The effectiveness of 5-bromo-3-sec-butyl-6-methyluracil (bromacil) for the selective removal of orchardgrass (Dactylis glomerata L.) from Kentucky bluegrass (Poa pratensis L.) turf and some physiological responses of the grasses to bromacil were evaluated in field studies. Bromacil reduced photosynthesis to a greater extent in orchardgrass than Kentucky bluegrass turf. Foliage carbohydrates were depressed initially in bluegrass followed by recovery in 2 weeks to 1 1/2 months following bromacil application. Orchardgrass, however, did not recover. Application of 0.56 kg/ha bromacil each summer and fall for 2 years gave the best control of orchardgrass. During the second year, increase in foliage crude protein was observed in treated bluegrass. Bluegrass foliage yields were equal to or greater than the controls. Orchardgrass yields were drastically reduced by bromacil. Effective seedling orchardgrass control was obtained with minimal bluegrass injury at 0.14 to 0.28 kg/ha of bromacil. Bromacil treated areas were effectively fall-seeded with bluegrass approximately 8 weeks after a 0.56 kg/ha application, Rooting of bluegrass sod was not inhibited at the rates used for selective control of orchardgrass in bluegrass turf. In controlled environmental growth chamber studies, bromacil had no effect on germination of Merion Kentucky bluegrass or Virginia Common orchardgrass, but reduced the growth of emerging shoots of orchardgrass more than bluegrass. Fresh weight gain, root growth, and transpiration were reduced in orchardgrass plants at 0.125 ppmw bromacil whereas 1.0 ppmw gave reductions in bluegrass. Photosynthesis was inhibited initially in both grasses, however, bluegrass recovered in 6 days. Foliage carbohydrate content was greater and was affected less by bromacil treatment in bluegrass than orchardgrass. Root absorption and translocation of 2-¹⁴C-bromacil to the shoot was directly related to transpiration in both grasses. Bromacil was absorbed and translocated acropetally in sheath and foliar treatments in both grasses. Higher metabolic conversion of 2-¹⁴C-bromacil occurred in bluegrass as compared to orchardgrass with 1.0 ppmw treatment. The major metabolites were 5-bromo-3-(2-hydroxy-1-methylpropyl)-6-methyluracil and an unknown. Trace amounts of 3-sec-butyl-6-methyluracil and 5-bromo-3-sec-butyl-6- hydroxymethyluracil were also detected. Bluegrass tolerance to bromacil involves high carbohydrate levels in tissues, hydroxylation of bromacil, and rapid recovery of photosynthesis. / Ph. D.

Endophyte infected Tall fescue (Festuca arundinacea Schreb.) is the most dominant grass used for pasture in the Southeastern U.S. As a result, fescue toxicosis is a major concern. Producers need alternative forages for grazing cattle that do not have this negative aspect. The objective of this experiment was to determine the grazing behavior of cattle grazing Lakota (L) prairie grass (Bromus catharticus Vahl.), endophyte infected (E+), endophyte free (E-), and novel endophyte (Q) tall fescues. Angus-crossbred steers (279±8 kg) steers wore electronic behavior data recorders in four sampling periods, and direct visual appraisals of behavior were taken in five sampling periods during the months of May to September, 2004. Overall, during the visual appraisal phase steers grazing L spent most time (P<0.05) grazing while E+ spent the least time grazing. Overall, steers grazing E+ spent more time (P<0.05) idling than those on L, E-, or Q. Steers grazing E+ spent more time (P<0.05) standing than steers grazing Q. Steers grazing Q and E- spent more time (P<0.05) lying than those grazing E+. During the data recorder phase there were no significant differences between treatments for time spent grazing. Steers grazing E+ spent less time (P<0.05) lying and ruminating than steers grazing Q or L. Conversely, time spent standing and idling for steers grazing E+ was higher (P<0.05) than for steers grazing Q or L. These results indicate that L, E-, and Q may offer benefits to producers due to more time spent in productive activities during summer months. / Master of Science

