Digital Commons Network^™

A Review Of Plant–Microbe Interactions In The Rhizosphere And The Role Of Root Exudates In Microbiome Engineering, Anagha Wankhade, Emma Wilkinson, David W. Britt, Amita Kaundal

Biological Engineering Student Research

Microbial interactions within the rhizosphere are fundamental to plant health, influencing nutrient availability, stress tolerance, and pathogen resistance. Beneficial microbes, such as plant growth-promoting microbes (PGPMs), including bacteria and mycorrhizal fungi, enhance plant resilience through mechanisms like nutrient solubilization, phytohormone production, and pathogen suppression via antimicrobial compounds and siderophores. Root exudates, composed of sugars, organic acids, and secondary metabolites, act as chemoattractants that shape the rhizosphere microbiome by recruiting beneficial microbes. Microbial metabolites can, in turn, modulate plant physiology and exudate profiles, thereby reinforcing mutualistic interactions. Stress conditions alter exudate composition, enabling plants to attract specific microbes that aid in …

The Perfect Pairing: Early Stand Dynamics In Conventional Aspen And Mixedwood Forests In Northern Minnesota, Usa, Chelsea C. Semper, John M. Zobel, Sawyer S. Scherer, Michael R. Reinikainen, Matthew B. Russell, Tyler S. Gifford, Marcella A. Windmuller‑Campione

Aspen Bibliography

In North America, mixedwood management is being increasingly considered by natural resource managers as an alternative to single species management for a variety of ecological, economic, and cultural reasons. In northern Minnesota, USA, natural resource managers are increasingly using treatments to establish mixedwood forests in aspen (Populus tremuloides Michx, Populus grandientata Michx) dominated ecosystems by planting white spruce (Picea glauca (Moench). However, little quantitative information is known regarding differences between stand structure and composition in conventional aspen and aspen-white spruce during early stand development. To provide greater clarity for managers, we sampled 40 aspen stands across a chronosequence …

Tomato Seedling Performance In Five Commercial Organic Growing Media With And Without Supplemental Fertilizer, Elizabeth Maynard, Wenjing Guan, Petrus Langenhoven, Lori A. Hoagland

Department of Horticulture & Landscape Architecture Faculty Publications

Commercially available growing media permitted for use in certified organic production differ substantially in quantity and availability of essential macronutrients. Nutrient availability from fertilizers applied during production will depend on chemical, biological, and physical characteristics of both media and fertilizers; therefore, best practices for fertilizing seedlings are likely to differ. This study evaluated tomato (Solanum lycopersicum L.) emergence, seedling growth, and posttransplant performance when grown in five organic growing media with and without supplemental fertilizer during transplant production in three diverse locations. A 5N–0.88P–3.32K–3Ca (5–2–4) dry fertilizer was tested in all media, and a liquid 3N–0.88P–2.49K (3–2–3) fertilizer was …

Roles Of Organic Agriculture For Water Optimization In Arid And Semi-Arid Regions, Shikha Sharma, Matt A. Yost, Jennifer R. Reeve

Plants, Soils and Climate Student Research

Water scarcity is a critical challenge in arid and semi-arid regions, where agricultural water consumption accounts for a significant portion of freshwater use. Conventional agriculture (CA) methods with high reliance on chemical and mechanical inputs often exacerbate this issue through soil degradation and water loss. This review aims to examine how different organic practices, such as mulching, cover cropping, composting, crop rotation, and no-till (NT) in combination with precision technologies, can contribute to water optimization, and it discusses the opportunities and challenges for the adoption and implementation of those practices. Previous findings show that organic agriculture (OA) may outperform CA …

Electric Weed Control—How Does It Compare To Conventional Weed Control Methods?, Catherine Borger, Miranda J. Slaven

Journal articles

Weed management practices in agroecosystems mainly rely on herbicide, mowing, or tillage. Electric weed control offers a novel alternative, with a range of commercially available products for weed management in agricultural environments. However, electrical weed control efficacy has not been effectively compared with conventional weed management practices. Further, electrical weed control products may have a fire risk, as highlighted but not assessed in prior studies. The current study evaluated an electric weed control machine (Zasso™ XPower) for weed management in four vineyard sites (in 2022 and 2023) in comparison to mowing and herbicide applications. Weed control tactics were applied in …

