Physical Sciences and Mathematics Commons^™

Modifying A Cow-Calf Biophysical Simulation Model For Analyses Of Alternative Enterprises, Jennifer L. Lutes

Graduate Theses and Dissertations

Cow-calf producers in the United States, tasked with providing beef calves for the beef industry, have had a multitude of difficulties to overcome in recent years. Producers in northwest Arkansas were negatively impacted by high hay prices coupled with low beef cattle market prices due to severe drought experienced in portions of 2010, 2011, and 2012. During this time they also faced high grain prices, due to a record low harvest, combined with portions of the corn harvest diverted from human and animal feed to ethanol production. Tight lending policies of this time, reminiscent of the housing market crash in …

Switchgrass Cultivar, Harvest Frequency, Fertilizer Source, And Irrigation Effects On Near-Surface Soil Properties In West-Central Arkansas, Alayna A. Jacobs

Graduate Theses and Dissertations

Switchgrass (Panicum virgatum L.) has been identified as a model bioenergy feedstock crop and is expected to become an important feedstock for future renewable fuel generation. Agronomic management combinations that maximize monoculture switchgrass yield are generally well understood; however, little is known about corresponding effects of differing switchgrass management combinations on near-surface soil properties. The objective of this research was to determine the residual near-surface soil property effects of three years (2008 to 2011) of consistent management combinations to maximize switchgrass biomass production, including cultivar (‘Alamo’ and ‘Cave-in-Rock’), harvest frequency (1-cut and 2-cut systems per year), fertilizer source (poultry …

Carbon Dioxide Emissions From Switchgrass And Cottonwood Grown As Bioenergy Crops In The Lower Mississippi Alluvial Valley, Michele Lea Helton

Graduate Theses and Dissertations

Marginal land of the Lower Mississippi Alluvial Valley (LMAV) has the potential to be utilized for the production of bioenergy feedstocks. Soil respiration is the gaseous emission of carbon dioxide (CO₂) from microbes and plant roots in the soil, and these emissions play an important role in the global cycling of carbon. Soil respiration can act as a positive feedback affecting climate change, and has been shown to vary depending on soil moisture, temperature, and vegetation. The objectives of this study where to evaluate the effects of land use [switchgrass (Panicum virgatum), cottonwood (Populus deltoides …

Improving Methods For The Successful Establishment Of Switchgrass, Whitney Marie Monin

Theses and Dissertations--Plant and Soil Sciences

Our research investigated whether priming switchgrass seeds with water or ethephon would increase stand establishment in the field. ‘Alamo’ seed germinated faster and grew taller than ‘Cave-in-Rock.Seeds primed for six days in water or for one day in ethephon 10 mM had the greatest seedling densities. In growth chamber environments seed priming were tested to hasten germination velocity. Seeds primed for two, four or six days in water germinated faster than unprimed seeds. Ethephon treatments reduced overall germination and germination velocity. Accent and Accent Q herbicides containing nicosulfuron are used to control weeds. To test ‘Alamo’ sensitivity to these herbicides, …

An Analysis Of The Impact Of Storage Temperature, Moisture Content & Duration Upon The Chemical Components & Bioprocessing Of Lignocellulosic Biomass, Arun Athmanathan

Open Access Dissertations

The successful utilization of lignocellulosic biomass as a feedstock for fuels and chemicals necessitates storage for 2-6 months. It is correspondingly important to understand the impact of storage parameters - moisture concentration, temperature and duration - on biomass quality.

As aerobic storage is the most viable large-scale solution, aerobic storage experiments were carried out with three projected bioenergy feedstocks - sweet sorghum (Sorghum bicolor) bagasse, corn (Zea mays) stover and switchgrass (Panicum virgatum). Stored samples of each were examined for dry matter loss and composition change to develop a material balance around carbohydrates and lignin.

A mean dry matter loss …

Swat Model Simulation Of Bioenergy Crop Impacts In A Tile-Drained Watershed, Chelsie Marie Werling Boles

Open Access Theses

Tile drains are an important component of agricultural production in the Midwest, and their inclusion in modeling studies is important in watersheds where they are a principal hydrologic pathway. The new tile drainage simulation method in the Soil Water Assessment Tool (SWAT) was parameterized and tile flow results were compared with reviewed literature. Streamflow, sediment, and nutrient outputs were compared to measured values and simulated crop yields were examined with respect to average county yields. Plant growth stressors were examined to account for differences between simulated and published yields. The bioenergy crop switchgrass (Panicum virgatum) was applied over …

Multiple Criteria Decision Analysis For The Selection Of A Land Use Impact Method For A Life Cycle Assessment Of Switchgrass As A Bioenergy Feedstock In The Pee Dee Region Of South Carolina, Joel Kohn

All Theses

The interactions of a growing human population and increasing demand for food and energy have led to governmental and social pressures encouraging the adoption of biofuels as a substitute for fossil energy sources; however, several potential biofuel feedstocks can compete directly with food products for valuable land area. Life Cycle Assessment (LCA) is a tool that examines the environmental impacts of a product or process and can assist decision makers in the development of policy. The environmental impacts of land use are not well incorporated into LCA. As an emerging field, there is no consensus regarding the best methods by …

Consumer Willingness To Pay For E85, Denise A. Skahan

Masters Theses

Concerns regarding energy security, resource sustainability, and environmental protection have heightened interests in renewable fuels and sparked the research and development of ethanol as a transportation fuel. This study examines consumers’ willingness to pay for ethanol from various potential feedstocks; corn, switchgrass and wood wastes. Data was collected via a survey of fuel consumers across the United States in 2009. Results show that consumers have a preference for E85 (a fuel blend with 85 percent ethanol and 15 percent gasoline) from corn, switchgrass and wood wastes compared to E0 (gasoline) and a preference for E85 from switchgrass and wood wastes, …