Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Environmental Sciences (119)
- Life Sciences (116)
- Plant Sciences (101)
- Water Resource Management (98)
- Agronomy and Crop Sciences (94)
-
- Oceanography and Atmospheric Sciences and Meteorology (93)
- Fresh Water Studies (91)
- Hydrology (82)
- Agricultural Science (28)
- Horticulture (27)
- Agriculture (20)
- Botany (12)
- Environmental Monitoring (12)
- Natural Resources and Conservation (12)
- Social and Behavioral Sciences (12)
- Sustainability (11)
- Agricultural Economics (10)
- Engineering (10)
- Civil and Environmental Engineering (9)
- Environmental Indicators and Impact Assessment (9)
- Plant Biology (9)
- Geology (8)
- Plant Pathology (8)
- Sedimentology (8)
- Weed Science (8)
- Ecology and Evolutionary Biology (7)
- Geography (7)
- Keyword
-
- Arkansas (49)
- Biological sciences (20)
- Water quality (20)
- Rice (19)
- Soil (17)
-
- Crop management (15)
- Crop production (14)
- Soil fertilizers (14)
- Nitrogen (11)
- Potassium (10)
- Soil fertility (10)
- Fertilizer (9)
- Phosphorus (9)
- Groundwater (8)
- Agriculture (7)
- Ground water (7)
- Soil test (7)
- Corn (6)
- Cover crop (6)
- Cover crops (6)
- Earth sciences (6)
- Irrigation (6)
- Soil sampling (6)
- Soil-test (6)
- Soybean (6)
- Struvite (6)
- Buffalo National river (5)
- Climate change (5)
- Ecosystem (5)
- Grain yield (5)
- Publication Year
- Publication
-
- Graduate Theses and Dissertations (94)
- Arkansas Water Resources Center Technical Reports (79)
- Arkansas Agricultural Experiment Station Research Series (29)
- Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences (17)
- Journal of the Arkansas Academy of Science (13)
-
- Crop, Soil and Environmental Sciences Faculty Publications and Presentations (8)
- Crop, Soil and Environmental Sciences Undergraduate Honors Theses (7)
- AAES Research Reports and Research Bulletins (3)
- Biological Sciences Undergraduate Honors Theses (2)
- Biological Sciences Faculty Publications and Presentations (1)
- Center for Advanced Spatial Technologies Publications and Presentations (1)
- Civil Engineering Undergraduate Honors Theses (1)
- Horticulture Faculty Publications and Presentations (1)
- Journal of Food Law & Policy (1)
- Water Systems (1)
- Publication Type
Articles 61 - 90 of 258
Full-Text Articles in Soil Science
Soil Quality Indices As Affected By Long-Term Burning, Irrigation, Tillage, And Fertility Management, Helen C.S. Amorim, Amanda Ashworth, Kristofor R. Brye, Brian J. Wienhold, Mary C. Savin, Phillip R. Owens, Sergio Silva
Soil Quality Indices As Affected By Long-Term Burning, Irrigation, Tillage, And Fertility Management, Helen C.S. Amorim, Amanda Ashworth, Kristofor R. Brye, Brian J. Wienhold, Mary C. Savin, Phillip R. Owens, Sergio Silva
Crop, Soil and Environmental Sciences Faculty Publications and Presentations
Understanding the impacts of long-term agricultural practices on soil quality (SQ) is key for sustaining agroecosystem productivity. This study investigated conventional and no-tillage (NT), residue burning and no burning, residue level (high and low), and irrigation (irrigated and dryland) effects on soil properties, SQ, and crop yields following 16 yr of a wheat (Triticum aestivum L.)–soybean [Glycine max (L.) Merr.] double-crop system via the Soil Management Assessment Framework (SMAF). A field experiment was conducted in the Lower Mississippi River Delta region on a silt-loam soil. Bulk density, soil organic C (SOC), total N (TN), pH, electrical conductivity (EC), …
Corn And Soybean Response To Wastewater-Recycled Phosphorus Fertilizers, Shane Ylagan
Corn And Soybean Response To Wastewater-Recycled Phosphorus Fertilizers, Shane Ylagan
Crop, Soil and Environmental Sciences Undergraduate Honors Theses
The ability to recycle phosphorus (P) from wastewaters could provide a sustainable, continuous source of P that might also help protect surface water quality from P enrichment. The mineral struvite (MgNH4PO4·6H2O) is an understudied material that can be created from Pcontaining wastewater and has been shown to have agricultural fertilizer value. The objective of this study was to evaluate the effects of electrochemically precipitated struvite (ECST), chemically precipitated struvite (Crystal Green; CG), diammonium phosphate (DAP), monoammonium phosphate (MAP), rock phosphate (RP), and triple super phosphate (TSP) on corn (Zea mays) and soybean (Glycine max) response in a 79-day greenhouse pot …
