A greater than 10-fold increase in Canada goose (Branta canadensis) populations over the past several years has resulted in concerns over grazing impacts on grass seed production in the mid-Willamette Valley, Oregon. This study was designed to develop methods to quantify and statistically analyze goose-grazing impacts on seed yields of tall fescue (Festuca arundinacea Schreb.) and perennial ryegrass (Lolium perenne L.). Yield-mapping-system equipped combines, incorporating global positioning system (GPS) technology, were used to measure and map yields. Image processing of ground-level photography to estimate crop cover and other relevant observations were spatially located via GPS to establish spatial-temporal goose grazing patterns. We sampled each field semi-monthly from mid-winter through spring. Spatially located yield data, soils information, exclosure locations, and grazing patterns were integrated via geographical information system (GIS) technology. To avoid concerns about autocorrelation, a bootstrapping procedure for subsampling spatially contiguous seed yield data was used to organize the data for appropriate use of analysis of variance. The procedure was used to evaluate grazing impacts on seed yield for areas of fields with different soils and with differential timing and intensity of goose grazing activity. We also used a standard paired-plot procedure, involving exclosures and associated plots available for grazing. The combination of spatially explicit photography and yield mapping, integrated with GIS, proved effective in establishing cause-and-effect relationships between goose grazing and seed yield differences. Exclosures were essential for providing nongrazed controls. Both statistical approaches were effective in documenting goose-grazing impacts. Paired-plots were restricted by small size and few numbers and did not capture grazing impacts as effectively as comparison of larger areas to exclosures. Bootstrapping to subsample larger areas of yield for comparison was an effective method of avoiding autocorrelation of data while better representing impacts within a field. Occasional yield increases, ranging from 1 to 5 percent, were recorded following goose grazing. Goose grazing generally resulted in seed yield reductions, ranging up to 20 percent. Later and more intensive grazing tended to increase yield reductions. Newly seeded tall fescue tended to be the most sensitive to grazing. Established perennial ryegrass tended to be more resilient. / Graduation date: 2003

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1986.

<p> Brown patch (caused by various <em>Rhizoctonia </em>and <em>Rhizoctonia-</em>like species) is one of the major summer diseases of tall fescue [<em>Schedonorus arundinaceus</em> (Schreb.) Dumort., nom. cons.]. Fungicides are available to suppress brown patch; however, there is increasing interest to reduce lawn pesticide inputs. Excessive summer nitrogen (N) applications and extended periods of leaf wetness have been suggested to enhance brown patch. Five projects were conducted from 2020 to 2022 to evaluate individual and various combinations of cultural management practices to improve brown patch management strategies through reducing chemical inputs and promoting environmentally sound integrated pest management (IPM) practices. Brown patch host resistance of 15 tall fescue cultivars was evaluated in a controlled environment study and various morphological characteristics were correlated to brown patch severity. A 45% reduction in brown patch was observed with a resistant cultivar, and cultivars with faster growth rates, wider sheath widths and shorter sheath length correlated with reduced brown patch resistance. A field study evaluated five cultivars fertilized with urea-N from April to July, totaling 73.5 or 245.0 kg N ha^-1. A resistant cultivar had the greatest influence on reducing disease, and N-rate generally did not influence disease severity. Differences in seasonal brown patch was compared in a three-year field study for various natural organic fertilizers. Feather-bone meal and soybean meal-based products decreased disease compared to non-fertilized turf. Chemical suppression of leaf-wetness was studied using different surfactant chemistries applied on a 14 to 21-d application frequency and some chemistries reduced disease. When evaluating the various interactions of cultivar, N rate, and surfactant compared to a granular fungicide, the greatest impact was achieved when planting a resistant cultivar, reducing disease severity by 68%. Additionally, the combination of a resistant cultivar and application of a surfactant had the same seasonal brown patch compared to a susceptible cultivar with fungicide applications during year two of evaluation. In summary, these studies demonstrate significant reductions in brown patch can be achieved when utilizing the aforesaid best management practices which can substantially reduce the need for frequent lawn fungicides.  </p>

No description available.

The Canterbury plains are frequently exposed to summer drought and climate predictions forecast that the severity and frequency of summer drought will increase. The most commonly used pasture grass, perennial ryegrass (Lolium perenne L.), is drought sensitive. One possible method to maintain sward dry matter (DM) production under water stress is to use an alternative grass species such as tall fescue (Festuca arundinacea Schreb.). The objective of this research was to compare summer DM production of monoculture swards of perennial ryegrass and tall fescue under various seasonal drought regimes to study physiological and biochemical drought responses of each species. Data were collected over a period of two-summer seasons, Season One (2006-2007) and Season Two (2007-2008) in an automated rain shelter at Lincoln, Canterbury. Drought treatments included exposure of plants to a spring or autumn drought or a four-weekly "irrigated" drought regime. DM yields of the two species were similar under each watering regime. The control treatment, under non-limiting conditions, has the highest accumulated yield in both Season One and Two for ryegrass (17.1 and 15.7 t DM ha⁻¹) and tall fescue (18.8 and 16.0 t DM ⁻¹) respectively. Spring and autumn drought treatments were similar for the two species in accumulated yield in either season, however the exposure to drought stress returned yields lower than the control. Consistently, the lowest-yielding treatment was the four-weekly irrigated drought, which resulted in an average yield across species in Season One of 10.1 t DM ha⁻¹ and 8.35 t DM ha⁻¹ in Season Two. Growth rates of the swards were calculated using accumulated DM production against accumulated thermal time using a base temperature of 3°C for both species. The control treatments showed a strong linear relationship for both species in both seasons, though Season Two showed a period of approximately 390 °Cd of no growth. Spring growth was similar for all treatments until October when both the spring drought and four-weekly irrigated treatment deviated from the control as water stress commenced. Growth also ceased under autumn drought later in the season. The physiological drought responses between species and among treatments differed. Tall fescue under control conditions had the highest photosynthesis rates of 20.5 µmol CO₂ m⁻² s⁻¹,or 22% higher than ryegrass, whereas the four-weekly irrigated treatment showed no inter-species differences. Differences were also found for other gas exchange parameters. Physiological water use efficiency (phys WUE) in ryegrass was 15% greater than tall fescue in Season Two. Photosynthesis and gas exchange rates against leaf water potential showed declining gas flow in both species across all treatments in response to drying soil conditions and across all irrigation treatments. The osmo-protectant proline was 22% higher in concentration in ryegrass than in tall fescue in Season Two and increased in drought stressed treatments in both seasons. Water stress was found to reduce total chlorophyll concentrations in all treatments and in tall fescue, while little change occurred in the chlorophyll a:b ratio. In conclusion, the findings from this thesis suggest similar DM responses for the two species under drought. The findings suggests that tall fescue performs more as a "water user" under drought conditions, compared with perennial ryegrass, which is more a "water saver." Resonses to the changing environment to a point, before "shuttting up shop" through lower stomatal conductance.