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Characterizing Water And Nitrogen Dynamics In Urban/Suburban Landscapes, Hongyan Sun

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research investigated the water use of different plant types in urban landscapes, nitrogen (N) and water transport in turf, and potential N leaching from urban landscapes to ground water. In the first study, three landscape treatments integrating different types of plants—woody, herbaceous perennial, turf—and putative water use classifications—Mesic, Mixed, Xeric—were grown in large drainage lysimeters. Each landscape plot was divided into woody, turf, and herbaceous perennial plant hydrozones and irrigated for optimum water status over two years, with water use measured using a water balance approach. For woody plants and herbaceous perennials, canopy cover, rather than plant type or …

Orchard Floor Management, Marc A. Rowley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Managing fruit orchards involves both the management of the orchard trees, and the orchard floor. Orchard floor management is vital to tree health, yield and fruit quality. Current standard management practices include maintaining a vegetation free tree row and a grass-covered alleyway. This system effectively controls weeds and creates a favorable environment for the fruit trees. However, limitations to standard orchard floor practices are that the grass alleyway provides no nutrient benefit, and current practices do not readily lend themselves to organic management. Alternative in-row and alleyway systems are requisite to creating improved orchard floor management systems.

Three different approaches …

Causes And Consequences Of Plant Spatial Patterns On Natural And Experimental Great Basin (Usa) Plant Communities, Andrew P. Rayburn

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The processes by which plant spatial patterns are formed, and the effects of those patterns on plant community dynamics, remain important areas of research in plant ecology. Plant spatial pattern formation has been linked to many ecological processes that act to structure plant communities at different spatiotemporal scales. Past studies of pattern formation are common, but recent methodological advances in data collection and analysis have permitted researchers to conduct more advanced observational studies of pattern formation in space and time. While studies of the effects of plant spatial patterns were formally rare, they have increased in the last decade as …

Ungulate Damage To Safflower In San Juan County, Utah, Michael J. Haney

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In Utah, farmers are concerned that ungulates are damaging safflower (Carthamus tinctorius) fields. I examined elk (Cervus elaphus) and mule deer (Odocoileus hemionus) damage to safflower production in San Juan County, Utah during 2009 and 2010. Data on damaged safflower plants were collected within 28 fields, totaling 1,581 ha (13 fields totaling 963 ha during 2009; 15 fields totaling 618 ha during 2010). I compared 3 methods to assess losses: ungulate-proof exclosures, adjacent plant compensation method, and counting the number of damaged plants in 50-m transects (safflower count method). Exclosures were of limited use …

The Transfer Of Agricultural Water To Municipal And Industrial Usages, Dallin Paul Stephens

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The water that is available for beneficial use in Utah is quickly approaching full appropriation; water that has been claimed is nearing the amount that is available for use. The Division of Water Resources of the State of Utah has organized a three-part plan to "Plan, Conserve, Develop and Protect Utah's Water Resources." One of these three elements has a focus to "provide comprehensive water planning." Such planning is best achieved when current and accurate data on the uses of the state's water are available.

The primary purpose of this thesis was to provide an evaluation, from data collected on …

Establishing Weed Prevention Areas And Evaluating Their Impact, Stephanie Christensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The spread of invasive weeds continues to be a serious economic and environmental threat. Weed prevention has the potential to stop weeds before they become well established in an area conserving time, energy, and resources. Unfortunately, weed prevention is often overlooked. Weed Prevention Areas (WPAs) are a relatively new tool developed to help improve the application of weed prevention. They are cooperatively managed areas that focus on implementing prevention and early detection strategies at a community level. The purpose of this research was to establish baseline data that will be used to evaluate the overall effectiveness of the WPA concept, …

Spatiotemporal Modeling Of Threats To Big Sagebrush Ecological Sites In Northern Utah, Alexander J. Hernandez

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study tested the performance of classification, regression, and ordination techniques to evaluate the spatiotemporal dynamics of threats to big sagebrush ecological sites. The research was focused on invasion by annual exotic grasses and encroachment by woodlands.

We sought to identify those areas that have had a persistent coverage of cheatgrass (Bromus tectorum) in big sagebrush ecological sites. We took advantage of the contrast in greenness between multi-temporal (within one year) remotely sensed vegetation indices captured in the spring and summer to find a distinct phenological signature that allowed mapping cheatgrass. We utilized support vector machines (SVM) to classify three …

Evaluating Fertilizer Rate, Crop Rotation And Trap Crops For Effects On Onion Growth And Yield, Soil Health, Thrips Densities And Iris Yellow Spot Virus Incidence, Kristine R. Buckland

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Onion production in the United States is seriously affected by the tospovirus Iris Yellow Spot (IYSV), whose symptoms include lenticular-shaped lesions that reduce photosynthesis and bulb yield. Thrips tabacai Lindeman, onion thrips (OT), is the only known vector of the disease and a primary arthropod pest of onion. Frequent insecticide applications, increasing resistance in OT populations to insecticides, high nitrogen (N) fertilization rates and loss of yield to disease and insect pressure threaten sustainable onion production. The objectives of this study were to identify crop management strategies to enhance onion productivity while suppressing OT and IYSV. Three fertilizer rates and …

Process-Based Management Of Downy Brome In Salt Desert Shrublands: Assessing Pre- And Post- Rehabilitation Soil And Vegetation Attributes, Merilynn Carol Hirsch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As an ecosystem driver, downy brome (Bromus tectorum L.) presents obstacles to land rehabilitation efforts, including restoring desirable species cover. Because damaged ecosystems may have crossed both abiotic and biotic thresholds, ecologically-based control strategies may assist with altering successional trajectories and restoring desirable plant species. My thesis research had three objectives: 1) assess soil and vegetation relationships in degraded salt desert ecosystems prior to implementing downy brome control treatments, 2) determine the effects of control treatments on soil properties and resident plant species, and 3) evaluate the relative importance of shrubland soil type, herbicide type, and herbicide rate on seedling …

Ecophysiology And Genetic Variation In Domestication Of Sphaeralcea And Shepherdia Species For The Intermountain West, Chalita Sriladda

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Low-water landscaping (LWL) using native drought tolerant species is an essential tool for water conservation in the arid Intermountain West (IMW) for managing limited water supplies. However, many potential species have not been evaluated for LWL. Some species are difficult to visually distinguish from each other, thus decreasing confidence in products from native plant industry. Meanwhile, some species are difficult to establish to urban landscape conditions. The overall goal of this study is to elucidate morphological, ecophysiological, and genetic distinctions within two IMW native plant genera containing species with high urban low-water landscape potential.

For the first study, a classification …

Factors Affecting Greater Sage-Grouse (Centrocercus Urophasianus) Survival And Movement In South-Central Utah, Danny Caudill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Greater sage-grouse are the largest North American grouse species and are dependent on sagebrush for survival. Sage-grouse populations have declined throughout the west. Habitat fragmentation and degradation are likely the main causes of declining populations, and concern has lead to the petitioning for the sage-grouse to be listed under the Endangered Species Act. Survival of adult and juvenile sage-grouse is thought to be limiting population growth. However, survival of juvenile sage-grouse is poorly understood. I aimed to improve the knowledge gap regarding juvenile sage-grouse survival. With improved knowledge of juvenile survival, management actions can be employed to benefit sage-grouse populations. …