Grass clippings may be recycled onto nearby areas of turf as an alternative to disposal of clippings in landfills. In May, 1991, two field studies were initiated to evaluate grass clippings as a nitrogen (N) source for tall fescue (Festuca arundinacea, Schreb. Rebel’) turf, and to determine the maximum feasible loading rate of clippings onto tall fescue turf. Test plots in both studies received additional clippings from adjacent donor plots. In the first study, grass clippings alone were applied to 2.2 m² test plots at rates of 1 "plot equivalent harvest" (PEH), 2 PEH, and 4 PEH; where PEH is the amount of clippings harvested from 2.2 m² of donor plots. In the second study, test plots had clippings removed (Rem), clippings returned (Ret), Ret+1 PEH, and Ret+3 PEH. These four clipping treatments were arranged in a factorial combination with three fertilizer-N rates: low (73 kg N ha⁻¹ yr⁻¹), medium (147 kg N h⁻¹ yr⁻¹), and high (220 kg N h⁻¹ yr⁻¹). Donor plots received identical fertilizer-N applications as test plots. For both studies, N uptake generally showed a linear response to total N applied. Clipping-N produced roughly the same amount of growth and N uptake as the fertilizer-N, even as the rate of N uptake varied with time. In both studies, soil nitrate levels remained low until excessive clippings smothered the turf and caused a reduction in N uptake. Soil nitrate concentration tended to decrease with depth for all plots. Soil total Kjeldahl nitrogen (TKN) levels did not differ among treatments, suggesting that clipping-N was not being stored in the soil. At the end of both growing seasons, thatch accumulation was less than 12mm in all plots. In general, increased additions of clippings resulted in improved color, density, and growth. However, at the very high rates of added clippings, excess biomass caused turf thinning, chlorosis, and low growth. Thus, if grass clippings are applied at rates that are low enough to prevent these problems, they can be an effective N source for tall fescue. Furthermore, in order to dispose of the maximum amount of clippings, tall fescue should not be fertilized. / Master of Science

For the rapid establishment of optimal conditions for a genetic transformation system for tall fescue, several factors influencing transient gene expression were studied in protoplasts, after the reporter β-glucuronidase (GUS) gene was introduced by electroporation. In a time-course study of transient gene expression, GUS activity peaked at 24 h after electroporation. Among the different field strength conditions tested, maximum GUS activity was observed at 750 V/cm. Increases in the amount of plasmid DNA to 80 μg/ml led to increased GUS activity. GUS activities increased in linear fashion with increasing protoplast densities up to 2 x 10⁶/ml. Age of suspension cells from which protoplasts were derived influenced transient expression with maximum GUS activity obtained in 3 and 5 day old suspensions. These results show that transient expression studies can be used to optimize electroporation parameters rapidly. Results of such rapid assays can be used as a basis for further studies on stable transformation of this important turf-grass species. / Master of Science

Urban soils are typically degraded due to land disturbance. The poor quality physical and chemical properties of the soil can benefit from application of organic amendments. Local sources of such amendments are biosolids, which are treated domestic wastewater sludges. The objective of this experiment was to compare effects of various high quality biosolids-based soil amendments with synthetic fertilizer on the growth and quality of tall fescue (Schedonorus arundinaceus) under two different soil moisture regimes. The research site was a disturbed soil at the Virginia Tech Turfgrass Research Center in Blacksburg, Virginia. The experimental design was a split plot with irrigation regime as the main factor and soil amendments as the split factor. All treatments were arranged in four randomized complete blocks. The study was established in late summer 2013. Soil amendment treatments, applied prior to seeding in September 2013, were: 1) inorganic N, P, K applied according to soil test laboratory recommendations; 2) anaerobically digested, dewatered biosolids to supply agronomic N rate; 3) anaerobically digested, dewatered biosolids blended with sand and sawdust to supply agronomic N rate; 4) anaerobically digested, dewatered biosolids blended with sand and sawdust to supply agronomic P rate; and 5) composted biosolids to supply agronomic N rate. The agronomic N rate for the turfgrass was 224 kg of estimated plant available nitrogen (PAN) ha-1. Inorganic fertilizer was applied to supply annual P and K requirements prior to seeding in late summer, and the N was split into three application timings (September 2013, April 2014, and June 2014). Supplemental fertilizer N to achieve full agronomic N rate was applied to the treatment plots that received the agronomic P rate of blended biosolids-sand-sawdust. The area was seeded on September 13, 2013 with a tall fescue blend at a rate of 488 kg ha-1. Following full tall fescue establishment, in June 2014, two irrigation regimes, consisting of 0% and 80% evapotranspiration replacement every three days, were initiated. The study had three phases denoted as the pre-drought, drought, and recovery phases which started in April and concluded in August of 2014. Turfgrass color and quality, volumetric soil moisture percentage to a 5 cm depth, normalized difference vegetative index (NDVI), clipping yield, and turfgrass N uptake were measured bi-weekly throughout the growing season. During the first May through July 2014 irrigation season, results were that the fertilizer control consistently provided improved responses relative to the biosolids amended treatments. Clipping yield, quality, and NDVI were all significantly greater in the inorganic fertilizer treatment, but volumetric soil moisture percentages were slightly greater in the biosolids treatments. Turfgrass responses appeared to have been associated with plant available nitrogen, which was lower in the biosolids treatments than in the fertilizer treatment. Calculated PAN for the biosolids products was too low to achieve ideal turfgrass growth and quality. Improving the estimated PAN and/or splitting the organic amendment application times should improve the growth and quality of the turfgrass. / Master of Science

