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Articles 1 - 25 of 25
Full-Text Articles in Soil Science
Impact Of Land Use On Soil Properties, Clay Mineralogy, And Behavior Of Ammonium Across A Precipitation Gradient, Isabel Delamater
Impact Of Land Use On Soil Properties, Clay Mineralogy, And Behavior Of Ammonium Across A Precipitation Gradient, Isabel Delamater
Theses and Dissertations--Plant and Soil Sciences
Like soil texture, clay mineralogy is considered a permanent or inherent characteristic of soils reflecting the influence of soil forming factors over long periods of time. Despite the importance of clay mineralogy in providing ecosystem services, much remains unknown about whether land use (native grassland sod versus no-tillage) can modify clay mineralogy under short periods of time. Furthermore, in no-tillage agroecosystems, lower crop yields are often ascribed to immobilization of added N fertilizer where inorganic nitrogen (such as ammonium) is converted to organic nitrogen. The possible role of clay mineralogy in retaining added ammonium has been overlooked in no-tillage systems. …
Advancing Root Trait Measurements For A Deeper Understanding Of Soil Biogeochemistry, Brian Rinehart
Advancing Root Trait Measurements For A Deeper Understanding Of Soil Biogeochemistry, Brian Rinehart
Theses and Dissertations--Plant and Soil Sciences
Climate change is disrupting (agro)ecosystems, with the potential for significant losses in crop productivity and ecosystem resilience due to changes in water and biogeochemical cycling. These disruptions can also release more carbon dioxide into the atmosphere through the degradation of soil organic matter. Plant roots have emerged as a potential tool for mitigating these effects, given their roles in plant function and in driving soil biogeochemistry. While this interest is growing, our ability to implement root trait selection is limited due to constraints on characterizing roots and limited clarity on the effects of traits on plant and ecosystem function. My …
Giving Props To Soil Property Predictive Models: Utilizing Mir To Predict Soil Health Properties, Diala M. Abboud
Giving Props To Soil Property Predictive Models: Utilizing Mir To Predict Soil Health Properties, Diala M. Abboud
Theses and Dissertations--Plant and Soil Sciences
Soil health is critical to sustaining life on Earth, influencing plant growth, agricultural productivity, water quality, and overall ecosystem sustainability. In response to climate change and intensifying land use, the need to improve our understanding of soil health has become increasingly urgent. The application of mid-infrared (MIR) spectroscopy coupled with statistical modeling has emerged as a promising, cost-effective approach to predict soil health parameters, offering a quicker alternative to traditional wet chemistry analyses. MIR methods have been successfully applied to predict various soil health properties, such as bulk density (BD), cation exchange capacity (CEC), base saturation (BS), electrical conductivity (EC), …
Nitrogen Behavior In A No-Tillage Agroecosystem Located In The Inner Bluegrass Of Kentucky, Alec William Besinger Mr.
Nitrogen Behavior In A No-Tillage Agroecosystem Located In The Inner Bluegrass Of Kentucky, Alec William Besinger Mr.
