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Title: Studies on bacterium pullorum
Creator: Mallmann, Walter L.
Date: 1924
Collection: Electronic Theses & Dissertations

Title: The replacement of cystine by some phenols in metabolism
Creator: Chen, Shwen-yuing
Date: 1926
Collection: Electronic Theses & Dissertations

Title: The rising risk of rising water : examining risk perception and other predictors of flood mitigation behavior
Creator: Rappolee, Eleanor
Date: 2020
Collection: Electronic Theses & Dissertations
Description: As a result of heat-trapping pollution from human activities, rising sea levels and increasing precipitation could within three decades push chronic floods on land currently home to more than 300 million people. Water levels in the Great Lakes, heavy rainfall, and flooding have all substantially increased in Michigan, causing erosion, water quality decline, and negative impacts on society. Taking action to mitigate flooding at all scales is essential to ensure social and economic...
Show moreAs a result of heat-trapping pollution from human activities, rising sea levels and increasing precipitation could within three decades push chronic floods on land currently home to more than 300 million people. Water levels in the Great Lakes, heavy rainfall, and flooding have all substantially increased in Michigan, causing erosion, water quality decline, and negative impacts on society. Taking action to mitigate flooding at all scales is essential to ensure social and economic sustainability. This study explores predictor variables of flood mitigation behaviors among Michigan residents in a proposed theoretical framework that synthesizes three behavioral theories: Theory of Planned Behavior, Values-Beliefs-Norms, and Protection Motivation Theory. This study also includes empirically measured actual flood risk in the theoretical framework, which is often left out in behavioral studies. Actual flood risk alone was found to weakly align with perceived flood risk and was a significant predictor of flood mitigation behavior during regression. However, when other variables were included, actual flood risk became an insignificant part of the model. Instead, subjective norms, perceived flood risk, self-efficacy, education level, having a flood-related home inspection, and having a basement emerged as significant predictors of flood mitigation behaviors. These findings lay the groundwork for future research and have implications for planning around flood mitigation and policy within and beyond the Midwest region.
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Title: ASSESSING REPRODUCTIVE SUCCESS OF LAKE STURGEON (ACIPENSER FULVESCENS) ASSOCIATED WITH NATURAL AND CONSTRUCTED SPAWNING REEFS IN A LARGE RIVER SYSTEM USING PEDIGREE ANALYSIS
Creator: Hunter III, Robert D.
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Habitat modification including barriers to migration, poor water quality, and modification of benthic habitat has contributed to the decline of lake sturgeon (Acipenser fulvescens) abundances in the Great Lakes. Lack of habitat was identified as a limiting factor for lake sturgeon recovery in the St. Clair-Detroit River System (SCDRS). To increase habitat availability in the SCDRS with the intent of increasing lake sturgeon populations, seven spawning reefs were constructed. Using 741 eggs...
Show moreHabitat modification including barriers to migration, poor water quality, and modification of benthic habitat has contributed to the decline of lake sturgeon (Acipenser fulvescens) abundances in the Great Lakes. Lack of habitat was identified as a limiting factor for lake sturgeon recovery in the St. Clair-Detroit River System (SCDRS). To increase habitat availability in the SCDRS with the intent of increasing lake sturgeon populations, seven spawning reefs were constructed. Using 741 eggs and larvae collected during traditional assessments, genetic pedigree analysis was used to further quantify spawning habitat use. In 2015 and 2016, 339-349 spawners were estimated to have contributed offspring across all sites. The effective number of breeders was estimated at 295-314 spawners, with mean (4.26-4.37 larvae) and variance (6.26-7.20) in individual reproductive success across all reefs and in 2015 and 2016. Evidence of adults spawning at multiple reefs within and between rivers was revealed by shared sib-ship of offspring collected at multiple locations. Comparison between gear types revealed that differences in the way individuals are collected can affect estimates generated from genetic pedigree analysis. Finally, species richness estimators were combined with genetic pedigree analysis to estimate the total number of spawners contributing offspring at constructed reefs (11-92 spawners per reef per year). Detailed information regarding lake sturgeon spawning behavior associated with spawning habitat construction in the SCDRS informs future assessment and management action for conservation of lake sturgeon throughout their range.
