Digital Commons Network^™

Practical Improvements For Pivot And Surface Irrigation, Jonathan A. Holt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Irrigation is critical to meeting global food and fiber demands. Optimizing agricultural irrigation may help sustain production levels, while reducing its demand for water. This research evaluated precision sprinklers and drip irrigation for pivots, five pivot track mitigation tools, three scientific irrigation scheduling (SIS) methods, sensors for surface irrigation cutoff, and automating surface systems to implement surge irrigation. With pivots and surface irrigation being the most common methods for irrigation in the West, small improvements from these tools could result in significant water savings.

Low energy precision application (LEPA) sprinklers and mobile drip irrigation (MDI) were tested on two pivots. …

Student Perceptions Of Male And Female Instructors In A Post-Secondary Welding Course, S. Kjersti R. Decker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Agricultural mechanics and welding have traditionally been perceived to be careers reserved for males, yet more females have entered professions using welding such as agricultural education. This research was developed because of the lack of gender research in welding. The purpose of this study was to examine students’ perceptions of learning from a male instructor versus a female instructor in a post-secondary welding course. We examined associations and differences between students’ preference of a male and a female welding instructor as well as individual self-efficacy and perceptions towards using welding technology. The population for this study was undergraduate students and …

The Relationship Between Bird Species Richness And Human Appropriation Of Net Primary Productivity, Kaeli Mueller

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As humans harvest increasing amounts of biomass, it is crucial to gain an understanding of how much energy is being appropriated and the impact that this could have on ecosystems and biodiversity. The primary way in which humans impact biodiversity loss is through land use change. One way of quantifying the impact of land use change is through human appropriation of net primary production (HANPP). This measurement represents the total amount of energy derived from photosynthesis that humans remove from ecosystems and appropriate for their own use. My research studies the relationship between HANPP and bird species richness at the …

Essays On The Economics Of Regional Development And Public Policy, Wai Yan Siu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

My dissertation integrating theory and practice into fostering sustainable, ecofriendly, and equitable public policy that promote the well-being of generations to come. My main research questions are: how can we transform the complex socioeconomic systems to build future resilience? In the first chapter, I identify and quantify the effect of the presence of tight oil and gas extraction on the agricultural productivity. This study informs evidence-based policymaking on pressing environmental issues. In the next chapter, I studied the effectiveness of existing policy of urban growth control from an evolutionary landscape and found that the decades-old regulation does not fulfill its …

Space-Time Dynamics Of The Uinta Fremont Agricultural Transition In Eastern Utah And Northwestern Colorado, Trista N. Schiele

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent work in Utah’s northern Uinta Basin documents associations between variability in precipitation and fluctuating populations during the Fremont period, AD 300-1350. In this study, I evaluate the role that precipitation variability had on observed regional population density and settlement patterns. I test a model of village formation in Cub Creek, Utah across the larger Uinta Basin and its periphery by creating two predictive statistical models using archaeological data anchored in space and time. I conclude that while precipitation variability plays a role in the initial adoption of farming practices which itself leads to higher population densities, changes in patterns …

Ranchers Adapting To Climate Variability In The Upper Colorado River Basin, Utah, Hadia Akbar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Changes in climate influence agricultural production. This study looks at the impacts of climate variability in the Utah regions of the Upper Colorado River Basin by combining regression techniques with interview data to explore how climate variability affects agricultural production and how the farmers are adapting their practices to these changes. The results show that climate does not have any significant impact on cattle and hay production in the study area on a decadal scale. However, on an annual basis temperature seems to have more impact than precipitation. Among non-climatic variables, commodity prices and their regulations by the government are …

Agriculture Teacher Attitudes Regarding Gifted Education And Teaching Gifted Students In The Agriculture Classroom, Olivia M. Hile

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Agriculture teachers are responsible for a wide variety of students in their classrooms. It was unclear before this research how much preservice teacher instruction agriculture teachers were receiving to prepare them to teach students identified as gifted. This research aimed to measure teacher attitudes, characterization of gifted students, professional development needs, and related demographic information. Of the agriculture teachers who completed a traditional teacher preparation program, 54.50% felt that they were adequately prepared to meet the needs of gifted students in their classroom.

Participants characterized gifted agriculture students as outstanding problem solvers, quick to memorize information, and excellent in science. …

Subsistence Strategy Tradeoffs In Long-Term Population Stability Over The Past 6,000 Years, Darcy A. Bird

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I conduct the first comparative analysis of long term human population stability in North America. Questions regarding population stability among animals and plants are fundamental to population ecology, yet no anthropological research has addressed human population stability. This is an important knowledge gap, because a species’ population stability can have implications for its risk of extinction and for the stability of the ecological community in which it lives. I use archaeological and paleoclimatological data to compare long term population stability with subsistence strategy and climate stability over 6,000 years. I conduct my analysis on a large scale to better understand …

The Value Of Farmland: Mapping Assessor Data To Understand Land Use Change, Lyndi Perry

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ideas developed by regional economists have potential applications within the urban planning field. One potential application is toward conserving farmland, and within this thesis this topic is examined for the study area of Utah County, Utah. Using assessor data, a land value map is created and further used to develop a regional economic model and spatial models that were analyzed for patterns of land use change.

