Earth Sciences Commons^™

Rice Biomass Response To Various Phosphorus Fertilizers In A Phosphorus-Deficient Soil Under Simulated Furrow-Irrigation, Jonathan B. Brye

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Wastewater-recovered phosphorus (P), in the form of the mineral struvite (MgNH4PO4⋅6H2O), may provide a sustainable alternative to rapidly decreasing rock phosphate reserves. Struvite can be generated via chemical and/or electrochemical precipitation methods, potentially reducing the amount of P runoff to aquatic ecosystems. The objective of this greenhouse tub study was to evaluate the effects of chemically- and electrochemically precipitated struvite (CPST and ECST, respectively) on above- and belowground plant response in a hybrid rice cultivar (Gemini 214, RiceTec) grown using furrow-irrigation compared to other common fertilizer-P sources [i.e., triple super phosphate (TSP) and diammonium phosphate (DAP)] in a P-deficient silt …

Polygonal Faults In The Austin Chalk: Invariance Of Scale From Mud Cracks To Polygons With Implications Of Structural, Geomorphic And Isotopic Data On Polygonal Fault Geometry And Origin., Kun Shang

Earth Sciences Theses and Dissertations

The Cretaceous Austin Chalk contains large numbers of fractures and normal faults whose orientations have been attributed to either regional stresses (e.g., the Balcones fault trend) or, by analogy with the mudrocks, to polygonal faulting resulting from compaction. In this study, we present geomorphic data, field study, and stable isotope data to support that the majority of these faults in North Texas are polygonal. Field-measured fault orientations suggest randomly distributed fault strikes, indicating a polygonal fault structure. Using geomorphologic data (topographic and DEM data) on stream orientations suggests that the polygonal fault patterns are best reflected in the headwater (1st …

Characterization Of Boreal-Arctic Vegetation Growth Phases And Active Soil Layer Dynamics In The High-Latitudes Of North America: A Study Combining Multi-Year In Situ And Satellite-Based Observations, Michael G. Brown

Dissertations, Theses, and Capstone Projects

This dissertation examined the seasonal freeze/thaw activity in boreal-Arctic soils and vegetation physiology in Alaska, USA and Alberta, Canada, using in situ environmental measurements and passive microwave satellite observations. The boreal-Arctic high-latitudes have been experiencing ecosystem changes more rapidly in comparison to the rest of Earth due to the presently warming climatic conditions having a magnified effect over Polar Regions. Currently, the boreal-Arctic is a carbon sink; however, recent studies indicate a shift over the next century to become a carbon source. High-latitude vegetation and cold soil dynamics are influenced by climatic shifts and are largely responsible for the regions …

Adaptation, Compatibility And Acceptability Of Grass-Legume Pastures In The Andean Region Of Colombia, E. Cárdenas, E. Castro

International Grassland Congress Proceedings

In Colombia, the specialised dairy production system is located in the high altitude Andean region. Its main feed resources are pure stands of Pennisetum clandestinum or/and Lolium spp. Nevertheless, the present market conditions require highly competitive and quality forages year round. These forages should be produced with low inputs (irrigation, fertilisers and agrochemicals) and be resistant to pests and diseases. The objective of this research was to evaluate the adaptation, compatibility and acceptability of introduced forage species for sustainable pasture management.

New Cultivars For High Quality, Persistent Legume-Grass Pastures In The Southern Usa, J. H. Bouton

International Grassland Congress Proceedings

In the southern USA one cannot depend on perennial legume-grass pasture systems to have persistently high nutritive quality. 'Jesup' tall fescue, a cultivar with better persistence in the region than 'Kentucky 31', was re-infected with a non-ergot alkaloid producing strain of the Neotyphodium coenophialum fungal endophtye (MaxQ^TM) and found to give persistence equal to Jesup with its endemic strain (E+), but without animal toxins (Bouton et al., 2002). 'Durana' white clover (Bouton et al., 2004) was developed from regional ecotypes of Trifolium repens f. hollandicum germplasm and found to improve animal performance in both E+ and …

Seed Productivity Of Festulolium And Lolium X Boucheanum Varieties, Iveta Gutmane, Aleksandr Adamovich

International Grassland Congress Proceedings

Hybrid ryegrasses are intermediate lines between perennial ryegrass and Italian ryegrass as regards growth parameters, productivity and resistance. Good quality and digestibility of forage and higher yield are the main advantages of hybrid ryegrass over perennial ryegrass. Climatic conditions in the Baltic States and North Europe are not favourable enough for ryegrass cultivation but Festulolium is a prospective forage crop for this area (Nesheim, 2000, Adamovich, 2003). Ryegrasses, including hybrid ryegrasses, surpass Festulolium in forage quality. However, Festulolium persistance (resistance, winter-hardiness and, thus, high productivity) are noteworthy. Due to yield quality and competitive productivity, Festulolium may rank equally with timothy …

