Digital Commons Network^™

Evaluating The Spray Patterns Of Boomless Spray Nozzles At Increasing Application Speeds, Thomas Hayden Duncan

Theses and Dissertations

Boomless nozzles have been largely ignored in spray studies, resulting in limited understanding of their spray patterns and how they are affected by operating parameters. A study was conducted to evaluate the effect of application speed on the performance of four boomless nozzles. Dyed water was applied to Kromekote® paper to assess spray distribution based on coverage data at three speeds, and MSMA was applied to a mixed turf stand to evaluate the effect of speed on performance. Overlap simulations were done to evaluate how uniformity could be improved, and nozzle performance was compared to manufacturer claims. Spray patterns of …

Assessing Vegetation Health Following The 2014 Carlton Complex Fire Using Remote Sensing, Rachael Sv Pentico

2026 Symposium

Climate change, combined with decades of altered fire regimes and fire suppression, has increased fuel accumulation across western U.S. forests, contributing to more frequent, larger, and more intense wildfires. Remote sensing offers an effective approach for analyzing these large-scale fire events and their ecological impacts, as satellite imagery enables affordable, accessible, and reproducible monitoring of vegetation change across broad spatial and temporal scales. This study examined the 2014 Carlton Complex Fire in the Methow Valley, Washington. Burning 265,108 acres, it was the largest wildfire in Washington State history at the time and caused extensive agricultural and forest damage. Post-fire vegetation …

A Gis Analysis Of The Relationship Between Ndvi Value, Slope, And Aspect Of The Terrain Of The Prairie Restoration Project, Basil Lund

2026 Symposium

The Prairie Restoration Project (PRP) encompasses 115 acres of land on the west side of the EWU campus. The goal of the PRP is to restore what was once a section of wheat farm back to its original Palouse prairie state. Here, I am using publicly available satellite data to examine some potential variables affecting the health of wheat plants planted in the years 2009 to 2017. I have used 4-band aerial imagery to create a map of NDVI values within the bounds of the PRP, which visualizes the near-infrared wavelengths that are reflected by healthy, chlorophyll-rich plants. I have …

Genetic Variation In Crops Of The Second Millennium Bce Revealed By Ancient Dna Analysis, Asi̇ye Uluğ, Funda Özdemi̇r Deği̇rmenci̇, Çi̇ğdem Kansu, Christina Luke, Christopher H. Roosevelt, Zeki̇ Kaya

Turkish Journal of Botany

For millennia, the Anatolian plateau has functioned as a major migratory corridor between Africa, Asia, and Europe and has subsequently been shaped by shifting settlement patterns, ranging from small communities to complex urban and imperial systems. These processes were closely associated with the development and diversification of agricultural practices. Archaeobotanical investigations at Kaymakçı, a Middle and Late Bronze Age (ca. 3500 years BP) site located in the middle Gediz Valley of western Anatolia, have provided substantial evidence of crop cultivation in the region. In this study, genetic variation in barley (Hordeum vulgare L.), chickpea (Cicer arietinum L.), bitter vetch (Vicia …

Improved Nutritional Value Of Spinach (Spinacia Oleracea L.) Through Moderate Salinity-Induced Regulation Of Vitamin C And Folate Pathways, Laleh Ahmadi, Hanieh Mohajjel Shoja, Elham Mohajel Kazemi, Maryam Kolahi

Turkish Journal of Botany

Soil salinity is a major abiotic stress affecting over 20% of cultivated and 33% of irrigated lands worldwide, significantly limiting crop productivity and nutrient biosynthesis. Vitamin C and folate are crucial antioxidants in plant stress tolerance and human nutrition; however, their regulation under salt stress remains unclear, particularly in leafy vegetables. This study evaluated the effects of different salinity levels (0, 50, 150, 250, and 350 mM NaCl) on physiological traits, antioxidant activity, vitamin C and folate accumulation, and the expression of related biosynthetic genes in spinach (Spinacia oleracea L.). High salinity (250–350 mM) reduced growth, leaf area, and pigment …

Identification Of Qtls And Molecular Markers Associated With Gray Mold Resistance In Grape, İlknur Polat, İbrahi̇m Çeli̇k, Onur Ergönül, Asli Polat, İlker Kurbetli̇, Görkem Sülü, Ayfer Daldal, Hali̇l İbrahi̇m Uzun

