sensors and 8 and 19cm for Turf Guard sensors (TG2). Sensors measured electrical conductivity (EC), volumetric soil water content (SWC), and soil temperature data were collected continuously during the 2008 and 2009 growing seasons. Correlation was observed between 5TE sensor-measured soil salinity vs. saturated paste extracted soil salinity (r = 0.77). A significant exponential relationship was observed between TG2 sensor-measured soil salinity vs. saturated paste extracted soil salinity (R² = 0.97). In-ground measurements indicated that salinity can vary widely across a seemingly homogenous golf course fairway in a manner reflective of the underlying soil physical characteristics. Plots exhibiting low and high salinities presented opposite seasonal trends at Heritage Golf Course. Strong correlation was observed between average soil salinity and mean soil water content (r =0.76), soil salinity and the percentage of sand in the soil texture composition (r = -0.63) for Heritage fairway 1. High salinity was found on fairway 19 at Common Ground Golf Course. However, the salinity level as high as 10.6 dS/m is not a result of water reuse, but a historical geological contribution. Drainage appears to be vital in maintaining low soil salinity levels under effluent irrigation in clay soils. Slow to infiltrate, percolate and difficult to leach; predominately clay soils irrigated with effluent water can accumulate soil salinity over time. Our data suggested that a robust drainage network in predominantly clay soils irrigated with effluent could better manage salinity accumulation associated with poor drainage. To determine long-term changes in soil chemistry in soils under effluent water irrigation on golf course fairways, soil testing data was provided by the superintendent for the years of 1999, 2000, 2002, 2003, and 2009 for Heritage Golf Course in Westminster, Colorado. Soil samples were tested by Brookside Laboratories, Inc, New Knoxville, OH. Parameters of each soil sample tested included pH, extractable salt content (calcium, magnesium, potassium, sodium, iron, manganese, copper, zinc, phosphorus, and boron), base saturation percent of calcium, magnesium, potassium and sodium, soil organic matter (SOM), and cation exchange capacity (CEC). Regression analysis was used to evaluate the changes in individual soil parameters over time after the use of effluent water for irrigation. Soil pH, CEC, extractable aluminum, copper, manganese and iron along with both base saturation percentages and exchangeable percentages of calcium and magnesium did not change over time. The strongest indications of change are seen for extractable boron (R² = 0.56), Bray II extracted phosphate (R² = 0.56), and sodium base saturation percentage (R² = 0.44). The regression analysis indicated that B, P, and sodium increased linearly during the 8 year's irrigation with effluent water. Further studies are needed to determine if these parameters would continue to increase or would stabilize. Continued accumulation of sodium could eventually result in loss of soil structure.
  • Thumbnail Image
    ItemOpen Access
    Responses of four shrub species to four levels of irrigation in a semi-arid environment
    (Colorado State University. Libraries, 2012) Smith, Jason F., author; Klett, James E., advisor; Andales, Allan A., committee member; Bauerle, William L., committee member
    In response to a severe regional drought that afflicted much of Colorado in 2002, Colorado State University initiated a study to determine the impacts of progressively decreasing irrigation treatments on some common shrub species. Irrigation treatments were based on the evapotranspiration of a short reference crop (ETo). In 2008, four shrub species were planted for trialing: Cornus sericea L. 'Isanti' (redosier dogwood), Hydrangea arborescens L. 'Annabelle' (smooth hydrangea), Physocarpus opulifolius (L.) Maxim. 'Monlo' (Diablo® ninebark) and, Salix pupurea L. 'Nana' (arctic blue willow). In addition to the shrubs, Poa pratensis L. (Kentucky bluegrass) was used as a control. After giving the shrubs and turf one growing season to establish, treatments were applied in 2009 and 2010. The study was comprised of a field component and a lysimeter component. The field component had four treatments based on ETo (0%, 25%, 50%, and 100%) and the lysimeter component had three treatments (25%, 50%, and 100%). All four species were planted in the field component and only the redosier dogwood and smooth hydrangea were planted in the lysimeter component due to space limitations. Data collection in both components included canopy height and width, visual ratings, predawn leaf water potentials, end of season leaf area, and end of season leaf fresh/dry weights. The field component also included soil moisture readings, osmolality, and infrared readings of the Kentucky bluegrass. The lysimeter component required daily weight measurements during dry down periods. As watering amounts increased for the field dogwoods, ninebarks, and willows various characteristics (overall stress, aesthetic appeal, size, osmolality) were also positively affected. However, all tested replicates of these three species in the 0% treatment appeared acceptable for landscape use, as well. The hydrangeas in the 100% treatment had the highest visual ratings. In addition, the water potentials were more negative in the 100% treatment. Due to the visual ratings and water potential data, it suggests that smooth hydrangea needs more than 100% ETo to improve growth and performance. All of the field hydrangeas in the 0% treatment were unacceptable for landscape use and were close to death, however, 80% of the replications survived until the conclusion of the experiment. As such, the smooth hydrangea can survive a short period without water and should recover when water becomes available. The lysimeter dogwoods and hydrangeas adjusted their growth habits based on water availability. Water was used on a daily basis at a faster rate as the irrigation treatments increased. The lysimeter shrubs in the 100% treatment used more water on a daily basis than the 50% treatment and the 50% treatment used more than the 25% treatment. The increased water use affected plant growth and if more water was available to the dogwood and hydrangea, a larger plant resulted.