Physical Sciences and Mathematics Commons^™

Quantifying Terrestrial Ecosystem Carbon Dynamics With Mechanistically-Based Biogeochemistry Models And In Situ And Remotely Sensed Data, Shaoqing Liu

Open Access Dissertations

Terrestrial ecosystem plays a critical role in the global carbon cycle and climate system. Therefore, it is important to accurately quantify the carbon dynamics of terrestrial ecosystem under future climatic change condition. This dissertation evaluates the regional carbon dynamics by using upscaling approach, mechanistically-based biogeochemistry models and in situ and remotely sensed data.

The upscaling studies based on FLUXNET network has provided us the spatial and temporal pattern of the carbon fluxes but it fails to consider the atmospheric CO2 effect given its important physiological role in carbon assimilation. In the second chapter, we consider the effect of atmospheric CO2 …

A Study Of Short-Season Winter Cover Crops For Organic High Tunnel Production Systems, Luke Riley Freeman

Graduate Theses and Dissertations

This two-year study investigated short-season winter cover crops to improve soil quality and growth of subsequent vegetable crops in an organic high tunnel production system. Five winter cover crop treatments including a nontreated control, Austrian winter peas (Pisum arvense), bell beans (Vicia faba), mustard (Brassica juncea cv. Kodiak), and Daikon radish (Raphanus sativus var. longipinnatus) were grown in a high tunnel in a randomized complete block design from mid-November to mid-March, mowed and incorporated into the soil, and followed by a succession of vegetable crops including tomato (Lycopersicon lycopersicum, cv. ‘Plum Dandy’) and broccoli (Brassica oleracea var. italica, cv. ‘Bay …

Willingness To Pay For Irrigation Water Under Scarcity Conditions, Tyler Robert Knapp

Graduate Theses and Dissertations

Reliance of Arkansas agricultural producers on groundwater for irrigation has led to depletion of the Mississippi River Valley alluvial aquifer. Without intervention, consequences include insufficient groundwater to meet irrigation demand as well as drawdown of the deeper Sparta Aquifer, upon which communities in eastern Arkansas rely for non-agricultural use. Among proposed solutions to combat groundwater decline is the construction of off-farm surface water infrastructure to meet the irrigation needs of producers. Despite the importance of irrigated agriculture to Arkansas, there is little know about the economic value of irrigation water to producers. Thus, we implement a double-bounded dichotomous choice contingent …

Manufacturer Perspectives On Content Transparency And Material Health In The Us Building Products Industry, Alexandra A. Muller

Open Access Theses

Flawed U.S. federal regulation of chemicals has resulted in a materials market that undervalues human and environmental health in favor of the more traditional attributes of price, performance and aesthetics. In the building products industry, global, dynamic supply chains and proprietary information concerns further complicate the task of assessing the material health of products.

Voluntary material health programs in the green building industry are intended to incentivize the manufacture and selection of safer products by getting companies to gather and assess ingredient, hazard and risk information from their supply chain. Building product manufacturers considered early adopters of the main material …

Enhancing Silymarin Fractionation Via Molecular Modeling Using The Conductor-Like Screening Model For Real Solvents, Emma C. Brace

Open Access Theses

The market for bio-based products from plant sources is on the rise. There is a global challenge to implement environmentally clean practices for the production of fuels and pharmaceuticals from sustainable resources. A significant hurdle for discovery of comparable plant-derived products is the extensive volume of trial-and-error experimentation required. To alleviate the experimental burden, a quantum mechanics based molecular modeling approach known as the COnductor-like Screening Model for Real Solvents (COSMO-RS) was used to predict the best biphasic solvent system to purify silymarins from an aqueous mixture. Silymarins are a class of flavonolignans present in milk thistle ( Silybum marianum …

The Impact Of Climate Change In Bangladesh On The Rice Market And Farm Households, Mst Ashrafun Nahar

Graduate Theses and Dissertations

Bangladesh is trying to achieve self-sufficiency in domestic rice production but climate change effects on agricultural production makes it challenging to attain the goal. The country is highly vulnerable to the effects of climate change since it is the major cause to rise in sea level, more warm summer, and happening food and cyclone in the country.