Turkish Journal of Botany

Grape (Vitis vinifera L.) is an economically important fruit that is both consumed fresh from the vine and used in the production of raisins, wine, and vinegar. One of the main factors limiting grape production is gray mold, caused by the fungal pathogen Botrytis cinerea. The cultivation of mold-resistant grape cultivars represents the most effective strategy for disease management; however, molecular tools to aid in the breeding of B. cinerea-resistant grapes remain limited. The present study maps the quantitative trait loci (QTLs) associated with B. cinerea resistance in grape using an F1 population derived from a reciprocal cross between the …

Oregon State Rank Assessment For Wiens' Dwarf Mistletoe (Arceuthobium Abietinum Ssp. Wiensii), Lindsey K. Wise

Institute for Natural Resources Publications

Oregon state conservation status assessment for Wiens' dwarf mistletoe (Arceuthobium abietinum ssp. wiensii) using NatureServe methodology, 2026.

Climate Impacts Apple Pollination, Yield And Economic Outcomes Of Farmers, Clémence Riva, Stella Gachoki, Noureddine Adjlane, Danilo Bevk, Yamina Haider, Fani Hatjina, Šimun Kolega, Marin Kovačić, Ioannis Manthos, Zlatko Puškadija, Thomas Sotiropoulos, Bojan Stipešević, Fabrice Requier

All Peer-Reviewed Publications

Animal-mediated pollination is crucial to global food production but is increasingly threatened by environmental degradation, habitat loss and climate change. The extent to which temperature affects pollination services and crop yields is poorly understood. Using standardised monitoring in 33 apple orchards across Europe and Northern Africa over two years, this study assessed how ambient temperature affects flower visitors, fruit set, fruit quality and economic outcomes. Observation-time warm temperatures increased pollinator abundance, particularly of honey bees, while long-term mean annual temperatures enhanced pollination services for apple weight. Apple yield and the economic benefits to farmers increase with temperature, while the role …

Oregon State Rank Assessment For Bedstraw Broomrape (Aphyllon Epigalium Ssp. Epigalium), Lindsey K. Wise

Institute for Natural Resources Publications

Oregon state conservation status assessment for Bedstraw broomrape (Aphyllon epigalium ssp. epigalium) using NatureServe methodology, 2026.

Fodder Maize Variety Trial: Broome 2021, Carla Milazzo, Samuel Crouch, Christopher Ham, Geoff Moore

Grain and other field crops research reports

• High yielding, highly digestible maize can be produced under irrigation on Pindan sands in northern Western Australia.
• Using high inputs, the biomass and digestibility of all trialled varieties equalled or exceeded varieties used in well-established maize growing regions of Australia.
• Eleven hybrid maize varieties were trialled near Broome. The average dry matter yield of all trialled varieties was 24t/ha at 10.5MJ/kg of dry matter.
• The impact of fall armyworm on yield was successfully reduced by using integrated pest management combining NPV virus (nucleopolyhedrovirus) with strategic insecticide applications.

Evaluation Of The Weed Control Efficacy And Potential Economic Returns Of An Autonomous Weeder In Vegetable Production Systems, Claire Plassmeyer

Graduate Theses and Dissertations

Vegetable production requires intensive weed management. Conventional producers rely on herbicide applications to manage weeds effectively at low costs; however, growers are under pressure to minimize chemical use due to environmental concerns and increased incidences of herbicide resistance. Non-conventional systems, including organic and sustainably focused small-scale production, rely primarily on cultural practices and physical weed control methods, which are labor-intensive and costly due to limited labor availability and rising wages. These concerns have prompted the development of autonomous weeding devices, such as unmanned ground vehicles (UGVs) equipped with navigation sensors and implements to provide repeated, high-precision weed control. Compact devices …

Bottles, Butterflies, And Biomass: Recycled Glass Sand, Microbial Additions, And Herbivory Effects On Milkweed Growth, Kealey Skinner

Honors Theses

Plant-soil-microbe interactions are integral components of ecological networks and drive ecosystem function from the bottom-up. Whereas herbivores regulate ecosystem function from the top-down, having opposing and potentially complementary effects on ecosystem function. My thesis sought to understand how below-ground microbial communities contribute to herbivore preference and plant biomass across varied soil substrates. My thesis asked: how do substrate and soil microbial communities influence herbivore preference and plant biomass accumulation on swamp milkweed (Asclepias incarnata)? To address this question, seedlings of A. incarnata were sown in 2.5 cm wide × 10 cm deep pots filled with either natural beach sand or …

