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Articles 53071 - 53100 of 59392
Full-Text Articles in Entire DC Network
Effects Of Tillage And Grass Filter Strips On Surface Runoff Of Water, Nitrate, Sediment, And Atrazine, C. E. Madison, Robert L. Blevins, Wilbur Frye
Effects Of Tillage And Grass Filter Strips On Surface Runoff Of Water, Nitrate, Sediment, And Atrazine, C. E. Madison, Robert L. Blevins, Wilbur Frye
Soil Science News and Views
The contamination of streams and other natural bodies of water through agricultural runoff has become a very important environmental issue. Surface water runoff can contain heavy loads of sediment and/or agricultural chemicals, such as nitrogen and atrazine. Conservation tillage methods with vegetative filter strips downslope from cropped fields help· to combat this problem. Conservation tillage has proven effective in decreasing erosion by decreasing exposure of the soil surface to rainfall. Vegetative filter strips provide an area where sediment and agricultural chemicals from cropland can be deposited before the runoff reaches a body of water.
Poultry Litter As A Nitrogen Source For Corn, Monroe Rasnake, Larry Reber
Poultry Litter As A Nitrogen Source For Corn, Monroe Rasnake, Larry Reber
Soil Science News and Views
Development of an intensive poultry production industry in western and south-central Kentucky will make poultry litter available to many farmers. It is estimated that 45, 000 tons per year will be produced just in the Jackson Purchase Area. One of the most efficient uses of this litter is as a nitrogen fertilizer source for corn.
Use Of Fluorogypsum To Reduce Subsoil Acidity In A Fragipan Soil, Grant W. Thomas, Gerald R. Haszler
Use Of Fluorogypsum To Reduce Subsoil Acidity In A Fragipan Soil, Grant W. Thomas, Gerald R. Haszler
Soil Science News and Views
In western Kentucky, there are several million acres of fragipan soils which are characterized by both acid subsoils and fragipans which commence at depths of 20 to 30 inches below the soil surface. The combination of subsoil acidity and a fragipan with massive structure impedes root growth and water movement, diminishing, somewhat, the usefulness of the soils for crop production. Alfalfa, a crop which is very sensitive to soil acidity and to poor drainage, was chosen as a test crop to measure the effects of adding fluorogypsum to Sadler silt loam, a soil representative of the fragipan soils found in …
Factors Affecting Crop Response To Liming, Kenneth L. Wells, J. L. Sims
Factors Affecting Crop Response To Liming, Kenneth L. Wells, J. L. Sims
Soil Science News and Views
Soil acidity levels directly affect the rate, kinds, and degree of chemical reactions which take place in soil. Crops respond to varying degrees to these chemical reactions. For the most part, these reactions affect the solubility of mineral elements in soil and the activity of the soil's biological processes. As a result, the availability of many plant nutrient elements is regulated by soil acidity. The level of availability of plant required nutrients can be adequate, deficient, or toxic to the plant, depending on the nutrient, soil acidity, and the crop. That is why measurement of soil acidity is regarded by …
Developing Efficient Crop Production Systems, Kenneth L. Wells
Developing Efficient Crop Production Systems, Kenneth L. Wells
Soil Science News and Views
Land is initially the most limiting resource to consider in setting up a farm system aimed at maximizing returns. This is because soil, its topographical features, and its physical and chemical properties are largely fixed. There is little which can be done about them except to manage soil fertility and control erosion. Over the long run, crop production from any land tract will be directly influenced by the nature and character of the soils in that land tract. For this reason, the most basic step in initiating or redesigning a farming operation is to get an evaluation of the soil …
Geology And Stratigraphy Of The Western Kentucky Coal Field, Stephen F. Greb, David A. Williams, Allen D. Williamson
Geology And Stratigraphy Of The Western Kentucky Coal Field, Stephen F. Greb, David A. Williams, Allen D. Williamson
Bulletin--KGS
The Pennsylvanian rocks of the Western Kentucky Coal Field produce between 40 and 55 million tons of coal a year from as many as 45 coal seams; however, three seams produce more than 75 percent of the total. In addition, Pennsylvanian strata contain numerous oil and natural gas reservoirs, tar-sand reservoirs, and industrial minerals. Pennsylvanian sandstones are also some of the most important bedrock aquifers in the coal field. Because of the economic importance of the Pennsylvanian strata to the region and the Commonwealth as a whole, a better understanding of these rocks is needed. This description of the nomenclature …
Low-Silica And High-Calcium Stone In The Newman Limestone (Mississippian) On Pine Mountain, Letcher County, Southeastern Kentucky, Garland R. Dever Jr., Thomas L. Robl, Jack R. Moody, Frank H. Walker, George W. Ellsworth Jr., Lance S. Barron
Low-Silica And High-Calcium Stone In The Newman Limestone (Mississippian) On Pine Mountain, Letcher County, Southeastern Kentucky, Garland R. Dever Jr., Thomas L. Robl, Jack R. Moody, Frank H. Walker, George W. Ellsworth Jr., Lance S. Barron
Information Circular--KGS
The coal industry of Kentucky is an important market for limestone. Coal producers use limestone as rock dust for explosion abatement in underground coal mines and as a neutralizing agent in surface-mine reclamation and acid-drainage control. Haulage-road construction and maintenance require crushed stone.
