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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Individuální akustický monotoring pěvců na příkladu lindušky lesní / Individual acoustic monitoring of songbirds - case study on the tree pipit

Pišvejcová, Iveta January 2014 (has links)
In field behavioural and ecological studies, it is often necessary to identify specific individuals. In birds, colour rings are often used as individual marks. However, rings might be difficult to observe, especially in small species and dense habitats. Thus recently, individual acoustic monitoring is becoming more commonly used to study of birds. This method is based on the recognition of individuals and often on the difference between temporal and spectral parameters of their vocalizations. However, in passerine species with more complex song these acoustic characteristics may not be reliable. In my thesis I used an alternative approach for the individual acoustic monitoring, based on differences in syllable repertoires of individual Tree Pipit males (Anthus trivialis). So far I have not found any study that would use a similar approach with other migratory passerine species with more complex song. The main aim of my study was to test the possibility of using syllable repertoires for recognition of specific individuals and to determine if this method is more efficient than identification by colour banding. From four years of research on the Tree Pipits population in the selected location in Brdy I received acoustic data from 59 males that I subsequently analyzed in a bioacoustic program. The...
2

Poa trivialis: physiological and pathological components of summer decline, and cultural, selective, and non-selective control methods

Thompson, Cole S. January 1900 (has links)
Doctor of Philosophy / Department of Horticulture, Forestry, and Recreation Resources / Jack Fry and Megan Kennelly / Rough bluegrass (RBG, Poa trivialis L.) is a difficult-to-control weed that commonly infests cool-season turfgrass swards after movement of vegetative propagules or contamination from seed lots. Rough bluegrass is less tolerant of heat stress than desirable cool-season species such as tall fescue (TF, Festuca arundinacea Schreb. Syn [italicize]Schedonorus [italicize]arundinaceus Schreb.), and often declines during mid-summer due to biotic or abiotic stresses. The objectives of these 2011-2013 controlled environment and field experiments were to: 1) observe growth and physiological differences between ‘Laser’ and ‘Pulsar’ RBG and TF; 2) differentiate between physiological and pathological contributors to RBG decline; 3) determine the effects of TF seeding rate and mowing height on TF/RBG establishment when RBG is a seed contaminant; 4) evaluate herbicide combinations for selective RBG control; and 5) evaluate seasonal timing of glyphosate for nonselective RBG control. Tall fescue was less affected by elevated temperature than RBG. At 35°C, Laser and Pulsar experienced similar reductions in quality, gross photosynthesis (Pg), shoot and root biomass, and root length density compared to when grown at 23°C, but maximum electrolyte leakage was greater for Pulsar (63%) than for Laser (49%). Cell membrane thermostability could contribute to the better heat tolerance of Laser RBG. Evaluation of RBG foliage and roots did not reveal a fungal pathogen associated with RBG decline. Still, repeated applications of azoxystrobin (610 g a.i. ha⁻¹) or pyraclostrobin (556 g a.i. ha⁻¹) increased RBG quality, cover, and Pg during summer compared to untreated RBG, possibly due to poorly understood non-target physiological effects of the fungicides. Mowing TF at 7.6 or 11.4 cm reduced RBG incidence up to 57% compared to mowing at 3.8 cm. Tall fescue seeding rate had no effect on RBG incidence. Several herbicides and herbicide combinations resulted in some RBG injury in the field, but bispyribac-sodium was the only treatment that provided RBG control (16 to 92%) in Manhattan, KS; Hutchinson, KS; and Mead, NE. Spring-applied glyphosate resulted in the lowest RBG coverage (1 to 31%) among field studies in Manhattan and Mead, followed by late-summer applications (6 to 58%), and mid-summer applications (9 to 86%).
3

Evaluation of Various Herbicides for Saw Greenbrier [Smilax bona-nox L.] and Southern Dewberry [Rubus trivialis Michx.] Control and Bermudagrass [Cynodon dactylon (L.) Pers.] Tolerance and Sharppod Morningglory [Ipomoea trichocarpa var. trichocarpa Ell.] Control in Roundup Ready Flex® and LibertyLink® Cotton Systems

