Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Earth Sciences

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 52171 - 52200 of 59400

Full-Text Articles in Entire DC Network

Theory Of Dipole Flow In Uniform Anisotropic Aquifers, Vitaly A. Zlotnik, Glenn Ledder Apr 1996

Theory Of Dipole Flow In Uniform Anisotropic Aquifers, Vitaly A. Zlotnik, Glenn Ledder

Department of Earth and Atmospheric Sciences: Faculty Publications

A theory of dipole flow is developed to model flow induced by a vertical circulation well consisting of injection and extraction chambers in a single borehole. Included in the theory are an analytical description of the kinematic flow structure around a vertical circulation well and the drawdown in the well chambers. Using Stokes’ stream function, simple criteria are derived to determine the region of intensive recirculation. This region extends (from the dipole center) approximately five distances between chamber centers in the radial direction and two distances between chamber centers in both vertical directions. The vertical scale does not depend on …


Observation Of Shelfwater Overrunning The Southern Slope Sea, Ajoy Kumar Apr 1996

Observation Of Shelfwater Overrunning The Southern Slope Sea, Ajoy Kumar

OES Theses and Dissertations

Analyses of two years (1992 and 1993) of high resolution (1.47 km2) sea surface temperature satellite images of the southern Mid-Atlantic Bight (MAB), showed that unusually extensive overhang of shelf water occurs episodically, and coherently over along shelf distances of several hundred kilometers. These episodes are dubbed overrunning of the Slope Sea by shelf water. The overrunning volume has a "face" and a "back" (southern and northern limit). It transports substantial quantities of shelf water southward, and does not retreat onto the shelf, but eventually joins the western edge of the Gulf Stream in the vicinity of Chesapeake …


A One-Dimensional Model For Storm Breaching Of Barrier Islands, Cheol Shik Shin Apr 1996

A One-Dimensional Model For Storm Breaching Of Barrier Islands, Cheol Shik Shin

Civil & Environmental Engineering Theses & Dissertations

A set of numerical models is developed for simulating the four stages of barrier breaching characterized by one horizontal spatial dimension.

The SBEACH model is employed for the first stage of dune/beach erosion. The Lax-Wendroff two-step explicit scheme for Stage II is developed to simulate initiation of ocean flood propagation on initially dry barrier islands and the method of characteristics (MOC), is employed to compute additional boundary data. The development of the Preissmann implicit scheme for water motion and a forward time centered space explicit scheme for sediment motion in Stages III and IV provide a tool to study the …


Factors Affecting Nitrogen Fixation Rates In Termites (Isoptera: Rhinotermitidae: Reticulitermes) And Termite Nitrogen Contributions Of Forest Ecosystems, Anthony Duane Curtis Apr 1996

Factors Affecting Nitrogen Fixation Rates In Termites (Isoptera: Rhinotermitidae: Reticulitermes) And Termite Nitrogen Contributions Of Forest Ecosystems, Anthony Duane Curtis

Biological Sciences Theses & Dissertations

Termites host symbiotic bacteria that fix atmospheric nitrogen, which makes termites important in the biogeochemical cycling of nitrogen in ecosystems. The objective of this study was to estimate annual nitrogen contributions by termites by examining seasonal rates of nitrogen fixation, seasonal abundance of different termite castes and their nitrogenase activity, the effects of dietary nitrogen on nitrogenase activity, and low oxygen and high carbon dioxide atmospheres on termite nitrogenase activity, and the accuracy of mark-recapture studies to estimate termite population size.

Termite nitrogen fixation rates were monitored monthly for 10 Reticulitermes Holmgren colonies from June, 1993, to December, 1995. Rates …


Groundwater Recharge Of The Middle Deschutes Basin, Oregon, Thomas Gene Boyd Mar 1996

Groundwater Recharge Of The Middle Deschutes Basin, Oregon, Thomas Gene Boyd

Dissertations and Theses

All surface water in the Middle Deschutes River basin of Oregon has already been allocated. Growth in the basin has put pressure on the Oregon Water Resources Department (OWRD) to grant an increasing number of groundwater permits. The OWRD is concerned that the allocation of too much groundwater will cause adverse effects on other groundwater users and surface water supplies and ultimately lead to groundwater depletion. For this reason, the U.S. Geological Survey is presently undertaking the first in-depth study of the groundwater resources of the basin.

