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Grazier's Pattern Of Understanding Vegetation In The Semi-Arid Rangelands Of New South Wales, S.M M. Kersten, R L. Ison

IGC Proceedings (1977-2023)

A matrix ranking (MR) technique was used by graziers in western New South Wales to rank rangeland plants according to preference. Graziers preferred a variety of plant species in their paddocks: "bushes" and "50f1 feed", perennials and annuals, winter-and summer­growing plants, on both stock-based and non-stock-based criteria, The criteria for evaluation were rarely independent of each other nor of different soil types on the grai:ier's property. Drought resistance was perceived as one of the more important criteria, followed by stock-based criteria such as "nutritious", "palatable" or "quick fattening" stock feed. The utility of MR for allowing graziers' knowledge to be …

Composition Of The Fractions Of Dry, Mature Subterranean Clover Digested In Vivo And In Vitro, L Klein, S K. Baker

IGC Proceedings (1977-2023)

A modified pepsin-cellulase procedure was used to improve the prediction of in vivo digestibility of dry, mature subterranean clovers (Trifolium subterraneum). Feed, faeces, and the residues from this /11 vitro procedure and the i11 vitro procedure of Tilley & Terry were analysed for protein, ash and fibre fractions lo determine the composition of the cell-wall functions that were digested. The extent of digestion of the cell-wall fractions differed between the two in vitro procedures, but the cell-wall fraction that was digested contained similar proportions of cellulose, hemicellulose, protein and lignin. The cellulose and protein contents of the cell-wall digested …

Effect Of Plant Leaf Age On The Production Of Tannins, Phenols, Proanthocyanidins And Flavanols In Eulalia Villosa, M M. Wolfson, E W. Du Toit, P Chesselet

IGC Proceedings (1977-2023)

Histochemical and biochemical analyses have confirmed the presence of condensed tannins in a number of southern African tropical grasses. The ability to precipitate proteins, total phenols, condensed tannin and proanthocyanidin levels were significantly higher in mature leaves of Eulalia villosa than in young leaves. The ratio of condensed tannin to Jlavan 3,4-diols indicated that the young leaf material contained more monomeric unpolymerised flavan 3,4-diol units than mature leaves. The trend is repeated in the ratio 'of proanthocyanidin to flavan-4-ols, These low molecular weight proanthocyanidin precursors probably do not have the ability to precipitate proteins, The histochemical tests can be used …

Effect Of Inoculants And Absorbents Incorporated In Grass Silage On Silage Quality, Effluent Production And Animal Performance, Raymond Jones

IGC Proceedings (1977-2023)

Unwilled ryegrass crops (151 kg DM) were enslled in 70-t bunker silos. Crop analysis (g/kg/DM) was water-soluble carbohydrates 153, nitrogen 24.1 and predicted digestibility (DOMD) 0.67. Molassed sugar beet feed pellets were incorporated at a rate of 25 kg/t in the harvested crop with or without inoculant treatment ("Live Systems", MMB, UK), and compared with a control silage with no additive. Absorbent addition with or without inoculant significantly reduced silage pH and ammonia-N compared with the control. Inoculant treatment further increased lactic acid content. Silage effluent production was reduced by up to 33% by absorbent inclusion with effluent DM losses …

Near-Infrared Spectroscopy Analysis Of The Nutrient Content Of Dairy Pastures, R C. Kellaway, C Stimson, R J. Tassell

IGC Proceedings (1977-2023)

Pasture samples from temperate and tropical species were collected before and after grazing, at regular intervals, on 3 dairy farms in New South Wales over a period of 3 years. All samples (n=693) were analysed on a near-infrared (NIR) spectrophotometer with a scanning monochromator. Subsets of samples selected for calibration and validation, were analysed by wet chemistry methods for estimated metabolisable energy (MID), crude protein (CP), organic matter (OM), acid-detergent fibre (ADF), Ca, P, Mg, K, Na, S, Cu, Mn and Zn. These data were used lo develop NIR equations using partial least squares analyses. Standard errors of laboratory analysis …

Influence Of Oxygen Leakage Through Stretch Film On Quality Of Round Bale Silage, P Lingvall, C M. Pettersson, P Wilhelmsson

IGC Proceedings (1977-2023)

The ensiling-process is based on anaerobic conditions. Therefore, it is important to get "air tight" parcels covering big-bale silage. Wrapping round bales wilh stretch film has improved silage quality, and reduced diy matter (OM) and energy losses. In this experiment we studied the influence of stretch film quality, film thickness, .storage temperature and storage place on fermentation, microbial growth/ and DM losses. Additionally, oxygen permeability of stretch film wrapped in 4 or 6 layers around artificial bales (metal) and DM losses was tested In a model. High storage temperature, low total film thickness and high film permeability to oxygen increased …

