Life Sciences Commons^™

Socioscientific Issues In School-Based Agricultural Education: Describing And Exploring Factors Of Integration, Michelle S. Burrows

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Socioscientific issues (SSI) are complex issues which are scientific in nature and have societal impacts. Many SSI have connections to agriculture and as such should be included in agricultural education curriculum. A clear understanding of what school-based agricultural education (SBAE) teachers know about SSI is needed. The purpose of this research was to explore the knowledge and integration of SSI among SBAE teachers by describing and explaining the factors that influence integration. This quantitative survey research was guided by the SSI-based instruction framework and the three-component model of agricultural education. The population for this study was all SBAE teachers in …

Monitoring Populations And Movement Of Bobcats (Lynx Rufus) On The Eastern Slope Of The Sierra Nevada Mountains Of California, Michael Brown

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Monitoring the spatial ecology and population densities of carnivores is critical for effective management and conservation of these populations and the ecosystems in which they exist. However, effective monitoring of carnivore populations through estimates of space use, habitat selection and densities can be difficult due to their relatively low densities and wide ranging, elusive behaviors. Bobcats (Lynx rufus) are medium sized, top-level predators which are widely distributed across North America. Quantifying space use, habitat selection and developing effective population monitoring strategies for this species will have important implications for wildlife management.

My first objective was to use telemetry …

Innovative Water Management Using Advanced Irrigation Systems And Biochar, Jonathan A. Holt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two approaches to water optimization in agriculture are to increase soil water retention and improve the efficiency of irrigation. A soil amendment that has received attention for its ability to increase soil water retention is biochar, the remaining biomass after high C materials have been pyrolyzed (burned with limited oxygen and heat). Two studies were conducted at a total of 10 site-years in Utah from 2018 to 2020 to evaluate how wood biochar influences the productivity and crop quality of irrigated alfalfa (Medicago Sativa L.), corn (Zea mays L.), and wheat (Triticum L.), along with soil water tension. One study …

Investigations Of Substrate Reduction By Nitrogenase: Light Powered Substrate Reduction By A Cds:Femoco System And Understanding Dinitrogen Inhibition Of Electron Transfer, Hayden Kallas

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nitrogen fixation is a key step of the nitrogen cycle which makes biologically inert N₂ gas available for organisms to use in the form of ammonia. Nitrogen fixing microorganisms all contain the same enzyme called nitrogenase which catalyzes the six electron transfers to N₂ required for conversion into ammonia. Nitrogenase is a two-component enzyme that contains a cofactor composed of iron and sulfur as well as heavier metals whose identity can be molybdenum, vanadium, or an additional iron atom depending on the variant. The two components of nitrogenase are the MFe protein and the Fe protein. The Fe …

Invasive Plant Occurrence Across Agency Boundaries: Two Case Studies From California, Natalie Otto

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Non-native invasive species (NNIS) are a major concern confronting land managers in and surrounding protected areas such as national parks. These areas are managed by a variety of entities, all of which have different mandates, management priorities, and resources that are allocated to NNIS programs. These differences can result in ecological divergences at land boundaries and can create barriers to cooperative management. Through interviews and ecological data collection, this research addresses three topics; 1. It identifies disparities in NNIS and disturbance occurrence between jurisdictions and tests the strength of correlations between these variables; 2. It seeks to determine what role …

Short- And Long-Term Mechanisms For Increasing Inputs Of Phosphorus In Mountain Waterbodies Of Northeastern Utah, Usa, Jessica Scholz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Phosphorus is an essential nutrient that allows life in water to flourish, but changes in phosphorus supplies are not well understood in remote watersheds. In mountain environments, remote watersheds contain critical high-quality water supplies and unique ecosystems, but excess phosphorus can diminish water quality by producing unfavorable aquatic species. Therefore, observed trends of increasing phosphorus concentrations in remote lakes and rivers in the US over the last two decades are a significant concern. Using the Uinta Mountains as a case study, we evaluated three different direct and indirect pathways for phosphorus increases in remote mountain watersheds that may explain observed …

