Physical Sciences and Mathematics Commons^™

Available Nitrogen And Denitrification In Soil Altered By Ground Cover And Nutrient Source In An Organic Apple Orchard, Jade Nicole Ford

Graduate Theses and Dissertations

A shift in public demand towards more organic and locally produced fruit and vegetables has been occurring across the United States in recent years. A common practice in organic fruit production is the application of organic ground covers to supply nutrients while enhancing other soil properties. A need for research exists in the southern region of the U.S. examining the effects of regionally applicable ground cover and nutrient management on nitrogen availability and the microbial community to provide information to organic farmers in the region. Two studies were conducted to determine how 12 treatment combinations of four ground covers (compost, …

A Bat-Guano-Derived Δ15N And Δ13C Record Of Paleoenvironmental Change: Zidită Cave, Romania, Daniel Martin Cleary

USF Tampa Graduate Theses and Dissertations

Because nitrogen isotopes are fractionated along the soil-plant-insect-bat-guano pathway, it may be possible to reconstruct environmental and climatic changes reflected in the nitrogen isotopic composition of guano. A 1.5-m core of bat guano from Zidită Cave (western Romania) provides a record of climatic and anthropogenic influence on the regional nitrogen cycle and paleoenvironmental controls on nitrogen transforming processes. Increasing and decreasing trends of nitrogen isotopic composition (δ¹⁵N values) correspond well with changes in the influence of farming practices, deforestation, and forest expansion. These influences likely had a significant effect on the openness of the nitrogen cycle, resulting in …

Carbon And Nitrogen Isotopic Investigations Of The Late Pleistocene Paleoecology Of Eastern Beringia, Yukon Territory, Using Soils, Plants And Rodent Bones, Farnoush Tahmasebi

Electronic Thesis and Dissertation Repository

During the late Pleistocene (130-12 ka), Beringia, a largely ice-free land located in the Mammoth Steppe Ecosystem, was home to a large grazing community of megafauna. Many of these animals, including the woolly mammoth, became extinct at the terminal Pleistocene. Assessment of the paleoenvironment, nutrient cycling and foraging ecology in Beringia should help to understand the role of climate change in their extirpation. Such information might also help to explain the curiously higher δ¹⁵N of woolly mammoths relative to other coeval herbivores.

This study assessed eastern Beringian paleoecology using stable nitrogen (N) and carbon (C) isotopic analyses of …

Bear Lake Limnology & Nutrient Limnology, Wayne A. Wurtsbaugh

Watershed Sciences Faculty Publications

No abstract provided.

Evidence Of Late Quaternary Fires From Charcoal And Siliceous Aggregates In Lake Sediments In The Eastern U.S.A., Joanne P. Ballard

Doctoral Dissertations

The late-glacial transition to the Holocene, 15,000–11,600 cal yr BP, is an enigmatic period of dynamic global changes and a major extinction event in North America. Fire is an agent of disturbance that transforms the environment physically and chemically, and affects plant community composition. To improve understanding of the linkages between fire, vegetation, and climate over the late glacial and Holocene in the eastern U.S., I analyzed lake-sediment cores for charcoal and indicators of wood ash, and compared results to existing pollen records. A new microscopic charcoal record from Anderson Pond, Tennessee revealed high fire activity from 23,000–15,000 cal yr …

Analysis Of Nitrogen And Phosphorus Nutrients In Lake Sediment, Kelsey L. Berrier

Senior Honors Projects, 2010-2019

Analytical methods for the determination of nitrogen and phosphorus nutrients (NO₃-N, NH₄-N and PO₄-P) in sediment were studied with the goal of developing extraction steps compatible with analysis by ion chromatography (IC). Research focused on extractant solution composition, Dionex OnGuard^® sample pretreatment cartridges for salt removal, and chromatographic resolution. Aqueous test samples, lake sediment samples and spiked lake sediment samples were analyzed. Dionex Ag, Ag/H, and H cartridges were studied for the pretreatment step. Silver (Ag) cartridges were found effective in removing >99% of interfering chloride ion to allow NO₃-N determination …

Rice Grain Yield And Nitrogen Uptake And Ammonia Volatilization From Urea As Affected By Urea Amendment And Simulated Rainfall, Randy Dempsey

Graduate Theses and Dissertations

The effect of rainfall between urea application and flood establishment on N loss and grain yield of rice (Oryza sativa L.) has not been studied. The first research objective was to compare the effects of simulated rainfall amounts and N-(n-butyl) thiophosphoric triamide (NBPT) urease inhibitor rate on NH3 volatilization and rice growth. Three field experiments were conducted and NH3 volatilization was measured in two experiments for 11 days after urea application (DAU) in semi-open chambers. Urea or NBPT-treated urea (NBPT-Urea) was subjected to six simulated rainfall amounts (0-25 mm) applied 5 to 15 h after urea application and flooded 7 …