Development And Application Of The Sinkhole Hazard Risk Index To Inform Karst Policy And Mitigation Planning, Meghan Puente

Masters Theses & Specialist Projects

Sinkholes are geologic hazards that occur in karst landscapes and can be highly destructive and costly. Sinkhole mitigation plans and development policies are nonexistent at the federal level within the United States and vary significantly at the state level. The lack of a unified standard for sinkhole mitigation planning is partly due to a lack of available data and resources needed to assess sinkhole risk. While there are established sinkhole assessments within the literature, they focus more on the detection and prediction of sinkholes rather than a holistic approach to risk assessment. The goal of this study is to create …

Landuse And Microplastic Transport In Karst Groundwater Of South-Central Kentucky, Katie Norman

Masters Theses & Specialist Projects

Groundwater in karst areas is susceptible to contamination from various sources of pollution. Microplastics are a prevalent source of pollution entering groundwater. This study examines karst groundwater in three areas of investigation. One point of interest is an area that is impacted by urban activities, the Lost River Groundwater Basin, which includes water drainage from the City of Bowling Green, Kentucky. Another study location is Great Onyx (GO) Spring, which is a part of the Great Onyx Groundwater Basin located in Mammoth Cave National Park, Kentucky, and that is relatively unimpacted by urban activities. The third point of interest is …

Developing A Controlled Traffic (Tramline) Farming System, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Controlled traffic farming (CTF) is a farming system built on permanent wheel tracks where the crop zone and traffic lanes are permanently separated. It can improve profitability and sustainability.

Implements for seeding, spraying, spreading and harvesting have a particular span, or multiple of it, and all wheel tracks are confined to specific traffic lanes.

CTF increases profit by more yield, better grain quality, improved operation timeliness, and reduced costs. The environment can improve, with less nutrient leaching, less water erosion, better water infiltration, and less greenhouse gas emission. Implementation needs a clear, long-term plan, and prioritisation of soil health.

Another …

Assessing Soil Properties & Suitability For Optimized Irrigation Development In Sudan, Northern Africa, Suhib O. Hamid

Department of Agricultural and Biological Systems Engineering: Masters Project Reports

In Chapter 1, soil properties essential for efficient irrigation are thoroughly assessed. Factors such as soil texture, infiltration rates, and nutrient content are analyzed to provide insights into the selection of modern irrigation systems. Utilizing data collected from 3,192 locations through GPS and laboratory analyses, alongside sophisticated ranking systems, the research determines the most suitable irrigation methods for specific soil series. Findings highlight the remarkable efficiency of drip irrigation across various soil types, contrasting with the consistently lower performance of surface irrigation. The chapter emphasizes the significance of considering soil variability, evapotranspiration, and investment factors in selecting irrigation methods for …

Evaluation Of Future Sea-Level Impacts Using A Sharp Interface Saltwater Intrusion Model, Caroline Hiott

All Theses

Saltwater intrusion is a growing problem that is being exacerbated by climate change. Saltwater intrusion is the process by which saltwater moves towards freshwater supplies driven by saltwater’s greater density compared to freshwater. Saltwater intrusion can contribute to the salinization of freshwater resources, degradation of underground storage tanks, communication systems, and pipelines, as well as lead to groundwater flooding (Ketabchi et al., 2016). Numerical modeling can be used to simulate saltwater intrusion along coastal areas. One of the more computationally efficient modeling tools is the sharp interface approach, SWI2, that is a part of the MODFLOW 2005 suite (Werner et …

Occurrence, Inputs, And Ecological Significance Of Antibiotics And Pharmaceuticals In Western Nebraska Streams, Katelyn F. Glause

School of Natural Resources: Dissertations, Theses, and Student Research

Few emerging environmental contaminants are as concerning as antibiotics. Human and animal health benefits greatly from the prudent use of antibiotics, yet we give little thought to environmental release of these biologically active compounds. Environmental occurrence of these and other pharmaceutical compounds must be measured in different environmental compartments such as municipal wastewater and in the vicinity of large animal feeding operations to understand potential effects. This study reports the results of a monitoring study in western Nebraska, with a large population of livestock and smaller but more concentrated population of humans, comparing the relative environmental concentrations and loading from …

Remotely Sensed Early Warning Of Algal Blooms In An Eastern Nebraska Reservoir: A Comparison Of Temporal And Spatial Indicators, Mercy Kipenda