Studies were conducted to explore the interactions among rye grass, chlorophenols and microorganisms. The objectives were to examine some of the processes by which plants affect the fate of subsurface organic contaminants. The research was divided into three studies: interactions between live grasses and 2,4-dichlorophenol (DCP), 2,4,6-trichlorophenol (TCP), and pentachlorophenol (PCP); physico-chemical interactions between the three chlorophenols and root tissue; and effect of root exudates on biodegradation of TCP. To study the interactions between plants and organic contaminants, rye grass plants were grown in solutions containing DCP, TCP or PCP for one to three weeks. The grass removed substantial amounts of the chlorophenols throughout the incubation time. The majority of each chlorophenol removed from solution could not be recovered by non-destructive solvent extraction. The removal of the chlorophenols from solution and the unrecoverability of the removed compound followed different kinetics, indicating that the two are different processes. Both contaminant removal and unrecoverability were closely related to root surface area but not to transpiration. A qualitative model was developed to describe the uptake of organic contaminants by plants. The data demonstrate the importance of physico-chemical interactions between contaminants and roots and suggest that maximization of root surface area should be one consideration when selecting a plant species for phytoremediation. To study the physico-chemical interactions between plant roots and organic contaminants, the distribution of DCP, TCP and PCP within a three phase system was examined. The three phases were severed grass roots, water and an organic solvent, either hexane or ethyl acetate. The chlorophenol mass that partitioned into the solvent phase was inversely correlated with root mass and root surface area index. Partition coefficients calculated with respect to the organic liquid phase were inversely correlated with root mass and root surface area index. A similar partitioning experiment was conducted using PCP placed in a solution containing only the dissolved organic material released by roots. These resulting partition coefficients decreased with increasing organic carbon concentration. It appeared that the organic compounds released into solution by the roots affected the movement of the chlorophenol into the organic liquid phase. It is proposed that the presence of roots simultaneously promoted retention of the chlorphenols in the aqueous phase and provided a sorption site. The effect of grass root exudates and glucose on the lag time associated with 2,4,6-trichlorophenol (TCP) degradation by an unacclimated microbial inoculant and an acclimated microbial inoculant was investigated. The presence of an alternate organic carbon source reduced lag time for both the acclimated microbial inoculant and the inoculant that had not been previously exposed to chlorinated phenols. The lag time for acclimation of microbes to TCP mineralization was affected by the ratio of the alternate organic carbon source concentration to the biomass concentration. It is proposed that the presence of a readily available, alternate organic carbon source affected lag time through promotion of microbial population growth and provision of a preferred source of carbon and energy. The results indicate that rye grass may directly, through partitioning and uptake, and indirectly, through soil microbes, affect the fate of chlorophenols in the subsurface environment. / Ph. D.

This investigation has been made with reference to the adaptability of Andropogon ischaemum, King Ranch bluestem, to various soils, various slopes, and various erosion conditions in Denton County.

This thesis discusses the symbolism found in Walt Whitman's second poetic period, as found in the collection Leaves of Grass.

Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This dissertation examines the photographs created by Edward Weston during his travels through the United States in 1941 and intended for a luxury reprint of Walt Whitman's Leaves ofGrass published by the Limited Editions Club in 1942. By contrasting the hundreds of photographs Weston made now residing in archives and collections with the forty-nine images ultimately selected and arranged by the Club's director, George Macy, I argue that Weston's larger, more complex and diverse version of America more closely resembled Whitman's text than his publisher's limited selection. Moreover, this under-examined body of work promotes a new understanding of Weston's late oeuvre; inspired by cross-country travel, Whitman's poetry, and other artists, Weston tackled new subject matter, experimented with different styles, and synthesized artistic and documentary modes in his photographs. Chapter I introduces the commission, the role of Weston's wife Charis Wilson in the project, the timely choice in 1941 of pairing Whitman and Weston, both of whom challenged boundaries of their respective media, and the outcome of the book's design. Chapter 2 turns to an analysis of the sequence of the first ten images as representative of Macy's caption-driven approach to the book, which generally discouraged the probing of close relationships among images. The chapter concludes with an analysis of the images themselves paired with close readings of select poems in order to establish the parallels in sensibility of the two artists. Chapters 3 through 5 broaden the discussion by including Weston's unpublished images from the 1941 trip. Focusing on Weston's portraits, Chapter 3 discusses Weston's diverse sitters-African and Native Americans and womensometimes selected while researching ethnography. Chapter 4 focuses on landscapesindustrial, urban, desert, and rural-in which he engaged with popular American imagery and created art and documentary images. Chapter 5 analyzes Weston's photographs of plantation ruins and cemeteries in Louisiana, and folk art and customs for which he recorded examples of American ethnography. Through examination of these images, a new picture of Weston emerges as not only a modernist art photographer, but also a photographer with deep interests in American people, landscape, and culture. / 2999-01-01

In 1990, creosote contamination was discovered at the location of a railroad tie treatment facility active in the 1950s until 1973. In 1997, a phytoremediation field study was implemented with the planting of 1,026 hybrid poplar trees and 36 cells of vegetated and unvegetated grass and legume treatments. The hybrid poplar tree phytoremediation system was designed to control infiltration and groundwater flow and enhance subsurface remediation. The grass phytoremediation system was designed to control erosion and enhance surface soil remediation. The overall objectives of this study were to: (1) assess the extent of subsurface remediation, (2) determine the mechanisms of remediation attributable to the hybrid poplar tree phytoremediation system and microbial degradation, (3) assess the effects of the grass phytoremediation system on surface soil remediation, and (4) determine the mechanisms of surface soil remediation resulting from the grass phytoremediation system. / Master of Science