Findings show that representing land value as continuous surface maps is a useful approach. The maps reveal that Utah County has densified as its population increased while farmland loss still occurred in agriculturally-important areas. …

The Power Law Distribution Of Agricultural Land Size, Lauren Chamberlain

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This paper demonstrates that the distribution of county level agricultural land size in the United States is best described by a power-law distribution, a distribution that displays extremely heavy tails. This indicates that the majority of farmland exists in the upper tail. Our analysis indicates that the top 5% of agricultural counties account for about 25% of agricultural land between 1997-2012. The power-law distribution of farm size has important implications for the design of more efficient regional and national agricultural policies as counties close to the mean account for little of the cumulative distribution of total agricultural land. This has …

Assessment Of Potential Changes In Crop Yields In The Central United States Under Climate Change Regimes, Neil Matthews-Pennanen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate change is one of the great challenges facing agriculture in the 21^st century. The goal of this study was to produce projections of crop yields for the central United States in the 2030s, 2060s, and 2090s based on the relationship between weather and yield from historical crop yields from 1980 to 2010. These projections were made across 16 states in the US, from Louisiana in the south to Minnesota in the north. They include projections for maize, soybeans, cotton, spring wheat, and winter wheat.

Simulated weather variables based on three climate scenarios were used to project future crop …

Measurement Of Agriculture-Related Air Pollutant Emissions Using Point And Remote Sensors, Kori D. Moore

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Measuring air pollution emissions from agricultural activities is usually difficult because of their large area and variability. Traditional air quality sensors, called point samplers, measure conditions in one location, which may not adequately measure a plume. Remote sensors, instruments that measure pollution along a line rather than at a single point, are better able to measure conditions around large areas. This dissertation reports on four agricultural air emissions studies that used both point and remote sensors for comparison. The methods used to calculate the emissions are based on previous work and are further developed in these studies. In particular, an …

Systems Modeling And Economic Analysis Of Photovoltaic (Pv) Powered Water Pumping Brackish Water Desalination For Agriculture, Michael A. Jones

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objective of this study was to determine the economic viability of solar powered water pumping and desalination systems for agriculture. Growing global demand for agricultural production has put increased pressure on limited freshwater resources in various locations around the word. Many areas have low quality groundwater resources that have not been utilized for agriculture due to limited availability to electricity, high operational costs of diesel generators and the economics associated with water pumping and processing. Reverse osmosis is a desalination technology that removes salts and other minerals from low-quality water, making it fit for drinking or irrigation. Reduced costs …

Nutritional And Economic Analysis Of Small-Scale Agriculture In Imbabura, Ecuador, Jake Erickson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Intervention projects in the developing world normally aim to satisfy either the nutritional needs of a group, or advancing the economic stability, but not both. One of the many issues that may arise by narrowly focusing and creating an aid program is that although a group may be fed, they are not equipped to mitigate risks that will arise after project completion and thus continue or revert back to a malnourished state. A bridge is required to join the economic and nutritional programs to create aid interventions that are sustainable past the point of donor separation.

This paper proposes the …

Coping Mechanisms And Level Of Occupational Stress Among Agriculture Teachers And Other Teaching Populations, Kasee L. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Teacher stress has been a concern in educational research for several decades. This research sought to identify the specific coping methods which Utah agriculture and non-agriculture teachers utilize to manage potentially stressful events, and to determine if differences exist in the coping mechanisms used between agriculture teacher and non-agriculture teacher groups.

Results showed that agriculture teachers showed a greater level of occupational stress than non-agriculture teachers. It was also concluded that occupational stress for the two teaching groups came from different sources. In regard to the agriculture teacher group, certain demographic characteristics that led to a higher frequency of use …

Estimation Of Field Alfalfa Evapotranspiration In A Windy, Arid Environment, J. Burdette Barker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Evapotranspiration (ET) of center pivot irrigated alfalfa was studied in the windy, arid, Curlew Valley, Northern Box Elder County, Utah, during the summers of 2009 and 2010. ET was estimated using eddy covariance (EC) and surface renewal (SR) techniques. ET estimates from the EC and SR analyses were compared with estimates using ASCE Standardized Reference ET Equation, with both dual and mean crop coefficients.