Three yearling and three 2-year-old Saddlebred horses were used to determine seasonal differences in apparent digestibility of Ky 31 tall fescue (Festuca arundinacea Schreb.) pasture by horses. Three trials were conducted with collection periods beginning August 27, 1984; January 8, 1985; and June 3, 1985. Each 72 h collection period followed a 2 wk preliminary grazing period. The horses were given a pulse-dose of Yb impregnated fescue forage at 0 h, and fecal grab samples were taken at 6, 12, 18, 24, 30, 36, 48, 60, and 72 h after dosing. Fecal output was estimated from Yb concentration in the feces. Apparent digestibilities of dry matter (DM), acid detergent fiber (ADF), neutral detergent fiber (NDF), crude protein (CP), and cellulose were estimated using indigestible NDF as an internal marker. Forage DM intake was calculated using the formula (fecal output/(100- % forage DM digestibility) x 100). Estimated DM intake and fecal DM were 4.5 and 1.7 kg/d for August; 7.5 and 2.7 kg/d for January; and 6.4 and 2.8 kg/d for June, respectively. Percent ADF and NDF were highest (P<.05) and apparent digestibilities of these components were lowest (P<.05) for the spring forage. / Master of Science

Low and high endophyte infected stockpiled tall fescue was harvested, chopped and ensiled in 210 liter metal drums, double lined with polyethylene bags. Endophyte infection averaged 4 and 70%, respectively, for the low- and high-endophyte fescue. A metabolism trial was conducted with 24 wethers fed diets consisting of 100% low-endophyte fescue silage, 50% low-endophyte and 50% high-endophyte fescue silage, and 100% high-endophyte fescue silage. Chopped alfalfa hay was used as a control forage. Single samples were analyzed, so statistical treatment of chemical composition was not possible. However, certain numerical differences were recorded. Lignin was higher for the high-endophyte than the low-endophyte fescue. Dry matter, CP, and ash were similar for the fescue silages. The high-endophyte fescue silage was lower in P, Mg, S, K, Fe, Cu, Mn, Zn, and Al than the low-endophyte silage. Digestibilities of DM, NDF, and cellulose were higher (P<.01) for fescue silages than alfalfa hay. Level of endophyte infection did not affect digestibility of DM, NDF or cellulose. Among silage treatments, apparent absorption of N, expressed as g/d, showed a linear effect (P<.05), with the lowest value obtained for sheep fed 100% high-endophyte fescue silage. Apparent absorption and retention of Ca were higher for silages than alfalfa. Among the silage diets, apparent absorption of P decreased linearly (P<.01) with increased endophyte level. Apparent absorption of K decreased linearly (P<.01) with increased endophyte level, but the effect was related to intake. Serum prolactin concentrations of the wethers fed fescue silage showed a linear decrease (P<.05) with increased proportion of endophyte-infected fescue. Endophyte infection of fescue appears to affect N and mineral metabolism. / Master of Science

