Agriculture Commons^™

Evaluating Fungicide Programs For Grapevine Disease Management And Fungicide Sensitivity Monitoring, Abraham Ahumada

Master's Theses

Grapevine diseases, such as powdery mildew and Botrytis bunch rot, require repeated fungicide applications to maintain fruit quality and reduce yield losses. However, fungicide performance can vary among products, application programs, disease pressure, and pathogen sensitivity. This thesis evaluated fungicide programs for control of powdery mildew in ‘Chardonnay’ grapes and assessed fungicide sensitivity of Botrytis cinerea isolates collected from California vineyards.

Powdery mildew, caused by the fungal pathogen Erysiphe necator, is a major threat to the production of Vitis vinifera grapes worldwide. Because powdery mildew management relies heavily on fungicide applications, field evaluations are needed to compare the efficacy …

City Farm Slo: A Case Study Of Nonprofit Regenerative Agriculture, Carver Tunnell

Master's Theses

The focus of this thesis is to create a case study on City Farm SLO, a nonprofit based in San Luis Obispo, California, that has engaged in education and regenerative agriculture on City owned land since 2013. This case study is intended for use in undergraduate agribusiness and natural resource management courses, to encourage thoughtful discussion surrounding nonprofit and regenerative agricultural systems. The case presents the nonprofit at a time of relative success, having recently secured a lease renewal, extending stewardship 40 years into the future. However, the reliance on grants and donations threatens the security of the operation going …

Chemical And Sensory Consequences Of Oxidative And Reductive Handling Of White Wines, Amelia Pargellis

Master's Theses

In the 2024 and 2025 vintage four experiments were performed each with a different varietal, namely Albariño, Grenache blanc, Loureiro, and Vermentino. These experiments investigated the effects of hyperoxygenation, reductive winemaking techniques, while monitoring the oxidation-reduction potential.

Albariño grapes were made following two juice protocols, control/reductive (Reductive Control) and oxidative (HyOx). Reductive Control received antioxidants (50 ppm SO₂, 160 mg/L ascorbic acid) and CO₂ blanketing, and HyOx underwent hyperoxygenation at approximately 700 mL/L/h of air for two hours through a stainless-steel sparging stone with 10-µm pores. Juice was cold-settled and racked. Reductive Control juice was split into …

Sustainable Management Of Soilborne Pathogens In Strawberry Production Through Host Resistance And Sanitation Practices, Maria G. Alvarez Arredondo

Master's Theses

Strawberry production in California is significantly impacted by soilborne pathogens that reduce plant productivity and increase management costs. This research addressed management of these pathogens through two independent approaches: evaluation of host resistance in strawberry cultivars and assessment of sanitation practices for reducing pathogen movement between fields.

Macrophomina root rot, caused by Macrophomina phaseolina, was evaluated over two growing seasons (2024–2025 and 2025–2026) using field trials at California Polytechnic State University, San Luis Obispo. In Year 1, disease incidence varied widely among genotypes, with mortality ranging from 1.3% to 88.8% and an average mortality of 26.4%. Area under the …

Exploring Regenerative Vegetable Systems On The Central Coast Of California, Una S. O'Connell

Master's Theses

As climate change and current agricultural practices place pressure on the long term sustainability and resilience of food production systems, there is growing interest in whether existing agricultural systems can adapt to maintain productivity while improving environmental outcomes.

This study evaluated the effects of regenerative versus standard organic vegetable production systems on yield, insect communities, and weed suppression across three field trials conducted on California's Central Coast. In addition, I collected baseline soil health data for all trials. Trials 1 and 2 were carried out at the Cal Poly San Luis Obispo Organic Farm using cabbage and broccoli as cash …

Measurement And Control Of The Oxidation-Reduction Potential And Its Chemical And Sensory Consequences In Wines, William Jordan Wright

Master's Theses

The oxidation-reduction potential (ORP) is a measurement thought to reflect the overall ability of a solution to oxidize or reduce substances within that solution. In wine, there is no absolute agreement as to which substances control or dominate the ORP; however, oxygen, ethanol, iron-tartrate and copper-tartrate complexes, and glutathione are suspected to play key roles, while sulfur dioxide and phenolics may act as buffers. Anecdotally, some varieties of Vitis vinifera are prone to oxidation while others are prone to reduction, though the chemical basis of this remains unclear. The following works aim to further elucidate the influence of specific chemical …