Insights Into The Floral Senescence Effects Of Nanoparticles, Vuk Uskoković

Administration and Staff Articles and Research

Flowers could be valuable addenda to nanomedicine labs as in vivo models crossing the gap between the cell culture and small mammals. However, as it is shown here, floral models continue to be predominantly utilized within resource-limited research environments and remain largely underrepresented in mainstream biomedical investigations conducted by well-funded institutions in the developed world. The ability to delay the senescence of Orange Jubilee wildflowers was tested here on three types of nanoparticles: selenite-doped hydroxyapatite (HAp), citrate-stabilized HAp, and superparamagnetic iron oxide. Integration of selenite into the HAp crystal lattice produced a mild increase in the senescence rate …

Influence Of Increasing Fires On Mixed Conifer Stand Dynamics In The U.S. Southwest, Simon D. Baker, Kristen M. Waring, David Auty, Nicholas Wilhelmi

Aspen Bibliography

(1) Stand-replacing fires may threaten the continued stability of mixed conifer forests in the U.S. Southwest. Increasing fire frequency and severity have made post-fire forest recovery trajectories uncertain for many coniferous species, potentially leading to long-term shifts in forest structure and composition. (2) The purpose of this study was to examine post-fire stand dynamics over a 10-year period, using a network of permanent plots established prior to wildfire events across Arizona and New Mexico. We assessed changes in over story composition, regeneration, and fuel loading across different fire severities. (3) High severity fire caused near-total over story mortality, with little …

Experiments To Enhance Post-Fire Aspen Seedling Survival And Growth, Larissa L. Yocom, Mark R. Kreider, Owen T. Burney, Tammy Parsons, Ryan T. Choi, Emily K. Liese, Karen E. Mock

Aspen Bibliography

Aspen forests provide wildlife, watershed, and aesthetic value, and the potential for reduced fire occurrence, behavior, and severity. There is interest in planting aspen to achieve various management objectives. However, few studies have investigated the optimal conditions for aspen seedlings in the western US. We conducted two experiments to address this knowledge gap. First, we tested the effects of shading structures (i.e., logs) and biochar on the survival and growth of 960 outplanted aspen seedlings in three exclosures in a recent fire footprint. Second, we tested whether experimentally placing logs near 120 naturally-occurring post-fire aspen seedlings affected survival or growth. …

Arts-Based Sustainability: From New York To Malawi, Martha B. Lerski

Publications and Research

Recognizing that libraries serve multiple constituencies and subject areas, this chapter documents and advocates for development of transdisciplinary arts-based research (ABR) and culture-related projects linked to environmental challenges. Libraries contribute collections and spaces, as well as the research of library and information scientists. Libraries are currently among invisible contributors to sustainability planning and services. The chapter will link this invisibility to the value of what visual arts refer to as negative space elements in subjects ranging from traditional ecological knowledge to environmental science. Library collections, projects, and research contribute to education for sustainable development (ESD) as required to achieve the …

Allelopathy Of Western Red Cedar, Douglas Fir, And Western Hemlock On Seed Germination, Lainey E. Mendoza Ms.

Honors Projects

Understanding the allelopathic interactions of native Pacific Northwest conifers, Douglas Fir, Western Hemlock, and Western Red Cedar is crucial to understanding the interactions of each species within their ecological niche. As of now there is little research on allelopathy of PNW conifers, specifically how different damaged states of the conifer tissue could impact the germination rates and radicle growth of a model organism. Analyzing these allelopathic interactions may be crucial to help predict forest regeneration of the PNW in the future. Presented here is the analysis of Douglas Fir, Western Hemlock, and Western Red Cedar tissue that is undamaged, damaged, …

The Ecophysiology Of The Enigmatic Namib Succulent, Lithops Ruschiorum, Garrett Macleod Althausen

Environmental Studies Senior Theses

Water availability is the primary constraint for plant survival and reproduction in hyper-arid ecosystems. In such environments, plant fitness depends on an alignment between physiological traits and limited water resources. The Namib Desert of Namibia exemplifies this extreme selection pressure. Within the Namib Desert, Lithops ruschiorum, a succulent endemic to the gravel plains, exhibits habitat specificity and numerous physiological adaptations to cope with the hyper-aridity.

This research explores the intersection of two fitness strategies for L. ruschiorum: habitat selection and exploitation of alternative moisture sources. The first chapter explores the population dynamics and micro-site habitat conditions preferred by …

Oviposition-Deterrent And Repellent Effects Of Synthetic Plant-Derived Compounds On The Pulse Beetle, Callosobruchus Chinensis (Coleoptera: Chrysomelidae: Bruchinae), Akki Suma, M Rajadurai, Ac Lokesh, Mb Anusha, S Krishna Kumar