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Title: Relationships between academic network and student engagement for construction education
Creator: Chen, Zhiting
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Student engagement is a significant predictor of student's academic performance that has shown essential benefits for collaborative learning in higher education. Activities of social networking are common practices for college students to pursue a higher academic achievement by taking advantages on collaborative learning. Nevertheless, there is a gap in understanding the relationship between student engagement and academic networking patterns. By involving Social Network Analysis (SNA) based...
Show moreStudent engagement is a significant predictor of student's academic performance that has shown essential benefits for collaborative learning in higher education. Activities of social networking are common practices for college students to pursue a higher academic achievement by taking advantages on collaborative learning. Nevertheless, there is a gap in understanding the relationship between student engagement and academic networking patterns. By involving Social Network Analysis (SNA) based research methods, this quantitative study explored the relationships between these two antecedents of academic performance at the individual level as well as the subgroup level in the construction domain. The self-reported interaction and engagement data used in regression analysis was collected from two construction-related undergraduate classes in the United States. The analysis results revealed positive relationship between student engagement and individual direct social connections with classmates. The subgroup-level correlations indicate that a small-sized low eccentricity network with efficient information exchanges is preferred by students to highly engaged in collaborative learning. These prominent findings suggest student leadership as a core motivator to facilitate all favorable engagement predictors uncovered in this study. A Confirmatory Factor Analysis was conducted to validate the student engagement framework. The author discussed implications for construction educators to focus on network-based interventions to advance understandings of student's needs and recommended effective instructional strategies for construction educators regarding student leadership development to optimize the outcomes of advanced course designs.
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Title: A systematic evaluation of computational models of phonotactics
Creator: Sarver, Isaac
Date: 2020
Collection: Electronic Theses & Dissertations
Description: In this thesis, recent computational models of phonotactics are discussed and evaluated and two new models are implemented. Prior phonotactic modeling, motivated by gradient acceptability judgments in nonce word judgment tasks (Albright 2009), claim that phonotactic grammaticality is gradient, and these models are evaluated by their ability to judge nonce words with scores that correlate with human acceptability judgments. Gorman (2013) argues that these gradient models do not account for the...
Show moreIn this thesis, recent computational models of phonotactics are discussed and evaluated and two new models are implemented. Prior phonotactic modeling, motivated by gradient acceptability judgments in nonce word judgment tasks (Albright 2009), claim that phonotactic grammaticality is gradient, and these models are evaluated by their ability to judge nonce words with scores that correlate with human acceptability judgments. Gorman (2013) argues that these gradient models do not account for the facts sufficiently and claims phonotactic grammaticality is categorical. In this thesis, the account of Gorman (2013) is implemented as well as a prominent gradient model from Hayes and Wilson (2008) and compared with the performance of two machine learning models (a support vector machine and a recurrent neural network), with all models trained on a corpus of English onsets. Results in this thesis show that the computational models are unable to correlate with human judgment data from Scholes (1966) as well as a categorical prediction of acceptability based on whether a sequence is attested in the lexicon or not, and that these models rely on assumptions which when challenged show that the models do not convincingly capture the gradience of the human judgment data used for evaluation.
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Title: Write before you speak : the impact of writing on L2 oral narratives
Creator: Bulow, Alyssa
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Current literature suggests that writing may better facilitate language learning than speaking practice alone, but direct empirical research demonstrating this is limited. Evidence is also limited as to whether grammar and vocabulary learned while writing can transfer to speaking. This study investigates the prediction that written planning, even more so than oral planning, leads to improved oral narratives. Thirty-four Spanish-speaking learners of English were randomly assigned to one of two...