EC energy balance closure was 0.80, on average, in 2009 and 0.76 in 2010. The SR weighting parameter (α) was calculated through linear regression of EC and SR sensible heat flux estimates. Alpha was found to …

Assessment Of Ruminal Fermentation Characteristics Of Condensed Tannin-Containing Forages Using Continuous Cultures, Christina Marie Williams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Two independent studies were conducted to assess the effects of feeding condensed tannin (CT)-containing forages to continuous cultures to evaluate their impacts on ruminal fermentation and digestibility, with an emphasis on methane (CH4) and ammonia-N (NH3-N) production. In Chapter 3, treatments consisted of: 1) 100% alfalfa hay (AH), 2) 50% AH and 50% birdsfoot trefoil hay (dry matter (DM) basis; AHBFTH), and 3) 100% birdsfoot trefoil hay (BFTH). Three replicated runs lasted 8 d each, with the first 5 d allowed for microbial adaptation to the diets, and 3 d for data collection and sampling. Methane, neutral detergent fiber (NDF) …

Evaluation Of Semiochemical Strategies For The Protection Of Whitebark Pine Stands Against Mountain Pine Beetle Attack Within The Greater Yellowstone Ecosystem, Greta Katherine Schen-Langenheim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

High-dose verbenone, verbenone plus nonhost volatiles (NHVs), and both semiochemicals in combination with aggregant-baited funnel traps were tested for stand- level protection against mountain pine beetle attack for two consecutive years (2004-2005) at three seral high elevation whitebark pine sites in the Greater Yellowstone Ecosystem. In 2004, two 0.25-hectare treatments comprised of 25 high-dose verbenone pouches or verbenone pouches combined with single baited funnel traps were tested in a push-pull strategy. In 2005, 25 high-dose verbenone and 25 NHV pouches, or verbenone and NHV in combination with baited funnel trap clusters were tested. In both years, treatments were compared to …

Physiological And Molecular Function Of Hap3b In Flowering Time Regulation And Cold Stress Response, Mingxiang Liang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Heme-activated proteins (HAPs) are transcription factors that have multiple roles in plant growth and development, such as embryogenesis, flowering time control, and drought tolerance.

In the present study I found that HAP3b was also involved in controlling response to cold stress. Transcript profiling and gene expression analyses indicated that HAP3b repressed the CBF3 regulon under normal growth conditions. As a result, plants with HAP3b-overexpressed showed decreased survival rates while plants homozygous for the null allele hap3b showed an improved freezing tolerance compared to wild-type plants.

To understand the mechanism of HAP3b in Arabidopsis, i.e. whether it also acts …

The Influence Of Collective Action And Policy In The Development Of Local Food Systems, Lori Porreca

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The modern global agrifood system has had significant negative impacts on consumers and producers. This has precipitated the rise of local food systems that are purported to improve the health and livelihoods of consumers and producers. High expectations have led to significant public and private resources dedicated to the development of local food systems. Despite this, there has been little systematic research exploring the social and institutional conditions that facilitate or frustrate local food system development.

Using a comparative case study approach, this study explored the ways local structural conditions, collective action, food system policies, and the political context affect …

That Dame's Got Grit: Selling The Women's Land Army, Pamela Jo Pierce

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis analyzes the marketing of the Women's Land Army (WLA) using archival sources. I explore how farmerettes, the name given to WLA members, used their patriotic work on the farm as a means of redefining femininity and interrogating the definition of "true womanhood." "That Dame's Got Grit" discusses how the WLA was sold in World War I and World War II. The first chapter describes the press book used to market Little Comrade, a 1919 film about a fashionable farmerette. The theme of uniforms, an idea that weaves throughout the thesis, emerges strongly in this chapter. "A Seductive …

Random Forests Applied As A Soil Spatial Predictive Model In Arid Utah, Alexander Knell Stum

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Initial soil surveys are incomplete for large tracts of public land in the western USA. Digital soil mapping offers a quantitative approach as an alternative to traditional soil mapping. I sought to predict soil classes across an arid to semiarid watershed of western Utah by applying random forests (RF) and using environmental covariates derived from Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and digital elevation models (DEM). Random forests are similar to classification and regression trees (CART). However, RF is doubly random. Many (e.g., 500) weak trees are grown (trained) independently because each tree is trained with a new randomly …

Evapotranspiration Of Kentucky Bluegrass, Lynda L. Fenton

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rapid population growth in arid regions of the western US is placing increased demand on water resources. Variability in precipitation and common occurrence of drought have promoted scrutiny of water use in urban lawns and gardens. However, few reliable measurements of water use of these landscapes exist. Quantifying the amount of water used vs. required by landscapes such as turfgrass would allow significant water conservation. Evapotranspiration (ET) is affected by biophysical factors such as: available energy, turbulent mixing, saturation deficit, soil water, and stomatal conductance. In order to simulate the water use by turfgrass, the relative importance of these processes …