Theses and Dissertations--Plant and Soil Sciences
Nitrogen (N) is a crucial element, often limiting productivity in ecosystems. This limitation is relieved N fertilizer additions. No-tillage (NT) agroecosystems are prone to lower N availability translating to lower crop yields. The default explanation for lower N availability in NT is microbial immobilization of added N fertilizer. Historically, N availability is often assessed using chemical extractions such as KCl to evaluate levels of inorganic N in the soil. The possibility of this abiotic clay mineral fixation as mechanism in well-drained NT soils has been overlooked. The objectives of this study are to quantify N availability using KCl, NaCl, and …
Lateral Spacing Of Subsurface Poultry Litter Bands: Effect On Gaseous Nitrogen Emissions, Nutrient Uptake, And Maize Yield, Jason R. Simmons
Lateral Spacing Of Subsurface Poultry Litter Bands: Effect On Gaseous Nitrogen Emissions, Nutrient Uptake, And Maize Yield, Jason R. Simmons
Theses and Dissertations--Plant and Soil Sciences
Poultry litter (PL) is traditionally applied to no-till maize (Zea mays L.) cropping systems by surface broadcast. Poultry litter is nutrient dense, and it has been repeatedly shown that surface applied PL nitrogen (N) is vulnerable to losses to the atmosphere and nearby water systems. An application method was developed by USDA-Agricultural Research Service scientists for banding poultry litter (PL) below the soil surface with minimal soil disturbance to reduce ammonia (NH3) volatilization and surface run-off. It is well documented that subsurface applied poultry litter (PL) reduces N losses by ammonia (NH3) volatilization; however, the …
Selenium Removal And Pollution Swapping Potentials Of Passive Anaerobic Bioreactors Receiving Coal Slurry Impoundment Wastes, Md Anik Mahmud
Selenium Removal And Pollution Swapping Potentials Of Passive Anaerobic Bioreactors Receiving Coal Slurry Impoundment Wastes, Md Anik Mahmud
Theses and Dissertations--Plant and Soil Sciences
Worldwide, selenium is a major contaminant of concern for coal and metal ore mining industries. In coal mining regions of the eastern USA, for example, billions of liters of wastewaters with elevated Se oxyanion concentrations (primarily SeO42- and SeO32-) are generated during coal washing which is often stored in > 700 man-made impoundments built into remote mountain valleys. Because impoundments are unlined systems, they tend to leak contents into nearby streams, which has detrimental effects on sensitive biota, particularly fish. The primary goal of this project was to evaluate the capacity of passive anaerobic bioreactors (PAB) …
What's In The Pan: An Evaluation Of Fragipan Evolution In Western Kentucky, Hannah Leigh Somerville
What's In The Pan: An Evaluation Of Fragipan Evolution In Western Kentucky, Hannah Leigh Somerville
Theses and Dissertations--Plant and Soil Sciences
The fragipan is a common diagnostic soil feature that does not follow a clear development path. Fragipans are found commonly throughout the southeastern US and cover 2.7 million acres in Kentucky alone. However prevalent, there is no currently accepted genesis theory for fragipans. In this study, we sought to better understand the formation of fragic features in Kentucky’s soils by evaluating fragipan characteristics across a sequence of pedons featuring varying degrees of fragipan development. We found that [Si/Al]Dithionite, [Si/(Si + Al)]Dithionite and SiDithionite concentration were all higher in well-developed fragipans, suggesting the involvement of an aluminosilicate …
Understanding The Effects Of Complex Topography On Cover Crop Dynamics And Maize Production In Kentucky Agroecosystems, Samuel John Leuthold
Understanding The Effects Of Complex Topography On Cover Crop Dynamics And Maize Production In Kentucky Agroecosystems, Samuel John Leuthold
Theses and Dissertations--Plant and Soil Sciences
In Central Kentucky, rolling hill cropland presents a number of challenges related to soil sustainability. Increased topographic complexity can lead to increased erosion, inefficient crop nutrient use and increased nutrient loss. Further, grain crop yields can be variable across both space and time in rolling hill fields and are less resilient to changes in weather conditions than flatter, more homogeneous areas. More than 30% of cropland in Kentucky has a slope greater than 3⁰, which means a large swath of the row crop production land in the state is at increased risk of contribution to soil and water resource degradation. …
Enhancing Agroecosystem Phosphorus Management: Root Phenotyping And Decomposition For Improved Phosphorus Cycling, Rebecca Kay Mcgrail
Enhancing Agroecosystem Phosphorus Management: Root Phenotyping And Decomposition For Improved Phosphorus Cycling, Rebecca Kay Mcgrail
Theses and Dissertations--Plant and Soil Sciences