Matua prairie grass has a potential to extend the grazing season in Virginia due to its higher early spring and fall production. However, little is known about the compatibility of Matua prairie grass with legumes or the effects of legumes on the yield and quality of Matua prairie grass/legume mixtures. An experiment was conducted in 1998 and 1999 to investigate the botanical composition, yield, and chemical composition of Matua prairie grass grown with legumes. Legume treatments consisting of ladino clover (Trifolium repens), red clover (Trifolium pratense), alfalfa (Medicago sativa), and annual lespedeza (Lespedeza stipulacea) were drilled into a Matua prairie grass stand. Nitrogen was applied once each fall at two treatment levels of 0 or 84 kg/ha. The experiment was arranged in a randomized split block design with four replications. Legume treatments had no effect on percentage Matua prairie grass or total dry matter yield in 1998. However, in 1999 the ladino clover and red clover treatments increased (P<0.05) total dry matter yield, but also resulted in a substantial decrease (P<0.05) in percentage Matua prairie grass. Nitrogen application in the fall of 1998 had a residual effect (P<0.05) on the percentage Matua prairie grass and yield in 1999. The highest response to nitrogen fertilization occurred in the harvest immediately after fertilization, in October of 1999, which resulted in the largest increase (P<0.05) in percentage Matua prairie grass and yield, and the greatest decrease (P<0.05) in percentage legumes. The legume and nitrogen treatments similarly influenced the chemical composition of the Matua prairie grass/legume mixed forage. Ladino clover, red clover, and alfalfa treatments generally improved forage quality as indicated by a decrease (P<0.05) in NDF, ADF, hemicellulose, and cellulose, and an increase (P<0.05) in CP and IVDMD. Nitrogen fertilization did not influence the chemical composition of the forages to the same extent as the legume treatments, as a decrease in fiber components and an increase in CP and IVDMD were observed due to nitrogen. Overall, alfalfa appeared to be most compatible with Matua prairie grass, and the incorporation of alfalfa into a Matua prairie grass stand resulted in some improvements in total dry matter yield and nutritive value of the forage, without the detrimental suppression of Matua prairie grass. / Master of Science

The primary objectives of this study were: 1) to evaluate the movement patterns, habitat use, and survival of triploid grass carp Ctenopharyngodon idella stocked to control hydrilla Hydrilla verticillata in a riverine reservoir (Claytor Lake, Virginia), 2) to examine grass carp population dynamics and hydrilla growth dynamics in Claytor Lake to guide long-term management efforts, and 3) to describe the aquatic plant community in the New River upstream of Claytor Lake to assess the potential for alterations due to potential grass carp herbivory. Only 3% of radio-tagged grass migrated out of Claytor Lake during the 2-year study. Grass carp movement patterns were significantly correlated with temperature-, weather-, and habitat-related variables. Grass carp selected specific cove, shoal and tributary habitats colonized by hydrilla. First-year survival of grass carp was 44% in 2011, and 25% in 2012. Grass carp growth rates were rapid in 2011, but declined in 2012 concurrent with significant reductions in hydrilla abundance. Based on grass carp population dynamics observed in Claytor Lake, our stocking model predicted that hydrilla could be controlled through 2030 by a grass carp standing stock of 5-6 metric tons. We documented 12 plant species in the New River upstream of Claytor Lake, 9 of which are preferred plants for grass carp suggesting that the plant community could be altered if migration rates increase. Grass carp can be effective for managing hydrilla in riverine reservoirs; however, continued monitoring of grass carp population dynamics, migration rates, and vegetation abundance could facilitate greater precision in management efforts. / Master of Science

Two environmental control chamber experiments were conducted to study the effects or temperature, nitrogen, and light intensity on the growth and physiological effects on Tifgreen bermudagrass, Cynodon dactylon (L) Pers., and Cohansey bentgrass, Agrostis palustris Huds. Each of the grasses was included in a field experiment to study the influence of nitrogen rates on carbohydrate reserves at different seasons. Increased temperatures with bentgrass caused decreased carbohydrates, root weights, and final growth of tops, but increased nitrogen content and respiration. NAR in bentgrass was highest at 75 F. The respiration rate, top growth, and carbohydrate content of bermudagrass tended to increase with temperature, but root weights and NAR were highest at medium temperatures. High N generally increased top growth, NAR, respiration, and nitrogen content, but lowered the carbohydrates and root growth for both grasses. Bentgrass, grown at 95 F during the day-, declined in yield, root growth, NAR, and respiration as night temperatures increased from 60 to 90 F. With bermudagrass HAR, top growth, and root growth were highest at 75 F and lowest at 90 F night temperatures. The AEC of bentgrass were highest at the mid-temperature, but the AEC: fer bermudagrass tended to increase with the high night temperature. Low light intensity generally decreased the yield of tops and roots, NAR, respiration, and carbohydrates, but increased the nitrogen content of both grasses. Bentgrass stolons increased in carbohydrate content during the tall and early vinter, and then declined rapidly during the spring. During the summer, the carbohydrates in bentgrass were low. The carbohydrates in bermudagrass stolons decreased during the winter and spring, increased during summer, and reached a maximum by late fall. For all experiments the oligosaccharides and monosaccharides made up a rather large portion of the AEC in bentgrass, polysaccharides being the largest fraction. Polysaccharides in bermudagrass made up the largest fraction of the AEC, the monosaccharides and oligosaccharides being less than 10% of the dry weight. / Ph. D.