As part of this USGS study, I estimated recharge rates and their distribution …


Long-Term Surveillance Plan For The South Clive Disposal Site, Clive, Utah, Jacobs Engineering Group Inc. Mar 1996

Long-Term Surveillance Plan For The South Clive Disposal Site, Clive, Utah, Jacobs Engineering Group Inc.

All U.S. Government Documents (Utah Regional Depository)

No abstract provided.


Flash-Flood Monitoring And Modeling In Kentucky, Mark French, Nageshwar Bhaskar, George K. A. Kyiamah Mar 1996

Flash-Flood Monitoring And Modeling In Kentucky, Mark French, Nageshwar Bhaskar, George K. A. Kyiamah

KWRRI Research Reports

This research project focused on the evaluation of hydrologic issue of flash-flooding in the state of Kentucky. The primary objectives of this project were the following:
(1) to initiate the establishment of a hydrologic database archive necessary for characterizing rainfall and runoff associated with flash-flooding;
(2) identification of appropriate modeling approaches for evaluating site-specific flash-flood runoff behavior.

Specific tasks accomplished to meet the objectives include the following:
(1) development of a rainfall and streamflow data archive using existing measurement gages and identification of the rain gage data from two sources for preliminary quality control;
(2) identification of the spatial and …


Marketing Options For Quality Kentucky Alfalfa Hay, Tom Keene Feb 1996

Marketing Options For Quality Kentucky Alfalfa Hay, Tom Keene

Kentucky Alfalfa and Stored Forage Conference

As today's farmer becomes more and more business like, running his farming operation as a commercial business, the production of alfalfa hay should be treated no differently. When the farmer makes the decision to plant alfalfa, he should have already done a great deal of research and given a great deal of thought into the markets he is going to try to target for his product. Any successful commercial business looks into market potential even before production begins, whether they produce toys, cars, appliances, computers, etc. Alfalfa hay production should be no different in regards to seeking out various markets …


What Leading Alfalfa Growers Do To Produce Quality Hay, Jimmy C. Henning, Garry D. Lacefield, Buddy Sims Feb 1996

What Leading Alfalfa Growers Do To Produce Quality Hay, Jimmy C. Henning, Garry D. Lacefield, Buddy Sims

Kentucky Alfalfa and Stored Forage Conference

Alfalfa is the highest quality forage legume crop grown in Kentucky and is the number one cash hay crop. Hay raised by Kentucky farmers has been recognized for its quality at local, state (state fair and Kentucky Alfalfa Conference), and national (American Forage and Grassland Council) hay contests. The testing records of the Kentucky Department of Agriculture also document the high quality alfalfa hay of Kentucky. However, little has been written about the farm practices used to produce high quality alfalfa hay in Kentucky. The current practices of top hay growers may be helpful in defining the options available to …


Are We Making Progress With Hay Quality In Kentucky?, Buddy Sims Feb 1996

Are We Making Progress With Hay Quality In Kentucky?, Buddy Sims

Kentucky Alfalfa and Stored Forage Conference

During the Kentucky State Fair, Garry Lacefield asked if I would be on the XVI Kentucky Alfalfa Conference program. Certainly I never miss an opportunity to talk, especially about testing forages. Then in October we communicated again and it was decided that my topic would be "Are We Making Progress With Hay Quality in Kentucky?" Seems like a simple yes or no question! Well ... l elected to think about this under the middle of December. Of course, during this time, the people of the Commonwealth elected a new Commissioner of Agriculture. Your selection was Billy Ray Smith, who throughout …


Role Of Alfalfa In Our Farming Operation, Larry Jeffries Feb 1996

Role Of Alfalfa In Our Farming Operation, Larry Jeffries

Kentucky Alfalfa and Stored Forage Conference

Our farming operation consists of 214 acres. We raise 14,000 pounds of tobacco, have a purebred beef cattle herd, and sell hay. Alfalfa is the only one of the three sources of income that we can project an increase for 1996.