This study develops an Aggregate Farm Household Model to analyze the impact of potential land loss and yield reduction from climate change on production, consumption, prices, welfare, and the ability of government to achieve self-sufficiency in rice production. The model is calibrated to …

Spread Trading In Corn Futures Market, Ryan D. Napier

Graduate Theses and Dissertations

The non-linear relationship between old crop – new crop year spreads in corn futures market and stock-to-use (S-U) ratios published by the United States Department of Agriculture is analyzed. Using a non-linear logarithmic smooth transition regression (LSTR) model, we capture asymmetric market behaviors in high and low S-U regimes. Capturing this relationship and understanding the non-linear aspects of the relationship is of interest of grain merchandizers and speculators in the market. A spread trading strategy is simulated for the sample period, January 1985 through April 2015, to determine if the non-linear relationship is a profitable arbitrage opportunity in the market.

Geospatial Analysis Of Droughts, Rice And Wheat Production, And Agrarian Vulnerability: A District-Level Study Of The Self-Calibrated Palmer Drought Severity Index In India, Aaron Michael Shew

Graduate Theses and Dissertations

Droughts have affected more people than any other natural disaster in the last century, causing billions in economic damages and millions of deaths. As the Sea Surface Temperatures (SST) have heated in the Indian Ocean, drought patterns across South Asia have changed; the Indian monsoon has become more volatile and less predictable. In this study, monthly self-calibrated Palmer Drought Severity Index (sc-PDSI) data for the time period between 1950 and 2009 were interpolated to India’s districts; then the data were analyzed for changes in frequency and severity. The data were further evaluated using Anselin’s Local Moran’s I Statistic to elicit …

Behavioral Responses And Policy Evaluation: Revisiting Water And Fuel Policies, Shanxia Sun

Open Access Dissertations

In my dissertation, I examine how policies regulating agricultural production and clean technology impact the environment. I focus on policies affecting water depletion, water pollution, and fuel consumption. I assess their cost-effectiveness by modeling and quantifying the behavioral responses of farmers and households.

My first essay focuses on decreasing groundwater depletion through increasing irrigation efficiency in Mexico. I quantify the impacts of different sources of inefficiency on groundwater extraction, and I evaluate the effectiveness of alternative policies that aim to reduce the over-extraction of groundwater. I find that mechanisms of electricity cost-sharing implemented in many wells have a sizable impact …

Economic And Environmental Impacts Of A Hypothetical Global Gmo Ban, Harrison H. Mahaffey

Open Access Theses

The objective of this research is to assess the global economic and greenhouse gas emission impacts of GMO crops. This is done by modeling two counterfactual scenarios and evaluating them apart and in combination. The first scenario models the impact of a global GMO ban. The second scenario models the impact of increased GMO penetration. The focus is on the price and welfare impacts, and land use change greenhouse gas (GHG) emissions associated with GMO technologies. Much of the prior work on the economic impacts of GMO technology has relied on a combination of partial equilibrium analysis and econometric techniques. …

Investigating U.S. Resident Perceptions Of Corporate Social Responsibility In Food And Agriculture, Carissa Jae Morgan

Open Access Theses

Corporations are prioritizing corporate social responsibility (CSR) activities by investing in and actively promoting their social practices. In the U.S. of the modern food supply chain creates a unique challenge for corporations to address concerns about social issues of consumers and non-consumers alike. This study is motivated by the need to better understand individuals’ perceptions of CSR as it pertains to the food supply chain. In April 2015 an online survey collected information from 1,201 U.S. residents with the objective of investigating individuals’ perceptions of relative importance of eight prominent CSR areas relevant to food and agriculture. Demographic, household consumption, …