Show moreCurrent literature suggests that writing may better facilitate language learning than speaking practice alone, but direct empirical research demonstrating this is limited. Evidence is also limited as to whether grammar and vocabulary learned while writing can transfer to speaking. This study investigates the prediction that written planning, even more so than oral planning, leads to improved oral narratives. Thirty-four Spanish-speaking learners of English were randomly assigned to one of two groups: writing rehearsal or oral rehearsal; rehearsal being individual practice before the final task. The writing group composed a story ending in the written modality while the oral group rehearsed by narrating theirs out loud. Both groups recorded their oral story continuation task as the final product. In order to compare the impact of writing versus oral rehearsal on learners' subsequent oral performance, final narratives were examined using complexity, accuracy, and fluency measures. Results showed that the writing group produced more fluent and lexically diverse narratives than the speaking group but there was no effect on accuracy, and limited effects on grammatical complexity. The study concludes with pedagogical implications for using writing tasks to prepare students for oral tasks.Keywords: L2 writing, complexity, fluency, story continuation task (SCT), EFL, benefits of writing for speaking, pre-task planning, rehearsal.
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Title: Fairness in AI-based recruitment and career pathway optimization
Creator: Mujtaba, Dena Freshta
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Work has long been a source of human livelihood, financial security, mental and physical well-being, dignity, and meaning. However, advances in computing, big data, artificial intelligence (AI), robotics, and related technologies are expected to usher in unprecedented and widespread changes in the economy and society. It is estimated that by 2030 up to 14% of the global workforce may need to change occupational categories as the world of work is disrupted by technological advances. Many...
Show moreWork has long been a source of human livelihood, financial security, mental and physical well-being, dignity, and meaning. However, advances in computing, big data, artificial intelligence (AI), robotics, and related technologies are expected to usher in unprecedented and widespread changes in the economy and society. It is estimated that by 2030 up to 14% of the global workforce may need to change occupational categories as the world of work is disrupted by technological advances. Many current and future workers that will enter the workforce lack skills that in-demand and future jobs require. In short, the landscape of work is poised for a major and unprecedentedly rapid transformation and this calls for a variety of strategies to meet the needs of workers, employers, the economy, and broader society.Motivated by these concerns, we investigate two key problems faced by organizations and workers in the future of work. As AI has expanded into human resource applications, organizations are increasingly using AI-based recruitment for sourcing, screening, and selecting talent. We explain how this can lead to biases in decisions and how this bias can be measured, review tools available for bias mitigation, and discuss future challenges for fairness in machine learning specific to recruitment applications. Alongside this, workers are affected not only by biased recruitment, but by the growing automation of tasks in occupations, which will increasingly require job and task transitions. To help workers navigate these transitions effectively, we propose a genetic-algorithm-based optimization engine to search for a worker's optimal career pathway in a network of occupations, given their current knowledge, skills, abilities, and other work-related characteristics. Overall, this thesis presents strategies for organizations to mitigate bias in AI-based recruitment and for workers to plan their career pathway in the face of unprecedented changes in the world of work.
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Title: Assessment of drinking water quality and related husbandry practices in North American zoos
Creator: Bohne, Christine E.
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Water is essential for life of all animals. However, drinking water might be of poor quality if it contains excess chemicals, nutrients or contaminants. Based on review of the scientific literature, the quality of drinking water in zoos has not been investigated.Therefore, objectives were to: 1) assess general quality of water in Association of Zoo and Aquarium zoos; 2) examine possible relationships among husbandry practices and water quality; and, 3) analyze iron concentrations in drinking...
Show moreWater is essential for life of all animals. However, drinking water might be of poor quality if it contains excess chemicals, nutrients or contaminants. Based on review of the scientific literature, the quality of drinking water in zoos has not been investigated.Therefore, objectives were to: 1) assess general quality of water in Association of Zoo and Aquarium zoos; 2) examine possible relationships among husbandry practices and water quality; and, 3) analyze iron concentrations in drinking water of zoos with black rhino. Forty zoos without and 10 with black rhino agreed to participate when randomly invited from a pool of 174 eligible zoos (29% response rate). Water samples were analyzed for pH, hardness, total dissolved solids, calcium, phosphorus, magnesium, potassium, sodium, iron, manganese, zinc, copper, chloride, sulfate, nitrate, total coliform, and Escherichia coli. A water quality index was used to rank overall quality among zoos. A questionnaire about husbandry practices and drinking water also was completed by a subsample of zoos (n = 39). Over 85% of zoos used municipal water primarily. Three of 50 zoos (above the 90th percentile) had poor quality water. Majority (59%) of zoos responded that drinking water quality was considered in nutritional management. However, only 18% routinely analyzed drinking water. Zoos with Black Rhino were aware of the recommendation to formulate for low dietary iron to reduce Iron Overload Disorder. However, only 2 of 8 zoos with Black Rhino routinely analyzed drinking water for iron.