Our alfalfa cash hay sales have increased for several years due to the increase of suburban horse owners in the Louisville area.

I think it is important to have a written plan for 1996. We wouldn't think of making a long trip without a map, especially into strange territory - we farmers are in strange territory. If you don't …


Utilizing Alfalfa Hay In Horse Diets, Laurie Lawrence Feb 1996

Utilizing Alfalfa Hay In Horse Diets, Laurie Lawrence

Kentucky Alfalfa and Stored Forage Conference

All horses need fiber in their diets. Forages, usually as pasture or hay, are the primary sources of fiber in most rations. The exact amount of hay that a horse will eat on a daily or yearly basis will depend on the size of the horse, the class of the horse (pregnant, working, etc) and the type of hay being fed. The type and amount of other feeds in the ration will also impact the amount of hay consumed, but in general, horse owners/managers should try to maximize forage intake and then supplement with grain or other feeds to meet …


Advances In Harvesting And Storing High Quality Alfalfa, Michael Collins Feb 1996

Advances In Harvesting And Storing High Quality Alfalfa, Michael Collins

Kentucky Alfalfa and Stored Forage Conference

On suitable soils, alfalfa produces the highest yields of dry matter and nutrients possible under Kentucky conditions. Limitations to achievement of this potential are often related to losses that occur during alfalfa harvest and storage. We have conducted a number of studies addressing technologies designed to minimize the extent of these losses.


Fencing And Watering Systems For Grazing Alfalfa, Larry Turner Feb 1996

Fencing And Watering Systems For Grazing Alfalfa, Larry Turner

Kentucky Alfalfa and Stored Forage Conference

Controlled or rotational grazing can result in better utilization of the forage resources on your farm. By better forage management through controlled grazing, you can increase profitability of cattle/forage systems. To effectively develop a controlled grazing system, however, fencing must be used to subdivide the pasture into sub-fields or paddocks. The animals may then be rotated among the paddocks to optimize forage and beef or dairy production from the system. Alfalfa grazing can play an important part in such a system. By using alfalfa, additional grazing management options are available, including avoiding high-endophyte fescue in hot summer periods thereby gaining …


Opportunities For Alfalfa As A Grazing Crop In Kentucky, Ken Johnson Feb 1996

Opportunities For Alfalfa As A Grazing Crop In Kentucky, Ken Johnson

Kentucky Alfalfa and Stored Forage Conference

As we think about the possibilities of alfalfa as a grazing crop, maybe we need to look at some of the limitations and where alfalfa may fit into Kentucky producers programs.

When looking at Kentucky's land area of 25 million acres we see that nearly half is in woodland. Of the 12 million acres remaining; about 3 million is in row crops, 2 million in hay, 2 million in non farm uses, and the rest is pasture. That is about 5 million acres in pasture or at least available to the pastured. With at least 7 million acres in hay …


Grazing Alfalfa: Putting The Puzzle Together, Garry D. Lacefield, Jimmy C. Henning, David Stalion Feb 1996

Grazing Alfalfa: Putting The Puzzle Together, Garry D. Lacefield, Jimmy C. Henning, David Stalion

Kentucky Alfalfa and Stored Forage Conference

Interest in alfalfa as a grazing crop has increased dramatically over the past decade. There are many research and demonstrations being conducted in Kentucky and across the U.S. as we continue to investigate and learn more about alfalfa's role in forage-based livestock production.

Listed below are some of the reasons farmers, researchers and agribusiness personnel are excited about the opportunity for alfalfa as a grazing crop.


Foreword [1996], Garry D. Lacefield, Christi L. Forsythe Feb 1996

Foreword [1996], Garry D. Lacefield, Christi L. Forsythe

Kentucky Alfalfa and Stored Forage Conference

This is the front matter of the proceedings.


