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Non-Methane Hydrocarbon Source Apportionment And Btex Risk Assessment Of Winter 2015 In Roosevelt, Utah, Jerimiah Lamb

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Non-Methane Hydrocarbons (NMHC) monitored in Roosevelt Utah including Benzene, Toluene, Ethylbenzene and Xylene (collectively known as BTEX) are associated with deleterious effects including cancer. This study was designed to assess the origin and effect of the toxicants and addressed two points: 1) Source identification using the USEPA’s Positive Matrix Factorization (PMF) and NOAA’s Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model and 2) A human health risk assessment based on ambient concentrations of BTEX collected at the Roosevelt site. Model fit indicated that the primary contributor to total NMHCs was local oil and gas operations and was supported by previous …

Nitrogen Availability And Use Efficiency In Corn Treated With Contrasting Nitrogen Sources, Avneet Kakkar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The plant-soil nitrogen cycle plays a significant role in allocation of available N to plants, and improved understanding of N cycling helps sustainably increase fertilizer use efficiency. There are various processes (nitrogen mineralization and nitrification) involved in the availability and mobility of nitrogen in the soil. The primary objective of this study was to determine the NUE under contrasting nitrogen treatments over a period of five years. Additionally, we examined the effect of different N treatments on N mineralization and nitrification in conventional and organic farming systems.

This project was funded by Agriculture and Food Research Initiative Competitive Grants Program …

Seasonal Development Of The Biological Control Agent Of Dalmatian Toadflax, Mecinus Janthiniformis (Curculionidae: Coleoptera), In Utah: Phenology, Overwintering Success, And Mortality, Samantha A. Willden

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

By outcompeting desirable vegetation, invasive weeds can dominate field crops and rangelands, drastically reducing yield and land value. One option in controlling the impact and spread of such weeds is reuniting them with their natural insect herbivores, a process called biological control. When successful, biocontrol can be the cheapest way to provide long-term control of invasive weeds, but continual monitoring of insect and weed activity is required to ensure success.

Dalmatian toadflax is an invasive weed that occurs widely throughout the northwestern U.S., and that is spreading south each year to warmer and drier regions, including sites in Utah. Although …

Sclerocactus Wetlandicus: Habitat Characterization, Seed Germination And Mycorrhizal Analysis, Kourtney T. Harding

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Uinta Basin hookless cactus (Sclerocactus wetlandicus) is a threatened species native to Eastern Utah. The cactus is found in a landscape highly disturbed by non-renewable energy production. To understand the environmental conditions that support natural growth of this cactus, we asked what types of plants were present in the same areas as the cactus, and if the types of plants were different in environments that were disturbed. From our assessment, we determined that the types of plants present in disturbed areas were drastically different from those present in undisturbed locations. Areas previously used for energy production are …

Understanding The Mechanisms Of Insecticide Resistance In Phlebotomus Papatasi And Lutzoymia Longipalpis Sand Flies (Diptera: Psychodidae: Phlebotominae), David Denlinger

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sand flies, like mosquitoes, ticks, fleas, and lice, transmit pathogens that cause disease in humans. Leishmaniasis, caused by pathogens transmitted by sand flies, kills tens of thousands of people every year. Insecticides have been used to control sand flies, but there is evidence of insecticide resistance in populations of sand flies around the world. The goal of this dissertation was to develop tools to maintain sand flies in the laboratory, develop the ability to identify insecticide-resistant populations of sand flies, and to investigate the genetic mechanisms of how sand flies become resistant to insecticides. I began by comparing live animal …

Effect Of Foliage And Root Carbon Quantity, Quality, And Fluxes On Soil Organic Carbon Stabilization In Montane Aspen And Conifer Stands In Utah, Antra Boča

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Soil organic carbon (SOC) positively affects many soil properties (e.g., fertility and water holding capacity), and the amount of carbon (C) in soil exceeds the amount in the atmosphere by about three times. Forest soils store as much C as is found in trees. Tree species differ in their effect on SOC pools. Quaking aspen forests in the Western US often store more stable SOC in the mineral soil than nearby conifers. During the last decades a decline in aspen cover, often followed by conifer encroachment, has been documented. A shift from aspen to conifer overstories may negatively affect the …

Precision Drought Stress In Orchards: Rootstock Evaluation, Trunk Hydration And Canopy Temperature, Lance V. Stott

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Tree fruit crops are of high value, but use a lot of water. Precision irrigation has the potential to save water while simultaneously improving crop quality. The timing and method of precision water stress in various tree fruit crops has been widely studied. However, in order to successfully employ precision irrigation methods in orchards, an accurate measurement of tree water status is required. Currently, stem water potential is the preferred indicator. However, this measurement is tedious and cannot be automated. Because measurements must be taken near solar noon (approximately 1:30 PM MDT in the summer in northern Utah), the number …