Herbivory Of Phragmites Australis Along A Salinity Gradient In Connecticut Wetlands, Sydney H. Kolz

Honors Scholar Theses

Invasive Phragmites australis (common reed) is widely distributed in New England wetlands, where it often outcompetes native plants and decreases biodiversity throughout the food web. Controlling its invasion is a priority, especially in salt marsh habitat, but current management techniques are inefficient. Leveraging natural processes may improve control strategies, but in order to do so, we must first better understand how abiotic and biotic stressors interact and affect Phragmites. This study focuses on herbivory and salinity, two factors limiting Phragmites’ fitness. I measured soil salinity and quantified the damage of three herbivore guilds (i.e. gall-formers and stem-borers, leaf-chewers, and …

Quantitative Genetics, Genomics, And Phenomics In Maize And Sorghum, Nikee Shrestha

Complex Biosystems Program: Dissertations and Student Research

Generating the best crop varieties and hybrids requires identifying genes associated with the phenotype of interest and screening thousands of varieties across multiple locations. Quantitative genetics, along with comparative genomics, phenomics, and machine learning approaches, can help us identify target genes associated with the phenotype of interest to develop the right genotypes. Satellite platforms offer logistical and technical advantages in scalability and accessibility and could facilitate plot-level predictions, especially with steadily improving spatial resolution, thereby empowering the large-scale screening of thousands of genotypes across diverse locations. In the first chapter, I evaluated over 20,000 plot-level images of over 80 hybrid …

Investigating The Taxonomic Uncertainties Of Potentilla Rupincola, Natalie Elizabeth Hieber

Master's Theses

Landscape stewardship is an integral role for land managers that becomes more important when rare or endangered species occur within managed areas. Conservation across the landscape is a primary concern for land managers, but resources allocated for conservation can be limited due to many competing goals. Taxonomic uncertainty surrounding rare and endangered taxa, particularly plant taxa, that have historically been classified solely using morphological features further complicates conservation planning. One such taxon is Potentilla rupincola, a rare plant endemic to the eastern Rocky Mountains in Colorado. For over a century, botanists have debated whether P. rupincola is a distinct species …

Sorghum Grain Secondary Metabolites And Underlying Genetics To Reduce Foodborne Pathogens In Poultry, Maria A. Conti

All Dissertations

The rise in antibiotic-resistant pathogens poses a threat to the poultry industry's ability to maintain animal health, prompting growing interest in alternatives to synthetic antibiotics. The use of non-tannin sorghum [Sorghum bicolor (L.) Moench] in poultry rations offers a valuable alternative, as this cereal grain has a high bioactive profile that can provide health benefits, including antimicrobial (AM) activity. The scope of this study was to examine the AM potential of non-tannin sorghum grain against Clostridium perfringens, a major foodborne pathogen that negatively impacts poultry health and production. To that end, the inhibitory effects of a non-tannin sorghum …

Dried Water Treatment Residuals Might Be An Option To Reduce Soluble Reactive Phosphorus Release From Soils, Katie B. Mckay

Biological and Agricultural Engineering Undergraduate Honors Theses

Nonpoint source pollution from agricultural landscapes contributes to freshwater eutrophication, with legacy phosphorus (P) in soils potentially driving soluble reactive phosphorus (SRP) losses to surface waters. The objectives of this study were to evaluate SRP adsorption by dried water treatment residuals (WTRs) produced by Beaver Water District, quantify reductions in soil SRP release across increasing WTR application rates, and compare dried WTR performance to prior WTR studies.

Dried WTRs (~98% solids) were assessed using batch sorption experiments and soil core incubations. Phosphorus sorption was measured by mixing WTRs with CaCl₂ solutions containing increasing SRP concentrations and fitting results to …

Preliminary Vascular Plant Checklist Of The City Of Chattanooga, Matthew J. Scott

Honors Theses

The City of Chattanooga, Tennessee was designated as a National Park City in April 2025 by the National Park City Foundation. Yet, there has not been a comprehensive vascular flora compiled for the city, though there have been extensive collections and observations made of the plant biodiversity in the area from the late 1800s onward. The goal of this project was to examine both the existing herbarium collections and public observation records from iNaturalist to compile a preliminary vascular plant checklist for Chattanooga, and to include conservation and ecological data for the species currently documented to provide a holistic review …

