Open Access. Powered by Scholars. Published by Universities.®
- Institution
-
- University of Kentucky (9522)
- University of Nebraska - Lincoln (1408)
- University of South Florida (620)
- Utah State University (606)
- University of Texas Rio Grande Valley (432)
-
- Old Dominion University (337)
- University of Arkansas, Fayetteville (291)
- Department of Primary Industries and Regional Development, Western Australia (266)
- Western Kentucky University (174)
- University of Nevada, Las Vegas (142)
- Portland State University (140)
- Boise State University (129)
- University of New Hampshire (127)
- Montclair State University (125)
- University of South Carolina (110)
- City University of New York (CUNY) (107)
- TÜBİTAK (107)
- Louisiana State University (105)
- Western Michigan University (98)
- South Dakota State University (93)
- University of Dar es Salaam (86)
- Missouri University of Science and Technology (84)
- University of Colorado Law School (84)
- The University of Southern Mississippi (78)
- University of North Dakota (74)
- Wright State University (71)
- University of Texas at El Paso (66)
- Chapman University (62)
- Universitas Padjadjaran (61)
- China Coal Technology and Engineering Group (CCTEG) (60)
- Keyword
-
- Grazing (393)
- Nitrogen (271)
- Climate change (236)
- Alfalfa (203)
- Soil (187)
-
- Grassland (174)
- Biodiversity (167)
- Sheep (167)
- Forage (164)
- Western Australia (164)
- Phosphorus (163)
- Pasture (159)
- Cattle (156)
- Water quality (154)
- Digestibility (146)
- Yield (141)
- Forage quality (137)
- Silage (137)
- Sustainability (126)
- Remote sensing (122)
- Legumes (120)
- Nutritive value (120)
- Groundwater (119)
- Hydrology (118)
- Geology (115)
- Stocking rate (115)
- Trifolium repens (113)
- Intake (112)
- Management (112)
- Drought (109)
- Publication Year
- Publication
-
- IGC Proceedings (1977-2023) (9261)
- United States Geological Survey: Staff Publications (519)
- School of Earth, Environmental, & Marine Sciences Faculty Publications (367)
- International Journal of Speleology (339)
- Memorandum (315)
-
- Theses and Dissertations (245)
- Faculty Publications (214)
- Department of Earth and Atmospheric Sciences: Faculty Publications (184)
- OES Faculty Publications (157)
- Electronic Theses and Dissertations (147)
- Graduate Theses and Dissertations (144)
- All Graduate Theses and Dissertations, Spring 1920 to Summer 2023 (121)
- School of Natural Resources: Dissertations, Theses, and Student Research (118)
- Bulletin of the University of Nebraska State Museum (1924–2023) (112)
- USF Tampa Graduate Theses and Dissertations (110)
- Masters Theses (109)
- Turkish Journal of Earth Sciences (107)
- School of Geosciences Faculty and Staff Publications (98)
- Tanzania Journal of Science (86)
- Department of Earth and Environmental Studies Faculty Scholarship and Creative Works (83)
- Geosciences Faculty Publications and Presentations (79)
- OES Theses and Dissertations (77)
- United States Geological Survey: Publications (69)
- Master's Theses (64)
- Masters Theses & Specialist Projects (64)
- Journal of the Arkansas Academy of Science (63)
- Open Access Theses & Dissertations (63)
- United States Environmental Protection Agency: Publications (63)
- Jurnal Kultivasi (61)
- Coal Geology & Exploration (60)
- Publication Type
- File Type
Articles 17551 - 17580 of 17781
Full-Text Articles in Entire DC Network
A Pre- And Post-Improvement Study On Six Southeast Kansas Strip-Mine Lakes, William Thomas Waller
A Pre- And Post-Improvement Study On Six Southeast Kansas Strip-Mine Lakes, William Thomas Waller
Electronic Theses & Dissertations
During the last sixty years extensive experimental research has been conducted in an attempt to establish methods of controlling the acid conditions resulting from coal mine operations.
