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Articles 4921 - 4950 of 59392
Full-Text Articles in Entire DC Network
Table Of Contents, The Editors
A Python Pipeline For Rapid Inversion Of Gravity Data Aimed At Early Career Researchers: Application To The Lost River Fault, Idaho, Bradford C. Mack
A Python Pipeline For Rapid Inversion Of Gravity Data Aimed At Early Career Researchers: Application To The Lost River Fault, Idaho, Bradford C. Mack
USF Tampa Graduate Theses and Dissertations
Gravity data and modeling can be used to create a 3D view of basin and fault geometries, a valuable tool for seismic hazard assessment. Additionally, access to a high-speed, easy-to-use modeling workflow will enable more researchers to supplement their work with a new method and allow students to be exposed to modeling earlier in their academic careers. The primary goals of this work are to create a widely usable 3D gravity and basin model, to create an introduction to modeling teaching module for undergraduate geology students, and to apply the model to the northernmost two segments of the Lost River …
A Nanoindentation-Based Study On The Micromechanical Properties Of Red Shales, Zhou Lang, Ma Zhenqian, Huang Qingrong, Shuai Yunlin, Zhang Jimin, Liu Rongke
A Nanoindentation-Based Study On The Micromechanical Properties Of Red Shales, Zhou Lang, Ma Zhenqian, Huang Qingrong, Shuai Yunlin, Zhang Jimin, Liu Rongke
Coal Geology & Exploration
Objective Investigating the micromechanical properties of minerals using nanoindentation tests is of great significance for revealing the microscale mechanisms behind mineral failure. Methods Focusing on the primary minerals in the surrounding rocks of red shales in a phosphate deposit, this study conducted qualitative and semi-quantitative analyses of these minerals, including their spatial distributions, using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), and targeted nanoindentation tests, determining the micromechanical properties of the minerals. This study developed a discrete numerical calculation model for the microscopic nanoindentation of minerals based on Voronoi tessellation and compared the simulation results with …
State Of The Art And Future Directions In Groundwater Contamination Risk Assessment, Xu Beiyi, Wang Ce, Zhou Guangyang, Zhou Pengpeng
State Of The Art And Future Directions In Groundwater Contamination Risk Assessment, Xu Beiyi, Wang Ce, Zhou Guangyang, Zhou Pengpeng
Coal Geology & Exploration
Background Rapid global socio-economic development has intensified the resource crisis and contamination of groundwater, rendering groundwater contamination risk assessments critical to contamination prevention, control, and remediation. Advances Through a systematic summary of domestic and international studies, this study reviews the development of theories on groundwater contamination risk assessments and the formation of the theoretical system. Based on the source-pathway-receptor assessment system, this study presents a summary of the research methods for the assessments of contamination source load risks, groundwater vulnerability, and contamination hazards. Groundwater contamination risk assessments have evolved from unidimensional qualitative assessments to quantitative process models highlighting contamination mechanisms …
Underground Coal Gasification In The Aidinghu Mining Area, Turpan-Hami Coalfield: Geological Evaluation System And The Selection Of The Optimal Coal Seam, Zeng Zhiwei, Lai Peng, Tian Jijun, Yang Shuguang, Hu Zhenpeng, Wang Bo, Yu Yu, Wang Haichao, Liu Yunxuan, Yuan Yixuan
Underground Coal Gasification In The Aidinghu Mining Area, Turpan-Hami Coalfield: Geological Evaluation System And The Selection Of The Optimal Coal Seam, Zeng Zhiwei, Lai Peng, Tian Jijun, Yang Shuguang, Hu Zhenpeng, Wang Bo, Yu Yu, Wang Haichao, Liu Yunxuan, Yuan Yixuan
Coal Geology & Exploration
Objective Underground coal gasification (UCG) is an innovation in traditional coal mining technology. The prerequisites for successful UCG include developing a systematic geological evaluation system and scientifically selecting the optimal coal seam.Methods Using mathematical analysis methods such as analytic hierarchy process (AHP), coefficient of variation method, and technique for order preference by similarity to ideal solution (TOPSIS), this study systematically analyzed the coal quality, coal seam occurrence, hydrology, surrounding rocks, geological structures, hazardous elements, and geological exploration degree of coal reservoirs in the Aidinghu mining area, Turpan-Hami coalfield. Accordingly, this study deeply explored the feasibility of UCG in the …
