Graduation date: 1994

Accurate taxonomy is essential to preservation and management of native grasses. Four problems in fescue taxonomy were investigated: the identity of the native fescue that dominates western Oregon and Washington prairies, the relationship of native Festuca roemeri to closely related grasses, the status of F. howellii and F. washingtonica, and fescue identification. The cespitose fine-leaved fescue that dominates prairies in western Oregon and Washington had previously been identified as F. rubra. Two fescues were found to dominate these habitats, one introduced F. rubra var. commutata, and the other native F. roemeri. The two differed in isozymes and subtle morphological traits. Isozymes, flow cytometry of DNA, and leaf anatomy clarified relationships among F. idahoensis, F. roemeri. and the northwest California fescue that shares characters with both of them. Isozyme band patterns divided them into two groups; F. roemeri and a mixture of populations of F. idahoensis and the northwest California fescue. All three fescues were tetraploid. All three fescues were distinguished using leaf anatomy. Festuca roemeri and the northwest California fescue shared leaves elliptic to obovate in cross section and usually having three sclerenchyma bands, at margins and midrib; F. idahoensis had leaves round to hexagonal in cross section, with five or more sclerenchyma bands, Festuca idahoensis and the northwest California fescue had numerous long adaxial leaf hairs; F. roemeri had few and short adaxial hairs. Leaf shape was phenotypically plastic in F. roemeri and the northwest California fescue, but constant in F. idahoensis. Leaf sclerenchyma development was greater in the field than greenhouse for all three fescues. The northwest California fescue was recognized as F. roemeri var. klamathensis B. L. Wilson fined. Morphometric analysis of F. howellii and F. washingtonica revealed that the two are distinct taxa. Festuca washingtonica appeared to be a rare species endemic to lightly grazed and ungrazed areas of eastern Washington. The F. howellii holotype was conspecific with F. elmeri, not F. viridula as previously thought. Because F. howellii is an earlier synonym, F. elineri must now be called F. howellii. Identification keys were provided for identifying fertile or sterile fescues and ryegrasses of the Pacific coast states. / Graduation date: 1999

A study investigating the effect of sheep stocking density and grazing duration on forage intake, grazing efficiency, dietary selectivity and subsequent forage accumulation in tall fescue(Festuca arundinacea)- subclover(Trifolium subtaranium) pastures was conducted near Corvallis, Oregon during early and late spring in 1988 and 1989. Grazing treatments were 2, 6, and 10-day duration and corresponding stocking densities 380, 130, 78 and 1390, 460 and 280 ewes/ha during early and late trials each year, respectively. Average daily intake and grazing efficiency were highest (P< 0.05) in the 10-day duration and lowest in the 2-day duration. During the first 2 days of all duration treatments, average daily intake decreased as stocking density increased (P< 0.05). Manure cover and crowding stress may explain lower average daily intake under the shorter duration/high density treatments. However, stocking density had little effect on grazing efficiency. This was largely due to the high amount of forage destroyed under the low density treatments which offset the effect of higher forage intake of that treatment. Within the 10-day duration treatment, average daily intake was the same over time (P> 0.05), while grazing efficiency decreased as grazing progressed (P< 0.05). The low grazing efficiency during the early stages of grazing reflected high initial forage destruction probably caused by the movement of animals at the start of grazing to establish bedding and habitual use areas. Growth rate of forage after grazing was highest in the longer duration paddocks and lowest in the shorter duration paddocks (P< 0.05), but the yield was similar under all treatments (P> 0.05). Although short duration/high density grazing is considered to be non-selective, sheep were equally or more selective under very short duration/very high density compared to longer duration/lower density treatments in this study. The 2 days duration was not an attractive management option since the intake and grazing efficiency were low, and the animals were selective. / Graduation date: 1993