It was the purpose of this research to determine the feasibility of reclaiming acid strip-mine lakes for use as potential fisheries management areas. To accomplish the objectives outlined above a two-phase program was initiated. The first phase involved the physical alteration of the drainage areas of the experimental lakes included in this study in an attempt to divert all visible signs of acid drainage to areas other than those incorporated into the drainage …
Movement Of Atrazine In Soil Under Furrow Irrigation, Jyothi Veerabhadrappa
Movement Of Atrazine In Soil Under Furrow Irrigation, Jyothi Veerabhadrappa
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Movement of atrazine in response to furrow irrigations was studied using the samples of Timpanogos silt loam soil. Distribution in soil profile of surface applied herbicide was determined by drawing samples of water extracts through porous cylinders. Atrazine quantity was determined by spectrophotometer.
It was observed that the herbicide found in the water extracts was an indication of the quantity present in the soil. The herbicide moved readily with the applied water. Irreversible thermodynamic model could not be applied because of the initial and final boundary conditions. The pattern of movement was in conformity with the chromatographic theory.
The Influence Of Thermo-Gradients Upon Water Movement And Retention In Unsaturated Soils, Jose V. Salazar
The Influence Of Thermo-Gradients Upon Water Movement And Retention In Unsaturated Soils, Jose V. Salazar
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Temperature differences of about 5, 10, and 15 V, were applied to uniformly packed and insulated horizontal column of Millville silt loam soil using mean temperatures near 13, 14, 15, 16, 17, 18, 19, 20 and 23.5 C. The temperature distribution along the soil column was determined using copper constantan thermocouples. Soil samples were taken to determine volumetric moisture content, and soil water potential, using the vapor pressure psychometer technique. The thermodynamic flow equation of Taylor and Cary, (1964) was used to calculate the hydro-thermal transfer coefficient (ß) as given by:
-ß = d(μw)T / dlnT
where …
The Interaction Between Water Movement, Solute Uptake, And Respirational Energy In Plant Roots, Mohamed Sadek Tawakol
The Interaction Between Water Movement, Solute Uptake, And Respirational Energy In Plant Roots, Mohamed Sadek Tawakol
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Sunflower plants (Helianthus annus, var. Russian mammoth) were grown in Hogland nutrient solution. The roots (after being subjected to treatments with either respiratory inhibitors or respiratory stimulators) were used to measure the flux of water Jw, flux of solute Js , and the rate of respiration Jo.
The thermodynamic theory of irreversible processes was used to examine the interaction between fluxes, and the changes in conductivity under different treatments. The rate equations for a root membrane of unit thickness were developed as:
Jw = LwwVw∆p + LwsRT ln …
Earthworms: Their Intensive Propagation And Use In Biological Soil Building - Part Vi, Thomas Barrett
Earthworms: Their Intensive Propagation And Use In Biological Soil Building - Part Vi, Thomas Barrett
Green Revolution
Reprint of section of book Earthworms by Thomas Barrett.
Earthworms: Their Intensive Propagation And Use In Biological Soil Building - Part V, Thomas Barrett
Earthworms: Their Intensive Propagation And Use In Biological Soil Building - Part V, Thomas Barrett
Green Revolution
Reprint of section of book Earthworms by Thomas Barrett.
Earthworms: In Biological Soil Building - Their Intensive Propagation And Use - Part Iv, Thomas Barrett
Earthworms: In Biological Soil Building - Their Intensive Propagation And Use - Part Iv, Thomas Barrett
Green Revolution
Reprint of section of book Earthworms by Thomas Barrett.
Earthworms: Their Intensive Propagation And Use In Biological Soil Building - Part Iii, Thomas Barrett
Earthworms: Their Intensive Propagation And Use In Biological Soil Building - Part Iii, Thomas Barrett
Green Revolution
Reprint of section of book Earthworms by Thomas Barrett.