An experiment was conducted to determine intake and apparent digestibilities of Kentucky 31 tall fescue (<i>Festuca arundinacea</i> schreb.) and orchardgrass/clover (<i>Dactylus glomerata</i> L./<i>Trifolium pratense</i> L.) pastures in different seasons of the year. Three digestion trials were conducted in December, 1985 (winter), May, 1986 (spring) and August, 1986 (summer). Five horses grazed each pasture type. A double marker procedure was used with indigestible neutral detergent fiber (INDF) and Yb as internal and external markers, respectively. Apparent digestibility of dry matter (DM), crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF) were determined. Digestibility of orchardgrass/clover components were not different between winter and spring, but were higher (P<.05) in DM, ADF and NDF digestibilities in the summer. Fescue DM and ADF digestibilities were higher (P<.05) in the winter while apparent digestibility of CP was higher (P<.05) in the spring. In summer orchardgrass/clover DM, ADF and NDF digestibilities were higher (P<.05) than fescue. Dry matter intake was not significantly different between forages. Orchardgrass/clover intake was lowest (P<.05) in the winter. Fescue dry matter intake was highest (P<.05) in the summer. / Master of Science

Integrating trees into pasture may be an effective management tool to improve water, nutrient, and light allocation and increase total system productivity in Appalachia. We tested this hypothesis in a silvopasture near Blacksburg, VA. In 1995, black walnut and honey locust trees were planted within plots (r=3) of predominantly tall fescue pasture. Across a 12% slope, trees were planted to create treatments of low, medium, and high tree densities at shoulder, mid, and toe slope positions within plots of honey locust and black walnut. Sampling sites (n=54) under tree density and slope position combinations were harvested May to October at 35-d intervals in 2002 and 2003 for determination of yield and nutritive value characteristics. Soil surface temperature, forage canopy temperature, soil moisture, and photosynthetically active radiation were measured to determine forage responses to field treatments as functions of resource allocation. Tree density had the greatest effect on forage production and nutritive value. Across both years, yields were 16% greater (P=0.0006) at medium density (6130 kg/ha) compared to forage mass at low (5280 kg/ha)) and high density (4970 kg/ha, SE=130). Increasing tree density did not affect (P>0.2) ADF, CP, P, K, and Mg levels, but reduced (P<0.001) NDF and TNC, and increased (P<0.0001) ADL and Ca. Elevated soil surface and forage canopy temperatures limited forage production and nutritive value at low density, while low light levels were the limiting factor at high density. Moderating forage microclimate with appropriately spaced trees is an effective way to improve forage production in temperate pastures. / Master of Science

Infection of tall fescue (<i>Festuca arundinacea</> Schreb.) with the endophyte fungus (<i>Acremonium coenophialum</i>, Morgan-Jones and Gam) has been associated with toxicity symptoms observed in cattle. The overall objective was to investigate the influence of endophyte infection on growth and chemical composition of tall fescue and the toxicity of endophyte-infected (EI) tall fescue to cattle. In a greenhouse study with pairs of genetically identical EI and non-infected (NI) ‘Kenhy’ tall fescue clones, concentration of N, Ca, Mg, Al, B, Mn and Zn was higher and K and S was lower in NI, compared to EI tall fescue. Insect resistance was higher in EI, compared to NI. Yield and chemical composition of high and low EI tall fescue were measured at four growth stages (stockpiled, prebloom, bloom and regrowth after harvest at bloom), two sites (Glade Spring and Blackstone) and three rates of N fertilization (0, 40 and 80 kg/ha) in a field study. Tall fescue grown at Glade Spring was higher in N, Mg, Al, Cu, Fe and Mn, compared to Blackstone. Nitrogen fertilization increased N, Mg, Ca, B, Cu, Na, Zn and decreased NDF, ADF, cellulose, P and S concentration in tall fescue. Neutral detergent fiber, ADF, cellulose, lignin, Fe and Na were higher in low, compared to high EI tall fescue. Concentrations of Cu, Na and Zn in stockpiled and Ca, Cu, Na and Zn in bloom-cut tall fescue hay were below dietary requirements for 227-kg steers. A disc meter was also evaluated for use in predicting yield of tall fescue. The meter is useful for non-destructive estimation of yield. Three feeding studies were conducted with steers (6/treatment/year). Diets were orchardgrass/alfalfa hay, spring-cut EI tall fescue hay, spring-cut EI tall fescue silage and fall-cut EI tall fescue silage. Serum prolactin and cholesterol were depressed in steers fed fescue hay and silages, compared to steers fed orchardgrass/alfalfa hay. Differences in mineral composition of hay and silage were reflected in serum minerals in steers. Ergopeptine alkaloids in EI tall fescue may have contributed to the depression of serum prolactin. The spring-cut silage contained the highest concentration of ergopeptine alkaloids, compared to other diets. Steers fed the spring-cut tall fescue silage had the lowest basal and thyrotropin-releasing hormone stimulated prolactin compared to steers fed the other diets. / Ph. D.