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Title: Movements of bonefish (Albula spp.) in the Bahamas : multiple migration routes and associated environmental cues
Creator: Burruss, Georgiana Marchant
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Migration, whether for the purpose of predator avoidance, foraging, or reproduction, results in the movement of individuals from one habitat to another spatially distinct habitat. Many tropical marine fishes migrate from foraging grounds to form spawning aggregations that are spatially and temporally distinct, highlighting a critical time and area for fish reproduction. In The Bahamas, bonefish (Albula vulpes) form spawning aggregations, migrating from nearshore flats and mangrove creeks to...
Show moreMigration, whether for the purpose of predator avoidance, foraging, or reproduction, results in the movement of individuals from one habitat to another spatially distinct habitat. Many tropical marine fishes migrate from foraging grounds to form spawning aggregations that are spatially and temporally distinct, highlighting a critical time and area for fish reproduction. In The Bahamas, bonefish (Albula vulpes) form spawning aggregations, migrating from nearshore flats and mangrove creeks to deep water shelf edges to spawn. Bonefish support a catch-and-release recreational fishery valued at approximately $141 million USD annually in The Bahamas. To manage and protect this economically-important fishery, the purpose of this thesis was to identify and describe migration patterns of bonefish on the Bahamian island of Eleuthera. Six spawning aggregation sites on four Bahamian islands have been identified, but recent findings indicate that islands may support multiple migration routes and aggregation sites. From 2015 to 2017, 78 bonefish were tagged in 11 main foraging grounds across five regions on Eleuthera and tracked using broad-scale acoustic telemetry arrays. This study identified four new migration routes and aggregation sites on Eleuthera. Migration routes on Eleuthera were shorter than those documented on other Bahamian islands and bonefish made repeated migrations throughout the study period. Bonefish migrated between October and June; migration activity was correlated with the first half of the lunar cycle, high tidal range, colder temperatures, and calm weather. The areas identified in this study should be protected from development and fishing pressures to ensure future reproductive success of bonefish in The Bahamas.
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Title: Environmental controls on phenoregions across an East African megatransect
Creator: Desanker, Gloria
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Semi-arid and savanna-type (SAST) systems in East Africa have unique plant species compositions and characteristics that make quantifying this area's seasonality and inter-annual variability difficult. Phenoregion classification offers a way to use seasonality of vegetation growth dynamics to help understand the phenology of complex landscapes. Here, we used Normalized Difference Vegetation Index (NDVI) time series from the Landsat 8 imagery to map phenoregions in scenes centered around...
Show moreSemi-arid and savanna-type (SAST) systems in East Africa have unique plant species compositions and characteristics that make quantifying this area's seasonality and inter-annual variability difficult. Phenoregion classification offers a way to use seasonality of vegetation growth dynamics to help understand the phenology of complex landscapes. Here, we used Normalized Difference Vegetation Index (NDVI) time series from the Landsat 8 imagery to map phenoregions in scenes centered around national parks from Mt. Kenya National Park (Kenya) to Limpopo National Park (Mozambique) to assess whether landscape-scale controls on phenology are consistent across the region or if they differ on a latitudinal gradient. We used MODIS Land Cover to assess land cover composition in each phenoregion, and discriminant analysis to determine the role that elevation, slope and aspect play in driving phenological differences. There was no clear latitudinal pattern seen in land cover or geologic composition. Most of the site's phenoregions showed no unique composition of either of the variables, meaning that land cover or geology type did not help in differentiating phenoregions. The discriminant analysis showed that topography was a strong predictor of many of the phenoregions, however, these also did not reveal any clear latitudinal pattern. Using seasonality of the NDVI time series to generate phenoregions provides different and even in some cases more ecologically relevant information, compared to past studies that use only land cover to generate ecoregions. With a significant population of humans and animals that live in and depend on SAST ecosystems, it is important to better understand vegetation processes and the factors that affect them as climate change becomes an increasingly pertinent issue in dry systems.