The Philippine Agricultural Scientist

The pulse beetle, Callosobruchus chinensis (Linnaeus, 1758), is a major stored pest of pulses (Fabaceae) in India. While effective control of this widespread and destructive insect pest is essential, continuous insecticide use poses environmental concerns, thereby necessitating alternative, eco-friendly control methods. This study evaluated the oviposition-deterrent effects of 7 synthetic compounds (linalool, guaiene, citral, estragole, 4-nonanone, alloaromadendrene, and citronellal) on C. chinensis. Linalool showed the strongest suppression of egg-laying at higher concentrations, with the lowest egg count at 500 ppm compared to the control, followed by citral, citronellal, and guaiene. Linalool was also effective in suppressing egg hatching at …

Antimicrobial Activity In Auxin-Induced Formation Of In Vitro Culture- Derived Aloe Vera Roots, Eufrocinio Marfori, Bernadette Rapiz

The Philippine Agricultural Scientist

Aloe vera is a perennial, succulent plant which has been used in folk medicine for wound-healing, as its roots have been reported to exhibit remarkable antimicrobial properties. However, collecting the roots is detrimental to plant growth and development. Hence, an alternative system of producing A. vera roots must be developed. Tissue culture is a potential tool to obtain A. vera root biomass, which can serve as raw materials for the large-scale production of antimicrobial compounds. In this study, individual shoots taken from the multiple shoot culture of A. vera were induced to form roots in MS medium supplemented with 1 …

Isolation And Enumeration Of Salmonella Enterica From Fresh Lettuce (Lactuca Sativa L.) Leaves And Its Susceptibility To Different Washing Protocols, Meinard Talplacido, Angella Melissa Carlos, Bryan Rey Oliveros, Ida Dalmacio

The Philippine Agricultural Scientist

Lettuce is one of the most consumed fresh produce items in the country, but it also serves as a vehicle for human pathogens, posing a risk of foodborne illness. This study used conventional microbiological and molecular analyses to obtain the concentration and prevalence of Salmonella enterica in fresh Green Ice and Iceberg lettuce leaves from selected supermarkets in Los Baños, Laguna, Philippines. The efficacy of different household washing procedures in reducing S. enterica on lettuce leaves was also investigated. Of the 19 composite Green Ice lettuce and 21 composite Iceberg lettuce samples tested, 5.26% and 4.76%, respectively, were contaminated with …

Sustainability Analysis Of Olive Production In Hatay Province, Turkey, Gülșen Keskin, Ahmet Duran Celik, Tugce Sarioglu

The Philippine Agricultural Scientist

Hatay Province, located in the Southern Mediterranean region of Turkey, contributes approximately 7% of the country’s olive production. This study assessed the sustainability of olive enterprises in the province by interviewing 100 producers across 5 districts. A total of 33 variables (10 economic, 14 social, 9 environmental) were identified and used to evaluate sustainability. Results showed that 76% of the enterprises were considered “fragile”, 14% were considered “good”, and 10% were considered “poor”, with the highest scores obtained for social sustainability (58%), and the lowest obtained for environmental sustainability (7%). Statistically significant relationships were also found between sustainability and the …

Effects Of Water Deficit Stress And Mycorrhiza, Azotobacter Chroococcum, And Azospirillum Lipoferum Biofertilizers On Yield And Morphological Traits Of Wheat (Triticum Aestivum L.) Cultivars, Mehdi Rashnou, Farshid Aref, Bahram Amiri, Masoud Rafiee, Mahdi Zare

The Philippine Agricultural Scientist

Crop production in various parts of Iran faces significant constraints due to insufficient water availability, which is a major challenge to agricultural productivity. To study the effects of water deficit stress on shoot and root growth characteristics and seed yield of different wheat (Triticum aestivum L.) cultivars, an experiment was conducted using a randomized complete block design with a split-plot arrangement and 3 replications. The main factor was irrigation treatments (full irrigation during the growing season [S1], water withholding after flowering [S2], and water withholding after grain filling at the milk stage [S3]). The secondary factors were wheat cultivars …

State And Transition Models For Mulga Rangelands Of Western Australia, Alison O'Donnell, Anna E. Richards, Suzanne Prober, Peter-Jon A. Waddell, Sarah Luxton, Ian Watson, Brett Abbott, Philip Thomas, Joshua E. Foster

Natural resources published reports

This report details a collaborative project between the Western Australian Department of Primary Industries and Regional Development and CSIRO that focused on developing State and Transition Models (STMs) for mulga rangelands in Western Australia. The overarching aim of the project was to improve the common understanding of the characteristics and dynamics of mulga rangeland ecosystems and the expected impacts of management. Specifically, the project aimed to collate expert knowledge and monitoring information using a nationally consistent framework to develop quantitative and dynamic STMs. The geographic scope of the project covers the extensive mulga rangelands of Western Australia, particularly the Gascoyne …