Research Progress On Variation Pattern And Monitoring Control Technology Of Negative Pressure For Gas Drainage In Directional Long Borehole, Li Quanxin, Cheng Zhuoer, Fang Jun, Mou Quanbin, Liu Fei, Cong Lin
Research Progress On Variation Pattern And Monitoring Control Technology Of Negative Pressure For Gas Drainage In Directional Long Borehole, Li Quanxin, Cheng Zhuoer, Fang Jun, Mou Quanbin, Liu Fei, Cong Lin
Coal Geology & Exploration
Significance Near-horizontal directional long borehole is an important technical approach and effective means for preventing and controlling the gas disasters of coal mine. Negative pressure is an important factor affecting the gas drainage effect of directional long borehole. Advances Herein, the research progress on gas drainage through near-horizontal directional long borehole was systematically summarized from three aspects: the attenuation mechanism and distribution law of negative pressure in the borehole, gas drainage parameter monitoring technology, and intelligent control system for gas drainage. Regarding the attenuation mechanism and distribution law of negative pressure in the borehole, the basic theoretical research results concerning …
Fine And Intelligent Interpretation Of Key Geological Structures In The Metal Metallogenesis Of Coal Measures, Yang Yi, Zhao Jingtao, Li Wenyu, Shi Suzhen
Fine And Intelligent Interpretation Of Key Geological Structures In The Metal Metallogenesis Of Coal Measures, Yang Yi, Zhao Jingtao, Li Wenyu, Shi Suzhen
Coal Geology & Exploration
Objective In order to identify the key geological structures in the metallogenic process of coal measures metal deposits, the Linxing block of Ordos Basin was taken as the research object. Based on the previous research results, geological data of the block, seismic and logging data, a geological model including tectonic volcanic activities and other events was constructed to analyze the key geological factors of deposit formation. Methods Firstly, based on the post-stack seismic data, the diffraction wave separation and imaging are realized by using the plane wave destruction filter technology, and the small-scale key geological information is extracted. Secondly, the …
Investigating Drought Response And Paleoclimate Potential Of A New Network Of White Oak Chronologies In Western Kentucky, Usa, Audrey J. Heichelbech, Megan Gibson, Maegen Rochner
Investigating Drought Response And Paleoclimate Potential Of A New Network Of White Oak Chronologies In Western Kentucky, Usa, Audrey J. Heichelbech, Megan Gibson, Maegen Rochner
The Cardinal Edge
In Kentucky, historic and paleo-climate data are limited, and current understanding of long-term climate change in the state relies on instrumental data spanning only 1895-present. Proxy data are necessary to extend the temporal and spatial span of climate information. One potential proxy source for Kentucky is tree ring data, but currently, only four such datasets are publicly available on the International Tree Ring Data Bank (ITRDB). Archaeological and archival timber sources may help to fill in this gap. In the 1940s, Florence Hawley-Ellis, the first woman dendrochronologist, collected samples of white oak (Quercus alba L.) from four counties in western …
Invertebrate Functional Diversity Of Fossils From Arrow Canyon, Nevada, Nathaniel Valentine
Invertebrate Functional Diversity Of Fossils From Arrow Canyon, Nevada, Nathaniel Valentine
Undergraduate Research Symposium Podium Presentations
Paleontology can be used to study how ecosystems evolve and respond to changes in the environment. Here we examine invertebrate fossils from the Pennsylvanian, a time period that ranged from 323.2 to 298.9 million years ago, which are preserved along the walls of Arrow Canyon (Nevada) in the Bird Spring Formation. We surveyed three sites within the canyon, and used data from the Paleobiology Database to create a list of taxa found on the canyon from this time interval. Although ecosystems have traditionally been studied using the composition of the ecosystem (the number of species), recent work has shown that …
Impact Of Young Biocrust On Dryland Surface Albedo, Rhynhardt Mudde, Rebekah Magness, Raul Roman, Nicole Pietrasiak