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Title: Seeking or encountering news on the Web : the role of need for cognition and need to evaluate
Creator: Lee, Heysung
Date: 2017
Collection: Electronic Theses & Dissertations
Description: Previous literature has dealt with news consumption patterns on the web, but not many attempts have done to clarify individual differences by focusing on a role of personality variables. This study suggests that high need for cognition will lead digital news consumers to actively seek out news websites to get political information, whereas low need for cognition will lead them to passively encounter political news on social media. The results of the online survey indicate that need for...
Show morePrevious literature has dealt with news consumption patterns on the web, but not many attempts have done to clarify individual differences by focusing on a role of personality variables. This study suggests that high need for cognition will lead digital news consumers to actively seek out news websites to get political information, whereas low need for cognition will lead them to passively encounter political news on social media. The results of the online survey indicate that need for cognition does not predict news consumption on the web, but only need to evaluate positively correlates to news website usage. Also, both variables positively correlate to active sharing and commenting on political information in social media, attention to political news, and political knowledge. -- Abstract.
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Title: A study of depraved appetite in dairy cattle
Creator: Taylor, George E.
Date: 1925
Collection: Electronic Theses & Dissertations

Title: Tenancy in Michigan
Creator: Behrens, Oscar W.
Date: 1925
Collection: Electronic Theses & Dissertations

Title: Fruit bud differentiation & growing habits in certain types of strawberries
Creator: Waldo, George F. (George Fordyce), 1898-
Date: 1926
Collection: Electronic Theses & Dissertations

Title: Exploring the potential of the biological control agent Hypena opulenta (Christoph) (Lepidoptera : Erebidae) at controlling invasive swallow-wort vines in Michigan and its indirect effects on monarch butterflies
Creator: Alred, Brianna Joy
Date: 2021
Collection: Electronic Theses & Dissertations
Description: This thesis focuses on swallow-wort, an invasive vine related to milkweeds, and the potential of Hypena opulenta for providing biological control in Michigan, as well as the indirect effects that the introduction of H. opulenta may have on the monarch butterfly. The first chapter covers the background of swallow-wort in its invasive range and outlines previous research done with H. opulenta in the United States and Canada.In the second chapter, the impact and the phenology of H. opulenta on...
Show moreThis thesis focuses on swallow-wort, an invasive vine related to milkweeds, and the potential of Hypena opulenta for providing biological control in Michigan, as well as the indirect effects that the introduction of H. opulenta may have on the monarch butterfly. The first chapter covers the background of swallow-wort in its invasive range and outlines previous research done with H. opulenta in the United States and Canada.In the second chapter, the impact and the phenology of H. opulenta on black swallow-worts in Michigan is examined in common garden experiments. Swallow-wort survival and reproductive output are measured and compared when different adult densities are released in one study. The second study assessed the phenology of H. opulenta when releases took place at different dates either in sunny or shaded sites. In southern Michigan, H. opulenta is found to produce two generations per season, though overwintering could not be confirmed. Damage caused by larval feeding was higher in the shade but was not enough to reduce plant fitness regardless of release size or light availability. Swallow-worts can serve as oviposition sinks for monarchs, however, the presence of H. opulenta larvae may serve as an oviposition deterrent. Examination of the indirect effects of H. opulenta on monarch butterflies in the third chapter found no evidence that H. opulenta deters monarch oviposition. In addition, the utilization of swallow-wort by wild monarch butterflies as an oviposition host in Michigan was confirmed.