Comparing Yield And Quality Of Milk From Dairy Cows Fed Stockpiled Annual Ryegrass (Lolium Multiflorum L.) And Cereal Rye (Secale Cereale L.), L. E. Meinhardt, R. L. Kallenbach

International Grassland Congress Proceedings

Stockpiling annual ryegrass and cereal rye provides a low cost substitute to hay and creates an excellent source of feed during winter (Kallenbach et al., 2003). In addition to lowering feed costs, grazing increases the conjugated linoleic acid (CLA) content of milk compared to feeding hay. Previous research suggested that forage species might differ in their ability to alter milk CLA content during the growing season (Wu et al., 1997). However, research is needed to determine if different forage species used for winter and early spring grazing impacts the CLA content of milk. The objective of this experiment …

A Grazing Method To Solve The Lack Of Pastures In The Dry Season Of Tropical Areas With Long Periods Of Drought, R. O. Martinez, R. Tuero, M. F. Díaz

International Grassland Congress Proceedings

Rotational grazing systems used in tropical areas in Latin America do not solve the great difference in pasture availability between the dry and the rainy season. The main studies on rational grazing (Voisin, 1963) were performed in temperate areas where the deficit of feeds in winter may only be solved with external feeds such as forages and silages produced out of the grazing system. The objective of this work was to demonstrate that it is possible to maintain pasture availability throughout the year with the use of a Pennisetum purpureum clone (Cuba CT-115) adapted to grazing (Martínez et al., …

Breeding And Evaluation Of Forage Soyabeans, T. E. Devine

International Grassland Congress Proceedings

The principal use of soyabean in the US in the early 1900s was as livestock forage. Soyabeans are less expensive to establish than small seeded perennial legume forages and can provide legume protein after winter killing of perennial legumes. Soyabean can improve production distribution by vigorous growth during the hot summer season when traditional perennial legumes are less productive.

Effect Of Utilisation Date On The Yield And Quality Of A Semi-Natural Grass Stand In Winter, Jiří Skládanka

International Grassland Congress Proceedings

Prolongation of the grazing period into the winter season reduces the costs of feedstuffs for dry cows. To enable the use of pastures in winter it is necessary to carry out the last cut or grazing cycle in June or July and to postpone the last grazing until the first week of August. (Opitz von Boberfeld, 1997). The time of the last utilisation in summer influences the yield and quality of herbage during the winter season (Bartholomew et al., 1997). This research studied changes in yield and quality of a semi-natural grass stand in autumn and in winter following …

Annual Forage Legume Response To Herbicides Labelled For Lucerne Establishment, Twain J. Butler, R. Bow, J. P. Muir

International Grassland Congress Proceedings

Weed competition reduces stand establishment, thus lowering forage production and quality. However, there are no herbicides labelled for annual legume establishment, despite several labelled for the establishment of lucerne (Medicago sativa). Some of these may be useful in the establishment and production of annual forage legumes. Lucerne herbicides have greater potential for use on other legumes, since they have grazing and feeding clearance. The objective of this paper is to summarize annual legume yield response trials to herbicides labelled for lucerne establishment.

4d Flow Pattern Of The Longest Cave In The Eastern Alps (Schönberg-Höhlensystem, Totes Gebirge), Lukas Plan, Eva Kaminsky, Pauline Oberender, Clemens Tenreiter, Maximilian Wimmer

International Journal of Speleology

The Schönberg-Höhlensystem (SBH) is not only the longest cave system in the Eastern Alps (length 156 km, depth 1061 m), but a significant proportion of the passages have developed on or just below two surfaces that dip 1.7° to the NE. These so-called "speleogenetic phases" are rarely developed in caves of the Northern Calcareous Alps and have not yet been confirmed by detailed morphological mapping. Furthermore, the deep parts of the cave offer the possibility to study the active epiphreatic zone for a distance of 1.6 km. Detailed morphological mapping shows that the main level at about 1500 m a.s.l. …

Impact Of The Macrophyte Nymphaea Odorata (Lily Pads) On Dissolved Organic Matter (Dom) In A Lake, Kyle Juetten, Warren J. De Bruyn, Zachary Landram, Aaron Harrison, Angela Strecker, Catherine D. Clark

Chemistry Faculty and Staff Publications

(Files are available for download below.)

Macrophytes are a potential source of dissolved organic matter (DOM) in lakes. To probe the contribution of Nymphaea odorata (lily pads), dissolved organic carbon concentrations (DOC) and optical properties of chromophoric DOM were measured in a lake in the Pacific Northwest, United States over a year. Lily pads are prevalent around the shoreline during summer, dying back in fall. Indices of recent autochthonous contribution (BIX), fluorescence (FIX) and S_R showed the lake was dominated by terrestrially-derived material. DOC concentrations were not correlated with rainfall, but were positively correlated with absorption coefficients. Values were …

Evaluation Of Temperature-Index And Energy-Balance Snow Models For Hydrological Applications In Operational Water Supply Forecasts, Tian Gan, David G. Tarboton, Tseganeh Z. Gichamo