Dendroclimatic Response Of The Wet Miombo Woodland Species: A Case Study Of Mufulira District, Copperbelt Province, Zambia, Collins Chibuye Malubeni

All-Inclusive List of Electronic Theses and Dissertations

Zambia is a tropical, landlocked country that lies in the South-Central part of Africa. The climate in Zambia includes distinct dry and rainy seasons, mainly influenced by the north-south movement of the Intertropical Convergence Zone (ITCZ), which shifts seasonally. This research is focused on understanding the relationship between tree growth and climate using dendrochronology. Forty-nine tropical species, including Julbernardia paniculata, Brachystegia longifolia, and Pericopsis angolensis, were analysed for dendroclimatic potential, and 70% showed clear ring formation, indicating that trees in this locality produce distinct annual ring boundaries. For the single species chronology, thirteen cores from eight trees that were initially …

Distribution Mapping And Modeling Of The Invasive Japanese Knotweed, Jossalyn Rogalski

Masters Theses

This thesis investigates the distribution of invasive Japanese knotweed across Michigan. This plant poses significant challenges to land management due to its rapid growth, environmental impacts, and difficulty of removal once established. Using geographic information systems (GIS), remotely sensed data, and secondary environmental datasets, this research maps current infestations and analyzes key factors influencing the species’ growth and dispersal, such as soil composition, hydrology, land use, and a range of environmental variables, including climatic (annual mean temperature, temperature seasonality, annual precipitation, precipitation seasonality), elevation, vegetation and hydrological indices (NDVI, EVI, NDWI), percent tree cover, and distance to roads. Spatial analysis …

Sequential Products Of Anaerobic Denitrification In Calcareous And Noncalcareous Soils By Use Of The Gas Chromatograph, Grant S. Cooper

All Graduate Theses and Dissertations, Fall 2023 to Present

The sequential products of anaerobic denitrification were determined on seven Western soils (four alkaline, two acid, and one neutral) by soil and gas analysis. The soils with 1% alfalfa and added KNO3 were incubated at moistures slightly greater than field capacity and with an atmosphere of He. The soils and gases were periodically analyzed and balance sheets prepared. The sequence of NO3-->NO2-->N2O-->N2 operated in all soils. The rates of nitrogen interchanges and maximal amounts of nitrate, N2O2 and N2 were determined. From this data it was postulated that the rate-limiting process for denitrification in acid soils is …

Evaluation Of Fertilizer Recommendation And Soil Amendment Impacts On Crop Production In The Intermountain West, Megan Baker

All Graduate Theses and Dissertations, Fall 2023 to Present

Fertilizers improve crop yield and quality by supplying crops with essential nutrients, but can also be a significant input cost. Determining what nutrients and rates to apply for optimal crop growth can be difficult, leading many growers to use external sources for these decisions. Land-grant universities are a common source for fertilizer recommendations, but often based on decades-old research and should be evaluated periodically to verify effectiveness and calibrated to current soil analysis methods. Current Utah State University (USU) guidelines for sulfur (S) and zinc (Zn) were tested across Utah in on-farm trials in 2021-2025. Zinc applications of 5 or …

Cannabis: A Model Plant To Study Light-Mediated Reproductive Development, Madigan J.H. Eckels

All Graduate Theses and Dissertations, Fall 2023 to Present

Cannabis (Cannabis sativa) is a plant of increasing importance for research, medical, recreational, industrial, and agricultural purposes, but a strict legal landscape means that it was chronically understudied. Now that research institutions can utilize this plant for study, we require updated terminology to describe various cannabis flowering types that occur under ideal and non-ideal growing conditions. We introduce new flowering terminology and describe them in text and with photographs.

Plants use light as a resource to power photosynthesis, and a greater total sum of photons generally increases yield. In controlled environment agriculture where growers utilize light fixtures instead …

Identification, Pathogenicity, And Fungicide Sensitivity Of Itersonilia Perplexans Associated With Petal Spot Of Gerbera Cut Flowers In Colombia, Matheus Beger

All Theses

Petal diseases significantly affect gerbera cut flower production, as minor visual damage renders flowers unmarketable. Among those pathogens causing petal spots, Itersonilia perplexans affects some Asteraceae plants. However, this pathogen's impact on Colombian gerbera remains poorly studied. This study was designed to fill four gaps: molecular identification of Colombian isolates, confirmation of pathogenicity, standardized culture media, and fungicide sensitivity data. Four objectives were pursued: (i) isolate and identify the causal agent through sequencing the Internal Transcribed Spacer, Small Subunit and Large Subunit from the rDNA; (ii) evaluate pathogenicity on detached gerbera petals; (iii) identify optimal culture media for I. perplexans …