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Title: “IN A NEW NORMAL SITUATION, A NEW APPROACH” : MID-PANDEMIC EFL TEACHER PERSPECTIVES ON IMPLEMENTING TASK-BASED LANGUAGE TEACHING IN EAP COURSES
Creator: Siddiqui, Tamoha Binte
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Scarce research exists with regards to TBLT implementation in EAP courses, especially those courses held in EFL settings. Hence, this study explores the extent to which EAP teachers from an EFL country, Bangladesh, hold beliefs that align with core TBLT principles, as well as their levels of receptiveness to using tasks in the classroom. In this mixed methods study, data was collected from 30 tertiary-level EAP teachers in Bangladesh using a questionnaire survey and follow-up interviews. A...
Show moreScarce research exists with regards to TBLT implementation in EAP courses, especially those courses held in EFL settings. Hence, this study explores the extent to which EAP teachers from an EFL country, Bangladesh, hold beliefs that align with core TBLT principles, as well as their levels of receptiveness to using tasks in the classroom. In this mixed methods study, data was collected from 30 tertiary-level EAP teachers in Bangladesh using a questionnaire survey and follow-up interviews. A convergent mixed methods analysis was used to triangulate the data and verify the findings. Results showed that participants agreed with core TBLT principles from a moderate to high level, and consistently favored use of tasks over traditional activities. Moreover, teacher beliefs and practices seem to have become further aligned with core TBLT tenets in light of the COVID-19 pandemic and subsequent shift to online teaching. I conclude the study by highlighting a number of implications for EFL teaching contexts. Additionally, I suggest that teacher and student autonomy need to be nurtured not only during curriculum development and implementation, but also in theoretical and research design.
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Title: The effect of alcoholic solutions on the thermo-mechanical properties of poly (lactic acid)
Creator: Xu, Dian
Date: 2021
Collection: Electronic Theses & Dissertations
Description: The effects of aqueous and deuterium oxide solutions of straight-chain alcohols with one to four carbon atoms on the thermo-mechanical properties of poly(lactic acid) – PLA – films were assessed by dynamic mechanical analysis (DMA). The glass transition temperature (Tg) of PLA films immersed in 25%, 50%, 75%, and 100% (v/v) alcoholic solutions were compared with the Tg’s of films immersed in 100% HPLC water and deuterium oxide. The Tg’s of PLA films immersed in methanol and ethanol (one to...
Show moreThe effects of aqueous and deuterium oxide solutions of straight-chain alcohols with one to four carbon atoms on the thermo-mechanical properties of poly(lactic acid) – PLA – films were assessed by dynamic mechanical analysis (DMA). The glass transition temperature (Tg) of PLA films immersed in 25%, 50%, 75%, and 100% (v/v) alcoholic solutions were compared with the Tg’s of films immersed in 100% HPLC water and deuterium oxide. The Tg’s of PLA films immersed in methanol and ethanol (one to two carbon atoms) aqueous solutions decreased as the concentration of the alcohol solutions increased. For methanol and ethanol, the Tg’s decreased by 8.6 °C and 7.6 °C per every 25% (v/v) increase of alcohol, respectively. When the PLA films were immersed in alcohol solutions with three to four carbon atoms, the Tg’s reduced until 75% (v/v). Tg’s of PLA films immersed in 1-propanol and 2-propanol decreased by 8.6 °C and 8.9 °C for every 25% increase of propanol, respectively. Aqueous and deuterium oxide solutions had similar effects on Tg. The sorption amount of ethanol in PLA films at 40 °C was measured by quantitative proton nuclear magnetic resonance (1H-qNMR). PLA films experienced the most significant sorption amount of ethanol (9.16%) at 4 h of immersion. The crystallinity (Xc) of PLA immersed in ethanol in the first 12 h, was less than 3%. When the time reached 24 h, the Xc exceeded 20%, and after 48 h stabilized at about 30% meanwhile the ethanol sorption stabilized at around 5%. The results of this work help in the development of PLA films needed to be in contact with aqueous-alcoholic solutions.
