Physical Sciences and Mathematics Commons^™

Viability Of Wetland Crops For Use In Treatment Wetlands: Nitrogen Removal From Water And Production Of Food, Andrew Denson Corder

Theses and Dissertations

Treatment wetlands are used to treat wastewater from a variety of sources, but their functionality depends on the macrophytes present therein. To better understand the viability of wetland macrophytes both as sources of food and as agents of nitrogen removal from wastewater, this study quantified plant growth, food production, and nitrogen removal capacity of three common wetland crops as well as three locally dominant graminoid species in a variety of relevant ecological contexts. All six plant species and a control were grown over a ten-week period in three related experiments: (1) under three moisture regimes, (2) with or without competition …

Development Of A Tunable Platform For The Study Of Geomacromolecular Matrices Using Controlled Radical Polymerization, Arjun Pandey

LSU Doctoral Dissertations

Soil is an important environmental component, and the study of soil processes have many practical implications such as improvement in agriculture, mitigation of climate change etc. The widespread use of Agricultural Chemicals (ACs) in modern agriculture has resulted in adverse effects in environment and human health mostly through contamination into food and water sources. Study of fate, bioavailability, and transport of ACs involves molecular level understanding of their interactions with soil. This can be challenging due to complex and heterogeneous nature of soil. One common approach used is the correlation of macroscopic properties of soil, (e.g. sorption) with empirical parameters …

On The Path To A Resilient Urban Food System In A Rural State: A Mixed-Method Needs Assessment Of Urban Producers And County Extension Agents In Arkansas, Catherine Elizabeth Dobbins

Graduate Theses and Dissertations

This project utilized a mixed-method needs assessment approach to urban agriculture in Arkansas, a predominately-rural state. Chapter II was a qualitative study, using semi-structured, in-depth interviews, that investigated the perceptions, needs, and experiences of Arkansas urban farmers and their interactions with the University of Arkansas Division of Agriculture Cooperative Extension Service (CES). Interviews were conducted with 16 urban farmers in Northwest and Central Arkansas. The interview data revealed individualized needs based on the size, years in operation, and mission of each urban farmer interviewed. General needs were determined, such as market pricing, co-ops, and access to appropriate equipment, but generally …

Application Of Semi-Hydrophobic Layers To Decrease Bare Soil Evaporation, Jesse Lee Barnes

UNLV Theses, Dissertations, Professional Papers, and Capstones

Evaporative water loss from bare agricultural soils is a primary area of water conservation research. Mulching is the commonly utilized method to decrease evaporative water loss. The most commonly utilized mulch is nonbiodegradable polyethylene sheeting because it tends to decrease evaporative water loss and increase crop yields more than environmentally friendly mulches. This study aimed to test the utility of sand coated with polymerized soybean oil (i.e., hydrophobic sand) as a treatment to reduce bare soil evaporation and an alternative to current practices. Evaporation rates were measured in laboratory soil columns containing both treated and untreated soils. Treatment parameters were …

Producer Preferences For Alternative Irrigation Practices In The Arkansas Delta, Robert Edward Rosene

Graduate Theses and Dissertations

We use a bivariate sample selection model to address peer network effects on participation in and/or intensity of use of land being irrigated by alternative irrigation practices in the state of Arkansas. As groundwater in the state becomes more limited, the use of scientific scheduling, flowmeters, and more efficient row crop water application systems will allow producers to better manage water resources. We find relatively large, positive relationships between belonging to a peer network of the same irrigation practice and participation in that practice. Intensity of use of alternative irrigation techniques is mostly influenced by which crop type the practice …

Green Energy At Any Cost: How Ethanol Producer Magazine Uses Science To Frame Ethanol Production, Ashley Kappers

Theses and Dissertations

This thesis investigates the use of science by media to shape discussions about policy in society. Specifically, it investigates how one influential trade publication, Ethanol Producer Magazine, used science in its construction of pro-ethanol production stories. This study is a multi-method analysis of Ethanol Producer Magazine’s feature articles. To determine how sources and writers use science to frame ethanol production during policy changes in the industry, 36 feature stories from four issues in 2009 and 2010 of Ethanol Producer Magazine were analyzed. The results of this study found that Ethanol Producer Magazine is a publication that presents one side of …

Effectiveness Of Windrow Composting Methodology In Killing A Thermo-Tolerant Species Of Salmonella During Mortality Composting, Spencer Gabriel Myers