Passive Microwave Remote Sensing Of Flash Drought Impacts On Vegetation, Quinton R. Deppert

School of Natural Resources: Dissertations, Theses, and Student Research

In 2002, Dr. Mark Svoboda characterized a new form of drought known as flash drought. Flash drought was defined as a rapid decline in vegetation health caused by severe heat and drought. In recent years, attempts to quantify the impacts of flash drought via precipitation, soil moisture, evapotranspiration, and temperature indicators have proliferated. What has rarely been quantified is what the rapid decline in vegetation health amid flash drought looks like through remote sensing. This is because vegetation health indices like the Normalized Difference Vegetation Index (NDVI) are derived from the visible and infrared regions of the electromagnetic spectrum and …

Degradation And Metabolic Analysis Of Synthesized Quorum-Sensing Signals By The Model Eukaryote Chlamydomonas Reinhardtii, Adam Josef Bach

Theses and Dissertations

Bacterial organisms can “talk” with one another on a colony-wide scale using a communication system known as quorum-sensing (QS) via chemical signals. These signals are produced at a basal rate throughout the life of the bacteria and are classified as autoinducers, which diffuse across the cell membrane. Once the critical concentration is reached, they begin to diffuse back into the cell and initiate a phenotypic change. As these signals exist outside the membrane of their producer, they are also accessible to other organisms. It has already been noted that some plant species uptake these compounds through their roots and break …

High Throughput Phenomics Pipeline For Pulse Crop Nutritional Breeding, Amod Udayanga Madurapperumage

All Dissertations

Dry pea (Pisum sativum L.), lentil (Lens culinaris Medik.), and chickpea (Cicer arietinum L.) are major pulse crops valued for their high nutritional composition and importance to global food systems. Pulses are rich in carbohydrates, protein, and essential minerals, making them ideal whole foods and critical contributors to food and nutrition security. Due to these advantages, pulse breeding programs are increasingly focusing on enhancing nutritional traits, such as protein quality, amino acid balance, and micronutrient density, through the process of biofortification. However, improvement of agronomic traits remains equally essential. Characteristics such as plant height, standability, stress tolerance, …

Arkansas Soybean Research Studies 2024, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

The 2024 Arkansas Soybean Research Studies includes research reports on topics pertaining to soybean across several disciplines from breeding to post-harvest processing. Research reports contained in this publication may represent preliminary or only data from a single year or limited results; therefore, these results should not be used as a basis for long-term recommendations. Several research reports in this publication will appear in other University of Arkansas Division of Agriculture’s Arkansas Agricultural Experiment Station publications. This duplication is the result of the overlap in research coverage between disciplines and our effort to inform Arkansas soybean producers of the research being …

Propagation And Cultivation Of Sarracenia Species, Kathryn M. Huether

Electronic Theses and Dissertations

This study evaluates the effectiveness of seed treatments on Sarracenina species to overcome seed dormancy; as well as evaluating fertilizer concentration and substrate mixture impacts on the growth of Sarracenia × wrigleyana, ‘Scarlet Belle’. The first portion of this study evaluated the effects of cold stratification and chemical treatments (smoke water and gibberellic acid) on the germination rates of Sarracenia alata and leucophylla. The primary objective was to determine whether increasing concentrations of these treatments paired with or without stratification could significantly enhance germination and serve as viable seed treatments for horticultural use. Germination did occur within all the …

Developing Aero-Floating Treatment Wetland (Aeroftw) Scaffolds: A Non-Plastic Alternative To Conventional Plastic-Based Ftws, Ada C. Montoya Gomez

All Theses

This research was conducted to explore the possibility of constructing floating treatment wetlands (FTWs) without using plastic materials. FTWs are floating platforms that hold plants on the water’s surface, letting roots dangle within the water column, to help remove contaminants from contaminated water, especially in stormwater ponds. Many conventional FTWs are made with plastic components, such as mats and plastic cup containers, which can release microplastics into the environment over time. The goal of this project was to design and test a new type of FTW that does not depend on plastics to support FTW flotation. The study took place …