Elephant Teeth From The Atlantic Continental Shelf, Frank C. Whitmore Jr., K. O. Emery, H. B. S. Cooke, Donald J. P. Swift
Elephant Teeth From The Atlantic Continental Shelf, Frank C. Whitmore Jr., K. O. Emery, H. B. S. Cooke, Donald J. P. Swift
United States Geological Survey: Staff Publications
Teeth of mastodons and mammoths have been recovered by fishermen from at least 40 sites on the continental shelf as deep as 120 meters. Also present are submerged shorelines, peat deposits, lagoonal shells, and relict sands. Evidently elephants and other large mammals ranged this region during the glacial stage of low sea level of the last 25,000 years.
A Revision Of The Bees Of The Genus Andrena Of The Western Hemisphere. Part I. Callandrena. (Hymenoptera: Andrenidae), Wallace E. Laberge
A Revision Of The Bees Of The Genus Andrena Of The Western Hemisphere. Part I. Callandrena. (Hymenoptera: Andrenidae), Wallace E. Laberge
Bulletin of the University of Nebraska State Museum (1924–2023)
This paper is the first part of a monograph of the bee genus Andrena in the western hemisphere and treats the subgenus Callandrena. Available data regarding phylogeny, distribution, biology, and flower preferences are presented together with keys to separate the species, diagnoses and descriptions of the species and discussions of geographic variation when applicable. Seventy-nine species and one subspecies are recognized. Sixteen names are relegated to synonymy, one to homonymy and eight are removed from the subgenus Callandrena. The thirty-nine species new to science are: aerifera, aeripes, afimbriata, ardis, auripes, balsamorhizae, beameri, bilimeki, bullata, calvata, dreisbachorum, fulminea, fulminoides, …
A New Species Of Rhinoceros, Aphelops Kimballensis, From The Latest Pliocene Of Nebraska, Lloyd G. Tanner
A New Species Of Rhinoceros, Aphelops Kimballensis, From The Latest Pliocene Of Nebraska, Lloyd G. Tanner
Bulletin of the University of Nebraska State Museum (1924–2023)
An uncrushed skull and associated skeletal elements of a very large rhinoceros are the basis for the description of a new species of Aphelops from Frontier County, Nebraska. The major differences are: the skull is much larger in most dimensions than other Aphelops; it has an extremely elevated occipital region in comparison to Aphelops mutilus; the narial notch is retracted to a point perpendicular to the center of molar one; and the teeth are more hypsodont than any other species of this genus. The sediments which yielded the skull and skeletal parts are considered to be Kimballian in …
The Monotypic North American Subgenus Larandrena Of Andrena (Hymenoptera: Apoidea), D. W. Ribble
The Monotypic North American Subgenus Larandrena Of Andrena (Hymenoptera: Apoidea), D. W. Ribble
Bulletin of the University of Nebraska State Museum (1924–2023)
Larandrena contains a single species, A. miserabilis Cresson. This small, common Andrena is found throughout most of the United States and southern Canada in the spring. The subgeneric position, nomenclature, redescription. variation, notes on the biology, parasites, range, seasonal activity and plant host records are included. A. rniserabilis is thought to be an important pollinator of fruit trees.
Citellus Kimballensis, A New Late Pliocene Ground Squirrel, Douglas C. Kent
Citellus Kimballensis, A New Late Pliocene Ground Squirrel, Douglas C. Kent
Bulletin of the University of Nebraska State Museum (1924–2023)
A new fossil sciurid, Citellus kimballensis, is described. This new species was found in the Kimball Formation, uppermost Ogallala (very late Pliocene) at the University of Nebraska State Museum Collecting Locality Cn-1O1, northeast of Sidney, Cheyenne County, Nebraska. Characters of the dentition and skull of C. kimballensis are compared with those of other species of the genus, and with those of Cynomys.
