Life Sciences Commons^™

Environmental Tradeoffs In Bioenergy Production And Agricultural Practices, Alicia Lynn English

Open Access Dissertations

The focus of this dissertation is the environmental tradeoffs of stover removal within the Corn Belt. The environmental tradeoffs considered are mainly concerned with managing soil erosion and soil quality. The analysis layers soil characteristics, management strategies and per acre costs using an integrated RUSLE2/WEPS model and an economic optimization model to illuminate a lower bound supply response. Different assumptions were tested in regards to sustainability, prices, and market integration for five states and 18,760 soil types throughout the Corn Belt. Sustainability was defined to limit soil erosion from wind and water to 5 tons/acre/year and the soil organic matter …

Management Of Potato Leafhopper And Maple Spider Mite On Nursery Grown Maples, Julia Prado Beltran

Open Access Dissertations

Potato leafhopper Empoasca fabae (Harris) (Homoptera: Cicadellidae) and maple spider mite Oligonychus aceris (Shimer) (Acarina: Tetranychidae) are important pests of maple trees. Investigations determined how insecticide use and fertilization impacted the abundance of E. fabae and O. aceris on `Red Sunset' red maple and `Autumn Blaze' Freeman maples. Bifenthrin applications directed against leafhoppers reduced damage to both cultivars, but increased O. aceris on Autumn Blaze. Using a threshold of one leafhopper per branch to trigger pesticide applications protected Red Sunset maples from leafhopper injury. It also prevented outbreaks of O. aceris on Autumn Blaze because few trees reached this density. …

The Role Of Soil Microorganisms In The Resistance Of Giant Ragweed, Horseweed, And Common Lambsquarters To Glyphosate, Jessica Renee Schafer-Bugg

Open Access Dissertations

Continuous glyphosate use has contributed to an increasing number of problematic glyphosate-resistant (GR) weeds. The mechanism of resistance in many GR weeds is poorly understood, in part, due to a poor understanding of how exactly glyphosate kills a plant. In previous research, the efficacy of glyphosate was demonstrated to be strongly influenced by root invading soil-borne microorganisms. However, this interaction among plants, glyphosate, and soil microorganisms has only been studied in a number of crop plants, but not in weed species. This is surprising since the soil biotic environment has a strong impact on the activity of this important herbicide. …

Impacts And Feasibility Of The Us And The Eu Sustainability Criteria On Existing Land-Use Practices, Krissana Treesilvattanakul

Open Access Dissertations

Several studies have examined the land use and economic consequences of national and multi-national biofuel policies. They explored the impacts of biofuels mandates mainly based on the quantitative biofuel targets. However, the recently updated renewable policies of the United States and the European Union, which are the US Renewable Fuel Standard (RFS) and EU Directive 2009/28 of the Renewable Energy Directive (RED) both place restrictions on land that can be used to produce biofuel, and these restrictions are generally known as sustainability criteria. This research aims to determine to what extent sustainability criteria are actually binding; that is, would they …

Genes With Physiological Roles In Callipyge Muscle Hypertrophy, Hui Yu

Open Access Dissertations

Callipyge sheep is an excellent model to study genes regulation in muscle growth since the up-regulation of DLK1 and/or RTL1 results in extreme postnatal muscle hypertrophy in loin and hindquarters. DLK1 and/or RTL1 are the primary inducers of muscle hypertrophy due to the inheritance model for the callipyge phenotype. The overall aim of this dissertation is to study the physiological pathways responding to the up-regulation of DLK1 and / or RTL1 in the hypertrophied muscles. Microarray analysis of gene expression identified 375 genes that were differentially expressed in callipyge semimembranosus. Twenty-five transcripts were further verified by quantitative PCR in two …

Functional Characterization Of Metallothioneins In Arabidopsis And Barley, Nimnara Yookongkaew

Open Access Dissertations

Metalothioneins (MTs) are metal binding proteins that can bind metals such as Cu, Zn, and Cd but the functions of MTs in plants are largely unknown. To understand the function of MTs in Arabidopsis, T-DNA insertion mutants lacking 4 MT genes including MT1a, MT2a, MT2b and MT3 were developed. The quadruple mutant (mt1a/mt2a/mt2b/mt3) showed no visible phenotype under standard growth conditions. However, it accumulated higher Cu in leaves compared to wild type but lower Cu in seeds. Further analysis showed that triple mutants lacking both MT1a and MT2b, which are highly expressed in vascular tissues, had similar …

Welfare Impacts Of False Codling Moth Threatening California Oranges, Azza Mohamed Kamal Ahmed Mohamed

Open Access Dissertations

Welfare impacts of alternative pest management strategies of False Codling Moth (FCM) threatening California's oranges are examined. Different economic agents along the supply chain of fresh oranges and orange products in the United States are considered, including consumers, retailers, wholesalers, and growers. A partial equilibrium dynamic framework that accounts for supply response from the other US orange producing states is developed. Data for supply shocks (orange yield losses and control costs) are obtained from the Animal and Plant Health Inspection Service of the United States Department of Agriculture (APHIS).

FCM is not presently in the United States. If introduced to …

Three Essays On The Interaction Between Global Trade And Greenhouse Gas Mitigation Agreements, Zeynep Burcu Irfanoglu

Open Access Dissertations

The role of trade sanctions in enforcing greenhouse gas mitigation agreements is the fundamental theme of the three essays comprising this dissertation. All three essays employ a multi-sector, multi-region computable general equilibrium model, GTAP-AEZ-GHG, documented in Golub et al. (2009) to investigate how the United States can use trade sanctions as an enforcement mechanism in a global greenhouse gas (GHG) mitigation agreement. The focus is placed on inducing China to comply with the global agreement.

The first essay contributes to the body of knowledge on global GHG emissions mitigation agreements by investigating the range of emission taxes that can be …

Use Of Flame Cultivation As A Nonchemical Weed Control In Cranberry Cultivation, Katherine M. Ghantous

Open Access Dissertations

Cranberry (Vaccinium macrocarpon Ait.) is a woody perennial crop that can remain productive for decades. Competition for resources between cranberries and weeds can depress cranberry farm yields, resulting in large annual crop losses. Renewed interest in reducing chemical inputs into cranberry systems has provided the motivation to evaluate methods, such as flame cultivation (FC), as potential nonchemical options for weed control. Also known as thermal weeding, FC exposes plants to brief periods of high temperature that causes the water in the plant tissue to expand rapidly, rupturing plant cells and leading to necrosis. Various FC methods have been used …

Fate Of 17Α-Estradiol, 17Β-Estradiol, And Estrone In Agricultural Soils And Sediments, Michael L. Mashtare Jr

Open Access Dissertations

The shift to concentrated animal production facilities and increasing rural-urban migration has increased the localized land application of nearly 1 billion tons of manure and biosolids annually. Although these applications provide nutrients and contribute to soil tilth, they also serve as a source for an estimated 49 tons of the natural manure-borne estrogens, 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), and estrone (E1). While these estrogens are critical to endocrine systems, the low concentrations observed in the environment can disrupt endocrine function in non-target organisms, e.g., altering secondary sex characteristics which can lead to changes in wildlife communities.

Research presented here focuses on …