Using Soil Geospatial Properties And Environments To Explore Microbial Diversity, Sharon Faye Smith
Using Soil Geospatial Properties And Environments To Explore Microbial Diversity, Sharon Faye Smith
Graduate Theses and Dissertations
Soil microorganisms help maintain nutrient cycling, control carbon sequestration, impact plant productivity, and influence several soil chemical and physical properties; yet, the processes that control the microbial composition of soil and how environmental changes may affect the composition and activity of these organisms at different scales remains a difficult and intriguing puzzle for soil scientists, ecologists, and modelers. Wetlands are endangered and important ecosystems that provide several services, which are directly linked to soil function. However, few wetland assessments consider the soil environment and microbial ecology. Linking soil microbial community composition and distribution patterns to soil physio-chemical properties would provide …
Earthworm Dynamics In Tallgrass Prairies In The Ozark Highlands Region Of Northwest Arkansas, Carlee Hensley
Earthworm Dynamics In Tallgrass Prairies In The Ozark Highlands Region Of Northwest Arkansas, Carlee Hensley
Graduate Theses and Dissertations
Tallgrass prairie was a historic and is presently a unique and endangered natural ecosystem throughout the Ozark Highlands region in the mid-southern United States. Tallgrass prairies have been disturbed for agricultural production and/or urban expansion; thus, as a result, efforts have been undertaken to reclaim areas previously used for agricultural production to mitigate the loss of tallgrass prairies. Limited research exists on earthworm dynamics in mounded tallgrass prairies or prairie restorations, particularly in the Ozark Highlands region of northwest Arkansas. The objectives of this study were to i) evaluate the effects of soil moisture regime (SMR; aquic and udic), landscape …
Projected Surface Water For Fruit And Vegetable Irrigation Under A Changing Climate In The Us, Marty Matlock, Greg Thoma, Kieu Ngoc Le, Eric Cummings, Zach Morgan, Andrew Shaw
Projected Surface Water For Fruit And Vegetable Irrigation Under A Changing Climate In The Us, Marty Matlock, Greg Thoma, Kieu Ngoc Le, Eric Cummings, Zach Morgan, Andrew Shaw
Water Systems
Increasing greenhouse gas concentrations in the atmosphere, resulting in climate impacts, are raising concerns over the hydrologic cycle and its effects upon agricultural productivity. If rainfall patterns change, meeting an increased demand for fruits and vegetables will pose a challenge for domestic production regions in the United States (U.S.). Information on potential water supply scarcity in the current production regions provides decision makers with critical information for risk mitigation for future production. We used a hydrologic balance-based model of historic and future water availability to evaluate risk of available irrigation water to support major fruit and vegetable production the US. …
Soil Microbial Diversity And Litter Decomposition Increase With Time Since Land Use Disturbance In Tropical Montane Forests Of Malaysian Borneo, Renee Sniegocki
Soil Microbial Diversity And Litter Decomposition Increase With Time Since Land Use Disturbance In Tropical Montane Forests Of Malaysian Borneo, Renee Sniegocki
Graduate Theses and Dissertations
Logging and forest conversion are occurring at alarming rates in the tropical forests of Southeast Asia. These disturbances alter soil chemistry, microbial diversity, and disrupt carbon cycling through shifts in litter decomposition. Direct links between microbial diversity and soil properties such as pH are well established; however, the indirect impacts of logging and forest conversion on microbial diversity and litter decomposition are poorly understood. We used surface (5 cm) soil to assess soil physicochemical properties, next-generation DNA sequencing to assess soil microbial diversity, and standardized litterbags to assess litter decomposition stabilization at five sites along a land use disturbance gradient …
Wayne E. Sabbe Arkansas Soil Fertility Studies 2019, Nathan A. Slaton
Wayne E. Sabbe Arkansas Soil Fertility Studies 2019, Nathan A. Slaton
Arkansas Agricultural Experiment Station Research Series
Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.