Responses Of Pacific Fishers To Habitat Changes As A Result Of Forestry Practices In Southwestern Oregon, Tessa R. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The fisher (Pekania pennanti) is a medium-sized carnivore found in mature forest stands across much of the northern United States. Although historically abundant in the west, fisher populations declined rapidly after fur trapping, extensive logging, and urban development reduced their numbers. Currently, biologists are concerned about the effects timber harvest practices have on fisher tolerance and adaptability when faced with changes to high-quality habitat stands. Tree removal and thinning of understory vegetation are frequently used to alleviate the spread of wildfires in previously dense forest stands with a potential for large-scale habitat loss; yet, a deficit of large …

Visitor Perceptions And Resource Conditions Of Campsites In Two Coastal Alaskan National Parks, Shannon T. Wesstrom

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Increasing visitation in parks and protected areas presents managers with the challenge of providing quality visitor experiences while mitigating ecological impacts from recreation. Successful management strategies often suggest determining desired conditions for visitor experiences and ecological conditions to establish thresholds. These thresholds can then be compared to existing conditions in order to determine if changes in management strategies should be made. By integrating visitor survey results with ecological assessments, this research is a unique coastal Alaskan regional analysis of the three components of a management framework: 1. Establishes visitor determined thresholds of acceptability for crowding and coastal resource conditions in …

Seeding Rate, Herbicide, And Irrigation Effects On Spring-Seeded Oat-Alfalfa Companion Crops, Carson D. Roberts

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Small grain companion crop seeding rate recommendations for alfalfa (Medicago sativa L.) establishment are dated and inconsistent, and how a small grain companion crop seeding rates should be adjusted at different moisture levels is unknown. A study was conducted to provide clarity about oat (Avena sativa L.) companion crop seeding rates that maximize weed suppression and forage yield and minimize the effect on alfalfa stand establishment. This experiment considered oat companion crop seeding rates at various irrigation levels. Companion crop treatments consisted of oats sown at 89, 45, 22, 10, and 0 (with and without herbicide) kg ha …

Effect Of Biocrust Development On Establishment Of Native Plants In A Salt Desert System, Merran Owen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Salt desert shrublands are semiarid, shrub-dominated ecosystems that inhabit salt- affected soils. In Great Basin salt deserts, exotic annual plants are invading and displacing native plants. Low plant productivity and slow population growth of native plants in these ecosystems makes them vulnerable to invasion and limits their ability to compete with invasive plants and return to a natural state. Active revegetation efforts, such as planting and direct seeding of native plants, are often unsuccessful for the same reasons. Biological soil crusts (communities of cyanobacteria, lichen, moss, microfungi and other microorganisms that live on the surface layer of the soil) are …

Demographics, Accuracy, And Impact Of Feed Laboratories In The United States, Jerald H. Severe

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Feed analysis is very important to modern society. In the United States feed analysis is used to optimize production of food animals. Feed analysis is also used as a tool to place value on crops. As important as feed analysis is to society, little research has been done that describes which feed laboratories are the most popular and why people use them. It has been thought by some patrons that different results from the same feed sample are obtained by different laboratories. Is this true? If so, what is the effect on those that use feed laboratories to produce animals, …

The Consequences Of Environmental Properties And Tree Spatial Neighborhood On Post-Fire Structure Of Forest In Yosemite National Park, Jelveh Tamjidi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Separating the contribution of habitat filtering and dispersal mechanisms in forming species distribution remains a challenge in community ecology. Despite the effect of environmental variables in structuring communities, only restricted numbers of them were considered as a habitat dissimilarity.

