Physical Sciences and Mathematics Commons^™

Long-Term Effects Of Rice Rotation, Tillage, And Fertility On Near-Surface Soil Carbon And Nitrogen Cycling, Jill Marie Motschenbacher

Graduate Theses and Dissertations

Rice (Oryza sativa L.)-based cropping systems are different from other row crops due to the flood-irrigation scheme used from about one month after planting to a few weeks prior to harvest. The frequent cycling between anaerobic (i.e., flooding during the growing season) and aerobic (i.e., generally, the remainder of the year) conditions can influence the rate of soil organic matter (SOM) decomposition, which can greatly influence carbon (C) and nitrogen (N) storage and sequestration in the soil over time. Therefore, a study was conducted on a silt-loam soil (fine, smectitic, thermic, Typic Albaqualf) at the Rice Research and Extension Center …

Evaluation Of The Effects Of Absorption Field Product Architecture Type On Effluent Dispersal And Soil Chemical Properties In A Profile-Limited Soil, Nina J.M. Prater

Graduate Theses and Dissertations

On-site wastewater treatment systems (OWTSs) are commonly used by households in areas of low population density to treat household wastewater and recycle it back to the environment. The traditional absorption field product used in OWTSs is a pipe-and-gravel architecture type, which has been used for decades and is the basis for most design regulations. However, new products of differing architecture types including chambers, polystyrene-aggregate, pipe-and-tire-chip, and gravel-less-pipe systems have recently become available. A three-year field study was conducted in Bethel Heights, AR to assess the performance of several newer products and to compare different architecture types to the traditional pipe-and-gravel …

Habitat Modeling Of Three Endemic Crayfish Species In The Black River Drainage Of Missouri And Arkansas: Factors Affecting Distribution And Abundance, Matthew Stephen Nolen

Graduate Theses and Dissertations

The Ozark faunal region of Missouri and Arkansas harbors a high level of aquatic biological diversity, especially in regards to endemic crayfish. Orconectes eupunctus, Orconectes marchandi, and Cambarus hubbsi are three such endemics that are threatened by a limited natural distribution and the invasions of Orconectes neglectus. I sought to determine how natural and anthropogenic factors influence these three species across multiple spatial scales. Local and landscape data were used in decision tree analyses (CART) to determine their influence effect on presence/absence and density of the three species. Predictive models were validated using k-fold cross validation. O. eupunctus presence was …

A Reexamination Of The Eastern Collared Lizard (Crotaphytus Collaris Collaris) In Arkansas, Ashley A. Grimsley

Graduate Theses and Dissertations

Loss of suitable habitat is a threat to species worldwide. Habitat destruction, including loss, change, and fragmentation of habitat, is the leading cause of species extinction. Eastern collared lizards (Crotaphytus collaris collaris) are habitat specialists on glades. Both C. c. collaris and glade habitats are rare and of special concern in the state of Arkansas. Many glade populations have already been extirpated in the Ozarks of Arkansas and Missouri. Increasing knowledge of the distribution, habitat structure, and population dynamics of C. c. collaris is important to ensure the survival of this species in Arkansas.

A literature review of …

Integrating Human Variables In Cross-Boundary Monitoring Of Aberdare Preserves In Kenya, Peter K. Njuguna

Graduate Theses and Dissertations

This research critically examines extant data systems and their linkage of scientific research to policy and public education in east African highland forest conservation preserves. The research indicates that the current state of data and monitoring systems in the region imposes substantial limitations on the ability to manage these preserves. Major outcomes of those constraints manifest in unprecedented cross-boundary pressure such as encroachment and conversion of forest to agriculture, increased human-wildlife conflicts, and constrained relations among primary stakeholders. Current monitoring is biodiversity focused within preserves and fails to capture human dimensions in adjoining areas across preserve boundaries. This study proposes …

Biological Strategies And Mathematical Approaches For Limiting Bacterial Contaminants And Chemical Pollutants In Bioethanol Fermentations, Alia Chahed Ep Limayem

Graduate Theses and Dissertations

During the most recent decades increased interest in fuel from biomass in the United States and worldwide has emerged each time petroleum derived-gasoline registered well publicized spikes in price. The willingness of the U.S. government to face the issues of more heavily high-priced foreign oil and climate change has led to more investment on plant-derived sustainable biofuel sources. Biomass derived from corn has become one of the primary feedstocks for bioethanol production for the past several years in the U.S. However, the argument of whether to use food as biofuel has led to a search for alternative non-food sources. Consequently, …

The Use Of Diatoms To Infer Environmental Change Of The Lower White River, Southeastern Arkansas, Ruchi Bhattacharya

Graduate Theses and Dissertations

This dissertation describes the limnology of the lower White River oxbow lakes in southeast Arkansas, inundated by the major 2008 spring flood. The flood water and sediment deposited in oxbow lakes were analyzed for water chemistry, sediment geochemistry and diatom assemblages and used as an analogue for past floods. The 2008 spring flood inundated and homogenized the entire floodplain; also represented by the predominantly planktonic diatom assemblage suggesting riverine input. Indicator species for eutrophication were also recorded consistent with the high nutrient content in the lakes. However, the variance in the surface diatom assemblage was best explained by the lake …

Territories,Territoriality, And Conservation Of The Louisiana Waterthrush And Its Habitat, The Watershed Of The Upper Buffalo National River, Leesia Cheryl Marshall

Graduate Theses and Dissertations

The Louisiana Waterthrush, Parkesia motacilla, is a migratory wood-warbler and breeding season resident of the eastern United States. Males defend breeding territories that extend linearly along clear, fast-flowing, gravel-bottomed, forest streams. Defense includes two song types, primary and extended song. As riverine specialists, birds rely upon aquatic invertebrates as prey and riparian habitat features for nesting. They use a unique foraging maneuver, leaf-pulling, that involves picking up or pulling a leaf from water, and turning it over to search for prey. Their relationship with riparian habitat introduces potential for Louisiana Waterthrushes to serve as indicators of stream health. The …