Quantifying Greenhouse Gas Emissions And Ammonia Volatilization From Soil Amended With Excreta From Ruminants Fed Alternative Forage-Based Diets, Samuel Park
Graduate Theses and Dissertations
Forage-based ruminant diets supplemented with condensed tannins or polyphenolic-containing legumes may alter nitrogen (N) metabolism in the animal and reduce gas emissions from soil receiving excreta. The objective of the study was to determine if soil receiving urine or manure from sheep fed forage diets supplemented with condensed tannin or polyphenolic-containing legumes would decrease N gas emissions. Two field trials were conducted: in the first trial, sheep were fed alfalfa (Medicago sativa L.) silage diets supplemented with 0, 9, 18, or 27% sericea lespedeza (Lespedeza cuneate [Dumont de Courset] G. Don) (n = 4). In the second trial sheep were …
Corn Response To Wastewater-Recycled Phosphorus Fertilizers, Shane R. Ylagan, Kristofor R. Brye
Corn Response To Wastewater-Recycled Phosphorus Fertilizers, Shane R. Ylagan, Kristofor R. Brye
Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences
The ability to recycle phosphorus (P) from wastewaters could provide a sustainable, continuous source of P that might also help protect surface water quality from P enrichment. The mineral struvite (MgNH4PO4 · 6H2O) is an understudied material that can be created from P- and nitrogen (N)-containing wastewater and has been shown to have agricultural fertilizer value. The objective of this study was to evaluate the effects of electrochemically precipitated struvite (ECST), chemically precipitated struvite (Crystal Green; CG), diammonium phosphate (DAP), monoammonium phosphate (MAP), rock phosphate (RP), and triple superphosphate (TSP) on corn (Zea mays) response in a greenhouse pot study. …
Microdialysis: A Method For Quantifying In Situ Nitrogen Fluxes In Soil Microsites, Srusti Maddala, Mary C. Savin, Julie A. Stenken, Lisa S. Wood
Microdialysis: A Method For Quantifying In Situ Nitrogen Fluxes In Soil Microsites, Srusti Maddala, Mary C. Savin, Julie A. Stenken, Lisa S. Wood
Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences
Microdialysis, a diffusion-based sampling technique commonly used in biomedical research, has recently been recognized as a candidate for monitoring chemical changes in the rhizosphere. The information it provides about nutrient diffusion may improve nitrogen use efficiency, leading to enhanced management and success of restoration projects. The objective of this study was to determine the efficacy of microdialysis sampling to quantify the relative recoveries (RR%) of nitrate-N and ammonium-N, the two inorganic nitrogen compounds typically found in soil. The effects of microdialysis flow rate, sample medium concentration, and the presence of both analytes in solution on the relative recoveries obtained from …
Observable Persistent Effects Of Habitat Management Efforts In The Ozark Highlands After 10 Years, Maxwell Carnes-Mason
Observable Persistent Effects Of Habitat Management Efforts In The Ozark Highlands After 10 Years, Maxwell Carnes-Mason
Graduate Theses and Dissertations
I investigated the lasting impacts of a management plan designed to improve oak regeneration and benefit wildlife in the Ozark Highlands in Madison, Co., AR. To assess the efficacy of the management plan, I used variables relevant to the success and establishment of oak trees. Controlled burns and selective logging were used to thin the canopy, increase ground level productivity, and increase the abundance of small mammals. I used measurements of overstory and understory densities, light availability, and the density of mice in the genus Peromyscus across time to look at the lasting impacts of management. Different treatment plots were …
Nematode Populations As Affected By Residue And Water Management In A Long-Term Wheat-Soybean Double Crop In Eastern Arkansas, Lucia Emperatriz Escalante Ortiz
Nematode Populations As Affected By Residue And Water Management In A Long-Term Wheat-Soybean Double Crop In Eastern Arkansas, Lucia Emperatriz Escalante Ortiz
Graduate Theses and Dissertations
