Earth Sciences Commons^™

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. …

Greening-Induced Runoff Loss In The Western United States, Xueyan Zhang

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study assessed how vegetation will influence long-term runoff trends across the western United States (western US) in the future. I used a land surface model with improved dynamic vegetation root processes to better quantify regional runoff trends across five regions (Upper and Lower Colorado, Great Basin, Pacific Northwest, and California). The model was driven by statistically downscaled and bias-corrected outputs from three global climate models under the Representative Concentration Pathway 4.5 and 8.5 scenarios. Vegetation greening dominated significant transpiration increases that contributed most to increasing evapotranspiration across the western US, especially during spring and summer. Consistent with these trends, …

Longitudinal Thermal And Solute Dynamics In Regulated Rivers, Muhammad Rezaul Haider

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Dam releases increase river stage and can reverse groundwater movement into and out of the river. As the flood, thermal, and solute waves travel downstream in a regulated river, the size of the waves is anticipated to be affected both by river processes and exchanges with near river groundwater. This study established a modeling framework to quantify the influences of the groundwater exchanges on the temperatures and solute concentration dynamics along regulated rivers. The wave properties, volume of exchanges, conservative solute mass exchanges, and heat energy exchanges were calculated as a function of time and distance downstream. Results show that …

Optimizing Barrier Removal To Restore Connectivity In Utah’S Weber Basin, Maggi Kraft

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

River barriers, such as dams, culverts and diversions are important for water conveyance, but disrupt river ecosystems and hydrologic processes. River barrier removal is increasingly used to restore and improve river habitat and connectivity. Most past barrier removal projects prioritized individual barriers using score-and-rank techniques, neglecting the spatial structure and cumulative change from multiple barrier removals. Similarly, most water demand models satisfy human water uses or, only prioritize aquatic habitat, failing to include both human and environmental water use benefits. In this study, a dual objective optimization model identified in-stream barriers that impede quality-weighted aquatic habitat connectivity for Bonneville cutthroat …

Quantifying Riverbed Sediment Using Recreational-Grade Side Scan Sonar, Daniel Hamill

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Colorado River in Glen, Marble, and Grand Canyons is subject to a complex regulatory framework, including the Colorado River Compact, the Endangered Species Act, and the Grand Canyon Protection Act of 1992. Physical, biological, and cultural resources are extensively monitored by the Glen Canyon Dam Adaptive Management Program (GCDAMP) to assess the effect of Glen Canyon Dam (GCD) operations on the downstream environment. The GCDAMP consists of a diverse group of stakeholders who identify priority resources and agree upon water releases at GCD. Large expenditures of money have been devoted to monitoring physical and biological resources in Grand Canyon. …

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 …

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 …

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 …

Alternative Sampling And Analysis Methods For Digital Soil Mapping In Southwestern Utah, Colby W. Brungard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Digital soil mapping (DSM) relies on quantitative relationships between easily measured environmental covariates and field and laboratory data. We applied innovative sampling and inference techniques to predict the distribution of soil properties, soil attributes, taxonomic classes, and dominant vegetation across a 30,000-ha complex Great Basin landscape in southwestern Utah. This arid rangeland was characterized by rugged topography, diverse vegetation, and intricate geology. Environmental covariates calculated from digital elevation models (DEM) and spectral satellite data were used to represent factors controlling soil development and distribution. We investigated optimal sample size and sampled the environmental covariates using conditioned Latin Hypercube Sampling (cLHS). …

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 …

A Post-Project Assessment Of The Provo River Restoration Project: Channel Design, Reconfiguration, And The Re-Establishment Of Critical Physical Processes, Randy Ray Goetz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A physical assessment of the Provo River Restoration Project was undertaken in order to determine how alterations to the channel were designed, the nature of as-built channel morphology, and the performance of the reconfigured channel in terms of achieving frequent (2-year recurrence) bankfull discharge and increasing transient storage. Measures of channelized and reconfigured channel morphology were obtained using total station survey, digital aerial photography, and pebble counts. Results of geomorphic analysis were compared with similar measurements made by a regional consulting company, and stream channel design data, in order to determine that intended mitigation included reducing channel capacity, increasing sinuosity, …

Utilization Of Spatially Distributed Soil Resources By Several Species Common To The Great Basin, Sarah Duke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Heterogeneous spatial and temporal distributions of soil resources important to plant growth have been documented in the sagebrush steppe ecosystem. There can exist as much variability in soil resources within the root zone of individual plants as exists across an entire field. The objective of this dissertation research was to evaluate how plants respond to, utilize and influence the spatial heterogeneity of soil resources. The three specific sets of questions addressed are outlined in the three main chapters of this dissertation.