Impact Of Young Biocrust On Dryland Surface Albedo, Rhynhardt Mudde, Rebekah Magness, Raul Roman, Nicole Pietrasiak
Undergraduate Research Symposium Posters
More than 40% of the Earth’s surface is covered by drylands. Due to limited availability of water, less surface area is covered by vascular plants. Instead, this space is occupied by microbial communities that exist in close contact with mineral soil, creating a living aggregate on the upper soil layer and are known collectively as biological soil crusts or “biocrusts”. Biocrusts play a vital role in ecosystem functioning in drylands specifically through their influence on hydrological processes (e.g., water retention, infiltration). However, the impact of biocrusts on evaporation is not well understood. Biocrusts have been reported to either increase or …
Assessing Ectomycorrhizal Advantage On Tree Species Within Differing Soil Materials In Spring Mountains, Nevada, Kirsten Soriano, Riley Jones, Daniel Thompson
Assessing Ectomycorrhizal Advantage On Tree Species Within Differing Soil Materials In Spring Mountains, Nevada, Kirsten Soriano, Riley Jones, Daniel Thompson
Undergraduate Research Symposium Posters
Ectomycorrhizal fungi (ECM) form symbiotic relationships with their partner plant, creating root systems which allow for the exchange of nutrients among connected plants. The Spring Mountains National Recreation Area (NRA) in Southern Nevada is the study site for examining ECMs due to its diverse ecosystem with numerous inhabiting species. To assess the effects of ECMs on the tree composition, literature review was conducted to outline previous methods. Through data analysis and observations of the sample sites, it is concluded that ECMs are highly likely to have an effect on tree composition of the Spring Mountains NRA. The purpose of this …
Characterizing The Mechanical And Visoelastic Properties Of Sodium Alginate, Vesper Evereux
Characterizing The Mechanical And Visoelastic Properties Of Sodium Alginate, Vesper Evereux
Undergraduate Research Symposium Posters
A crucial part of tissue engineering lies in understanding and characterizing the mechanical and viscoelastic properties of various types of biomaterials. Understanding these properties allows better biomaterials to be produced with characteristics more similar to those of the human body and with better biocompatability. In this study, sodium alginate was chemically crosslinked with calcium chloride and subsequently tested for it's instantaneous Elastic Modulus, instantaneous Shear Modulus, and equivalent viscosity using indentation testing methods consisting of a stress-relaxation test and nonlinear curve-fitting analysis. Two and three millimeter indentation tests were performed using a low-cost and portable device built in-lab that resulted …
Biochar/Hydrochar Applications In Disinfection Byproduct Removal For Drinking Water, Ashleu Mussio Marquez, Donna Rouhani, Ismail Abdulraheem, Kers Ung-Watson, Ahmadreza Khatamgooya, Scarlet Nelson, Dr. Jaeyun Moon, Dr. Erica Marti
Biochar/Hydrochar Applications In Disinfection Byproduct Removal For Drinking Water, Ashleu Mussio Marquez, Donna Rouhani, Ismail Abdulraheem, Kers Ung-Watson, Ahmadreza Khatamgooya, Scarlet Nelson, Dr. Jaeyun Moon, Dr. Erica Marti
Undergraduate Research Symposium Posters
This project aims to investigate the process of disinfection byproduct (DBP) removal in drinking water, looking into the applications of biochar and hydrochar, which are low cost and environmentally sustainable adsorbents. These carbon-based adsorbents are derived from agricultural waste biomass, such as walnut shells. These adsorbents will be used to capture and remove contaminants in water, such as DBPs. DBPs are formed when chemical disinfectants react with organic and inorganic substances naturally present in water. The targeted DBPs for adsorption include trihalomethanes, haloacetic acids, haloacetonitriles, and nitrosamines. An example of high concentration DBP formation is during emergency chlorination, where excess …
Red Harvester Ants Pogonomyrmex Barbatus (Smith, 1858) (Hymenoptera: Formicidae) Do Not Distinguish Between Sorghum Head Mold Symptomatic And Asymptomatic Seeds, Lilly Victoria Elliott-Vidaurri, Hannah J. Penn, Robin A. Choudhury
Red Harvester Ants Pogonomyrmex Barbatus (Smith, 1858) (Hymenoptera: Formicidae) Do Not Distinguish Between Sorghum Head Mold Symptomatic And Asymptomatic Seeds, Lilly Victoria Elliott-Vidaurri, Hannah J. Penn, Robin A. Choudhury