Soybeans (Glycine max) are one of the major row crops in the United States, particularly in Arkansas. Soybean cyst nematode (SCN, Heterodera glycines) and southern root-knot nematode (RKN, Meloidogyne incognita) are two of the most damaging pests that cause major economic losses in soybeans. Little is known concerning the effects of common and alternative agronomic practices on nematodes in fields with nematode population densities below threshold levels. Therefore, the objective of this study was to evaluate the effects of the combination of tillage (conventional tillage and no-tillage), irrigation (irrigated and non-irrigated), wheat (Triticum aestivum) residue burning (burned and no burned), …
Development Of A Multimode Instrument For Remote Measurements Of Unsaturated Soil Properties, Sean Elliott Salazar
Development Of A Multimode Instrument For Remote Measurements Of Unsaturated Soil Properties, Sean Elliott Salazar
Graduate Theses and Dissertations
The hydromechanical behavior of soil is governed by parameters that include the moisture content, soil matric potential, texture, and the mineralogical composition of the soil. Remote characterization of these and other key properties of the soil offers advantages over conventional in situ or laboratory-based measurements: information may be acquired rapidly over large, or inaccessible areas; samples do not need to be collected; and the measurements are non-destructive. A field-deployable, ground-based remote sensor, designated the Soil Observation Laser Absorption Spectrometer (SOLAS), was developed to infer parameters of bare soils and other natural surfaces over intermediate (100 m) and long (1,000 m) …
Factors Influencing The Spatial Distribution Of Southern Rust In Corn, Justin Bailey
Factors Influencing The Spatial Distribution Of Southern Rust In Corn, Justin Bailey
Graduate Theses and Dissertations
Southern rust caused by the fungus Puccinia polysora (Underwood) is the most economically important foliar disease in corn (Zea mays) (Linnaeus) (Cyperales: Poaceae)) for Arkansas. The objective of this work was to determine distribution of southern rust in corn and to determine factors that may control its distribution.
During the 2017 and 2018 season, seven corn fields in Arkansas were rated for southern rust. After disease confirmation, fields were marked with GPS sample point locations in a grid pattern across the entire field. Ratings for disease severity were taken below, at, and above the ear leaf at each point every …
The Potential Acidification Of The Mulberry River, Arkansas, Jason Richard Burgess-Conforti
The Potential Acidification Of The Mulberry River, Arkansas, Jason Richard Burgess-Conforti
Graduate Theses and Dissertations
The Mulberry River is a 110 km long tributary of the Arkansas River in northwest Arkansas and has been designated as a National Wild and Scenic River since 1992. In 2008, the Mulberry River was added to the 303(d) list of impaired water bodies due to the low pH of a 14.6 km segment of the river which has since increased to 68.7 km. To date, there has been little research performed on the Mulberry River and long-term routinely sampled water quality data is unavailable. The objectives of this dissertation were 1) to evaluate changes in water quality of the …
Incorporating Recent Geochemical And Isotopic Constraints In Age Dating The Waters Of Hot Springs National Park, Arkansas, Kristina Marie Raley
Incorporating Recent Geochemical And Isotopic Constraints In Age Dating The Waters Of Hot Springs National Park, Arkansas, Kristina Marie Raley
Graduate Theses and Dissertations
Mean water age for spring discharge in Hot Springs National Park was calculated as approximately 4,400 years by Bedinger et al (1978) using carbon-14. Their analysis indicated that the water was a mixture of a small portion of cold water that was less than twenty years old with a preponderance of hot water. However, this result includes some error due to Bedinger et al. using general isotopic values for soil dissolved inorganic carbon and mineral carbon instead of obtaining actual values from the study area. A more accurate age calculation for the springs has been made possible by additional geological …
Using Cover Crops To Recycle Nutrients In An Arkansas No-Till Corn System, Kelsey Lynn Hoegenauer