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

Chewings fescue [Festuca rubra L. subsp. fallax (Thuill.) Nyman] is a desired turfgrass with dense sod forming capabilities and superior shade tolerance. Thermal residue management (open-field burning) has traditionally been used to remove post-harvest residue and maintain seed yield over the life of the stand. However, alternative non-thermal residue management practices have been observed to produce adequate seed yields dependent upon cultivar. Strong creeping red fescue (F. rubra L. subsp. rubra) is desired for its prolific tillering capacity and creeping rhizomatous growth habit. In contrast to Chewings fescue, maintenance of seed yield in strong creeping red fescue has only been profitably produced under thermal residue management. Slender creeping red fescue [F. rubra L. var. littoralis (Vasey)] is a desired turfgrass with a compact, less rhizomatous growth habit, similar to Chewings fescue in desirable turf attributes. However, little is known about the effects of post-harvest residue management in slender creeping red fescue. The objectives of this study were: 1) to evaluate seed yield and yield components among different cultivars to thermal (open-burning), and non-thermal (flail low and flail high) post-harvest residue management; 2) to evaluate harvest index and percent cleanout to thermal and non-thermal residue management in different cultivars; and 3) and to provide an economic analysis of thermal and non-thermal residue management in all cultivars based on partial budgeting. Three post-harvest residue management treatments (burn, flail low and flail high) were applied over the course of two years. Seed yield components measured included: total dry weight, fertile tiller number, spikelets per panicle, florets per spikelet, and panicle length. Final seed yield in each cultivar and residue management treatment method was determined after seed harvest and conditioning. Seed yield component analysis was conducted over three production seasons. Chewings fescue, strong creeping red fescue, and slender creeping red fescue cultivars responded differently to residue management as indicated by a residue management by cultivar interaction. In 2003 and 2004, residue management by cultivar interactions were evident in seed number, seed weight, fertile tiller number, percent cleanout, harvest index, and seed yield. Residue management by cultivar interactions occurred in spikelets per panicle in 2003, whereas in 2004 a residue management by cultivar interaction occurred in panicle length and florets per spikelet. In 2004, non-thermal flail low, and thermal residue management resulted in significantly greater spikelets per panicle in all cultivars. Thermal residue management resulted in the greatest number of spikelets per panicle. Results indicate that thermal residue management best maintained seed yield in most subspecies and cultivars across both years. However, in 2003, non-thermal flail low residue management produced profitable seed yield in only Marker slender creeping red fescue. In contrast, thermal residue management resulted in poor seed yields in Marker slender creeping red fescue and enhanced yields in Seabreeze slender creeping red fescue in 2003. However, following the second year of thermal treatment in 2004, Marker and Seabreeze both had lower seed yields, thus exhibiting the only negative impact of thermal management among the cultivars tested in this study. Moreover, upon review of an economic analysis, Marker slender red fescue was the only cultivar that produced a positive net return of $78 and $4 ha⁻¹ under non-thermal residue management in 2003 and 2004, respectively. Furthermore, in 2003, thermal residue management net return increases ranged from $104 ha⁻¹ to -$996 ha⁻¹ in Barnica and Shademark, respectively. In 2004, thermal residue management net return increases ranged from $115 ha⁻¹ and $1,332 ha⁻¹ in Seabreeze and Shademark, respectively. Poor seed yields were observed in all strong creeping red fescue cultivars under non-thermal residue management across both years of the study. This may be attributed to an observed reduction in fertile tiller number and seed yield. In addition, percent seed cleanout was increased with non-thermal residue management. In 2004, as stand age increased, thermal residue management resulted in greater seed yields in all cultivars and species, except both cultivars of slender creeping red fescue. Thus, this study provided substantial evidence that thermal residue management has the potential to maintain or increase fine fescue seed yield as stands age as well as to maintain stand profitability. / Graduation date: 2005

Open-field burning has been an effective, economical, and widespread method of post-harvest residue management in creeping red fescue seed production in the Willamette Valley since the late 1940s. However, the use of field burning has been legislatively restricted due to air quality and safety issues. The foliar-applied plant growth regulator trinexapac-ethyl (TE), commercialized in the USA as Palisade, has been accepted by producers as a yield enhancing agent and is considered here as an alternative to open-field burning over a four-year period. The effects of open-field burning versus mechanical removal (flailing) of post-harvest residue, and spring versus fall applications of TE on seed yield, dry matter partitioning, and seed yield components were evaluated in a split-plot design. The response to the different treatment combinations differed across years. The young stand responded with a seed yield increase to spring TE applications, regardless of residue management treatment. However, as the stand aged, field burning became critical for maintaining high yields and, in 2003 and 2004, only spring TE applications resulted in seed yield increases in burned plots. The higher potential seed yield achieved in burned plots over flailed plots, as a result of a higher number of panicles per unit area and spikelets per panicle, was critical for maintaining high seed yields as the stand aged. Spring applications of TE, further increased seed yield over the untreated check by increasing the number of florets per spikelet, reducing fertile tiller height and lodging and consequently, favoring pollination and fertilization of the florets. Late spring TE applications also increased 1000-seed weight in 2003 and 2004. Although spring applications of TE were a promising alternative to open-field burning early during the life of the stand, as the stand aged they did not increase seed yield on flailed plots. Fall TE applications did not have a consistent effect on seed yield, dry matter partitioning or seed yield components, and were found not to be a viable management practice. / Graduation date: 2005