Master's Theses

In a large agricultural operation, such as the one at Cal Poly San Luis Obispo, disposal of deceased animals is an immense issue. The cost of transporting and rendering every dead animal is inhibitory to the general function of the agricultural operations and their thin budget. Therefore, we propose that composting mortalities could be an economical alternative. Composting is a recognized method for taking animal waste products along with carbon waste and turning it into a pathogen-free, nutrient-rich topsoil. Carcass composting is in fact performed in other countries and states to varying degrees of success. However, the California EPA limits …

Farm To Label: A Critique Of Consumer Activism In The Sustainable Food Movement, Olivia Whitener

Pomona Senior Theses

“Local,” “organic,” “natural,” and “Fairtrade” are just several of the many claims adorning the food products that line grocery store shelves. These promises of environmental sustainability and social responsibility are pillars of the “good food revolution” sweeping the nation as consumers demand alternatives to the products of the industrial food system. Green consumerism, the premise that consumer demand for environmentally sustainable goods will bring about ecologically beneficial outcomes, is at the heart of the sustainable food movement. This thesis takes a critical look at the operation of green consumerism in the food system. It explores the ideology and shortcomings of …

Conservation Agriculture In The Heartland: Farmer Perceptions Of Soil Health And The Adoption Of Cover Crops, Lillian Clarissa Cobo

Graduate Research Theses & Dissertations

The benefits of cover crops are widely recognized by those interested in conservation agriculture and soil health. These benefits include soil erosion control, nutrient loss reduction, and overall improvement of soil health. However, while these benefits are well-documented, the adoption rate of cover crops in the American Heartland remains astoundingly low. While some studies have attempted to determine the reasons for this low adoption rate, the information relating to how farmer perceptions of soil health impact cover crop adoption is almost nonexistent. Furthermore, there is a clear absence of mixed method studies in the literature relating to this subject. This …

Utilization Of Various Methods And A Landsat Ndvi/Google Earth Engine Product For Classifying Irrigated Land Cover, Andrew Nemecek

Graduate Student Theses, Dissertations, & Professional Papers

Methods for classifying irrigated land cover are often complex and not quickly reproducible. Further, moderate resolution time-series datasets have been consistently utilized to produce irrigated land cover products over the past decade, and the body of irrigation classification literature contains no examples of subclassification of irrigated land cover by irrigation method. Creation of geospatial irrigated land cover products with higher resolution datasets could improve reliability, and subclassification of irrigation by method could provide better information for hydrologists and climatologists attempting to model the role of irrigation in the surface-ground water cycle and the water-energy balance. This study summarizes a simple, …

Shizen Nōhō: Restoring The Relationship Between Food, Nature, And People In Japan, Katharine Graham

Scripps Senior Theses

In Japan’s postwar era, agriculture has become highly industrialized, involving heavy machinery, chemical fertilizers, and pesticides, all in the name of “progress.” Through employing such practices, humans have attempted to improve upon nature’s way of doing things, and in turn have degraded the soil’s fertility, natural ecosystems, and human health. In response to this, Shizen Nōhō has emerged in Japan as an alternative way of cultivating food. Shizen Nōhō practitioners challenge the notion that we need chemical fertilizers, pesticides, and machinery to farm successfully. Rather, they advocate for a way of growing food that functions seamlessly with natural ecosystems. This …

Local Farmer Knowledge Of Adaptive Management On Diversified Vegetable And Berry Farms In The Northeastern Us, Alissa White

Graduate College Dissertations and Theses

Agricultural adaptation to climate change is notoriously context specific. Recently updated projections for the Northeastern US forecast increasingly severe and erratic precipitation events which pose significant risks to every sector of agricultural production in the region. Vegetable and berry farmers are among the most vulnerable to the risks of severe precipitation and drought due to the intensive soil and crop management strategies which characterize of this kind of production. To successfully adapt to a changing climate, these farmers need information which is tailored for the unique challenges of vegetable and berry production, framed at the level of climate impacts, and …

Modeling Agricultural Outcomes In A Warmer, Wetter Vermont, Rachel Mason

Graduate College Dissertations and Theses

This thesis aimed to model agricultural outcomes that are important to Vermont dairy farms and their surrounding communities -- runoff, erosion, nitrogen and phosphorus losses, crop yields, and timeliness of farm operations -- under a set of possible future climates. The Agricultural Policy/Environmental eXtender (APEX) model was used for this work, and the models were calibrated using data from a project that measured most of these outcomes on a set of local farms. The model setup and calibration methodology is thoroughly documented and may be a useful starting point for others who are new to agricultural modeling.