Janak, Travis Wayne 2011 December 1900 (has links)
Field studies were conducted during 2006 and 2007 to evaluate control of saw greenbriar and southern dewberry by various pasture herbicides and to assess forage tolerance of Tifton 85 bermudagrass to these herbicides. Herbicides evaluated in each study included triclopyr, picloram, 2,4-D, fluroxypyr, dicamba, aminopyralid, metsulfuron methyl and various combinations of the above. Visual ratings were taken on each herbicide efficacy experiment. Visual evaluations of phytotoxicity, measurements of dry matter yield, and forage quality were quantified for each of the bermudagrass tolerance trials. Saw greenbriar was best controlled at approximately one year after treatment by triclopyr at 10.9% ae v/v with diesel as the carrier (88-98%), although the lower rate of triclopyr + diesel at 0.87% ae v/v + 5% v/v and triclopyr alone at 0.87% ae v/v provided 49 to 86% control. Triclopyr + fluroxypyr at 0.25% ai v/v + 0.086% ai v/v gave best control of southern dewberry in both years when applied as an individual plant treatment (IPT) six weeks after shredding. In general, shredding 45 days prior to herbicide application gave an advantage to southern dewberry control versus not shredding. In 2006, triclopyr + fluroxypyr (IPT) was the only treatment to decrease Tifton 85 dry matter yield at the first harvest, with no effect observed at the second harvest. In 2007, both broadcast treatments containing triclopyr + fluroxypyr and the IPT treatment of triclopyr decreased dry matter yield at the first harvest, with triclopyr (IPT) being the only treatment to lower dry matter yield at the second harvest. Field studies were also conducted in 2006 and 2007 to assess sharppod morningglory control in Roundup Ready Flex® and LibertyLink® cotton systems. Herbicides evaluated included glyphosate, glufosinate, prometryn, fluometuron, and diuron. Visual ratings of percent weed control and sharppod morningglory plant counts were taken to assess control. Prometryn at 1.8 kg ai ha⁻¹ and fluometuron at 1.8 kg ai ha⁻¹ provided significant preemergence control (33-81%) of seedling sharppod morningglory. All rates of glyphosate (1.06 and 1.54 kg ai ha⁻¹) and glufosinate (0.45 and 0.6 kg ai ha⁻¹) controlled sharppod morningglory from 55 to 100% at both application timings. The addition of diuron at 1.12 kg ai ha⁻¹ to glyphosate and glufosinate at the late season application enhanced sharppod morningglory control by 3 to 16%. Additionally, in both years, no reduction in cotton yield was observed in the morningglory infested treatment when compared to the weed free treatment.
4

Influence of Annual Bluegrass on Putting Green Trueness and Control of Weedy Poa Species in Kentucky Bluegrass and Creeping Bentgrass Turf

Rana, Sandeep Singh 08 December 2016 (has links)
Annual bluegrass (Poa annua L.) and roughstalk bluegrass (Poa trivialis L.) are among the most troublesome grass weeds on golf courses throughout the United States. Herbicides for selective control of these weeds in cool-season fairways are limited and ineffective. Methiozolin is a new isoxazoline herbicide that controls annual bluegrass on putting greens and shows promise for possible weed control in fairways. Kentucky bluegrass (Poa pratensis L.) is among the most common turfgrass species used for golf fairways in the Northern United States and its response to methiozolin has scarcely been tested. A 2.5-yr field study was conducted at four Virginia locations to evaluate methiozolin efficacy for selective annual bluegrass and roughstalk bluegrass control in creeping bentgrass (Agrostis stolonifera L.) or Kentucky bluegrass fairways. Another study evaluated the response of 110 Kentucky bluegrass varieties to three rates of methiozolin. Annual bluegrass has long been presumed to impact putting green trueness, or the ability of the greens canopy to provide a smooth and directionally-consistent ball roll. Although much research has evaluated the impact of greens management on ball roll distance, no peer-reviewed research has evaluated how canopy surface factors, such as weedy annual bluegrass, will influence ball roll direction. Laboratory and field research was conducted to elucidate and overcome experimental errors that may be limiting assessment of ball directional imprecision caused by greens canopy anomalies. Techniques to minimize experimental error were employed in field studies at two Virginia golf courses to determine the influence of annual bluegrass on ball directional imprecision, bounce, and acceleration. Study results suggest that annual bluegrass patches in a creeping bentgrass putting surface can cause subtle increases in ball directional imprecision and bounce but several sources of error must be controlled before these effects can be measured. By using a mechanical putter to avoid directional errors associated with simulated-putt devices, selecting golf balls with balanced centers of gravity, eliminating legacy or "tracking" effects of repeated ball rolls via canopy brushing, and scoring ball direction 30 cm prior to terminal acceleration, we were able to detect an increase in ball directional imprecision of 8 mm m⁻¹ when balls rolled over a single patch of annual bluegrass compared to adjacent rolls on visually-pure creeping bentgrass. In herbicide efficacy studies, methiozolin-only treatments did not significantly injure creeping bentgrass or Kentucky bluegrass, reduce quality, or reduce normalized difference vegetative index regardless of application timings and rates. In general, fall applications of methiozolin reduced roughstalk bluegrass and annual bluegrass cover more than the spring-only treatments. At 1 year after the last treatment, methiozolin at 1500 g ha⁻¹ applied four times in fall at 2-wk intervals for two consecutive years controlled roughstalk bluegrass and annual bluegrass ≥85% and more consistently than other herbicides or treatment regimes. Spanning 110 Kentucky bluegrass varieties, a commercially-acceptable threshold of 30% Kentucky bluegrass injury required between 3.4 to more than 10 times the methiozolin rate needed for annual bluegrass control. Results indicate that annual bluegrass increases directional imprecision and bounce of golf balls rolling across a greens canopy. Methiozolin could be a viable herbicide for managing annual and roughstalk bluegrass in Kentucky bluegrass and creeping bentgrass fairways but weed control efficacy may be dependent on application timing. By measuring small differences in ball directional imprecision as influenced by greens canopy factors, future research efforts will aim to help turf managers choose appropriate greens management techniques. / Ph. D.
5