In Chapter 2, I used topography and soil properties to define habitats within the Yosemite Forest Dynamics Plot (YFDP). The soil enzymes were added in soil samples due to their important role in releasing nutrients into the soil environment. The preference of eleven species to a specific habitat were examined. Also, the relative importance of habitat filtering and dispersal limitation were …

Classification And Prediction Models For Natural Streamflow Regimes In The Arid Southwestern Usa, Angela M. Merritt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding how natural variation in flow regimes influences stream ecosystem structure and function is critical to the development of effective stream management policies and actions. Spatial variation in flow regimes is well understood for stream reaches in mesic regions, but a more robust characterization of flow regimes in arid regions is needed, especially to support biological monitoring and assessment programs. Methods are specifically needed that can accurately predict the flow regime expected at ungauged reaches. We used long-term (41 y) records of mean daily flow from 287 stream reaches in the arid western USA to develop and compare several alternative …

Fruit Tree Responses To Water Stress: Automated Physiological Measurements And Rootstock Responses, William D. Wheeler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

New orchard plantings utilize trees grafted to dwarfing rootstocks planted close together to facilitate larger harvests. These dwarfing rootstocks have not been comprehensively studied for their ability to withstand drought. This is of special importance in the Intermountain West which has limited rainfall. Additionally, orchard growers face competition for water from a growing population and increased uncertainty in rainfall from climate change. My research examined the use of dendrometers, which measure changes in trunk diameter, and sap flow sensors, which measure how quickly sap moves, as methods to inform growers about tree water status. I also used a weighing lysimeter …

Novel Polymorphisms Of Zrsr2 And Gpm6b Gene Homologs And Their Use In Sex Identification Of Bovine And Porcine Species, Evan K. Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Accurate and cost-effective PCR based sex identification is important in animal production because it gives producers the ability to determine the sex of embryos prior to transfer, saving time and money. The most efficient PCR sex identification assays work by using a single primer pair to amplify a specific target region located on the Y-chromosome and a second, separate target region on the X-chromosome.

This thesis reports the design of two novel assays. The first assay was designed to target the Zinc finger CCCH-type, RNA binding motif and serine/arginine rich 2 (ZRSR2) gene found on the X-chromosome and its Y-chromosome …

Selection And Propagation Of Pinyon Pine, Kylie M. Lawson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Single-leaf pinyon pines are drought tolerant trees native to the Great Basin. This species is a source of wild-collected, edible pine nuts that are in great demand. With no previous research apparent, this thesis aimed to identify wild trees with high cone production as sources for evaluating grafting onto immature and mature trees. Wild sources of scions were identified from four wild stands and six trees per stand. Counting and analyzing the number of scars left by mature cones along the leader branch provided an estimate for each tree‚Äôs productivity and identified trees with greater productivity within a stand. The …

Effects Of Wi-Fi-Enabled Smart Irrigation Controllers On Water Use And Plant Health Of Residential Landscapes In The Intermountain West, Shane R. Evans

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Residential and commercial landscapes provide home and business owners with several benefits. These benefits range from improved air quality and flood control to the reduction of noise and breakdown of organic chemicals. However, these landscapes are routinely overwatered which can lead to plant disease, nutrient pollution, and large amounts of water being wasted. Utah State University, in conjunction with the Center for Water Efficient Landscaping (CWEL), the Utah Division of Natural Resources and Weber Basin Water Conservancy District, conducted an experiment to determine if Wi-Fi-enabled smart irrigation controllers conserve water as compared to average residential irrigation amounts and manually programmed …

Examination And Empirical Forecast Of Wheat Yield In Northwest India Based On Climate And Socio-Economic Factors, Avik Mukherjee

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study summarizes the findings of research organized in two parts. The first part includes the impact of climate and socio-economic factors that affected wheat yield in northwest India during the 2000s. The second part focused on the forecast of average wheat yield for the two highest wheat producing states Punjab and Haryana.

Initial study focused on the impact of climate factors on wheat yield in northwest India. It has been found that above normal temperature coupled with water shortage i.e. irregular irrigation and low soil moisture contributed to the prolonged yield reduction during 2002-2010.