Integrating High Throughput Phenotyping Approaches To Characterize Plant Traits And Support Nutrient Management Research, Katie J. Bathke

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Over the past decade, considerable research has addressed the social, economic, and agronomic challenges posed by imbalanced nutrient applications, particularly nitrogen and, more recently, sulfur. In response, high throughput plant phenotyping, as one of the latest approaches, has contributed to the development of innovative techniques for assessing key plant phenotypes under stress over time in both field and greenhouse environments. However, there is a limited number of studies applying these techniques for nutrient management, particularly in scenarios where two abiotic stressors coexist, such as the combination of water stress and nitrogen deficiency, or concurrent nitrogen and sulfur deficiencies.

In chapter …

The Ethnobotany And Pharmacology Of Medicinal Plants For Caribbean Women’S Health, Ella Thomas Vardeman

Dissertations, Theses, and Capstone Projects

Approximately 55% of the world’s population lives in cities, and the United Nations estimates that this number will rise to 68% by 2050. Urban ethnobotany, the study of people’s traditional knowledge and use of plants in cities, is increasingly important as people adapt their cultural traditions to changing environments. In New York City (NYC), there have been several urban ethnobotany investigations in collaboration with Caribbean immigrant groups. However, there has yet to be an ethnobotanical survey that documents and botanically authenticates the medicinal plants used in the Haitian community. Previous collaborative research with women from the Caribbean in NYC has …

Arkansas Corn And Grain Sorghum Research Studies 2024, Jason Kelley, Travis Faske

Arkansas Agricultural Experiment Station Research Series

The 2024 edition of the Arkansas Corn and Grain Sorghum Research Studies Series includes research results on topics pertaining to corn and grain sorghum production, including weed, disease, nematode, and insect management; economics; irrigation; agronomics; soil fertility; drone use; and research verification program results.

Our objective is to capture and broadly distribute the results of research projects funded by the Arkansas Corn and Grain Sorghum Board. The intended audience includes producers and their advisors, current investigators, and future researchers. The Series serves as a citable archive of research results.

The reports inform and guide our long-term recommendations, but should not …

Optimization Of Downy Mildew Management And Baby Kale Production On The Central Coast Of California, Emily M. Locke-Paddon

Master's Theses

Baby kale (Brassica oleracea and other species) is a vital commodity as a salad green in spring mix and is widely produced on the Central Coast of California. Downy mildew, caused by Hyaloperonospora brassicae, is a devastating disease infecting economically important crops like cabbage, broccoli, cauliflower, horseradish, rapeseed, kohlrabi, Brussels sprouts, and kale. This foliar disease causes plant tissue to exhibit chlorotic and necrotic flecking and gray-white sporulation, affecting both the yield and quality of the crop and rendering the affected leaves unmarketable. The Central Coast’s cool climate and nighttime moisture, combined with dense plantings and sprinkler irrigation, …

Subalpine And Alpine Plant Community Turnover In Yosemite National Park Following 30 Years Of Climate Warming, Rachel Friesen

Master's Theses

Subalpine and alpine regions in California are warming more rapidly than lower elevations. In response, high-elevation plants may acclimate or adapt to the new climate, move to higher elevations or latitudes, persist in refugia, or go extinct. While models predict substantial declines in subalpine and alpine plant communities due to discontinuous population distributions and lack of upslope area, actual responses may vary due to lags in dispersal, establishment, and extinction. Although shifts in high-elevation plant communities have been documented in other regions of the world, such changes have not yet been studied in Yosemite National Park. To assess high-elevation plant …

A Vacuolar Proton Pump Controls The Post-Germinative Growth Of Rice (Oryza Sativa Ssp. Japonica), Peter James Icalia Gann, Soumen Nandy, Rodrigo Botelho, Kari Vinzant, Mariya Khodakovskaya, Vibha Srivastava

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Post-germinative growth in plants is controlled by sucrose mobilization from the endosperm. Regulation of this process, however, is not fully understood. Transcriptional suppression of the rice vacuolar H+ translocating pyrophosphatase (V-PPase) referred to as VPP5 led to enhanced starch content in mature grains. However, vpp5 suppressed lines displayed a slower post-germinative growth rescuable by sucrose, indicating inefficient sucrose mobilization from the endosperm. Biochemical and gene expression analyses showed a slower rate of starch to sucrose conversion and altered expression of the key starch utilization pathway genes. We hypothesized that the modulation of metabolic activities in the vpp5 lines was based …