Coal-bearing rocks of Pennsylvanian age in the Eastern Kentucky Coal Field generally do not contain limestones that are sufficiently thick to quarry or mine economically, but in the southeastern part of the coal field, fault movement has brought the Newman Limestone to the surface along Pine Mountain. The Newman was sampled at three sites in Letcher County …
Geologic Highway Cross Sections: Interstate Highway 75 Conway, Kentucky, To Jellico, Tennessee, Donald R. Chesnut Jr.
Geologic Highway Cross Sections: Interstate Highway 75 Conway, Kentucky, To Jellico, Tennessee, Donald R. Chesnut Jr.
Map and Chart--KGS
Highway roadcuts along Interstate Highway 75 from Conway, Kentucky, to Jellico, Tennessee, expose Mississippian and Pennsylvanian rocks in south-central Kentucky (Fig. 1). The roadcut exposures offer easy access and stratigraphic variety for educational purposes, and are ideal for high school, university, and professional geology field trips. Several national and international field trips, and many out-of-State university field trips have examined these exposures. In addition, scientific studies involving elastic and carbonate sedimentology, coal geology, paleontology, biostratigraphy, and karst (cave) development have been undertaken along this road.
Design, Construction, And Monitoring Of The Ground-Water Resources Of A Large Mine-Spoil Area: Star Fire Tract, Eastern Kentucky, David R. Wunsch, James S. Dinger, Page B. Taylor
Design, Construction, And Monitoring Of The Ground-Water Resources Of A Large Mine-Spoil Area: Star Fire Tract, Eastern Kentucky, David R. Wunsch, James S. Dinger, Page B. Taylor
Report of Investigations--KGS
By the year 2010, the Star Fire mining operation in Knott, Breathitt, and Perry Counties in eastern Kentucky, which uses mountaintop-removal and hollow-fill mining techniques, will have created approximately 5,000 acres of gently rolling terrain that could support alternative land uses. The present research is centered on approximately 1,000 acres of spoil created since mining began in 1981. An aquifer fed by both ground and surface water will be created within the spoil. Spoil-handling techniques such as cast blasting, dragline placement, end dumping by trucks, and surface grading have created porous coarse-rock zones within the spoil through which ground water …
The Role Of Benthic Fluxes Of Dissolved Organic Carbon In Oceanic And Sedimentary Carbon Cycling, Davd J. Burdige, Marc J. Alperin, Juliana Homstead, Christopher S. Martens
The Role Of Benthic Fluxes Of Dissolved Organic Carbon In Oceanic And Sedimentary Carbon Cycling, Davd J. Burdige, Marc J. Alperin, Juliana Homstead, Christopher S. Martens
OES Faculty Publications
Benthic fluxes (sediment-water exchange) of dissolved organic carbon (DOC) represent a poorly quantified component of sedimentary and oceanic carbon cycling. In this paper we use pore water DOC data and direct DOC benthic flux measurements to begin to quantitatively examine this problem. These results suggest that marine sediments represent a significant source of DOC to the oceans, as a lower limit of the globally-integrated benthic DOC flux is comparable in magnitude to riverine inputs of organic carbon to the oceans. Benthic fluxes of DOC also appear to be similar in magnitude to other sedimentary processes such as organic carbon oxidation …
Boulder Streams, Debris Fans, And Pleistocene Climate Change In The Blue Ridge Mountains Of Central Virginia, G. Richard Whittecar, Derek W. Ryter
Boulder Streams, Debris Fans, And Pleistocene Climate Change In The Blue Ridge Mountains Of Central Virginia, G. Richard Whittecar, Derek W. Ryter
OES Faculty Publications
The west slope of the Blue Ridge mountains in central Virginia is a polygenetic landscape containing interglacial and periglacial features. This paper proposes a general model relating the distribution and origin of hillslope and toeslope Quaternary landforms to climatically influenced geomorphic processes. Two generations of interglacial debris fans in the study area differ in their degree of soil development and clast weathering. Boulder streams, which clog debris flow chutes for the upper debris fans, are interpreted as solifluction features formed during successive periglacial episodes. Growth of the boulder streams and associated talus slopes can influence the magnitude and frequency of …