Calculating The Campus Nitrogen Footprint, Allison Leach, Jennifer Andrews

NECSC Conference 2015

Many universities interested in sustainability have calculated their carbon footprint. The carbon footprint is well-established and understood: it tells us how much carbon dioxide and other greenhouse gases are emitted to the atmosphere as a result of university activities. While important, this calculation addresses just one part of a university’s environmental impact. Universities that want to expand their approach to sustainability can now also calculate their nitrogen footprint.

Nitrogen footprints connect entities, such as individuals or universities, with the reactive nitrogen (all species of nitrogen except N2) lost to the environment as a result of their activities. While necessary to …

Biogeochemical Cycling In Lake Superior Tributaries: Seasonality, Quantity And Quality Of Export, Ashley Anne Coble

Dissertations, Master's Theses and Master's Reports - Open

Seasonal and spatial variability in environmental factors may affect dissolved organic matter composition and nutrient transformation and retention in streams. The objective of this research was to quantify and describe seasonality, quantity, and quality of nutrient processing and export of ammonium (NH₄), soluble reactive phosphate (SRP), and dissolved organic carbon (DOC) into Lake Superior through intensive study in a small 1st order watershed coupled with snapshot measurements across 12 tributaries that varied in size, location, and wetland coverage. Our results suggest biodegradable C is exported from a small headwater stream year-round and that DOC mineralization rates can be …

Reductions Of Wheat Yield And Yield Components And Nitrogen Loss Following Frozen Soil Nitrogen Applications, Carrie Ann Knott, Edwin L. Ritchey, Lloyd W. Murdock

Plant and Soil Sciences Research Report

Most wheat producers in Kentucky apply nitrogen (N) as a split application. The first N increment is applied when wheat plants begin actively growing (green-up) in late winter, which is typically in mid- February between growth stages Feekes 2 to 3. The second N increment typically occurs in March when wheat is between Feekes 5 to 6. Many producers in Kentucky, especially Western Kentucky, have become accustomed to beginning first N applications in late January when the ground is frozen and the wheat is still dormant. This practice allows them to apply N to large acreages of wheat while avoiding …

Epr Methods For Biological Cu(Ii): L-Band Cw And Nars, Brian Bennett, Jason M. Kowalski

Physics Faculty Research and Publications

Abstract: Copper has many roles in biology that involve the change of coordination sphere and/or oxidation state of the copper ion. Consequently, the study of copper in heterogeneous environments is an important area in biophysics. EPR is a primary technique for the investigation of paramagnetic copper, which is usually the isolated Cu(II) ion, but sometimes as Cu(II) in different oxidation states of multitransition ion clusters. The gross geometry of the coordination environment of Cu(II) can often be determined from a simple inspection of the EPR spectrum, recorded in the traditional X-band frequency range (9–10 GHz). Identification and quantitation of the …

Synthesis Of Nitrogen-Doped Graphene Via Thermal Treatment Of Graphene Oxide Within Methylimidazole And Its Capacitance Performance As Electric Double Layer Capacitor, Md. Monirul Islam, Shaikh Nayeem Faisal, Anup Kumar Roy, Sonia Ansari, Dean Cardillo, Konstantin K. Konstantinov, Enamul Haque

Australian Institute for Innovative Materials - Papers

Nitrogen-doped graphene was successfully synthesised from graphene oxide (GO) and 2-methylimidazole composite via thermal treatment under argon flow at 700oC within 1h. This synthesised N-doped graphene exhibits homogeneous nitrogen doping with concentration of ~5% in three different nitrogen configuration namelypyridinic N, pyrrolic N and graphitic N. The electric double layer capacitor (EDLC) made up with this N-doped graphene showed excellent specific capacitance 274 F/g at current density of 1A/g, which was ~7 times higher than GO. This EDLC capacitor showed excellent cyclic stability up to 5000 cycles with capacity retention of ~91%.