Summaries Of Arkansas Cotton Research 2024, Fred M. Bourland

Arkansas Agricultural Experiment Station Research Series

Planted cotton acreage in Arkansas increased in 2024 to 670,000 planted acres, which was 160,000 acres more than in 2023 when Arkansas producers planted approximately 510,000 acres of cotton. A wet spring, and two hurricanes in three weeks in late summer/early fall led to a slight decrease in harvested acres that culminated in a final number of 640,000 (https://www.nass.usda.gov/Quick_Stats/Ag_Overview/stateOverview.php?state=ARKANSAS). Producers harvested 640,00 acres of cotton, which ranked third nationally, behind Texas and Georgia (https://downloads.usda.library.cornell.edu/usda-esmis/files/k3569432s/nk324887m/qn59s0097/cropan25.pdf). The total harvested acreage is the greatest amount since 680,000 acres in 2011. The average cotton yield in Arkansas in 2024 was …

Fire Fossils: Biomineral Infrastructures In Untangling Climates, Tanmayee More

Masters Theses

Diatoms drift, sediments sink, wildfires generate their own weather. Lightning strikes can blast sand into glass, and microscopic organisms do the same in the cold recesses of the ocean. What alchemies and metabolisms catalyze space, time, and energy? What are the thermodynamics of infrastructure in Climate Change?

Places, materials, and beings are afterimages. Through alchemical experiments, and multi-scalar imaging, I develop simulations of wildfires, and their profound, reverberating effects. In this thesis, a glass-meets-landscape experimental process enters these obscured conditions and renders new material relations for the built environment.

Tree Story, Jia Hu

Masters Theses

What is Nature?

Nature is a system of intelligence. It means designing for efficiency—often by learning from strategies that have evolved over time. In my research, I use patterns to interpret and decode nature.

To explore nature, I began with the red cedar tree, aiming to simulate and predict its growth patterns—forms shaped by both internal biology and external forces. By analyzing its geometry, I sought to understand how trees embody the dynamic relationship between organism and environment. These patterns reveal the adaptive logic of life.

Patterns are central to understanding nature. While tree geometry may appear chaotic, it follows …

Field Journal: The Excluded Middle, Carrie E. Kouts

Masters Theses

What does it look like to engage with organisms and landscapes at the periphery of anthropocentric value structures? How does one break the internalized myth that the “built” environment is excluded from the natural world? When does a hyper-mobile and hyper-commodified society confront the exponential crisis of animal death? Within this series of journal entries, field notes, collection observations, weird prose, and sensory musings, one will find questions on the nature of being human and the complex narratives of care we encounter in a world shared with more-than-humans. Each handwritten vignette and photograph from daily life weaves a non-linear and …

Oregon State Rank Assessment For Siskiyou Iris (Iris Bracteata), Nora Dunkirk

Institute for Natural Resources Publications

Oregon state conservation status assessment for Siskiyou iris (Iris bracteata) using NatureServe methodology, 2025.

Integrating Cover Crops And Targeted Herbicide Applications In Cotton Production, Tristen H. Avent, Jason K. Norsworthy, Gerson L. Drescher

Crop, Soil and Environmental Sciences Faculty Publications and Presentations

Cover crops are part of integrated weed control management to help mitigate herbicide resistance evolution. Targeted sprays from the John Deere See & Spray are currently not recommended in cover crops. Experiments were conducted yearly from 2022 to 2024 in Keiser, AR, to evaluate targeted applications (TAs) with cover crops in cotton (Gossypium hirsutum L.). Treatments assessed the main effect of winter cover crop (fallow, cereal rye [Secale cereale L.], or hairy vetch [Vicia villosa Roth]), herbicide application methods (nontreated, broadcast [BC], TA + BC residuals [TA + BCRs], or TA only), and the interaction on cotton tolerance, weed control, …

Potential Economic Impact Of Grapevine Phylloxera (Hemiptera: Phylloxeridae) On Western Australian Winegrapes, David C. Cook, Andrew S. Taylor, Peter S. Gardiner, Rodrigo Pires, Hamish L R Mckirdy, Karen W. Holmes, Helen Spafford

Viticulture Research Articles

Grapevine phylloxera Daktulosphaira vitifoliae Fitch (Hemiptera: Phylloxeridae) has been present in Australia for almost 150 years but has not spread to south-west Western Australia, in part due to the relative isolation of the region. Recent improvements in tourist access, with interstate flights now arriving at Busselton Margaret River Airport, raise concerns about potential phylloxera introductions via wine tourism. In this paper, we simulate the potential economic impact on the Western Australian winegrape industry following a hypothetical arrival event in the Margaret River wine region. We use soil texture maps to assess the suitability of winegrape-growing areas to phylloxera establishment and …