Denitrification In The Elk Valley Aquifer, Northeastern North Dakota, Gale G. Mayer
Denitrification In The Elk Valley Aquifer, Northeastern North Dakota, Gale G. Mayer
Theses and Dissertations
Biological denitrification controls nitrate distribution in the Elk Valley aquifer, which underlies approximately 725 square kilometres of northeastern North Dakota and provides drinking water for farms and rural communities in the area. Increased irrigation has raised concerns over potential contamination from agricultural practices. The purpose of this study was to establish the role of biological denitrification in minimizing concentration and distribution of nitrate and to determine the effect irrigation practices have on groundwater flow and nitrate distribution in the saturated zone.
The aquifer is unconfined and consists of up to 20 metres of glacial outwash and deltaic shale-rich sand deposits. …
The Stratigraphy And Sedimentology Of The Sentinel Butte Formation (Paleocene) In South-Central Williams County, North Dakota, Wesley D. Peck
The Stratigraphy And Sedimentology Of The Sentinel Butte Formation (Paleocene) In South-Central Williams County, North Dakota, Wesley D. Peck
Theses and Dissertations
Approximately 163 meters (535 feet) of the Paleocene Sentinel Butte Formation crop out in southcentral Williams county, North Dakota. To determine their mode of deposition and stratigraphic position within the formation, twelve stratigraphic sections were measured. These strata were deposited in alternating fluvial and lacustrine environments as determined by sedimentary structures, lithology, lithologic sequences, and fossil occurrences. A fining upward trend in grain size of the tabular sandstones, and the identification of epsilon cross-stratification in the tabular sandstones support a fluvial origin for some of the strata. The strongest evidence for the interpretation of lacustrine deposition is the presence of …
Row Cleaners In No-Till Corn, Lloyd W. Murdock, James H. Herbek, Tim Gray
Row Cleaners In No-Till Corn, Lloyd W. Murdock, James H. Herbek, Tim Gray
Soil Science News and Views
Row cleaners are planter attachments mounted in front of the double-disc openers on planters. They are designed to move most of the surface residue to the sides of the row, allowing no-till planting into a band with a fairly clean surface. This attachment is best suited for wet, cool soils to allow a more rapid warming of the soil surface, on rough soil to allow some smoothing before planting, and in heavy residue to prevent "hairpinning" of residue into the planting slot. There is evidence that cleaning the residue from the row raises soil temperatures which results in quicker corn …
The Origin Of Metalliferous Argillites In The Shoal Arm Formation Of North-Central Newfoundland, Volker Brüchert
The Origin Of Metalliferous Argillites In The Shoal Arm Formation Of North-Central Newfoundland, Volker Brüchert
Geology Theses and Dissertations
The Middle Ordovician Shoal Arm Formation, which is located in the central volcanic belt of north-central Newfoundland, is a tripartite assemblage of hematitic argillites, grey cherts, and black shales directly underlying a flysch sequence. The hematitic argillites are enriched in Fe, Mn, Ni, Pb, and Co. Factor analysis and principal component analysis indicate the presence of a hydrothermal component, presumably derived from hydrothermal activity in the coeval Lawrence Head volcanics. Unusual, (?) calcareous Mn-Fe-oxide nodules are present in the top parts of turbidites in the hematitic argillites. Electron microprobe analysis of a color transition from a red to a green …
Thermal-Mechanical Response To An Intruding Magma Chamber, Christoph Arz
Thermal-Mechanical Response To An Intruding Magma Chamber, Christoph Arz
Geology Theses and Dissertations
The thermal-mechanical response of rock at shallow to medium depth beneath the earth's surface has been modeled as a magma body ascends toward it. The overall stress field is calculated by considering the country rock as a viscous fluid, a thermal-elastic material, or as an elasto-plastic material that fractures when its strength is overcome.