The Use Of Hydrochemistry To Identify Potential Processes Operating In The Saddle Mountains Basalt Aquifer And The Use Of The Nitrate-Nitrogen Isotope To Distinguish Between Potential Sources Of Nitrate To The Shallow Alluvial Aquifer In The Lower Umatilla Basin, Oregon, Margot Truini Feb 1996

The Use Of Hydrochemistry To Identify Potential Processes Operating In The Saddle Mountains Basalt Aquifer And The Use Of The Nitrate-Nitrogen Isotope To Distinguish Between Potential Sources Of Nitrate To The Shallow Alluvial Aquifer In The Lower Umatilla Basin, Oregon, Margot Truini

Dissertations and Theses

Nitrate concentration in excess of national drinking-water standards (10 mg/l) are present in the shallow alluvial aquifer and Saddle Mountains Basalt (SMB) aquifer in the Lower Umatilla Basin, Oregon. To determine sources responsible for elevated nitrate concentrations in the SMB aquifer mass-balance and reaction-path models (NETPATH and PHREEQE) were used to understand observed geochemical trends. Nitrate-nitrogen isotopes were used to distinguish potential nitrate sources in the shallow alluvial aquifer. NETPATH-validated simple water/rock reactions in the SMB aquifers in Irrigon (dissolving glass, precipitating smectite, dissolving or precipitating calcite, and cation exchange) using constituents (calcium, magnesium, sodium and carbon). Diversity of composition …


Geology Beneath The Primary Management Systems Evaluation Area (Msea) Site Southwest Of Shelton, Buffalo County, Nebraska, Robert F. Diffendal Jr., Frank A. Smith Feb 1996

Geology Beneath The Primary Management Systems Evaluation Area (Msea) Site Southwest Of Shelton, Buffalo County, Nebraska, Robert F. Diffendal Jr., Frank A. Smith

Robert F. Diffendal, Jr., Publications

In 1990, as part of a national presidential initiative on water quality, researchers from the University of Nebraska–Lincoln (UNL) Institute of Agriculture and Natural Resources (IANR) received a multiyear grant from the U.S. Department of Agriculture, Cooperative State Research Service, to study management of irrigated corn and soybeans to minimize groundwater contamination. D. G. Watts, R. F. Spalding, and J.S. Schepers, of the IANR led a study at one of the Management Systems Evaluation Areas (MSEA). This area was made up of two sites, a primary site on a terrace of the Platte River near Shelton and a secondary site …


Geometry Of Continental Normal Faults: Seismological Constraints, Jochen Braunmiller, John L. Nabalek Feb 1996

Geometry Of Continental Normal Faults: Seismological Constraints, Jochen Braunmiller, John L. Nabalek

School of Geosciences Faculty and Staff Publications

Teleseismic body waves from large earthquakes are used to study the downdip geometry of continental normal faults in the Aegean. Waveform modeling techniques together with rigorous statistical tests are applied to put firm bounds on the amount of downdip curvature of these faults and the role of coseismic slip on a basal detachment. Synthetic modeling shows that good azimuthal station coverage and inclusion of SH waves are necessary to resolve fault curvature. The data indicate ruptures of the Aegean events occurred on planar faults extending across the entire brittle portion of the crust. No seismogenic low-angle detachment faulting at the …


Geologic History Of Ash Hollow State Historical Park, Nebraska, Robert F. Diffendal Jr., Roger K. Pabian, J. R. Thomasson Feb 1996

Geologic History Of Ash Hollow State Historical Park, Nebraska, Robert F. Diffendal Jr., Roger K. Pabian, J. R. Thomasson

Conservation and Survey Division: Faculty and Staff Publications

Contents:

