What shapes instruction in course-based undergraduate research experiences? & Spatial, temporal, and structural drivers of soil microbial communities in regenerative agricultural systems

<p>CHAPTER 1 Course-based undergraduate research experiences, also known as CUREs, integrate authentic scientific investigations into STEM curricula. These experiences prioritize scientific practices, discovery, real-world relevance, collaboration, and iterative experimentation. CUREs offer a more accessible approach to engaging diverse student populations in science compared to traditional labs. However, they can place heavy demands on instructors, with challenges such as time limitations, scalability constraints, and resource availability. This research focuses on (1) the importance instructors place on implementing CURE characteristics and (2) the factors that influence their planning and implementation of CUREs. Instructor perspectives were analyzed using the Teacher-Centered Systematic Reform model (TCSR) in a multiple-case study at a primarily undergraduate institution. Qualitative data from observations and interviews were deductively coded to identify challenges and gather detailed perspectives. Findings indicate that CURE characteristics vary in application across instructors’ courses; instructors more often prioritize scientific practices and collaboration over iteration and real-world relevance. Analyses of the three TCSR factors (personal, teacher-thinking, and contextual) revealed that each factor influences instructors in their implementation of CURE characteristics. Trends varied among TCSR factors: personal factors generally supported instructors, teacher-thinking factors frequently posed barriers, and contextual factors had mixed effects. These factors interact, creating a variety of impacts. Consequently, successful and sustainable CURE implementation requires comprehensive support across all three TCSR factors. Ongoing instructor support may help overcome common challenges like limited planning and grading time and staying current with evidence-based teaching practices. This will ultimately benefit both instructors and students. CHAPTER 2 Conventional agricultural practices degrade soil structure, nutrients, and microbial communities essential for food production. Regenerative agriculture (RA) can counter these effects through practices that support microbial diversity and ecosystem resilience. This study analyzed soils from three RA sites over two years and two seasons in the Klamath-Siskiyou ecoregion near Ashland, Oregon. The Haney soil health test was used to assess chemical properties and 16S rRNA gene amplicon sequencing identified microbial diversity and relative abundance. Results showed that soil microbial communities were shaped by a combination of spatial, seasonal, and annual factors, with site being the strongest determinant of microbial diversity. Additionally, out of the chemical properties tested (pH, H2O Organic N, and H2O Organic C), H2O Organic C was the only property to significantly influence soil microbiomes. These findings highlight the complexity of soil systems in RA, and understanding these relationships is an important step for identifying management practices that promote soil health.</p>

Name thesis:degree_name

Master of Science (MS) in Biology

Level thesis:degree_level

Thesis: EWU Only

Discipline thesis:degree_discipline

Biology

Year

2025

Author dc:creator

• Romaker, Bailee

• Agriculture
• Curriculum and Instruction
• Educational Methods
• Environmental Microbiology and Microbial Ecology
• Science and Mathematics Education

Statement dc:rights

• Access perpetually restricted to EWU users with an active EWU NetID

Repository record dc:identifier

https://dc.ewu.edu/theses/976

OAI identifier oai:identifier

oai:dc.ewu.edu:theses-1978