The stress field within and around a spherical magma body surrounded by a homogeneous, Newtonian fluid has been evaluated and can be used at deeper levels in the earth's crust where the viscosity of the country rock is relatively low. With decreasing depth wall rock material …
A Kinematic Study Of The Summit Valley Plutonic Complex, Klamath Mountains, California, Nancy E. Griesau
A Kinematic Study Of The Summit Valley Plutonic Complex, Klamath Mountains, California, Nancy E. Griesau
Geology Theses and Dissertations
The Summit Valley plutonic complex (SVPC) is a multi-phase intrusive body of Late Jurassic age. Crystallization age for a zircon of 150±1 Ma and a cooling age for a hornblende of 144±1 Ma indicate a protracted period of high temperature. The SVPC is irregularly shaped, covers <15 km2, and is believed to be in the western limb of a post-Nevadan syncline, with an easterly dip estimated at about 45°. The SVPC penetrated the Orleans Fault and intruded and contact metamorphosed the upper and lower plates of the thrust. The Orleans Fault is a major tectonic boundary separating the Western Paleozoic …15>
The Geology Of The Vermont Valley And The Western Flank Of The Green Mountains Between Dorset Mountain And Wallingford, Vermont, Rolf Herrmann
The Geology Of The Vermont Valley And The Western Flank Of The Green Mountains Between Dorset Mountain And Wallingford, Vermont, Rolf Herrmann
Geology Theses and Dissertations
The carbonate sequence of the Vermont Valley has been generally believed to lie on the east limb of a major unfaulted syncline ("Middlebury Synclinorium"), and the exposed Precambrian basement and overlying cover rocks of the Green Mountain massif on the west limb of the adjacent major unfaulted anticline ("Green Mountain Anticlinorium"). Except for the Basal Thrust of the Taconic Allochthon, all faults shown on previous maps die out north of Dorset Mountain.
In contrast, detailed mapping for this thesis in the Vermont Valley and the western flank of the Green Mountain massif has revealed several major north/south trending thrust faults, …
The Last Interglacial-Glacial Transition In North America: Evidence From Uranium-Series Dating Of Coastal Deposits, Daniel R. Muhs
The Last Interglacial-Glacial Transition In North America: Evidence From Uranium-Series Dating Of Coastal Deposits, Daniel R. Muhs
United States Geological Survey: Staff Publications
Considerable uncertainty exists as to whether the last interglacial was relatively "short" (~10 ka) or "long" (-20-60 ka), although most investigators generally agree that the last interglacial correlates with all or part of deep-sea oxygen-isotope stage 5. A compilation of reliable U-series ages of marine terrace corals from deposits that have been correlated with isotope stage 5 indicates that there were three relatively high sea-level stands at ca 125-120 ka, ca. 105 ka, and ca. 85-80 ka, and these ages agree with the times of high sea level predicted by the Milankovitch orbital-forcing theory. At a number of localities, however, …
A Brief Literature Review Of Open-Channel Current Meter Testing, Kirk G. Thibodeaux
A Brief Literature Review Of Open-Channel Current Meter Testing, Kirk G. Thibodeaux
United States Geological Survey: Staff Publications
The U.S. Geological Survey (USGS) has undertaken the task of conducting an evaluation of the USGS's standard water-flow current meter, the Price type-AA current meter. The first part of the USGS's task was to conduct a comprehensive literature review to determine the extent and types of testing that has been conducted to evaluate the performance of various types of current meters used for open-channel flow measurements. The meter types included in the review were the vertical-axis mechanical type, the horizontal-axis mechanical type, the electromagnetic type, and the point-velocity acoustic (ultrasonic) type current meters. The review revealed that current meters have …
In Situ Stress Measurements To 3.5 Km Depth In The Cajon Pass Scientific Research Borehole: Implications For The Mechanics Of Crustal Faulting, Mark D. Zoback, John H. Healy