Introduction
Acknowledgments
Cautions
General Stratigraphy
Oligocene Series-White River Group-Brule Formation-Whitney Member
Miocene Series-Ogallala Group-Ash Hollow Formation
Pliocene Series-Broadwater Formation
Quaternary deposits
Older colluvium and loess
Younger colluvium and alluvium
General Paleontology
Evidence of past life: fossils and subfossils
Collecting fossils
Vertebrate fossils
Fossils from the Whitney Member of the Brule Formation
Plants
Invertebrates
Vertebrates
Fossils from the Ash Hollow Formation
Plants
Invertebrates
Vertebrates
Fossils from the Broadwater Formation
Plants
Vertebrates
Quaternary fossils
Plants
Invertebrates
Vertebrates
Additional studies of Nebraska fossils
Geologic History
Prehistory and History
References
Appendices I-IV


Paleolimnological Records Of Climatic Change In North America, Sherilyn C. Fritz Feb 1996

Paleolimnological Records Of Climatic Change In North America, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

Lacustrine fossil records provide long time series of data on limnological and climatic conditions; these data are useful for establishing natural patterns of climate variability and for generating testable hypotheses about atmospheric circulation and climate-ecosystem linkages. Shoreline features can indicate past lake-level fluctuations that may reflect changes in moisture balance, but often these records are discontinuous and are evidence of only extreme conditions. The organisms, geochemistry, and sedimentology of lake sediments may provide a more continuous sequence of direct and indirect lake-climate interactions in the past. The most clearly interpretable paleolimnnological records of climatic change are those that use several …


Century-Scale Paleoclimatic Reconstruction From Moon Lake, A Closed-Basin Lake In The Northern Great Plains, Kathleen R. Laird, Sherilyn C. Fritz, Eric C. Grimm, Pietra G. Mueller Feb 1996

Century-Scale Paleoclimatic Reconstruction From Moon Lake, A Closed-Basin Lake In The Northern Great Plains, Kathleen R. Laird, Sherilyn C. Fritz, Eric C. Grimm, Pietra G. Mueller

Department of Earth and Atmospheric Sciences: Faculty Publications

Estimates of past lake-water salinity from fossil diatom assemblages were used to infer past climatic conditions at Moon Lake, a climatically sensitive site in the northern Great Plains. A good correspondence between diatom-inferred salinity and historical records of mean annual precipitation minus evapotranspiration (P - ET) strongly suggests that the sedimentary record from Moon Lake can be used to reconstruct past climatic conditions. Century-scale analysis of the Holocene diatom record indicates four major hydrological periods: an early Holocene transition from an open freshwater system to a closed saline system by 7300 B.P., which corresponds with a transition from spruce forest …


Linking Planktonic Diatoms And Climate Change In The Large Lakes Of The Yellowstone Ecosystem Using Resource Theory, Susan S. Kilham, Edward C. Theriot, Sherilyn C. Fritz Feb 1996

Linking Planktonic Diatoms And Climate Change In The Large Lakes Of The Yellowstone Ecosystem Using Resource Theory, Susan S. Kilham, Edward C. Theriot, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

Resource-based physiology of the eight important planktonic diatom species in the large lakes of the Yellowstone region can be used to explain their relative abundances and seasonal changes. The diatoms are ranked along resource ratio gradients according to their relative abilities to grow under limitation by Si, N, P, and light. Hypotheses based on resource physiology can be integrated with observations on seasonal changes in diatom assemblages to explain the present distributions of diatoms and to test the causal factors proposed to explain diatom distributions over the Holocene. Knowledge of the limnology of these lakes and process-oriented physiology provide the …


Geology Beneath The Primary Management Systems Evaluation Area (Msea) Site Southwest Of Shelton, Buffalo County, Nebraska, Robert F. Diffendal Jr., Frank A. Smith Feb 1996

Geology Beneath The Primary Management Systems Evaluation Area (Msea) Site Southwest Of Shelton, Buffalo County, Nebraska, Robert F. Diffendal Jr., Frank A. Smith