My first study addressed how the number and concentration of phosphorus (P) patches in the root zone of an …

Channel Narrowing Of The Green River Near Green River, Utah: History, Rates, And Processes Of Narrowing, Tyler M. Allread

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Previous scientific research has documented channel narrowing on the Green River near Green River, Utah, but the exact timing, rates, and causal mechanisms of that narrowing have been the source of disagreement in the scientific literature. This thesis demonstrates that the Green River has narrowed in two separate periods during the last 100 years. The narrowing is driven primarily by changes in the hydrologic regime and not by the invasion of saltcedar. The channel narrowed between 1930 and 1938, when a shift from wetter than normal conditions to a period of draught led to a reduction in river discharge. Channel …

Evaluation Of Lake Fertilization As A Tool To Assist In The Recovery Of The Snake River Sockeye Salmon (Oncorhynchus Nerka), Howard P. Gross

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I analyzed lake fertilization (with nitrogen and phosphorus) as a tool to assist in the recovery of the Snake River sockeye salmon (Oncorhynchus nerka) in the oligotrophic Sawtooth Valley Lakes in southcentral Idaho. These analyses involved monitoring, manipulating, and modelling several aspects of the lakes' primary producer, nutrient, and light parameters.

In Pettit Lake, I evaluated the effects of metalimnetic and epilimnetic fertilization in 330-m³ mesocosms. The metalimnetic treatment was equal to or more effective than the epilimnetic treatment in increasing chlorophyll a, phytoplankton biovolume, and primary productivity, yet caused smaller changes in periphyton growth and …

Soil Heterogeneity And Its Exploitation By Plants, Robert B. Jackson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In this dissertation I first examine the ability of individual plants in the field to garner localized soil nutrients. I then measure actual soil variability around perennial plants and use various statistics to quantify the scale and degree of that variability.

Soil patches on opposite sides of Pseudoroegneria spicata tussocks were treated with distilled water or a nutrient solution containing N, P, or K in three field experiments. When P was augmented in the enriched soil patches, rates of P uptake increased significantly for roots from enriched patches compared with roots in control patches. Rates of ammonium and potassium uptake …

Root Exploitation Of Fertile Soil Microsites, Robert B. Jackson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Root exploitation of enriched soil microsites was examined for the tussock grasses Agropyron desertorum and Agropyron spicatum and the shrub Artemisia tridentata. Two mechanisms of exploitation of the microsites were examined: root proliferation and changes in nutrient uptake capacity. One day after nutrient solution was applied to small soil patches, the mean relative growth rate of Agropyron desertorum roots in enriched patches was two to four times greater than for roots of the same plants in soil patches treated with distilled water. This rapid and striking root proliferation occurred in response to N-P-K enrichment as well as to P or …

Nonpoint Source Transport Model For Indicator Bacteria From Western Rangeland Watersheds, Everett P. Springer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Grazing is a primary land use in much of the western United States, but little is known about grazing impacts on water quality. The most sensitive water quality indicators of grazing are the fecal indicator bacteria. The objective of this study was to develop a general transport model describing the movement of fecal indicator bacteria from upland sources to channel systems.

Model development was done using simulated rainfall and a runoff surface 30.48 m by 1.83 m.

Initially the runoff surface was smooth concrete and was used to examine the effects of distance from the outlet on coliform counts by …

Chemical Changes In Groundwater Of Northern Utah Valley, Utah, Paul E. Fairbanks

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Northern Utah Valley is one of the fastest growing areas of Utah and has increasing needs for domestic, industrial, and agricultural water. To meet these needs, groundwater and surface water systems must be understood to maximize their use. Chemical studies of the sediment mineralogy and related water-chemistry give insight to the movement of the water.