Using Cover Crops To Recycle Nutrients In An Arkansas No-Till Corn System, Kelsey Lynn Hoegenauer
Graduate Theses and Dissertations
Cover crops can provide many benefits to cropping systems including erosion control, weed suppression, and increased soil organic matter. Regardless of the intended goal for using cover crops, the changes to the nutrient flux in a cropping system caused by cover crops retaining and recycling nutrients needs to be considered in order to maximize the productivity of the following commodity crops. This research encompassed complementary greenhouse, field, and laboratory experiments to evaluate nutrient uptake and release by tillage radish (Raphanus sativus) and cereal rye (Secale cereale) cover crops, as well as the subsequent early-season recovery of recycled nutrients by the …
The Evaluation Of Low-Use-Rate Zinc Fertilization Strategies On Seedling Canopy Coverage, Zn Concentration, Biomass, And Grain Yield, Maxwell David Coffin
The Evaluation Of Low-Use-Rate Zinc Fertilization Strategies On Seedling Canopy Coverage, Zn Concentration, Biomass, And Grain Yield, Maxwell David Coffin
Graduate Theses and Dissertations
Zinc (Zn) is the most common micronutrient deficiency in flooded rice (Oryza sativa L.). Some new Zn fertilization methods have been advertised, but have limited research supporting their efficacy. This study mainly compared the effect of Zn-seed treatment rate in combination with other low-use-rate Zn-fertilization methods to the standard of 11 kg Zn ha-1 as ZnSO4 on rice early-season canopy cover, tissue-Zn concentration, and grain yield. A secondary objective evaluated an alternative method (to seed treatment with ZnO) of enhancing seed-Zn concentration using post-heading foliar-Zn application on seedling tissue-Zn concentration and grain yield. For the main objective, rice seed was …
Landuse And Soil Property Effects On Infiltration And Soil Aggregate Stability In The Lower Mississippi River Valley, Rebecca Lynn Anderson
Landuse And Soil Property Effects On Infiltration And Soil Aggregate Stability In The Lower Mississippi River Valley, Rebecca Lynn Anderson
Graduate Theses and Dissertations
Following European settlement of the Lower Mississippi River Valley (LMRV), agricultural expansion and unsustainable, agriculturally related practices have caused groundwater depletion, soil erosion, and surface water contamination by eroded sediments and sediment-bound nutrients to become major environmental threats to the region. The objective of this study was to evaluate the effects of common landuses [i.e., native prairie, deciduous forest, coniferous forest, Conservation Reserve Program (CRP) grassland, and conventional-tillage (CT) and no-tillage (NT) agriculture] on surface water infiltration and aggregate-stability-related properties [i.e., water-stable macroaggregate (WSA) size distribution, total water-stable macroaggregate (TWSA) concentration, and mean weight diameter (MWD)]. The overall infiltration rate …
Reduced Disposal Area Performance Utilizing Secondary-Treated Effluent In Profile-Limiting Soils, David A. Meints
Reduced Disposal Area Performance Utilizing Secondary-Treated Effluent In Profile-Limiting Soils, David A. Meints
Graduate Theses and Dissertations
Onsite wastewater systems dispose of primary treated effluent by utilizing the soil for final recycling and renovation of wastewater into the environment. Soil and site limitations have become a challenge to design a wastewater system and dispose of onsite wastewater using a conventional pipe and gravel design. Using secondary-treated effluent from an advanced treatment unit applied to a reduced disposal area offers an additional alternative when developing an onsite wastewater system. The objective of this study was to determine the feasibility of hydraulically loading limiting soils with secondary-treated effluent in a reduced disposal area. A reduced disposal area was constructed …
Wayne E. Sabbe Arkansas Soil Fertility Studies 2018, Nathan A. Slaton
Wayne E. Sabbe Arkansas Soil Fertility Studies 2018, Nathan A. Slaton
Arkansas Agricultural Experiment Station Research Series
Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.