From relict to future model? Common pastures as biodiversity refuges in the pre-alpine agricultural landscape

Schwarz, Cinja 10 May 2022 (has links)
Wir befinden uns inmitten einer globalen Biodiversitätskrise mit steigender Aussterberate, die die natürliche Hintergrundrate bereits jetzt um das Tausendfache überschreitet. In terrestri-schen Lebensräumen geht vom Landnutzungswandel die größte Gefahr für die Biodiversität aus. Besonders die ursprünglich hohe Vielfalt im mitteleuropäischen Grünland ist seit der In-dustrialisierung durch Nutzungsintensivierung und -aufgabe stark zurück gegangen. Traditionell genutztes, beweidetes Grünland ist in Mitteleuropa selten geworden. Dennoch deuten einige aktuelle Studien auf seine große Bedeutung für den Erhalt der Biodiversität in der Agrarland-schaft hin. Allerdings fehlen umfassende, systematische Untersuchungen für viele traditionelle Grünlandsysteme. Um diese Wissenslücke zu verringern, untersuchte ich in meiner Dissertation die Relevanz voralpiner, traditionell bewirtschafteter Allmendweiden als Refugium für bedrohte Zielarten (Baumpieper [Anthus trivialis], Blaukernauge [Minois dryas]) sowie für arten- und individuenreiche Zoozönosen (Heuschrecken [Orthoptera]) der mitteleuropäischen Agrarlandschaft. Gepaarte Vergleiche von Allmendweiden und angrenzenden Flächen mit identischen Standortbedingun-gen (Referenzflächen) ermöglichten den Vergleich der Arten bzw. -gruppe anhand von Umwelt-parametern in den Vegetationstypen Grünland auf Mineralboden und offenen Mooren. Der Un-tersuchungsraum in Südbayern stellt den Verbreitungsschwerpunkt für Allmendweiden und intakte bis naturnahe Moorökosysteme in Deutschland dar. Meine Analysen zeigen, dass sich der Landnutzungswandel drastisch auf die Referenzflä-chen, die früher überwiegend Teil der Allmendweiden waren, auswirkte: Im Vergleich zu den Weiden weisen sie (i) homogene Strukturen auf Landschafts- und Habitatebene, (ii) geringe Anteile nährstoffarmer Habitate und (iii) eine geringe Besiedlung von Vögeln und Insekten auf. Somit sind sie weitgehend ungeeignet für den Erhalt der Biodiversität. Die einzige Ausnahme innerhalb der Referenzflächen bilden traditionell genutzte Heu- und Streuwiesen. In den Allmendweiden sorgt die traditionelle Beweidung (0.5–2.0 Großvieheinheiten/ha von Mai–Oktober) für eine hohe strukturelle Vielfalt mit nährstoffarmen Habitaten und fließende Übergänge zwischen Wald und Offenland. So können saisonal bzw. innerhalb des Lebenszyklus wechselnde Ansprüche vieler typischer Agrarlandschaftsarten im eng verzahnten Mosaik wert-voller Habitate erfüllt werden. Der Erhalt der Allmendweiden ist für das Überleben von Agrar-landschaftsarten im Untersuchungsgebiet essenziell. Eine Ausdehnung der Allmendweiden-Nutzung auf angrenzende Flächen ist unbedingt zu empfehlen.

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