Serum Concentrations Of Inflammatory Markers And Selected Nutrient Metabolites In Holstein And Jersey Cows Across The Transition Period, Avery Orr

Master's Theses

The transition period, spanning the weeks surrounding parturition, requires dairy cows to undergo synchronized metabolic, endocrine, and immunological adjustments that support the onset of lactation but also heighten disease susceptibility. Although individual inflammatory or metabolic biomarkers have been extensively studied, the integrated immunometabolic dynamics that occur across this period and the difference between breeds is not fully understood. The objective of this study was to characterize longitudinal patterns in key nutrient metabolites and inflammatory markers in Holstein and Jersey cows and assess how these systems interact across the transition period.

A total of 63 Holstein and Jersey cows were sampled …

Owl Integrations Soil Monitor, Derek Chau, Armaan Kahlon

Electrical Engineering

This paper examines the design process and results concerning the OWL Integrations soil monitor. Disaster relief relies heavily on digital communications, especially in environments where conventional methods (e.g. Wi-Fi, cellular, fiber optics) are unusable. To help emergency services assess disaster-stricken areas, a soil monitoring system was developed using LilyGo T-Beams (ESP32), programmed with specialized firmware known as the ClusterDuck Protocol to collect data pertaining to moisture and temperature. The project is sponsored by OWL Integrations, with help from the Cal Poly Electrical Engineering (EE) Department. Results show positive prospects, with the product able to make 4 km transmissions, operate for …

Evaluating Nanobubble-Enriched Water Treatments For Cleaning Stainless Steel Winery Tanks At The Gallo Winery Research Station In Livingston, California, Edgar Godoy-Garcia

Master's Theses

ABSTRACT

Evaluating nanobubble-enriched water treatments for cleaning stainless steel winery tanks at the Gallo winery research station in Livingston, California.

Edgar A. Godoy-Garcia

Sanitation of stainless steel wine storage tanks is a critical component of quality control in commercial winemaking operations. Ineffective cleaning can lead to microbial contamination, product spoilage, and safety concerns. Traditionally, wineries rely on manual scrubbing, chemical cleaning agents, and extensive water rinsing cycles to maintain sanitary tank conditions. However, these methods are resource-intensive and may pose risks to both workers and the environment due to chemical exposure and wastewater generation. In response to growing industry interest …

"The Effect Of Methylobacterium Symbioticum On The Growth And Yield Of Dent Corn And Romaine Lettuce", Sinead Carney

Master's Theses

Nitrogen (N) is an essential nutrient for plant growth and is often a limiting nutrient in cropping systems. An estimated half of applied N fertilizers are lost from cropping systems by processes that can be environmentally destructive, such as leaching and volatilization, and cause economic loss for growers. Effective N biofertilizers offer a means to mitigate the need for high inputs of synthetic N. The objectives of this study were to determine the effects of leaf inoculation with the N-fixing bacteria, Methylobacterium symbioticum, in combination with different rates of urea-N fertilizer on the physiology and yield of dent corn …

Improved Management Strategies For Botrytis Fruit Rot, Macrophomina Root Rot, And Verticillium Wilt In California Strawberry Production, Joseph A. Ramirez

Master's Theses

Strawberry production in California is limited by plant diseases such as Macrophomina root rot (MRR) caused by Macrophomina phaseolina, Verticillium wilt (VW) caused by Verticillium dahliae, and Botrytis fruit rot (BFR) caused by Botrytis cinerea. Current disease management strategies are compromised due to fumigant regulations or ineffective disease management practices. This thesis investigated methods to potentially improve the management of these three diseases. Two host plant resistance evaluations for MRR and VW were conducted for the 2022-2023 and 2023-2024 growing seasons. Sixty-three strawberry genotypes were screened in both years. All plants were exposed to the pathogen via artificial …

Treating Ground Water For Agricultural And Individual Consumption, Gabby Miller, Bronson Scott, Michael Clawson

Biomedical Engineering

This project, conducted in collaboration with Cal Poly seniors and Da Vinci High School students, aims to develop a solar-powered groundwater purification system. This system is designed to provide clean water for agricultural use and individual consumption, addressing the growing concerns of groundwater contamination and accessibility needs. The final prototype integrates a gravity filtration system combined with chemical purification, utilizing aluminum sulfate and chlorine to remove particulates, bacteria, and organic compounds.