Assessment Of Soil Properties And Vegetation In A Mounded Native Tallgrass Prairie With An Aquic And Udic Soil Moisture Regime In The Ozark Highlands Region Of Northwest Arkansas, Tyler Joseph Durre
Assessment Of Soil Properties And Vegetation In A Mounded Native Tallgrass Prairie With An Aquic And Udic Soil Moisture Regime In The Ozark Highlands Region Of Northwest Arkansas, Tyler Joseph Durre
Graduate Theses and Dissertations
Native tallgrass prairies were once considered to be the dominant pre-settlement vegetation type in the eastern third of the Great Plains, but are now designated as America’s most endangered ecosystem due to conversion to agricultural land. Prairie mounds are unique soil features still present in remnant native tallgrass prairies across the United States. The main objective was to determine the effects of soil moisture regime (i.e., aquic and udic), mound position, (i.e., mound summit, backslope, toeslope, inter-mound), soil depth (i.e., 10-cm intervals from 0 to 90 cm), and their interactions on soil physical, chemical, and hydraulic properties in a mounded …
Carbon Sequestration In Grassland Soils Across Arkansas, Marya Jean Mckee
Carbon Sequestration In Grassland Soils Across Arkansas, Marya Jean Mckee
Graduate Theses and Dissertations
The capture, conversion, and long-term storage of carbon dioxide (CO2) as soil organic carbon (SOC), a process known as soil C sequestration, is a possible solution to the current and ever-increasing threat of rising greenhouse gas emissions and global climate change. Tallgrass prairies, which once historically covered the country, are known to accumulate and sequester large amounts of C from the atmosphere deep within the soil, due to their extensive rooting systems. The purpose of this research was to increase understanding of soil C sequestration dynamics and general functioning in disappearing native grassland ecosystems within Arkansas, as well as the …
Evaluation Of Soybean Maturity Group And Planting Date In A Soybean-Rice Rotation On Overall Crop Productivity, Carrie Ortel
Evaluation Of Soybean Maturity Group And Planting Date In A Soybean-Rice Rotation On Overall Crop Productivity, Carrie Ortel
Graduate Theses and Dissertations
Little is known about the effects of soybean (Glycine max L.) management techniques on soil-nitrogen (N) credit development and its impact on the subsequent rice (Oryza sativa L.) crop’s success. This study was conducted to determine how soybean maturity group (MG) and planting date effect overall soybean productivity and its influence on the following rice crop. Various soybean planting dates (optimum and late) and MGs (3.5, 4.7, 5.4, and 5.6) were grown and followed in rotation with a rice crop. Six rates of pre-flood fertilizer-N (0, 44, 89, 134, 179, 224 kg N ha-1) were applied to the rice crop. …
Methanogens, Plausible Extraterrestrial Life Forms On Mars, And Their Tolerance To Increasing Concentrations Of Illite Clay, Chandler Kern
Methanogens, Plausible Extraterrestrial Life Forms On Mars, And Their Tolerance To Increasing Concentrations Of Illite Clay, Chandler Kern
Biological Sciences Undergraduate Honors Theses
Methanogens, some of Earth’s most primitive prokaryotic organisms, are candidates for possible life forms capable of inhabiting Mars. Specifically, four different species (Methanobacterium formicicum, Methanococcus maripaludis, Methanosarcina barkeri, Methanothermobacter wolfeii) were analyzed for their tolerance to the presence of illite clay. Illite is a crystalline mineral that has been identified from regions of Mars’s surface. Results indicated that all four species grew with some success in the illite at different concentrations. This experimentation with methanogens’ abilities to survive and reproduce in the presence of illite allows for a more accurate understanding of the potential capability of microbial …
Geophysical Assessment Of Subsurface Soil Conditions Using Capacitively Coupled Resistivity, Folaseye Coker
Geophysical Assessment Of Subsurface Soil Conditions Using Capacitively Coupled Resistivity, Folaseye Coker
Graduate Theses and Dissertations