Treatment of endophyte-infected tall fescue [Lolium arundinaceum (Schreb.) Darbysh] with the broad leaf herbicide Chaparral® can mitigate fescue toxicosis and enhance forage quality by suppressing seedhead emergence. Applying the herbicide to fescue pastures also reduces forage mass and promotes severe spot grazing when pastures are continuously grazed. A grazing experiment was conducted with steers (2013) and heifers (2014) to evaluate animal and plant responses in fescue-bluegrass (Poa pratensis L.) mixtures treated with Chaparral to determine the effects of grazing management on pasture carrying capacity, nutritive values, botanical composition, and animal performance. Continuous and rotational (i.e., four subdivisions to provide a 7-d grazing period and a 21-d rest period) grazing treatments were assigned to six, 3.0-ha fescue-bluegrass pastures in a randomized complete block design with three replications. Each pasture had six tester animals, and stocking rates were varied using put-and-take animals. Pastures were grazed from 16 April to 8 July 2013 (Year 1) and 20 May to 12 Aug (Year 2) and cattle were blocked by body weight for allotment to pastures. Pasture carrying capacities were greater (P = 0.07) for rotational compared to continuous pastures across both years. Calves on rotationally grazed pastures had greater average daily gain (P = 0.03) and gain per acre (P = 0.05) than those on the continuous treatment across both years. Canopies of continuously grazed pastures contained less (P = 0.01) tall fescue than those in rotationally grazed pastures. Herbage in pre-grazed paddocks had less NDF and ADF than post-grazed paddocks and continuously grazed pastures in 2013 (P < 0.10), but did not differ in 2014 (P > 0.10). In vitro digestible dry matter was greater (P = 0.07) in pre-graze rotational pastures in 2013 compared with continuous and post-graze rotational, and IVDDM did not differ (P < 0.01) between pre-graze rotational and continuous in 2014, but was greater than post-graze rotational. Crude protein was lower (P = 0.06) in both years in post-graze rotational pasture than in continuous or pre-graze rotational pasture, which did not differ. In 2013, there was no difference (P = 0.60) in root WSC among treatments; however, in 2014, WSC levels were greater (P = 0.01) in rotationally grazed pastures compared with continuously grazed pastures. This grazing experiment indicated that rotational grazing of Chaparral treated fescue-bluegrass mixtures can improve both animal performance and the sustainability of pasture productivity.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Steven J. Keeley / Non-structural carbohydrates (NSC) are important for plant health and recovery from stress. Controlled-release N sources may moderate turfgrass vegetative growth, thereby maximizing NSC levels. Three studies were conducted to determine the effect of N source/timing on NSC levels, turfgrass visual quality, and color of ‘Midlawn’ bermudagrass and turf-type tall fescue. Additionally, the effect on low temperature tolerance of bermudagrass and brown patch incidence on tall fescue was investigated. Nitrogen sources included two polymer-coated ureas (PCU), a polymer-sulfur coated urea (SCU) and urea formaldehyde (UF). Total annual N was applied in either late summer or spring for bermudagrass, and either late summer or split between late summer and spring for tall fescue. Urea, applied at traditional timings, was a control in all studies. NSC status was determined at regular intervals by extracting two cores from each plot, defoliating, and measuring regrowth in a dark growth chamber. Turfgrass color, visual quality and brown patch incidence were rated monthly during the growing season. Bermudagrass low temperature tolerance was evaluated by subjecting plugs to a freezing regime and evaluating regrowth. Over the 2-yr study, N source did not have a significant effect on bermudagrass or tall fescue NSC levels, color, or visual quality. Timing of application, by contrast, did have a significant impact. For bermudagrass, August-applied N resulted in higher overall NSC levels and improved fall color. For tall fescue, split Sept/March applications improved color; but split Sept/ May applications reduced NSC compared to a single Sept application. Brown patch incidence was unaffected by N source or timing, though disease pressure was low. Timing of PCU application did not affect low temperature tolerance of bermudagrass, but PCU improved low temperature survival compared to urea.