The research phase involved an extensive review of groundwater contamination issues, existing filtration technologies, and market analysis. Key design constraints included cost-effectiveness, ease of maintenance, and minimal energy consumption, …

Survey Of Soilborne Pathogens Infecting Strawberry In Oxnard, California & Effect Of Planting Date And Chill Treatment On Yield Of Strawberry, Samantha Z. Simard

Master's Theses

Survey to quantify the frequency of the five main pathogens (Macrophomina phaseolina, Fusarium oxysporum f. sp. fragariae races 1 and 2, Verticillium dahliae, and Phytophthora spp.) infecting strawberry in the Oxnard growing district of California. M. phaseolina was the most prevalent pathogen detected in diseased plants in the Oxnard growing district, present in 67.6% of samples positive for at least one pathogen. F. oxysporum f. sp. fragariae race 1 (35.3%), V. dahlia (8.8%), F. oxysporum f. sp. fragariae race 2 (5.9%) and Phytophthora spp. (2.9%) followed at lower prevalence. Associations were found between fewer drip irrigation lines …

Gps Accuracy Of Smartphones For Crowdsourcing Research, Derron L. Dike

Master of Science in Environmental Sciences and Management Projects

ABSTRACT GPS Accuracy of Smartphones for Crowdsourcing Research Derron Dike Utilizing crowdsourcing with smartphones as a method for field data collection can contribute an array of data for scientific studies and land management applications. This study used crowdsourcing to examine smartphone built-in GPS performance for providing location-specific information with potential forestry applications. The usability of smartphones for GPS data collection in forestry studies or other practical applications is dependent on the level of accuracy required for those applications. A Smartphone Accuracy Trial was designed to test the GPS accuracy performance of current smartphones. Participants used the ArcGIS Field Maps application …

Cultivating Agriculture - Cultivando Agricultura: Content Creator, Sophia L. Garcia

Agricultural Education: Graduate Internship Reports

Agriculture is rooted in culture, yet we rarely discuss the people who drive the industry today. Many voices have yet to share their stories of influencing or making a difference in the agriculture industry. As a result, the idea of a podcast arose as a free, convenient, and accessible way for everyone to hear and communicate stories. During the project, my co-host, Daniela Ramos, and I will work together to address this issue. To diversify and separate the workload, we will each host three episodes individually. As part of my role, I will also be responsible for marketing, including creating …

Aged 539 - Graduate Internship, Braidyn R. Cossa

Agricultural Education: Graduate Internship Reports

This report reflects on the Cal Poly Rodeo Program's alignment with the National Standards for Sport Coaches, showcasing a comprehensive approach to athlete development across multiple critical domains. Emphasizing a well-defined coaching philosophy, the program promotes sportsmanship, ethical behavior, and academic success. Personalized coaching addresses the developmental stages of athletes, ensuring a balance between their academic and athletic roles. The program employs effective teaching methods, clear communication, and constructive feedback to foster a positive environment and build strong coach-athlete relationships based on mutual respect and trust.

The coaches possess deep knowledge of rodeo skills and strategies, utilizing psychological techniques to …

The Effect Of Probiotic Supplementation On Serum Metabolite Concentrations In Young Holstein Heifers, Emily G. Meissner

Master's Theses

The objective of this trial was to evaluate the effect of a multi-strain probiotic on serum concentrations of selected metabolites in young calves. Holstein heifers (n = 112) from a commercial dairy were enrolled within 48 h of birth and placed into individual hutches. Calves were weaned at 60 d of age and remained in their hutches until 90 d of age, when they were moved to group housing. Calves were placed into 2 treatment groups: 1) control and 2) B. subtilis, B. lichenformis, L. animalis, and P. freudenreichii probiotic (Bovamine Dairy Plus, Chr. Hansen, Milwaukee, WI). Control calves received …

Implementation And Efficiency Of Electric Motors In Lygus Bug Vacuums For Strawberries, Adam J. Rantz

Master's Theses

Further automation of the agricultural industry and an increase in organic fruit production are needed to address labor shortage and increased demand. The move to an autonomous bug vacuum is easier if the equipment is electric, and not powered by a tractor’s PTO (power take-off) shaft. The main objective of this project was to design a set of lygus bug vacuums to go on a robot that meets industry standards while using electric power instead of hydraulic. The frame of the vacuum was designed using the industry standard. While hydraulic systems have been a very effective power source for vacuums …