School of Earth, Environmental, & Marine Sciences Faculty Publications
Red harvester ants, Pogonomyrmex barbatus (Smith, 1858) (Hymenoptera: Formicidae), common in the Lower Rio Grande Valley of Texas, are known to gather seeds from areas around their nests and store the seeds inside their nests for later consumption. As these ants often nest in and near agricultural fields, some of these seeds may be from crops and may also be infected with fungal plant pathogens. These pathogens can degrade seed coats and may cause the seeds to rot within the ant nests, decreasing storage time and potentially spreading the pathogen to other stored seeds. We studied how head mold, a …
New Ichnofossil Discovery In Mallorcan Caves: Linking Ancient And Moden Bat-Ectoparasites Coporolites., Antonio Merino Juncadella, Joan J. Fornós, Antoni Mulet, Joaquin Gines
New Ichnofossil Discovery In Mallorcan Caves: Linking Ancient And Moden Bat-Ectoparasites Coporolites., Antonio Merino Juncadella, Joan J. Fornós, Antoni Mulet, Joaquin Gines
International Journal of Speleology
Bat ectoparasitic ichnofossils can be useful to elucidate microbial mediation in mineralization processes of organic material, supplying valuable information on ancient parasitology and palaeoecology, among other topics. Rod-shaped features found in Cova des Pas de Vallgornera (Mallorca, Spain) are described for the first time. They are related to an ancient bat colony inhabiting the cave in the Early Pleistocene. These micro-morphologies are cylindrical in shape with sizes of a few hundred microns in length and less than one hundred microns in diameter. They are composed by a mash of microscopic calcite particles of different sizes and shapes, lying on deposits …
Statistical Methods For Interpreting Spatial And Temporal Heterogeneity Of Martian Tropical Water Ice Informed By Properties Of Crater Ejecta Types, Jamie D. Riggs, Michelle R. Kirchoff
Statistical Methods For Interpreting Spatial And Temporal Heterogeneity Of Martian Tropical Water Ice Informed By Properties Of Crater Ejecta Types, Jamie D. Riggs, Michelle R. Kirchoff
College of Population Health Faculty Papers
The martian tropical water ice spatial and temporal distribution was characterized using impact crater ejecta type, location, size, and age in one of two epochs, (Formula presented.) Ga and (Formula presented.) Ga, using statistical models designed for spatial and temporal correlation structures. The indicator thought to identify the presence of ice is craters with layered ejecta, while the indicator thought to identify no ice is craters with radial ejecta. These indicators imply the location (longitude and latitude) and, potentially, depth (crater diameter as a proxy) of ice, and when the ice was present. The spatial and temporal distribution of layered …
Emerging Consensus On Net Energy Paves The Way For Improved Integrated Assessment Modeling, Louis Delannoy, Matthieu Auzanneau, Baptiste Andrieu, Olivier Vidal, Pierre -Yves Longaretti, Emmanuel Prados, David J. Murphy, Roger W. Bentley, Michael Carbajales- Dale, Marco Raugei, Mikael Ho¨O¨K, Victor Court, Carey W. King, Florian Fizaine, Pierre Jacques, Matthew Kuperus Heun, Andrew Jackson, Charles Guay- Boutet, Emmanuel Aramendia, Jianliang Wang, Hugo Le Boulzec, Charles A.S. Hal
Emerging Consensus On Net Energy Paves The Way For Improved Integrated Assessment Modeling, Louis Delannoy, Matthieu Auzanneau, Baptiste Andrieu, Olivier Vidal, Pierre -Yves Longaretti, Emmanuel Prados, David J. Murphy, Roger W. Bentley, Michael Carbajales- Dale, Marco Raugei, Mikael Ho¨O¨K, Victor Court, Carey W. King, Florian Fizaine, Pierre Jacques, Matthew Kuperus Heun, Andrew Jackson, Charles Guay- Boutet, Emmanuel Aramendia, Jianliang Wang, Hugo Le Boulzec, Charles A.S. Hal
University Faculty Publications and Creative Works
Extracting, processing, and delivering energy requires energy itself, which reduces the net energy available to society and yields considerable socioeconomic implications. Yet, most mitigation pathways and transition models overlook net energy feedbacks, specifically related to the decline in the quality of fossil fuel deposits, as well as energy requirements of the energy transition. Here, we summarize our position across 8 key points that converge to form a prevailing understanding regarding EROI (Energy Return on Investment), identify areas of investigation for the Net Energy Analysis community, discuss the consequences of net energy in the context of the energy transition, and underline …