In Situ Stress Measurements To 3.5 Km Depth In The Cajon Pass Scientific Research Borehole: Implications For The Mechanics Of Crustal Faulting, Mark D. Zoback, John H. Healy
United States Geological Survey: Staff Publications
Measurements of in situ stress orientation and magnitude at the site of the Cajon Pass research borehole have been made from depths of 0.9-3.5 km using the hydraulic fracturing technique and analysis of stress-induced well bore breakouts. The results of these measurements support two important conclusions about the mechanics of crustal faulting. First, the magnitudes of measured in situ stresses indicate ratios of shear to normal stress. on favorably oriented fault planes that are consistent with predictions based on Mohr-Coulomb theory and laboratory-determined coefficients of friction in the range of 0.6-1.0 assuming hydrostatic pore pressure (this is commonly known as …
Stress Field Constraints On Intraplate Seismicity In Eastern North America, Mary Lou Zoback
Stress Field Constraints On Intraplate Seismicity In Eastern North America, Mary Lou Zoback
United States Geological Survey: Staff Publications
Focal mechanisms of 32 North American midplate earthquakes (mb = 3.8-6.5) were evaluated to determine if slip is compatible with a broad-scale regional stress field derived from plate-driving forces and, if so, under what conditions (stress regime, pore pressure, and frictional coefficient). Using independent information on in situ stress orientations from well bore breakout and hydraulic fracturing data and assuming that the regional principal stresses are in approximately horizontal and vertical planes ( ± 10 °), the constraint that the slip vector represents the direction of maximum resolved shear stress on the fault plane was used to calculate relative …
Geologic Highway Cross Sections: Interstate Highway 64 Farmers To Catlettsburg, Kentucky, Donald R. Chesnut Jr.
Geologic Highway Cross Sections: Interstate Highway 64 Farmers To Catlettsburg, Kentucky, Donald R. Chesnut Jr.
Map and Chart--KGS
Highway roadcuts along Interstate Highway 64 from Farmers to Catlettsburg, Kentucky, provide scientifically significant exposures of rocks of Devonian, Mississippian, and Pennsylvanian ages in northeastern Kentucky. The roadcut exposures offer easy access to a variety of stratigraphic units and are ideal for educational field trips. However, Kentucky law prohibits vehicles from stopping on the shoulders of limited- access highways except in case of emergency, so any planned field trips must be coordinated with State authorities. Several national and international field trips, as well as many out-of-State university field trips, have examined these exposures. In addition, scientific studies involving carbonate sedimentology, …
Stratigraphic And Structural Framework Of The Carboniferous Rocks Of The Central Appalachian Basin In Kentucky, Donald R. Chesnut Jr.
Stratigraphic And Structural Framework Of The Carboniferous Rocks Of The Central Appalachian Basin In Kentucky, Donald R. Chesnut Jr.
Bulletin--KGS
A series of seven cross sections across the Central Appalachian Basin in Kentucky, Tennessee, Virginia, West Virginia, and Ohio was constructed in order to determine a stratigraphic and structural framework of the Carboniferous rocks for the basin. Oil and gas well logs, coal-company core descriptions, measured sections, and mapping of surface geology were used to construct these sections. New surface and subsurface faults, folds, and flexures were identified.
New, formal and informal lithostratigraphic nomenclature was introduced to clarify the stratigraphic framework. Formalized nomenclatural changes are (1) elevating Breathitt Formation to Breathitt Group, (2) dropping the Lee Formation, (3) elevating four …
Available Coal Resources Of The Booneville 7.5–Minute Quadrangle, Owsley County, Kentucky, Gerald A. Weisenfluh, R. E. Andrews, John K. Hiett, Stephen F. Greb, Richard E. Sergeant, Donald R. Chesnut Jr.