Civil and Environmental Engineering Faculty Publications

In the western United States, snow accumulation, storage, and ablation affect seasonal runoff. Thus, the prediction of snowmelt is essential to improve the reliability of water supply forecasts to guide water allocation and operational decisions. The current method used at the Colorado Basin River Forecast Center (CBRFC) couples the SNOW-17 temperature index snow model and the Sacramento Soil Moisture Accounting (SAC-SMA) runoff model in a lumped approach. Limitations in parameter transferability and calibration requirements for changing conditions with the temperature-index model motivated this research, in which new avenues were investigated to assess and prototype the application of an energy-balance snow …

Landslide Forecast In Taiwan Based On Machine Learning In The Gis Field, Yi Shen

Honors Capstones

Landslides can pose a significant risk to life, property, and infrastructure in mountainous regions, and can be triggered by various factors, including intense rainfall, earthquakes, and water level changes. Machine learning is commonly used to forecast landslides, based on statistical relationships between past landslides and multiple variables to create a general forecasting model. However, these models often require large amounts of data to achieve accurate results. This project aims to use only a few variables but take advantage of both their spatial distribution and temporal trends to improve the accuracy of landslide forecasts. This approach is tested in Taiwan, a …

Evaluating The Relationship Between Methane Seeps And Seafloor Geomorphology On The Northern Us Atlantic Margin, Gabriel Hernandez

Theses and Dissertations

Methane seeps are a transport pathway for carbon from seafloor sediments to the marine environment with important implications for global biogeochemical cycling. Accordingly, there is substantial interest in better understanding the processes that control seep location and predicting the distribution of seeps with existing seafloor datasets. Visual evaluation of methane seeps, in multibeam sonar water column data, suggests a spatial relationship between seeps and specific seafloor morphologic features such as ridge crests. In this thesis, seafloor geomorphology at 1996 seep detection sites on the US Atlantic margin was quantitatively characterized by geomorphologic phonotype, bathymetric position index, slope, rugosity, and aspect …

Limits Of Tectonic Reactivation On Mars Using Earth Analogue Analysis And Numerical Modeling, Jonathan Rich

Theses and Dissertations

Recent geodynamic modeling studies suggest that the geometry of structural landforms in the Ouachita Mountains (OM) has been influenced by the reactivation of a weak scar in the mantle-lithosphere during intracontinental orogenesis. As deformation on one-plate planets such as Mars can be considered intracontinental, and impact cratering deeply scarred the Martian lithosphere, we hypothesize that structural geometries on Mars may also reflect heterogenous networks of lithospheric scarring. To investigate this hypothesis, we model the pre-erosional fold structure of the Maumelle Chaotic Zone in the OM to compare fault and fold geometries with that of the seismically-imaged mantle-lithosphere scar. We then …

Paleotemperature Estimates From Diatom Morphometrics In The Amundsen Sea For Marine Isotope Stage 5, Cesar Lopez

Honors Capstones

Because of ever rising temperatures driven by anthropogenic climate change, much attention has been given to the West Antarctic Ice Sheet (WAIS) by the scientific community. This is due to its sensitivity to global climate change and vulnerability for collapse as evidenced by Pleistocene interglacial events. Paleotemperature estimates from the Amundsen Sea are crucial for understanding how global temperature changes impacted WAIS throughout the Pleistocene. Marine Isotope Stage 5 (MIS 5) is of particular interest as it contains different substages and intervals of fluctuating temperatures. This period also is estimated to have had temperatures equal to, or slightly higher than …

Small Community Water Systems Have The Highest Prevalence Of Mn In Drinking Water In California, Usa, Miranda Aiken, Samantha C. Ying

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Manganese (Mn) is currently regulated as a secondary contaminant in California, USA; however, recent revisions of the World Health Organization drinking water guidelines have increased regulatory attention of Mn in drinking water due to increasing reports of neurotoxic effects in infants and children. In this study, Mn concentrations reported to California’s Safe Drinking Water Information System were used to estimate the potentially exposed population within California based on system size. We estimate that between 2011 and 2021, over 525,000 users in areas with reported Mn data are potentially exposed to Mn concentrations exceeding the WHO health-based guideline (80 μg L …

Investigation Of The Sheep Creek Carbonatites, Ravalli County, Montana, Sarah Risedorf

Graduate Theses & Non-Theses

Carbonatite-related REE-Nb mineralization in southern Ravalli County, Montana was first discovered in the late 1950s and early 1960s. Over 30 discontinuous carbonatite bodies occur in a ~ 10 km² area centered on Sheep Creek, a tributary to the headwaters of the West Fork of the Bitterroot River (WFBR). The deposits are contained in a belt that extends to the southeast into the Mineral Hill district of Lemhi County, Idaho. Country rocks include a deformed and metamorphosed bimodal igneous suite of diabase and A-type granite, both dated to 1.37 Ga by previous workers. These rocks are locally metamorphosed to amphibolite …