Human Impacts On Mammal Diversity From The Pleistocene To The Present, Carson P. Hedberg
Human Impacts On Mammal Diversity From The Pleistocene To The Present, Carson P. Hedberg
Biology ETDs
Humans have fundamentally altered the planet’s biodiversity. It is critical to characterize these changes, but also to understand how they impact the structure and function of modern ecosystems. This dissertation investigates how anthropogenically mediated species losses and/or introductions influence ecological function and community structure in mammals across multiple temporal and spatial scales. We found that selective loss of large-bodied mammals over the Late Quaternary has led to severe losses in functional diversity in modern ecosystems, suggesting megafaunal mammals contribute distinct ecological functions. These changes to mammal diversity and distribution over millennia have altered both global patterns in functional diversity and …
Ambient Noise Tomography Of The Southern M9.2 1964 Great Alaska Earthquake Rupture Area, Joshua Ojuoluwa Osasona
Ambient Noise Tomography Of The Southern M9.2 1964 Great Alaska Earthquake Rupture Area, Joshua Ojuoluwa Osasona
Earth and Planetary Sciences ETDs
We used data from a densely spaced node array to investigate seismic velocity structure within the southern rupture area of the M9.2 1964 Great Alaska earthquake. The node array was deployed along a ~50 km section of the road system on Kodiak Island as part of the Alaska Amphibious Community Seismic Experiment (AACSE). The full ~400-node array was active for 25 days in May-June 2019. We extracted Rayleigh wave dispersion curves from ambient noise cross-correlations between station pairs in the node array to compute phase velocity maps from 2-8 s periods. Using these phase velocity maps, we performed a Bayesian …
Place-Based Conservation In Coastal And Marine Ecosystems: The Importance Of Engagement With Underrepresented Communities, Viniece Jennings, Kelly M. San Antonio, Mya J. Brown, Lalah Choice, Queriah Simpson, Imani Ford, Hyun Jung Cho, Pedro Solis, Ashley Lacey, De’Marcus Robinson
Place-Based Conservation In Coastal And Marine Ecosystems: The Importance Of Engagement With Underrepresented Communities, Viniece Jennings, Kelly M. San Antonio, Mya J. Brown, Lalah Choice, Queriah Simpson, Imani Ford, Hyun Jung Cho, Pedro Solis, Ashley Lacey, De’Marcus Robinson
School of Earth, Environmental, & Marine Sciences Faculty Publications
Through the years, research has described the importance of community-based approaches in the management of coastal and marine ecosystems. Coastal and marine issues are multifaceted and require place-specific approaches developed in partnership with vulnerable communities who are impacted by environmental stressors. Place-based conservation, a management approach that focuses on unique, place-specific characteristics, and other similar methods. It considers the need to integrate human dimensions and location-centered approaches, which are often lacking in typical natural resource management. Meaningful engagement with underrepresented communities can holistically account for socioeconomic factors and cultural knowledge that inform best management practices. As the health of marine …
Construction, Emplacement, And Structure Of Cretaceous Plutons In The Ebbetts Pass Region, North-Central Sierra Nevada Batholith, California, Hollianne C. Mcclure
Construction, Emplacement, And Structure Of Cretaceous Plutons In The Ebbetts Pass Region, North-Central Sierra Nevada Batholith, California, Hollianne C. Mcclure
Master's Theses
Field, petrographic, and geochronologic analyses were conducted for five Cretaceous plutons in the North-Central Sierra Nevada batholith to better understand their construction, emplacement, and deformation histories. All the plutons in the study area were constructed incrementally, but timing and degrees of mixing between increments vary. The lack of internal contacts and heterogeneity in the interiors of the Stanislaus Meadow and Ebbetts Pass plutons suggest that there were sizeable magma chambers where there was thorough mixing of increments. The West of Elbow, Lookout Peak, and Kinney Lakes plutons were constructed from small batches of magma based on their textural and compositional …