Available Coal Resources Of The Booneville 7.5–Minute Quadrangle, Owsley County, Kentucky, Gerald A. Weisenfluh, R. E. Andrews, John K. Hiett, Stephen F. Greb, Richard E. Sergeant, Donald R. Chesnut Jr.
Information Circular--KGS
The Booneville Quadrangle lies within the Southwestern Reserve District of the Eastern Kentucky Coal Field. Six coal beds in the quadrangle have been commercially developed, mainly by surface mining methods, and comprise the basis of this Coal Availability Study. These beds are, in descending stratigraphic order, Copland, Whitesburg, Amburgy, Upper Elkhorn No. 3, Jellico and Manchester. A computerized Geographic Information System (GRASS) was used to calculate estimates of original, mined-out and remaining resources, restrictions to mining and available resources.
Groundwater Levels In Nebraska, 1991, Gregory V. Steele, Perry B. Wigley
Groundwater Levels In Nebraska, 1991, Gregory V. Steele, Perry B. Wigley
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Groundwater-Level Changes In Nebraska, Predevelopment To Fall 1992, Conservation Survey Division, U.S. Geological Survey
Groundwater-Level Changes In Nebraska, Predevelopment To Fall 1992, Conservation Survey Division, U.S. Geological Survey
Conservation and Survey Division: Faculty and Staff Publications
No abstract provided.
Evaluation Of Gamma Ray Attenuation For Measuring Soil Bulk Density Part I. Laboratory Investigation, Xiwen Luo, Larry G. Wells
Evaluation Of Gamma Ray Attenuation For Measuring Soil Bulk Density Part I. Laboratory Investigation, Xiwen Luo, Larry G. Wells
Biosystems and Agricultural Engineering Faculty Publications
Gamma ray attenuation was evaluated as a means of determining soil bulk density. Experiments were conducted using clay, silt, and sandy loam soils wherein samples were compacted to uniform densities at various moisture contents. We determined the attenuation characteristics of dry soil to be independent of soil texture while being significantly different from that of water. Comparison of gamma density measurements with known soil sample densities indicated that the gamma gauge provided reliable measurement of soil bulk density, provided that the effect of soil moisture on attenuation was accounted for and the manufacturer-prescribed calibration procedure was followed daily. Further, we …
Evaluation Of Gamma Ray Attenuation For Measuring Soil Bulk Density Part Ii. Field Investigation, Larry G. Wells, Xiwen Luo
Evaluation Of Gamma Ray Attenuation For Measuring Soil Bulk Density Part Ii. Field Investigation, Larry G. Wells, Xiwen Luo
Biosystems and Agricultural Engineering Faculty Publications
A field investigation was conducted at sites near Lexington and Central City, Kentucky, to evaluate the use of gamma ray attenuation for measuring soil bulk density. Experiments were conducted whereby the gamma gauge was calibrated by various means and compared with volumetric cores collected from the field soils. Calibration by the manufacturer’s recommended procedure was determined to be as accurate as more rigorous laboratory calibration or calibration via regression of soil bulk density data, provided that the effect of soil water on gamma attenuation is correctly considered. We also developed a linear regression equation to correct for the occurrence of …
Effect Of Sinkholes On Soil Moisture And Ground Water Recharge At An Abandoned Underground Coal Mine Near Wilton, North Dakota, Michael M. Sonderman
Effect Of Sinkholes On Soil Moisture And Ground Water Recharge At An Abandoned Underground Coal Mine Near Wilton, North Dakota, Michael M. Sonderman
Theses and Dissertations
Subsidence at abandoned underground mines in south-central and southwest North Dakota has produced numerous sinkholes. Previous studies in the Northern Great Plains have suggested depression-focused recharge may be a significant ground water recharge mechanism in this region. Thus, sinkholes may increase soil moisture and ground water recharge. Current reclamation practices include filling sinkholes with non-topsoil fill material. However, the benefits of increases in soil moisture and ground water supplies may outweigh the benefits of expensive reclamation. The purpose of this study was to determine whether soil moisture and, hence, the potential for ground water recharge, was greater in sinkholes than …