An Autonomous Unmanned Aerial Vehicle-Based Imagery System Development And Remote Sensing Images Classification For Agricultural Applications, Yiding Han

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This work concentrates on the topic of remote sensing using a multispectral imag-ing system for water management and agriculture applications. The platform, which is alight-weight inexpensive runway-free unmanned aerial vehicle (UAV), namely, AggieAir, ispresented initially. A major portion of this work focuses on the development of a light-weight multispectral imager payload for the AggieAir platform, called GhostFoto. Theimager is band-recongurable, covering both visual red, green, and blue (RGB) and nearinfrared (NIR) spectrum, and interfaced with UAV on-board computer. The developmentof the image processing techniques, which are based on the collected multispectral aerialimages, is also presented in this work. One application …

Soil Organic Carbon And Site Characteristics In Aspen And Evaluation Of The Potential Effects Of Conifer Encroachment On Soil Properties In Northern Utah, Mical K. Woldeselassie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In the Intermountain West, aspen (Populus tremuloides) has declined mainly due to a combination of successional processes, fire suppression and long-term use of ungulates which has led to replacement by conifers, sagebrush or other shrub communities. Conifer encroachment is believed to cause critical changes in the ecosystem properties. In order to understand the impacts of conifer encroachment on soil properties such as soil organic carbon (SOC) storage, soil morphology, and soil chemical properties, and the implications of such changes, it is very important to assess the soil properties under the two vegetation types. The objectives of this study …

Evaluation Of Competition Between Turfgrass And Trees In The Landscape, Christopher A. Hendrickson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Population growth in regions of the Intermountain West has resulted in rapid growth of residential neighborhoods. In Utah, the landscapes associated with these expanding neighborhoods consume vast quantities of treated water. This is a concern in all states of the Intermountain West, as water becomes increasingly scarce. Traditionally used turfgrasses, trees and other plants in Intermountain West landscapes require significant amounts of supplemental water considering the intense sunlight, dry winds and sparse rainfall typical of the region. Characterizing the interactions between turfgrass and tree species in these landscapes can aid in the identification of candidate species that consume less nutritional …

Evaluation Of Arrayed-Field Concentration Measurements And U. S. Epa-Regulatory Models For The Determination Of Mixed-Source Particulate Matter Emissions, Derek Jones

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

With the continued population growth and the blurring of the urban and rural interface, air quality impacts associated with agricultural particle-producing processes are becoming increasingly important. There is a lack of emission rate data from these source types and no prescribed measurement technique available to the agricultural and regulatory communities. One technique that has shown promise is combining field measurements with inverse modeling. This approach was used herein to examine particulate emissions from an almond harvesting operation, a cotton ginning facility, and comparative emissions from conservation versus conventional tillage practices. EPAapproved models ISCST3 and AERMOD were used with AirMetrics samplers. …

Self-Medicative Behavior Of Sheep Experiencing Gastrointestinal Nematode Infections And The Postingestive Effects Of Tannin, Larry D. Lisonbee

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Diet selection and self-medication are fundamental to the survival of all species. The abilities to choose healthy foods in response to past consequences are basic elements of evolution. This study explores self-medication regarding tannins both as a medication and as a dietary challenge. In the first study, sheep with natural parasite infections were offered a low quality supplement containing a dose of tannins considered to be therapeutic (medicine), while the control infected lambs received the same supplement without tannins (placebo). This study included a group of parasite-free lambs. The parasitized lambs ate more of the tannin containing supplement than non-parasitized …

Hydrological Characterization Of A Riparian Vegetation Zone Using High Resolution Multi-Spectral Airborne Imagery, Osama Zaki Akasheh

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Rio Grande River (MRGR) is the main source of fresh water for the state of New Mexico. Located in an arid area with scarce local water resources, this has led to extensive diversions of river water to supply the high demand from municipalities and irrigated agricultural activities. The extensive water diversions over the last few decades have affected the composition of the native riparian vegetation by decreasing the area of cottonwood and coyote willow and increasing the spread of invasive species such as Tamarisk and Russian Olives, harmful to the river system, due to their high transpiration rates, …

Treatment Of Saltcedar (Tamarix Spp.): Economics And Feasibility, Christopher L. Thompson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The invasive species Saltcedar is affecting water and land resources throughout the western states of America. Because of great water use capabilities and other ecosystem detriments, Saltcedar has been targeted for treatment.

For successful management of Saltcedar, individual landowners need to be aware of the costs and benefits of treating Saltcedar. Eleven of the most commonly reported treatment methods were evaluated for firm level economic feasibility. Evaluated on the basis of treatment cost, treatment effectiveness, Saltcedar water-use, and re-vegetation water-use, a production plan of ten years was created for each treatment method. Some treatment methods required re-treatment and were evaluated …