Applied to two …

Through The Eyes Of Locals: A Changing Climate In Bolivia, Jacob D. Rex

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Deforestation and Agricultural Land-Use Change in Bolivia as a Function of Socio-Economic Realities.

This research combines semi-structured interviews of key informants and local participants, as well as field observations, which were conducted between January and April of 2019 in the Departments of Santa Cruz & Chuquisaca.

Residual Soil Phosphorus In Tropical Oxisols: An Opportunity To Enhance Fertilizer Use Efficiency?, Lauren Bomeisl

Graduate College Dissertations and Theses

Phosphorus (P) is essential to life on Earth and often the limiting nutrient in agricultural systems. P fertilizer is thus an essential resource to maintain food security. In the last half century, agricultural intensification has led to an increase in P fertilizer consumption from 4.6 to 17.5 Tg of P/year to meet rising global food demand. Mineral P (i.e., phosphate rock) is a non-renewable resource in the context of the Anthropocene, and its price is vulnerable to global market fluctuations. Increased efficiency of P use on farms is considered the most effective strategy to conserve P. The soybean industry demands …

Governing Water Quality Limits In Agricultural Watersheds, Courtney Ryder Hammond Wagner

Graduate College Dissertations and Theses

The diffuse runoff of agricultural nutrients, also called agricultural nonpoint source pollution (NPS), is a widespread threat to freshwater resources. Despite decades of research into the processes of eutrophication and agricultural nutrient management, social, economic, and political barriers have slowed progress towards improving water quality. A critical challenge to managing agricultural NPS pollution is motivating landowners to act against their individual farm production incentives in response to distant ecological impacts. The complexity of governing the social-ecological system requires improved understanding of how policy shapes farmer behavior to improve the state of water quality. This dissertation contributes both theoretically and empirically …

Consumer Support For Renewable Energy Systems: A Case Study Of Community Biodigesters In Vermont, Katelynn Maria Conedera

Graduate College Dissertations and Theses

From the steady rise in dairy farm closures to concerns over algae blooms in Lake Champlain, Vermont’s dairy industry is facing a multitude of challenges. While many potential solutions have been proposed, this study focuses specifically on community anaerobic digester systems (CADS) to aid in manure management, help to mitigate runoff, produce renew energy, and even provide an alternative revenue source to participating farms. CADS technology converts the gas emissions from manure and other organic substances into biogas through a process called anaerobic digestion. Unlike traditional on-farm biodigesters, which are often only financially viable for the largest dairy farms, CADS …

On The Application Of Computational Modeling To Complex Food Systems Issues, Serge William Wiltshire

Graduate College Dissertations and Theses

Transdisciplinary food systems research aims to merge insights from multiple fields, often revealing confounding, complex interactions. Computational modeling offers a means to discover patterns and formulate novel solutions to such systems-level problems. The best models serve as hubs—or boundary objects—which ground and unify a collaborative, iterative, and transdisciplinary process of stakeholder engagement. This dissertation demonstrates the application of agent-based modeling, network analytics, and evolutionary computational optimization to the pressing food systems problem areas of livestock epidemiology and global food security. It is comprised of a methodological introduction, an executive summary, three journal-article formatted chapters, and an overarching discussion section.

Chapter …

Diversifying Cornfields By Interseeding Cover Crops: Practical Implications And The Response Of Invertebrate Communities, Michael Bredeson

Electronic Theses and Dissertations

The lack of suitable habitat conditions for beneficial organisms in simplified agroecosystems leads to unstable invertebrate communities and overreliance on chemical control of herbivores. It is possible to manage pest populations without agrichemicals by manipulating farmland so that herbivores are impaired by plant-driven bottom-up and enemy-driven top-down antagonisms. Interseeding cover crops between established crop rows is a method used by farmers to improve habitat suitability for natural enemies and hinder host-finding, feeding and movement by herbivores. Here I address three important research gaps related to interseeding cover crops. A calcium carbonate seed coating, used to improve seed-broadcasting efficiency, was tested …