Next, we reviewed the socio-economic …

Utilizing Earth's Microbiology To Develop The Framework For A Manufactured Martian Nitrogen Cycle, Kyle Valgardson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

History has shown us that space travel is a complicated activity not to be taken lightly. Extended missions such as those that would accompany a manned mission to Mars are guaranteed to have increased complexity and require creative solutions to problems we likely take for granted. One such issue is how to supply the necessary amount of nitrogen to the astronauts to keep them alive. Nitrogen is an essential component to life on Earth as most biological molecules, such as protein and DNA, contain a significant amount of it. Most organisms have to get it from what they eat, but …

Water Use In Jujube (Ziziphus Jujuba) With Applications In Irrigation Timing And Quantity, Preston S. Colver

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Jujube (Ziziphus jujuba) is a major fruit crop in China where it has been a favored cash crop and successfully used to address erosion problems in the Loess Plateau region of western China. Further use of jujube in forestry projects and improved agricultural efficiency are very promising. This study sought to repeat a water-use study in two climates: a hot, semi-arid climate in Yangling, Shaanxi, China and a dry-summer, continental climate in Logan, Utah, USA. The study took physiological measurements on the trees with the aim of characterizing the way that jujube uses water. This would help to …

Nodulation And Growth Of Shepherdia × Utahensis ‘Torrey’, Ji-Jhong Chen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Shepherdia ×utahensis ‘Torrey’ (Elaeagnaceae) is a hybrid of two native actinorhizal plants in the Intermountain West, S. argentea (silver buffaloberry) and S. rotundifolia (roundleaf buffaloberry). Due to actinorhizal symbiosis, atmospheric nitrogen (N₂) can be converted to ammonium, a bioavailable form. Actinorhizal plants have great value in sustainable nursery production and urban landscape use. However, nitrogen fertilizer negatively affects the nodulation of actinorhizal plants. As a newly developed hybrid, both the symbiont identity and nodule formation of S. ×utahensis ‘Torrey’ remain largely unknown. Therefore, experiments were conducted to investigate the nodule formation of S. ×utahensis ‘Torrey’ inoculated with field …

Habitat, Diet, And Foraging Ecology Of Willow Flycatcher In Sierra Nevada Meadows, Scott E. Dietrich

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The last stronghold of the California Willow Flycatcher (Empidonax traillii) population, which exists in the Sierra Nevada, continues to decline, necessitating a clearer understanding of how meadows provide habitat for the species. To gain this understanding, we assessed vegetation type, saturation levels, and invertebrate species at 51 different sites within four meadows located in the Little Truckee River drainage. 17 of these sites were occupied by nesting Willow Flycatcher during the time of the study, 17 sites had been occupied by nesting Willow Flycatcher in annual surveys between 1997 and 2010 but are no longer used, and 17 …

Rumen Fermentation Responses To Purified Palmitic, Stearic, Or Oleic Fatty Acids And The Impact Of A Palmitic Acid-Enriched Supplement On Animal Performance, Austin Paul Sears

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Our research examined the responses of palmitic, stearic and oleic fatty acids on neutral detergent fiber (NDF) digestibility and rumen fermentation and the impact of a palmitic acid-enriched supplement on animal performance. In the first research chapter, we evaluated the effect of purified palmitic, stearic, and oleic fatty acids on NDF digestibility and rumen fermentation. Palmitic acid increased NDF digestibility and total production of volatile fatty acids (VFA) compared with oleic acid. Bacterial fatty acid composition was altered by palmitic acid, increasing anteiso-C15:0, C18:2n6 and C18:3n3 fatty acids compared with oleic acid. Compared with control, …

Assessment Of Compost On Dryland Wheat Yield And Quality, Soil Fertility And Water Availability In Utah, Kareem A. Adeleke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In 2014-2016 Kareem Adeleke undertook a graduate project under the supervision of Utah State University (USU) Plants, Soils and Climate professors, Drs. Jennifer Reeve, Astrid Jacobson, and Earl Creech. Organic wheat producers face numerous challenges, such as low soil moisture, soil erosion, and low soil fertility. Organic wheat growers generally do not apply fertilizer due to inability to recoup the costs in the short-term. Compost enhances long-term improvement in soil quality, soil fertility and increase yield in low input environments. Understanding of compost carryover effects in dryland wheat systems is necessary for increased yield that will allow adequate supply of …