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Title: UNDERSTANDING THE ROLES OF INTERKINGDOM MICROBIAL INTERACTIONS, MICROBIAL TRAITS, AND HOST FACTORS IN THE ASSEMBLY OF PLANT MICROBIOMES
Creator: Liber, Julian Aaron
Date: 2021
Collection: Electronic Theses & Dissertations
Description: The community of organisms that associate with plants are vital to both the survival of the host plant but also the diseases which may kill it. The processes by which this community, called the microbiome, assemble and function can contribute to the traits of the host, including plants that humans rely on for food, resources, and ecosystems services. This thesis focuses on understanding the assembly of microbiomes at the scale of microbe-microbe interactions and traits of individual microbes,...
Show moreThe community of organisms that associate with plants are vital to both the survival of the host plant but also the diseases which may kill it. The processes by which this community, called the microbiome, assemble and function can contribute to the traits of the host, including plants that humans rely on for food, resources, and ecosystems services. This thesis focuses on understanding the assembly of microbiomes at the scale of microbe-microbe interactions and traits of individual microbes, as well as how characters of the host may change this process. I first address this by examining the in vitro and in planta interactions within small synthetic communities of root-inhabiting bacteria and fungi and with the plant host and viral disease of the host. While intermicrobial interactions in vitro were not predictive of in planta interactions, adding host disease or additional organisms to the system altered the assembly process. I then show the development and applications of the CONSTAX2 classifier, a taxonomic assignment tool for metabarcoding studies, which offers improved accuracy and ease of use for conducting metabarcoding studies exploring the diversity and structure of microbial communities. Last, I present a study testing which factors affected the composition of forest fungal communities to understand the ecology of litter-inhabiting fungi and improve methodologies for sampling leaf-associated fungal communities. The factors affecting the assembly of plant microbiomes are complex and varied but connecting individual interactions to community composition and ultimately function may improve our abilities to predict and manage microbiome processes.
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Title: EFFECTS OF NUTRIENT MANAGEMENT STRATEGIES ON DRY MATTER AND GRAIN YIELD OF SOYBEAN AND DRY BEAN CROPPING SYSTEMS
Creator: Terwillegar, Christian Raymond
Date: 2021
Collection: Electronic Theses & Dissertations
Description: Increases in soybean (Glycine max L. Merr.) grain yield can be partially attributed to greater total dry matter (TDM) accumulation, but the relationship between dry matter (DM) accumulation and nutrient uptake across irrigated and non-irrigated conditions remains uncertain. Two multi-year trials investigated soybean dry matter and nutrient accumulation and partitioning, grain yield, and net economic return across multiple seeding rates and fertilizer strategies. The 148,000 seeds ha-1 rate...
Show moreIncreases in soybean (Glycine max L. Merr.) grain yield can be partially attributed to greater total dry matter (TDM) accumulation, but the relationship between dry matter (DM) accumulation and nutrient uptake across irrigated and non-irrigated conditions remains uncertain. Two multi-year trials investigated soybean dry matter and nutrient accumulation and partitioning, grain yield, and net economic return across multiple seeding rates and fertilizer strategies. The 148,000 seeds ha-1 rate significantly decreased yield in two of four site-years but no differences occurred at the remaining two site-years. Fertilizer strategies did not interact with seeding rate to influence grain yield across all site-years. When contemplating fertilizer application strategies, soil test values should still be the first factor considered. Greater grain yield potential from improved dry bean (Phaseolus vulgaris L.) varieties coupled with potential decreases in soil sulfur (S) supply may have affected the likelihood of a grain yield response to nitrogen (N) and sulfur application. Three multi-year trials were established in Michigan to evaluate nitrogen rate, sulfur rate, and sulfur source on dry bean growth and grain yield. Nitrogen and S application including S source did not improve grain yield or interact with variety to affect grain yield across site-years. Other factors including plant nodulation, biomass, and residual nitrate after harvest were affected by N or S treatments. Nutrient application, especially N, may still be required but in nominal quantities to account for the variable June planting conditions of this shorter-season cropping system. Sulfur applications may be better suited for more N-responsive crops within the dry bean cropping rotation.
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