Active Tectonics, Erosion Rates, And Topographic Metrics In The Hayword-Calaveras Fault Zone, Simone I. Yeager
Active Tectonics, Erosion Rates, And Topographic Metrics In The Hayword-Calaveras Fault Zone, Simone I. Yeager
Master's Theses
In northern California, the complex geometry of the San Andreas Fault system, and how it steps and propagates across the Earth’s surface, is revealed in the topography. Activity along the Mission and Arroyo Aguague oblique reverse faults, located where the right-lateral Hayward Fault steps to the left of the Calaveras Fault, are manifested in the Diablo Mountain Range. The high topography in the restraining step can be observed in lidar imagery and seismicity studies show these faults are connected at depth. In this study, we investigate active tectonics, erosion rates, and topographic metrics from the southern end of the restraining …
No Change In Functional Ecology Or Body Size In Response To A Global Climate Event In The Late Maastrichtian Owl Creek Formation, William T. Rizza
No Change In Functional Ecology Or Body Size In Response To A Global Climate Event In The Late Maastrichtian Owl Creek Formation, William T. Rizza
Master's Theses
During the last 300 ka of the Maastrichtian, global temperatures increased and decreased by ~2℃, likely caused by a pulse of Deccan volcanism. The Owl Creek Type Section in Mississippi records some portion of the last 400 ka of the Late Maastrichtian. It is expected that marine invertebrates will demonstrate a taxonomic, ecological, or morphological response to rapid temperature change. I anticipate a decrease in taxonomic diversity and shell volume and an increased abundance of low activity-level species, similar to the ecological impacts observed in response to Large Igneous Province eruptions in the geologic record. Clumped isotope paleotemperature reconstruction recovers …
Towards An Ideal Seed Coating, J M. Scott
Towards An Ideal Seed Coating, J M. Scott
IGC Proceedings (1977-2023)
Coated pasture seeds have been formulated in the past based largely on "trial and error" with relatively few objective criteria being employed to define desirable formulations, A description of desirable propelties of various layers of seed coatings and of the seeds themselves is presented.
Lolium Endophyte Viability: Effect Of Seed Storage, M P. Rolston, J R. Crush, M D. Hare, K K. Moore
Lolium Endophyte Viability: Effect Of Seed Storage, M P. Rolston, J R. Crush, M D. Hare, K K. Moore
IGC Proceedings (1977-2023)
The effects of seed storage on the endophyte Acremonium lolii in ryegrass (Lolium perenne L.) were evaluated over 7 years. The long• term effects of 4 seed moisture contents (SMC) 8.6-13.1 %: tempemture (ambient, 5, O, -15°C) 'aitd packaging types: calico, polyethylene fi,Jm. 9-140 µm, and aluminium-polyethylene (AIP) on endophyte viability were assess·ed. • Endophyte viability was maintained by lower seed moisture content and low temperatures. In ambient warehouse conditions endophyte viability declined to zero in 12 months in calico bags,' but was maintained for 3 years at 8.6% SMC in AIP: • Endophyte viability was maintained for …
Effect Of Dormancy-Releasing Treatments On Germination Of Bahiagrass Seed, J. Jeffrey Mullahey, D S. Fisher
Effect Of Dormancy-Releasing Treatments On Germination Of Bahiagrass Seed, J. Jeffrey Mullahey, D S. Fisher
IGC Proceedings (1977-2023)
Low seed germination and dormant seed in bahiagrass (Paspalum nonatutum Flugge.) necessitate high seeding rates for successful pasture establishment. A study of dormancy-releasing treatments and age of seed on germination of bahiagrass was conducted in an incubator at the Southwest Florida Research and Education Center near Immokalee, Florida. Five seed treatments (Crop-Start (Solid Matrix Seed Priming, Kamterter Products Inc., Lincoln, NB), potassium nitrate (KNO3), heat/humidity, palea removed, and a check), 2 cullivars (Pensacola, Tifton 9) of bahiagrass and 2 ages (10 and 16 months) of seed were used. A significant (P<0.05) age ·x treatment interaction occurred for all response variables. Based on total germination at 28 days, % dormant seed and rate of germination, Crop-Start and heat/humidity were consistently the best treatments. Additional research on germination with dormancy-releasing treatments is needed to study the Interaction of seed age and bahiagrass cultivar.