Applied Species Delimitation In Microbial Taxa And Plants, Austin C. Koontz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Species are a fundamental concept in biology, and many subdisciplines in biology utilize species in aspects of theory and in the communication of results. Given the centrality of species in biological science, it can seem surprising that there is no universal definition amongst biologists of what, strictly speaking, a species is. In fact, there are, by some estimates, over 20 different "species concepts", and this lack of a consensus is termed "the species problem". This problem has theoretical underpinnings, but has become more relevant as advances in sequencing technologies over the past two decades have allowed researchers to probe the …

Assessing The Effects Of Cold Storage Regimes Of North American Bombus Queens: Long Live The Humble Queen, Thuy - Tien Thai Lindsay

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bumble bees (Bombus) provide critical pollination services for wild plants and crops. They are generalist pollinators, and do not depend on one singular floral type. Native bumble bees are adapted to pollinating many native plants, such as blueberries, squash, and tomatoes. A critical component of bumble bee pollination in the greenhouse tomato industry is the domestication of commercially bred colonies. However, the domestication of Bombus is pretty early in its development, and not all aspects of the bumble bee life cycle is fully understood. This thesis addresses one of the major obstacles in domestication, which is successful mimicking …

Influences Of Forest Edges On The Growth And Health Of Old-Growth Coast Redwood Forests, Cody R. Dangerfield

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Coast redwood (Sequoia sempervirens) is the tallest species in the world, frequently attaining heights greater than 300 ft. The unique characteristics of the redwoods has led to the establishment of several preservation areas including national and state parks. However, abrupt forests edges created by previous logging and landcover changes has left the remaining stands exposed to elevated temperature, sunlight, and wind intensities, thereby making redwoods along the forest edge more susceptible to windthrow and drought stress. Despite the rarity of old-growth coast redwood forests and their ecological and cultural significance, very few studies have investigated how forests edges …

Soil Health, Phosphorus And Carbon Dynamics In Response To A One-Time Compost Application And Cover Crops In Organic Dryland Winter Wheat, Idowu Ademola Atoloye

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Organic dryland winter wheat (Triticum aestivum) growers in the U.S. are faced with high interannual variability in yields. This is related to the low annual precipitation and low soil fertility on the cultivated soils. Improving soil health is the key to increasing and maintaining crop yields. In this study, we compared the effects of different rates (0, 12.5, 25 and 50 Mg DW ha^-1 compost and 2 Mg ha manure^-1) of large quantities of steer manure compost and the inclusion of cover crops versus fallow on soil health and on carbon and phosphorus dynamics in …

The Role Of The Recently Deorphanized G-Protein Coupled Receptor, Gpr171, In Morphine Tolerance And Withdrawal, Leela Afrose

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Opioid analgesics, such as morphine, represent the gold standard pain killer and the most frequently used drugs for the treatment of moderate to severe pain. Despite being a potent analgesic, morphine has unwanted and dangerous side effects with repeated use, such as tolerance and withdrawal. Tolerance is a state when a person no longer responds to a drug and a higher dose is required to achieve the same initial pain relief. Withdrawal is a set of undesirable psychological and physiological symptoms that occur after someone stops taking a drug or reduces the dose. Morphine tolerance and withdrawal play a vital …

Leadership Styles And Barriers To Leadership For Women In Agriculture: A Mixed Methods Study, Erica Ramsey Louder

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Women are a growing demographic in agriculture, yet women holding positions in agricultural leadership is limited. This research sought to identify the ways women in agriculture lead by examining their leadership styles and the barriers they face as they strive to advance within their professions.

The results show that women are relationship-based leaders and that there are significant barriers that inhibit women’s advancement in agriculture. Many of these barriers are related to gender bias, self-perception, and life issues such as stress and workload.