The Brule-Gering (Oligocene-Miocene) Contact In The Wildcat Ridge Area Of Western Nebraska, C. Bertrand Schultz, Charles H. Falkenbach, Carl F. Vondra
The Brule-Gering (Oligocene-Miocene) Contact In The Wildcat Ridge Area Of Western Nebraska, C. Bertrand Schultz, Charles H. Falkenbach, Carl F. Vondra
Bulletin of the University of Nebraska State Museum (1924–2023)
The contact between the Brule Formation (Oligocene) and the Gering Formation (Miocene) can be readily distinguished in the Wildcat Ridge area, as elsewhere in western Nebraska. At the critical fossiliferous exposures at Castle Rock in Scotts Bluff County, the contact on the south face between the two formations is defined as 129 feet above the base of the "Upper Ash" bed, which corresponds to the upper portion of Darton's (1899, PI. C, Fig. D, following p. 754) "sandy phase" in the upper part of the Brule. Certain key beds in the Gering Formation can be traced laterally from a channel …
Time And Soil Development On Lateral Moraines, Martin River Glacier, South-Central Alaska, John R. Tinker Jr.
Time And Soil Development On Lateral Moraines, Martin River Glacier, South-Central Alaska, John R. Tinker Jr.
Theses and Dissertations
During the summer of 1966, eighteen soil profiles on a series of 21 lateral moraines, were studied to ascertain the relationship of time to soil development. The moraines are located on Charlotte Ridge on the south margin of the Martin River Glacier in south-central Alaska. The elevation of the highest moraine is approximately fifteen hundred feet and is located 800 feet above the present level of the glacier.
To determine the direct effect of time on soil formation, the remaining soil forming factors were kept constant; the soil pits were located so that relief, exposure, and vegetation of the sites …
Recent Fluvial Geology In Western North Dakota, Thomas M. Hamilton
Recent Fluvial Geology In Western North Dakota, Thomas M. Hamilton
Theses and Dissertations
The thesis here abstracted was written under the direction of Lee Clayton and approved by Walter L. Moore -and John R. Reid as members of the examining connnittee, of which Mr. Clayton was chairman.
In western North Dakota many drainage channels that are incised into valley fill are characterized by steep, unvegetated sides. Many such channels contain actively eroding scarps. The origin of these scarps is most frequently related to increased water velocity causing accelerated erosion on a steepened reach of the valley flat.
The principal mechanism of scarp migration is soilfall which is initiated by undercutting of the scarp …
A Geographical Interpretation Of Coles County Soils Through A Comparative Analysis Of Modern Soil Classification Systems, John C. Klink
A Geographical Interpretation Of Coles County Soils Through A Comparative Analysis Of Modern Soil Classification Systems, John C. Klink
Masters Theses
No abstract provided.
Sur La Faculté D'Absorption De Substances Colorées Par La Cuticule De Caecosphaeroma Burgundum Dollfus, Crustacé Isopode Des Eaux Souterraines, François Graf, Claude Marvillet
Sur La Faculté D'Absorption De Substances Colorées Par La Cuticule De Caecosphaeroma Burgundum Dollfus, Crustacé Isopode Des Eaux Souterraines, François Graf, Claude Marvillet
International Journal of Speleology
The discovery, in certain subterranean waters, of “pigmented,” brown or black Caecosphaeroma burgundum, led to the systematic study of the action of pigmented substances on these crustaceans. The results of these experiments demonstrate that the colorations thus obtained or observed in nature are due to the agglutination of coloured substances on the surface of the carapace and, in certain cases, to an impregnation of the cuticle itself.
The Technique Of Lineaments And Linears Analysis And Its Application In The Minerogenic Province Of Southeast Missouri, Hassan A. Etr
The Technique Of Lineaments And Linears Analysis And Its Application In The Minerogenic Province Of Southeast Missouri, Hassan A. Etr
Doctoral Dissertations
"Current terminology in the field of lineaments and linears (lineations) analysis was reviewed and quantitative definitions of the common terms offered. A general classification of lineations is herein proposed. Characteristics of drainage and airphoto lineations were reviewed and the procedure used in their analysis discussed.