School of Natural Resources: Dissertations, Theses, and Student Research

Cyanobacterial harmful algal blooms (CyanoHABs) detrimentally affect human, animal, and ecosystem health. Remotely sensed early warning systems for cyanoHABs in inland lakes could contribute to more proactive water quality monitoring and help mitigate negative impacts. Advances in freely available remote sensing imagery, with finer spatial, temporal, and spectral resolutions, present new opportunities for the development and comparative analysis of methods to detect sudden deterioration in lake water quality. In this thesis, I compared and tested for temporal and spatial early warning signals of cyanoHABs in field-based and remotely sensed datasets from 2019 to 2023 in Pawnee Lake in southeast Nebraska, …

Impacts Of Invasive Carp And Their Population Dynamics On Fish Communities In The Missouri River, Joshua F. Kocik

School of Natural Resources: Dissertations, Theses, and Student Research

Invasive Carp species: Silver Carp Hypophthalmichthys molitrix, Bighead Carp Hypophthalmichthys nobilis, Grass Carp Ctenopharyngodon idella, and Black Carp Mylopharyngodon piceus have both potential and realized abilities to negatively impact native species. Specifically, Bighead Carp and Silver Carp as filter feeders have been theorized to be detrimental not only to adult filter-feeding species, but to many fish which rely on plankton and algae in their early-life stages. The impact of Invasive Carp on the overall fish community remains underexplored. The fish communities below Gavins Point Dam (Invasive Carp present) and Fort Randall Dam (Invasive Carp absent) afford the …

Spatiotemporal Plasticity In Reproductive Readiness And Recruitment Of Ichthyoplankton Of Invasive Silver Carp Along A Western Invasion Front, Jessi L. Urichich

School of Natural Resources: Dissertations, Theses, and Student Research

Individuals of invasive species at the edge of their invasion distribution may exhibit enhanced reproductive capacity and phenotypic plasticity leading to accelerated range expansion. Environmental conditions in highly fluctuating environments at distribution edges may either promote or hinder such reproductive readiness and phenotypic plasticity. Dynamic habitat conditions and periodic disturbances experienced in prairie streams, such as drought (e.g., low-flow, high water temperatures), may potentially reduce suitable spawning environments and ichthyoplankton recruitment of invasive Silver Carp, potentially slowing range expansion or enabling management strategies that reduce abundance in the absence of a reproducing population. Female Silver Carp batch fecundity, Gonadosomatic Index …

Assessing, Restoring, And Centering Social–Ecological Relationships For Advancing Social–Ecological Resilience In The Northern Great Plains Grasslands, Katia Pilar Carranza Bernal

School of Natural Resources: Dissertations, Theses, and Student Research

The Northern Great Plains grasslands are social-ecological systems that were shaped by evolutionary and Indigenous social-ecological relationships. European colonization disrupted many of these interactions, including the coupling of fire and grazing, and degraded social-ecological resilience, shifting these grasslands to a new state. For those reasons, my research focused on assessing, restoring, and centering evolutionary and Indigenous social-ecological relationships for advancing social-ecological resilience in the Northern Great Plains grasslands. I first performed a study in the Nebraska Sandhillls assessing the potential of patch-burn grazing to support grassland resilience by comparing its effects to those of rotational grazing. Through vegetation and bird …

Integration Of Matlab And Machine Learning To Accelerate Evaluation Of Biological Activity In Agricultural Soils And Promote Soil Health Improvement Goals, Andrew Stiven Ortiz Balsero

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Traditionally, assessments of soil biological activity have been confined to laboratory settings, creating a disconnect with practical in-field methods. To bridge this gap, cotton fabric degradation has been used to illustrate soil microbial activity under different management practices. While effective, these demonstrations are subjective and labor-intensive.

Researchers have explored using image processing software like ImageJ and Adobe Photoshop to streamline this process. Although these tools accurately quantified fabric degradation under varying soil conditions, the methods remained labor-intensive and complex. Consequently, these methods were still not ideal for on-farm use by agricultural practitioners.

To further address labor and complexity limitations, the …

Soil Additives And Alternative Crops For Drought Defense In The Intermountain West, Tina M. Sullivan

All Graduate Theses and Dissertations, Fall 2023 to Present

The Western U.S. looks for water optimization and conservation as agriculture is the largest water diverter, and resources are pressured by urban growth, winter snowpack instability, and drought persistence. Agricultural producers have several potential options to optimize water use with different investments associated with them. Options with varying levels of risks and known management practices include alternative crops, soil wetting agents, and crop biologicals.