Department of Earth and Atmospheric Sciences: Faculty Publications

In 1990, as part of a national presidential initiative on water quality, researchers from the University of Nebraska-Lincoln (UNL) Institute of Agriculture and Natural Resources (IANR) received a multi-year grant from the United States Department of Agriculture, Cooperative State Research Service, to study management of irrigated com and soybeans to minimize groundwater contamination. D.G. Watts, R.F. Spalding, and J.S. Schepers, of the IANR led a study at one of the Management Systems Evaluation Areas (MSEA). This area was made up of two sites, a primary site on a terrace of the Platte River near Shelton and a secondary site nearer …


Fertility Status And Changes Of 50 Crp Fields, Lloyd W. Murdock, Dottie Call Jan 1996

Fertility Status And Changes Of 50 Crp Fields, Lloyd W. Murdock, Dottie Call

Soil Science News and Views

The CRP program in Kentucky has 435,000 acres ofland which will be released soon. Since these fields were highly eroded when they were placed into the program, it was felt it would be helpful to determine the general fertility status of the CRP fields in Kentucky and see what changes had taken place during their years of enrollment in the CRP program. Since most of the fields had a previous erosive history, we expected the fields to be low in pH and in the low to medium range for phosphorus and potassium.

We would like to thank the producers who …


Seeding Cover Crops In Kentucky, Kenneth L. Wells, Morris J. Bitzer Jan 1996

Seeding Cover Crops In Kentucky, Kenneth L. Wells, Morris J. Bitzer

Soil Science News and Views

The most common reason for seeding a cover crop is to establish cover onto a tilled area following harvest of the previous crop, or onto a disturbed area for a "critical seeding", as soon as possible after tillage or disturbance. The reason for establishing the cover crop is to stabilize the exposed surface of bare soil to prevent erosion.


Soils Of The Weaber Plain, East Kimberley, Western Australia, J C. Dixon Jan 1996

Soils Of The Weaber Plain, East Kimberley, Western Australia, J C. Dixon

Resource management technical reports

The Weaber Plain, north-east of Kununurra, is one of three "black soil" plains in the Kimberley area of Western Australia. It comprises about 15,000 hectares of irrigable land, part of which is known as Stage 2 of the Ord River Irrigation Area (ORIA). The area was surveyed in 1977 following a similar survey of the nearby Keep River Plain and preceding a survey of the Ivanhoe Plain, which has since been developed commercially. Map units and soil series used in those reports have also been used for this rep ility in crop selection, preferring high water use crops.


The Anomalous Behavior Of Sh‐Waves Across The Water Table, P. Michaels, W. Barrash Jan 1996

The Anomalous Behavior Of Sh‐Waves Across The Water Table, P. Michaels, W. Barrash

CGISS Publications and Presentations

Most theoretical studies of seismic wave propagation in a porous medium do not predict a significant increase in SH-wave velocity with increasing water saturation. Although that type of behavior is commonly predicted for P-waves (and confirmed by countless observations), the expectation for SH-waves is a slight decrease in propagation velocity with increasing water saturations. While published measurements of SH-wave velocity in laboratory studies have been supportive of such a slight decrease in velocity, the data have been biased towards high pressures (typical of oil reservoirs at large depths of burial). On the other hand, the few published low pressure laboratory …


No-Tilling Corn Into Hairy Vetch: Fertilizer Nitrogen Substitution Without Penalty Due To Delayed Planting, H. M. Saha, John H. Grove Jan 1996

No-Tilling Corn Into Hairy Vetch: Fertilizer Nitrogen Substitution Without Penalty Due To Delayed Planting, H. M. Saha, John H. Grove

Soil Science News and Views

Previous studies conducted in Kentucky have shown that hairy vetch is an agronomically viable winter legume cover crop for notill corn production. However, to fully realize the benefits of this cover crop it is necessary to allow enough time for it to accumulate biomass and nitrogen (N) before no-till corn is planted. Thus, early corn planting may not always be feasible. Since delaying corn planting after May 15 in Kentucky usually leads to a decline in corn grain yields, the main question addressed in this study (one for which little information was available) was whether the benefits provided by hairy …