An area about 1880 square miles was analyzed for lineations based on drainage networks and the resulting patterns showed preferred orientation. These drainage lineations were later compared with the airphoto lineations of the same area and a limited degree of similarity was observed.
The airphoto lineations of an area approximately 7000 sq. mi. covering the …
A New Species Of Gomphonema (Bacillariophyta) From Mammoth Cave, Kentucky, Sam L. Van Landingham
A New Species Of Gomphonema (Bacillariophyta) From Mammoth Cave, Kentucky, Sam L. Van Landingham
International Journal of Speleology
In some materials collected from Mammoth Cave, Kentucky, a diatom was found which could not be identified with any known species. A taxonomic description of Gomphonema hotchkissii nov. spec. is given.
Die Ökologische Stellung Der Höhlen-Und Spaltengewässer Innerhalb Der Subterranaquatilen Lebensbereiche, Siegfried Husmann
Die Ökologische Stellung Der Höhlen-Und Spaltengewässer Innerhalb Der Subterranaquatilen Lebensbereiche, Siegfried Husmann
International Journal of Speleology
Bodies of waters in caves and in crevices of rocks are distinguished from the other subsoil water ecosystems (“eustygon”, “stygorhithron”, “stygopotamon”) under the names “troglostygon” and “petrostygon”. The colonisation of subsoil water biotopes involves a fundamental principle which controls the development of the main biotopes for the stygobiont undergroundwater organisms. According to this ecological rule, which is described in detail and formulated, the several interstitial biotopes (for example “eustygopsammal,” “rhithrostygopsammal,” “potamostygopsephal”) are to be considered as the real biotopes of the stygobiont subsoil water organisms; waters in caves, on the contrary, are secondary biotopes of these animals. Caves which contain …
Mise En Evidence De Substances Fluorescentes Dans Les Organes Jaunes De Caccosphaeroma Burgundum Dollfus, Crustacé Isopode Des Eaux Souterraines, H. Descimon, C. Marvillet
Mise En Evidence De Substances Fluorescentes Dans Les Organes Jaunes De Caccosphaeroma Burgundum Dollfus, Crustacé Isopode Des Eaux Souterraines, H. Descimon, C. Marvillet
International Journal of Speleology
Chromatographic analysis of the yellow organs of the fresh-water Isopod Crustacean Caecosphaeroma burgundum Dollfus revealed, through observation of the chromatograms in ultraviolet light, the occurrence of both absorbing and fluorescent substances. Among the latter, only isoxanthopterin has been identified. The yellow pigment, which probably has a pteridine nucleus, could not be identified as a known compound and will be the object of later investigations.
Analyse Du Comportement Alimentaire Du Poisson Cavernicole Aveugle Anoptichthys Gen. Et D'Hybrides F1 (Astyanax X Anoptichthys) Et F2, Georges Thines, Monique Soffie, Erik Vandenbussche
Analyse Du Comportement Alimentaire Du Poisson Cavernicole Aveugle Anoptichthys Gen. Et D'Hybrides F1 (Astyanax X Anoptichthys) Et F2, Georges Thines, Monique Soffie, Erik Vandenbussche
International Journal of Speleology
The feeding behaviour of the blind cave fish Anoptichthys is characterised by two phases, an initial short chemioreceptic one and second one in which the fish explores the bottom systematically for a longer period. The whole process last approximately 30 seconds, both in adults as in youngsters.