Manganese Dioxide-Anchored Three-Dimensional Nitrogen-Doped Graphene Hybrid Aerogels As Excellent Anode Materials For Lithium Ion Batteries, Zhu Yin Sui, Caiyun Wang, Kewei Shu, Quan-Sheng Yang, Yu Ge, Gordon G. Wallace, Bao Hang Han

Australian Institute for Innovative Materials - Papers

The capacity of manganese dioxide (MnO₂) deteriorates with cycling due to the irreversible changes induced by the repeated lithiation and delithiation processes. To overcome this drawback, MnO₂/nitrogen-doped graphene hybrid aerogels (MNGAs) were prepared via a facile redox process between KMnO₄ and carbon within nitrogen-doped graphene hydrogels. The three-dimensional nitrogen-doped graphene hydrogels were prepared and utilized as matrices for MnO₂ deposition. The MNGAs-120 obtained after a deposition time of 120 min delivered a very high discharge capacity of 909 mA h g^-1 after 200 cycles at a current density of 400 mA g^{-1 …}

Role Of Anions On Structure And Pseudocapacitive Performance Of Metal Double Hydroxides Decorated With Nitrogen-Doped Graphene, Nasir Mahmood, Muhammad Nawaz Tahir, Asif Mahmood, Wenlong Yang, Xingxing Gu, Chuanbao Cao, Yawen Zhang, Yanglong Hou

Australian Institute for Innovative Materials - Papers

Electrochemical capacitors (EC) bear faster charge-discharge; however, their real applications are still on a long away due to lower capacitance and energy densities which mainly arise from simple surface charge accumulation or/and reaction. Here, a novel synthesis strategy was designed to obtain the purposeful hybrids of nickel cobalt double hydroxide (NiCoDH) with genetic morphology to improve their electrochemical performance as electrode of EC. Nanostructures of metal hydroxides were grown on t he nitrogen-doped graphene (NG) sheets by utilizing defects as nucleation sites and their composition was optimized both by tuning the ratio of Ni:Co as well as the counter halogen …

Grassland Renovation And Consequences For Nutrient Management, Johannes Isselstein, Manfred Kayser

IGC Proceedings (1997-2023)

Sward degradation is a serious threat to the functioning of grassland and the provision of ecosystem services. Renovation measures are frequently applied in order to restore degraded swards. However, the success is highly variable and substantial tradeoffs are often found following renovation such as among agronomic and environmental services. Starting from a general classification of renovation measures the paper investigates the processes induced by renovation that lead to a change of the vegetation and that affect carbon and nitrogen fluxes. These processes are strongly interrelated and dependent on site, climate and management condition as well as on the time scale. …

An Examination Of El Niño's And Agricultural Runoff's Effect On Harmful Algal Blooms And California Sea Lion (Zalophus Californianus) Health In Monterey Bay, Nadine Lafeber

Scripps Senior Theses

An increase in marine mammal stranding and die-off events has been observed along the California coast. The exact cause to explain for these recent events is unknown, but El Niño and harmful algal blooms are established sources for temporary decreases in marine mammal health. To determine whether El Niño could be causing and amplifying harmful algal blooms, particularly in Monterey Bay where they occur frequently, data was analyzed from the Marine Mammal Center in Sausalito, California. Data analysis focused on California sea lions (Zalophus californianus), because they have the largest data set and are directly affected by harmful …

At-Grade Stabilization Structure Impact On Surface Water Quality Of An Agricultural Watershed, Kyle R. Minks, Matthew D. Ruark, Birl Lowery, Fred W. Madison, Dennis Frame, Todd D. Stuntebeck, Matthew J. Komiskey, George J. Kraft

United States Geological Survey: Staff Publications

Decades of farming and fertilization of farm land in the unglaciated/Driftless Area (DA) of southwestern Wisconsin have resulted in the build-up of P and to some extent, N, in soils. This build-up, combined with steep topography and upper and lower elevation farming (tiered farming), exacerbates problems associated with runoff and nutrient transport in these landscapes. Use of an at-grade stabilization structure (AGSS) as an additional conservation practice to contour strip cropping and no-tillage, proved to be successful in reducing organic and sediment bound N and P within an agricultural watershed located in the DA. The research site was designed as …

Water Quality Of The Upper Little Miami River Watershed In Ohio: Impacts Of Natural And Anthropogenic Processes, David Allan Huff

Browse all Theses and Dissertations

Stream water quality is increasingly threatened by expanding anthropogenic activities, mainly through point source discharges and urban and agricultural runoffs of contaminants getting through a water body's watershed resulting in pollution. Concerns developed as to whether urban or agricultural type activities were causing most water quality impairment issues in the upper Little Miami River watershed in southwest Ohio.

Characterizing the upper Little Miami River (LMR) watershed with respect to water chemistry and Land Use/Land Cover (LULC) while evaluating the sources of any higher than expected natural parameter concentrations, with a strong emphasis on the nutrients phosphorus and nitrate, serves as …