There are three major aquifers present in the valley: shallow Pleistocene; deep Pleistocene; and Tertiary. They are composed of sands and gravels and are separated by confining layers (aquitards) composed mostly of clay. Along the flanks of the bordering mountains there are undifferentiated aquifers which …

Turbidity - Suspended Sediment Relations In A Subalpine Watershed, Thomas A. Holstrom

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of particle size distribution of suspended sediment vii upon a turbidity reading at a known concentration has been relatively quantified for stream bank materials on the Moccasin Basin - North Fork Fish Creek (MB-NFFC) Watershed, located in northwestern Wyoming. As expected, an increase in the median particle size in suspension results in a decrease of turbidity at a given concentration. The relationship derived correlates the particle size distribution of a chemically dispersed stream-bank material sample, with the Coefficient of Fineness for a mechanically dispersed portion of the sample.

Seasonal Course Of Root Respiration In Atriplex Confertifolia, Richard S. Holthausen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Root respiratory response of mature Atriplex confertifolia plants growing in established communities was measured during two growing seasons using freshly excised root segments and gas chromatography techniques. Respiratory response at fixed test temperatures changed significantly during the growing season, and this pattern of respiratory adjustment varied for root segments located at different depths in the soil profile. Respiration measured at a constant test temperature was highest during early sumner, and declined to minimum values in late summer and fall. Root segments taken from the top 30 cm of the soil profile displayed peak activity several weeks before root segments from …

A Study Of The Radiation Quality Under Plant Canopies In The Wave Range 0.4 To 2.5 Microns, Nolasco G. Baldazo

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The spectral distribution of the global radiation from 0.4 to 2.5 microns penetrating deciduous and coniferous canopies were measured during clear days between 10 a.m. and 2 p.m. using a double-quartz monochromator.

In the visible region (0.4 to 0.7 micron) the average relative spectral transmissions under both canopies are about one percent beginning at 0.4 micron and decreasing to about half a percent at 0.67 micron. There is only a small peak in the green (0.55 micron) transmission under deciduous stands while there is none under coniferous canopies. The slightly higher transmission in the blue (0.4 micron) is attributed to …

Bromegrass Productivity In Relation To Precipitation, Shrub Canopy Cover And Soil Nitrogen Content, Lawrence G. Kline

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In seasons of above normal precipitation, populations of annual weedy species increase in great abundance in semi-arid desert plant communities. These increases in biomass tie up a considerable portion of the available nitrogen of such ecosystems and may depress subsequent annual grass germination.

A big sagebrush-annual bromegrass plant community was irrigated to simulate a spring growth period of abundant precipitation amenable to annual bromegras s productivity. Productivity and nitrogen content parameters were monitored throughout the spring and summer to evaluate the short and potential long term effects of this seasonal increase in "precipitation".

Irrigation increased annual bromegrass productivity almost 50 …

Effect Of Early Growth Cultivation On Beans And Sweet Corn, Raymond L. Cartee

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Investigations involving four cultivation treatments were conducted at the Utah State University Greenville Experimental Farm to determine the effect of these treatments on yields of beans and sweet corn. The effects of the different treatments on soil water content, soil temperature, and weed control in beans and corn were investigated. The effect of cultivation on the degree of root rot infection and the effect of different planting dates were also investigated in the bean study.

The pre-emergence treatment (ridged just before the plants emerge) produced a 48 percent greater bean yield and a 40 percent greater corn yield than the …

The Effects Of Certain Environmental And Biological Factors On Rally Calling In The Chukar Partridge, H. Warrington Williams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Naturalists for many years have known that birds sing most at dawn and at dusk, but to which of many physical variables they are responding has not been completely determined. This problem has taken on importance in the field of wildlife management because calling rate has been used as an index of abundance for numerous game birds, namely the Pheasant, Phasianus colchicus (Kimball, 1949); the Mourning Dove, Zenaidura macroura (McClure, 1939); the Bobwhite Quail, Colinus virginianus (Bennitt, 1951; Rosene, 1957): and the Woodcock, Philohela minor (Pitelka, 1943).