Algal Growth Experiments In The Baradla Cave At Aggtelek (Biospeleologica Hungarica Xxi), Erzsebet Kol
Algal Growth Experiments In The Baradla Cave At Aggtelek (Biospeleologica Hungarica Xxi), Erzsebet Kol
International Journal of Speleology
The author kept 108 algal strains (Cyanophyta 53, Chlorophyta 35, Chrysophyta 20), of axenic cultures from the Kol-Algotheca in the Botanical Division of the Hungarian National Sciences Museum in the Baradla Cave, at Aggletek (Hungary) in darkness for 204-420 days under different environmental conditions. The experiments have proven that several algal strains can tolerate well the complete absence of light. Furthermore, that some algal strains show intensive development even under such conditions. These axenic cultures kept in the cave in metal boxes on inorganic medium have shown that the energy source used by these green coloured algae is not …
Earthworms: Their Intensive Propagation And Use In Biological Soil Building - Part Ii, Thomas Barrett
Earthworms: Their Intensive Propagation And Use In Biological Soil Building - Part Ii, Thomas Barrett
Green Revolution
Reprint of section of book Earthworms by Thomas Barrett.
The Influence Of Organic Matter And Ph On Transformations Of Nitrites To Elemental Nitrogen, Mohammad A. Rashid
The Influence Of Organic Matter And Ph On Transformations Of Nitrites To Elemental Nitrogen, Mohammad A. Rashid
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Nitrogen occupies an important and prominent place in plant and animal nutrition. Large quantities are required by plants and must be available in the soil. Recently the use of nitrogenous fertilizers has increased manyfold. In view of the importance of this element in crop production, even greater use is anticipated in the coming years. In order to make full use of the applied nitrogen, continued investigations of soil-nitrogen relationship are imperative; however, this element presents many complex and challenging problems to investigators.
Movement Of Phosphorus In Soils As Influenced By Chelates And Soil Types, Abd-Elmonem Sayed-Ahmad Mostafa
Movement Of Phosphorus In Soils As Influenced By Chelates And Soil Types, Abd-Elmonem Sayed-Ahmad Mostafa
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The problems of phosphate fertilization have attracted the attention of agronomists, nutritionists, and other biological scientists due to the importance of phosphorus in animal and plant nutrition. However, the fundamental behavior of phosphorus in soil systems is not well understood. Because of its far-reaching effects, a solution of a portion of this problem is of importance.
Nature Of Non-Biological Decomposition Of Nitrite In Acid Media, Mukkatira Kariappa Mahendrappa
Nature Of Non-Biological Decomposition Of Nitrite In Acid Media, Mukkatira Kariappa Mahendrappa
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Curiosity is the cause of investigations, and the thirst for knowledge originates from it. Many times at the end of investigations, the number of questions raised are greater than those for which answers are sought. Therefore, all the information gathered through scientific investigations may not be of value for immediate application in practical life. Nevertheless, no research can be considered less important than the other because the integration of several scientific findings considered less less important at the time of investigation may reveal something of very high significance. Similarly, the study of various transformation reactions that the added fertilizers undergo …
Simultaneous Movement Of Water And Herbicides In Unsaturated Soils, Ming-Shyong Yang
Simultaneous Movement Of Water And Herbicides In Unsaturated Soils, Ming-Shyong Yang
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Since weed killers were developed in the early part of the decade beginning in 1940, herbicides have been increasing in use until they are now widely used to control weeds. The application of herbicides has thus become a regular agricultural and ecological practice.
Simultaneous Flow Of Heat And Water In Plant Tissue, Gaylon Sanford Campbell
Simultaneous Flow Of Heat And Water In Plant Tissue, Gaylon Sanford Campbell
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Although biological phenomena may be partially described in a general way without the use of mathematics and physics, the experimental results may be more meaningful if they are analyzed on the basis of physical and mathematical laws. The complexity of biological systems has made the application to them of mathematics and physics rather difficult, and only recently has much progress been made. Although it has yet been possible to describe only a few simple biological systems by actual equations, a great deal of qualitative information may be obtained by applying physics and mathematics. Russell (1960, p. 439) said
In principle …