The purpose of this research is to explore the applicability of Capacitively-Coupled Resistivity (CCR) as an improvement on traditional drilling and sampling methods for subsurface soil investigations. The CCR method could be used to identify critical locations for drilling and sampling such as expansive clay layers and anomalies (sinkholes, unknown landfills, etc.) rather than uniformly sampling across a site. CCR surveys were performed at Alpena, Arkansas along a highway expansion project changing US 62 from a two lane to four lane highway, and at Alton, Illinois along the Mel Price Levee, a 5.2 mile levee along a portion of the …
Proposed Astm Standard For The Stokoe-Type Resonant Column Torsional Shear Device, Anh Tuan Tran
Proposed Astm Standard For The Stokoe-Type Resonant Column Torsional Shear Device, Anh Tuan Tran
Graduate Theses and Dissertations
Resonant Column Torsional Shear (RCTS) testing has become one of the most commonly used methods for determining laboratory soil stiffness and soil damping. The RCTS test has been accepted and is commonly utilized during the permitting of new nuclear facilities. However, there is still no available public standard for performing RCTS tests using the Stokoe-type device. Therefore, an ASTM standard for calibration and performance of RCTS tests using the Stokoe-type RCTS device is presented herein. Data collected using the Stokoe-type RCTS devices at the University of Arkansas (UofA) and at the Norwegian Geotechnical Institute (NGI) also aided in the development …
Flow Regime Influences On Stream And Riparian Soil Carbon Dynamics In The Ozark Highlands And Boston Mountains Of Arkansas, Allyn Dodd
Graduate Theses and Dissertations
The natural flow regime exerts primacy over lotic ecosystem patterns and processes. However, little work has examined the influence of flow regime on instream and riparian carbon (C) dynamics in minimally-impacted, temperate forested systems. To date, most research efforts have focused on characterizing C movement and transformations across biomes and land use categories; however, flow regime represents an overlooked, finer level of detail that may drive differences in ecosystem function. My dissertation objective was to measure C fixation and movement within and across multiple environmental spheres (e.g. within stream channels, between stream surfaces and the atmosphere, and from riparian soils …
Nitrous Oxide Emissions From Rice Production On A Silt-Loam Soil In Arkansas, Casey Rector
Nitrous Oxide Emissions From Rice Production On A Silt-Loam Soil In Arkansas, Casey Rector
Graduate Theses and Dissertations
Rice (Oryza sativa L.) is a common crop grown in Arkansas under flooded-soil conditions. The saturated to nearly saturated soil makes rice production an ideal environment for the production of potent greenhouse gases, such as nitrous oxide (N2O). The objectives of this study were to i) evaluate the impact of water management practice (full-season-flood and intermittent-flood) and cultivar (pure-line and hybrid) on N2O fluxes, season-long N2O emissions, and global warming potential (GWP; 2016) and ii) evaluate the impact of tillage practice [conventional tillage and no-tillage (NT)] and type of urea fertilizer [ N-(n-butyl) thiosphosphoric triamide (NBPT)-coated and non-coated urea] on …
Soil Properties That Influence The Occurrence Of Hydrogen Sulfide Toxicity In Rice Fields, Julia Marie Fryer
Soil Properties That Influence The Occurrence Of Hydrogen Sulfide Toxicity In Rice Fields, Julia Marie Fryer
Graduate Theses and Dissertations
Rice (Oryza sativa L.) producers face many challenges throughout each growing season. Hydrogen sulfide (H2S) toxicity is a physiological disorder where sulfate (SO42-) is excessively reduced to the toxic gas, H2S. This can reduce yield and, in severe cases, result in crop death. The main research objectives were to: i) understand chemical and physical characteristics in soils prone to H2S toxicity, ii) determine influential soil characteristics on the incidence of H2S toxicity, iii) determine ammonium sulfate ((NH4)2SO4) fertilizer additions influence on H2S toxicity, and iv) predict when and where H2S will occur. Three greenhouse experiments were conducted using Arkansas field …