Effect Of Chloropicrin And Metam Sodium On Soil Nitrogen Dynamics In California Strawberry Production, Colin Timothy Koubek

Plant Sciences

California strawberries (Fragaria x ananassa Duch.) bring in ~3 billion yearly for the state's economy. Strawberry growers use fumigants like chloropicrin and metam sodium to manage a variety of soilborne diseases in conventional production. The yield-boosting effects of fumigation on strawberries are often attributed to disease management, but the ‘fertilizer effect’ from mineralization may play an equally significant role. This experiment conducted in a grower field sought to find out the influence that fumigation had on the mineralization of soil organic nitrogen and if preplant fertilizer application affected early season nitrogen (N). There were six treatments: control, control with controlled …

Deep Semantic Hashing For Aerial Livestock Detection, Shosei Anegawa, Franz Kurfess, Sumona Mukhopadhyay

College of Engineering Summer Undergraduate Research Program

The goal of this project is to be able to accurately detect and count livestock in footage captured by a drone in real time. The main problems with this arise from the fact that a drone can only carry limited computing resources, and hashing is conventionally thought of as a great method of doing image classification very quickly and thus even on low-power devices. In this project, we use both a Faster-RCNN, which is a state-of-the art object detection model as a benchmark to develop a hashing model that can perform a similar task much more quickly. These two models …

Aged 539 Internship Report: Cal Poly Rodeo Media, Marina Levine

Agricultural Education: Graduate Internship Reports

Cal Poly Rodeo is one of the oldest, largest, and winningest college rodeo programs in the country. While completing my Masters in Agricultural Education, I held the position of Assistant Coach for Cal Poly Rodeo and served as head of media and marketing. The program’s social media rivals that of a professional sports media page. This year, I strived to take it to the next level. Throughout the year, I filmed, edited, and produced videos introducing our freshmen, highlighting our seniors and graduate students, and promoting our events such as the Break-A-Wave and Poly Royal. I also spent time in …

Integrative Analyses Of Genomic And Metabolomic Data Reveal Molecular Mechanisms Associated With Uterine Disease Traits In Transitioning Dairy Cattle, Leanna C. Sanchez, Mohammed Abo-Ismail, Daniel Peterson, Fernando Campos-Chillon

Master's Theses

The metritis complex (MC), characterizing post-partum uterine diseases in dairy cattle has negative implications on animal welfare, production efficiency, and the economic stability of the dairy industry. The studies in this thesis aimed to investigate the genetic architecture of the metritis complex and identify genomic regions and metabolites associated with the development of MC. Thereby enhancing our understanding of the biological pathways and molecular mechanisms involved in the pathophysiology of MC during the transition period in Jersey and Holstein dairy cattle.

Chapter 2 sheds light on the previous work done on MC. The goals of this review were to (1) …

Reducing Scope 3 Emissions By Investing In Regenerative Agriculture In Supply Chains, Stephanie Cain

Master's Theses

The agricultural industry has an opportunity to shift to a more sustainable practice that helps restore vital topsoil, improve water quality, reduce environmental impact, and sequester atmospheric carbon into the vast soil carbon pool. However, to implement these practices at considerable scale, agricultural producers require access to resources and capital they rarely have and can be difficult to acquire. As a company, investing in regenerative agriculture in supply chains can lead to reduced Scope 3 emissions, more resilient supply chains, and better marketability as an investment fund, an employer, and a brand. Insetting regenerative agriculture can protect supply chains against …

​ Soilborne Pathogens Of Strawberry In The Central Coast Region Of California: ​ Survey And Cover Cropping With Wheat For Management Of Macrophomina Phaseolina, Mary Steele

Master's Theses

Surveys of the four major soilborne pathogens of strawberry (Fusarium oxysporum f. sp. fragariae, Macrophomina phaseolina, Phytophthora spp., and Verticillium dahliae) to determine their relative prevalence were conducted in Watsonville-Salinas, CA in 2021 and in Santa Maria, CA in 2022. All four major pathogens were detected at relatively similar prevalence in Watsonville-Salinas, between 22% and 31% of sampled fields. In Santa Maria, M. phaseolina was far more prevalent at 52% of sampled fields, the other three falling between 14% and 17%. Additionally replicated greenhouse and field trials were conducted to evaluate the effects of wheat as …