Weed Seed Contamination: Use Of A Seed Testing Database To Identify Processing Limitations, J S. Rowarth, M P. Rolston, A A. Johnson
Weed Seed Contamination: Use Of A Seed Testing Database To Identify Processing Limitations, J S. Rowarth, M P. Rolston, A A. Johnson
IGC Proceedings (1977-2023)
A computerised database maintained by the Official Seed Testing Station of New Zealand provided the opporlunity to survey weed seed contamination in clover and grass seed-lots. Broad-leaf weeds such as Slierardia arvensis, Stellaria ,nedia and Chenopodium album were the major contaminants in Trifolium repens seed-lots. In grass seed-lots the main contaminants were seeds of other grasses such as Bromus hordaeceus, Vulpia spp. and Holcus lanatus. Weed seeds were found to be a major reason for downgrading or rejection from certification of clover and grass seed-lots in New Zealand; this reflects strict quality control measures.
An Investigation In To The Effect Of Some Factors On The Germination Of Erodium Seeds, Myrna Johnston, Alfredo Olivares, Gladys Fernandez
An Investigation In To The Effect Of Some Factors On The Germination Of Erodium Seeds, Myrna Johnston, Alfredo Olivares, Gladys Fernandez
IGC Proceedings (1977-2023)
Erodiurn seeds present variable dormancy in and even within each species. Thus, it is important to know the factors that determine this variation as related to the persistence of its species. E. rnoschatmn and E. rnalacoides seeds were collected at the end of the annual cycle at La Rinconada de Maipli (33°28'S and 7S050'W). Effects of seed sour.ce (collecting in 1986, 1988 and 1990), age (keeping seeds under laboratory conditions) and maternal factors (cutting plants at early flowering) were analysed. Seeds were tested for germination capacity and germination rate at a constant temperature of 15°C on Petri dishes provided with …
Long-Term Seed Dormancy In Poa Pratensis L. Northern Norway, Trygve S. Aamlid, Dagfinn Arntzen
Long-Term Seed Dormancy In Poa Pratensis L. Northern Norway, Trygve S. Aamlid, Dagfinn Arntzen
IGC Proceedings (1977-2023)
Inadequate gennination has often been obseived when planting Poa pratensis L. cv. Lavang (69°N) in northern Norwegian grasslands. This investigation was intended to elucidate whether this was due lo longterm seed dormancy, Seed-lots grown in different years in northern and southern Norway and stored at O-to•c, were germinated in Jakobsentype germinators al various combinations of temperature and light. Significant dormancy was expressed at 21 °C even after 10 years of storage. Al this constant temperature, germination was promoted by 8 h fluorescent light compared with darkness and continuous light. Al 21/ I 2°C alternating temperature, seed genninated well irrespective of …
Seed Vigour In Lucerne And White Clover, Y R. Wang, J G. Hampton
Seed Vigour In Lucerne And White Clover, Y R. Wang, J G. Hampton
IGC Proceedings (1977-2023)
Accelerated ageing (AA) was used to assess the seed vigour of 5 lucerne (Medicago sativa L, cv. Wairau) and 8 white clover (Trifolium repens L. cv. Grasslands Huia) seed-lots. Germination prior to AA ranged from 86-94% and 87-94% for the lucerne and white clover seed-lots respectively. All seed-lots hl\d been harvested in 1988 and were certified either as basic or first generation. Germination after 72 h at 40:t0.5°C (AA test) ranged frcim 31-76% for the lucerne seedlots and 15-56% for che white clover seed-lots, indicating significant differences in seed.vigour among lots of both species. Time of ageing influenced …