An alternative crop that grew incredibly fast in popularity was industrial hemp (Cannabis sativa) despite limited agronomic knowledge for best management practices. Field trials occurred (2020-2022) near Logan, UT to test a total of …

Interactions Between Nano/Micro-Sized Particles And Microbes For Agricultural And Environmental Applications, Li-Ting Yen

All Graduate Theses and Dissertations, Fall 2023 to Present

Among the challenges posed by a growing global population, diminishing arable land and water resources affected by climate change are critical for enhancing crop yields, ensuring food security, and maintaining water quality and environmental health.

Iron (Fe), an essential micronutrient, is vital to plant growth. The partially oxidized form of vivianite, metavivianite (metaVT), is reported to be a promising alternative Fe fertilizer. Previous studies have shown the effectiveness of bulk metaVT on plants grown on calcareous soil for mitigating Fe efficiency and the extremely low solubility of bulk metaVT (Ksp=10^-36) in electrolyte solutions, such as CaCl₂. …

Tales In The Teeth: Using Isotopic Analysis To Understand The Paleoecology And Social Behavior Of Brontotheres Of The Intermountain Basins During The Middle Eocene, John Michael Michalski

All Graduate Reports and Creative Projects, Fall 2023 to Present

Isotopic analysis has been a common practice used in paleontology to study ancient ecosystems, and the lives of animals therein. Oxygen isotopic analysis is of particular importance not only because of its use in studying paleoecology, diet, and migration, but also its use in studying mountain elevation, and its impact on ancient ecosystems. I use stable oxygen isotopic analysis to study the habits and ecology of brontotheres from intermountain basins surrounding the Uinta Mountains of Utah and Wyoming, USA. I studied the oxygen isotopes from 16 fossil specimens of teeth, most of which belonged to brontotheres, including the genera Palaeosyops …

Robust Hydropower Planning Balances Energy Generation, Carbon Emissions And Sediment Connectivity In The Mekong River Basin, M. Tangi, Rafael Schmitt, Rafael M. Almeida, S. Bossi, Alexander S. Flecker, F. Sala, A. Castelletti

School of Earth, Environmental, & Marine Sciences Faculty Publications

We present a framework for strategic dam planning under uncertainty, which includes GHG emissions mitigation as a novel objective. We focus on the Mekong River Basin, a fast‐developing region heavily relying on river‐derived ecosystem services. We employ a multi‐objective evolutionary algorithm to identify strategic dam portfolios for different hydropower expansion targets, using process‐related and statistical models to derive indicators of sediment supply disruption and GHG emissions. We introduce a robust optimization approach that explores variations in optimal portfolio compositions for more than 5,000 state‐of‐ the‐world configurations, regarding sediment origins and trapping and GHG emissions. Thus, we can rank dam projects' …

Staying Fresh: Unconventional Approaches Towards Advancing Energy Sustainability, Water Resources, And Community Resiliency In The Southwestern United States, Judith Hoyt

Open Access Theses & Dissertations

This dissertation addresses critical challenges in urban heat management, sustainable energy resource utilization, and water quality communication through three studies. Study 1 investigates the impact of roof color on urban heat islands in Tucson, Arizona where approximately 70% of roofs display high albedo (i.e., light) colors. Energy consumption simulations conducted indicate that converting dark- to light-colored roofs could save Tucson approximately $1,400,000 annually in energy costs, highlighting the potential of cool roofs for energy savings and improved thermal comfort. Study 2 assesses the sources of lithium in subsurface waters in West Texas and South Central New Mexico. Water chemistry data …

Method Development For The Quantification Of Critically Valuable Elements In Permian Basin Produced Waters, Carley Oliver

Open Access Theses & Dissertations

Produced waters (PW) are a major byproduct of the oil and gas industrial hydraulic fracturing processes that create a major waste disposal issue with a need for disposal, treatment, and reuse method developments. The current primary disposal method is subsurface injection, which can lead to high pressures in the subsurface. PWs are often highly saline from mineral leaching due to long residence in subsurface reservoirs. According to the USGS National Minerals Information Center, bromine, calcium chloride, iodine, lithium, magnesium, and sodium chloride have been found in and extracted from these domestic subsurface brines, suggesting that there may be other economically …

Shedding Light On Past Ice-Free Intervals In Northwest Greenland: Luminescence Dating Of The Base Of The Camp Century Ice Core, Hawke Woznick

All Graduate Theses and Dissertations, Fall 2023 to Present

The goal of this thesis is to provide greater resolution on the age and character of the subglacial sediment recovered from the base of the Camp Century ice core, northwestern Greenland. Geochemical analysis indicated that the upper sub-ice sediments were geochemically different and experienced greater weathering than the basal unit underlying a one-meter silty ice lens. Analysis of feldspars within the very fine sand fraction indicates they are dominated by potassium feldspar. Sediment was dated using luminescence, which provides an age for the last time sediment was exposed to light. Luminescence analysis returned ages around 420 thousand years old, which …