The Temporal Evaluation Of Mouthfeel And Retronasal Sensations In Red Wines From The Central Coast Of California, Emily S. Stoffel

Master's Theses

Time-based sensory analysis techniques capture the dynamic retronasal and mouthfeel sensations in wines. It is important to understand how common winemaking practices and popular varietals impact the retronasal and mouthfeel profile as consumers tend to judge wine quality based on the taste, flavor, and mouthfeel of a wine. Three time-based sensory analysis methods were utilized with the objective to understand the effect of five commonly applied winemaking techniques (blending, varietal choice, fermentation temperature, cap management, and stem addition) on the dynamic retronasal and mouthfeel profile of six different varietals (Merlot, Malbec, Petite Sirah, Pinot noir, Grenache, and Tannat) grown on …

Analysis And Installation Of A Demonstration Agroforestry Orchard For Californian Mediterranean Plant Communities, Brandon Hurd

Master of Science in Environmental Sciences and Management Projects

Climate-appropriate agroforestry can provide low-input food security and ecosystem services for local Californian Mediterranean climates, while conserving natural resources (e.g., water, nitrogen, etc.). This project showcases a variety of agroforestry methods for five common plant communities of California and other analogous Mediterranean climates at the CAFES Experimental Farm on the campus of Cal Poly San Luis Obispo. Plant community species and their ethnobotanical uses were analyzed to mimic and incorporate aspects of native flora. Agricultural plants were also characterized to represent each of the five selected plant communities. GIS was used to assess the project site for soil, slope, and …

Vermicompost Versus Traditional Compost Amendments Leads To Different Soil Health Outcomes In A Mediterranean Vineyard, Elizabeth L. Luck

Master of Science in Environmental Sciences and Management Projects

Compost application has become a common practice in vineyard management to increase soil and crop health, however, the environmental externalities such as greenhouse gas emissions (GHG) from cropping systems that utilize organic fertilizers, such as compost, is uncertain. Vermicompost, which is compost created through the digestion of organic matter by earthworms, and its related ‘extract’ are commonly thought to provide more benefits for soil and crop health compared to standard compost. However, organic fertilizers such as vermicompost, vermicompost extract, and compost have not been compared in their effects on soil health in Mediterranean vineyards. In this two-year study, I assessed …

Determination Of Fungicide Resistance In Botrytis Cinerea On Wine Grapes In California's Central Coast Region, Evelyn Alvarez-Mendoza

Master's Theses

Botrytis bunch rot, caused by Botrytis cinerea, is a fungal disease that primarily affects the fruit of wine grapes. Infection of fruit consequently results in reduced yields and wine quality. These factors lead to significant economic losses for growers which prompts the implementation of management practices to control the disease. One objective of this study was to evaluate the level of resistance that populations of B. cinerea in the Central Coast region showed to various chemicals. A fungicide assay was conducted to determine resistant phenotypes to six fungicide active ingredients (pyrimethanil, iprodione, fenhexamid, fludioxonil, trifloxystrobin, boscalid). Thirty-five (2020) and …

An Integrated Approach For Controlling Verticillium Wilt Of Strawberry, Jack T. Koster

Master's Theses

Strawberry (Fragaria x ananassa, Duch.) is an important crop in California, with more than 35,000 acres planted in 2018 resulting in a farm gate value of $3.1 billion. In 2020, California strawberry production accounted for more than 85% of national strawberry production and faces serious threats to production due to various soil-borne diseases. One such disease, Verticillium wilt, is caused by the fungal pathogen Verticillium dahliae and is commonly found in temperate zones around the world where strawberries are grown. Due to the phase-out of efficacious fumigants like methyl bromide, alternative disease management methods have become necessary to …

Cofermentation, Post-Alcoholic, And Post-Malolactic Fermentation Blending Of Malbec, Merlot And Petite Sirah Wines, Armando Arturo Vega-Osorno

Master's Theses

A two-year study was conducted to assess the effects of cofermentation on red wine varietals. During the winemaking process, wines can be made from two or more varieties by picking, crushing and fermenting them together, a practice known as cofermentation. They can also be blended either after the completion of alcoholic fermentation or after malolactic fermentation. In the first year of the study, two grape varieties, Merlot (Mer), and Malbec (Mal) were cofermented. On the second year, a third varietal, Petite Sirah (PS) was also studied. Cofermented wines containing every possible binomial combination of the varietals was made and one …