Exploring Overbank Sediment Deposition Variation In Heavily Modified Floodplains Of The Lower Mississippi River: A Sedimentological And Geophysical Analysis, Seth Fradella

Master's Theses

Since the 1930s, the Lower Mississippi River (LMR) has experienced large-scale modifications to the channel profile and surrounding floodplains through dams, dikes, revetments, dredging, and channel cutoffs. Although these changes have improved navigation and reduced flood risk, unanticipated changes to the major flood return period, individual flood severity and duration, and sediment regime have become increasingly apparent and sometimes problematic, such as the 2011 and 2018-2020 floods. Flood control levees along the LMR have reduced the natural floodplain area by 70-90%, resulting in heavily restricted overbank storage capacity of water and sediment. For the same flood events in recent history, …

Phylogenetic And Biogeographic Patterns Of Devonian Proetid Trilobites, Katherine Jane Jordan

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Ecological disruption events such as mass extinctions can result in the permanent alteration in clades and ecosystems. A pivotal time of change during the history of life on Earth can be seen in the Devonian Period. During this time, major transitions in marine and terrestrial system resulted in a different world at the end of the period in comparison to the beginning. One such group most heavily impacted were trilobites. Trilobites were reduced to one order by the end of the Devonian: Proetida. My dissertation focuses on phylogenetic, biogeographic, and paleocommunity patterns of this group, known as the last of …

Cover-Crop Effects On Near-Surface Soil Properties Over Time In The Lower Mississippi River Valley, Cooper Fanning

Graduate Theses and Dissertations

Human population growth and climate change are present stressors that continue to put pressure on current agricultural production systems, where typical row-crop agricultural practices can negatively impact soil health. Extensive use of cover crops (CC) to increase soil health remains widely unrealized. Soil health in Arkansas is a major concern for sustaining agricultural output, therefore research into CC implementation across Arkansas to maintain or improve soil health is needed. The objective of this study was to evaluate the effects of CC (i.e., with and without CC) across various physical, hydraulic, biological, and chemical soil indicators in the Lower Mississippi River …

Analyzing Fe/Mg-Silicate Chemical Gardens As Analogs To Silicate-Rich Hydrothermal Chimneys On Early Earth And Mars, Nancy Alejandra Carman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hydrothermal systems have been proposed as environments for prebiotic chemistry on early Earth. Ancient Mars was an ocean world and could also have had hydrothermal vents supporting biological or prebiotic processes. The Strytan Hydrothermal Field (SHF) in Iceland is a basalt-hosted alkaline vent that forms massive hydrothermal Mg-saponite chimneys and is a potential analog to basalt-hosted alkaline vents that may have existed at the Eridania basin on Mars, where saponite deposits are thought to have formed from ancient hydrothermal activity. Chemical garden experiments have previously been used to simulate aspects of hydrothermal chimney growth for other types of vent systems; …

Effects Of Climate Change On (Semi)-Arid Ecosystems In The Southwestern United States, Charlotte Van Der Nagel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Climate change is considered amongst the most severe threats to terrestrial and aquatic ecosystems globally. Ecosystems in the southwestern United States have specifically been impacted by intense drought conditions since 2000. Higher temperatures combined with altered precipitation stresses many ecosystems; however, ecosystem specific responses to such stressors may vary. Here, the effects of climate change on semi-arid ecosystems are analyzed for some of the most vulnerable ecosystems in the southwestern United States: lacustrine, riparian, and dryland ecosystems.

Lakes and reservoirs in arid environments often serve as drinking water sources and recreational areas where high water quality is essential. Climate change …

Struvite Effects On Greenhouse Gas Emissions From Flood- And Furrow-Irrigated Rice In The Greenhouse, Chandler Arel

Graduate Theses and Dissertations

Over time, as the influences of climate-change and declining, mineable, global phosphorus (P) reserves begin to impact agricultural production systems, alternative fertilizer sources and management practices, such as struvite (MgNH₄PO₄ · 6H₂O) and furrow-irrigation, will be necessary to accommodate nutrient and water demands. The precipitation and use of struvite as a fertilizer-P source could reduce environmental damages caused by nutrient-rich wastewater streams, supplement domestic P supply, and improve the sustainability of flood-, and furrow-irrigated rice production by reducing greenhouse gas emissions. The study of struvite from both chemical and electrochemical precipitation processes is well documented, …