Plant roots are often overlooked when making nutrient management decisions. Evaluating differences in P acquisition strategies and cycling resulting from years of shoot-specific plant breeding will aid in reducing fertilizer inputs, with the ultimate goal of improving economic sustainability of crop production and preservation of ecosystem services. To achieve this goal, this research screened a diverse panel of winter wheat cultivars that included old and modern, dwarfed and wild type varieties for physical and chemical root phenotypes related to P acquisition. Old cultivars had larger root systems with more roots that grew two times faster than intermediate/modern cultivars. Wild type …
Topographic Gradients In Bulk Soil Properties In Central Kentucky Karst Sinkholes, Anne Kathryn Mcgraw
Topographic Gradients In Bulk Soil Properties In Central Kentucky Karst Sinkholes, Anne Kathryn Mcgraw
Theses and Dissertations--Plant and Soil Sciences
The Bluegrass physiographic region of Kentucky is underlain by the late Ordovician Lexington Limestone formation. This area has many identifiable karst features, including sinkholes. Karst sinkholes and associated soils coevolve, which may influence the distribution of bulk soil properties and storage of carbon across karst landscapes. Two sinkholes on the University of Kentucky’s C. Oran Little Animal Research Center in Woodford County, central Kentucky, were selected for analysis. We described and sampled nine pedons at the dominant landscape positions (e.g., summit, shoulder, backslope, footslope, and toeslope) within the two sinkholes; we characterized the physical, chemical, and mineralogical soil properties across …
The Impact Of Ryegrass On A Fragipan Soil, Keegan Patrick Smith
The Impact Of Ryegrass On A Fragipan Soil, Keegan Patrick Smith
Theses and Dissertations--Plant and Soil Sciences
Fragipans are soil horizons which negatively impact row crop yields due to their cemented nature. Annual ryegrass has been proposed as a cover crop to help remediate these dense horizons. The objectives of this study were to (1) evaluate potential ryegrass root exudates and their ability to solubilize proposed fragipan cementing agents, aluminum (Al), iron (Fe), and silica (Si) in stirred-batch reactor studies; and (2) evaluate annual ryegrass’ ability to remediate the fragipan through an 8-week greenhouse growth study using non-destructive, mini-rhizon samplers installed on soil cores for in situ pore water sampling, and non-invasive soil porosity calculations using X-ray …
Soil Carbon Dynamics And Greenhouse Gas Emissions In Conservation Tillage Systems At Multiple Scales, Yawen Huang
Soil Carbon Dynamics And Greenhouse Gas Emissions In Conservation Tillage Systems At Multiple Scales, Yawen Huang
Theses and Dissertations--Plant and Soil Sciences
Conservation tillage practices like no-tillage and reduced tillage have been widely implemented worldwide, with expectations they would provide multiple benefits (e.g., yield enhancement and soil carbon sequestration) for food security and climate adaptation and mitigation. However, the adoption of conservation tillage faces both opportunities and challenges. A knowledge gap still exists regarding the effects of conservation tillage on the carbon cycle in agroecosystems. This dissertation reflects a comprehensive evaluation of conservation tillage at multiple scales using an integrated systems approach, a combination of data synthesis, the agriculture ecosystem model, and field observations and measurements. I first conducted a meta-analysis to …
Long-Term Land Management Practices And Their Effect On Soil Health And Crop Productivity, Thomas Joseph Muratore Jr.
Long-Term Land Management Practices And Their Effect On Soil Health And Crop Productivity, Thomas Joseph Muratore Jr.
Theses and Dissertations--Plant and Soil Sciences
Agricultural intensification reliant on monocrops could change soil health in a way that does not support maximum crop productivity. Twenty-nine-year-old no-till field plots at the University of Kentucky Spindletop research farm showed a significant reduction in corn yields from continuous corn plots compared to those from plots in various types of rotation. The objective of this study was to determine what role soil microbes might play in yield reduction and how management and time effects microbial community structure. Samples were collected from the following treatments: continuous corn (CC), continuous soybean (SS), a 2-year corn/soybean rotation (CCSS), Corn in rotation with …
Spatial Estimation Of Hydraulic Properties In Structured Soils At The Field Scale, Xi Zhang
Spatial Estimation Of Hydraulic Properties In Structured Soils At The Field Scale, Xi Zhang
Theses and Dissertations--Plant and Soil Sciences
Improving agricultural water management is important for conserving water during dry seasons, using limited water resources in the most efficient way, and minimizing environmental risks (e.g., leaching, surface runoff). The understanding of water movement in different zones of agricultural production fields is crucial to developing an effective irrigation strategy. This work centered on optimizing field water management by characterizing the spatial patterns of soil hydraulic properties. Soil hydraulic conductivity was measured across different zones in a farmer’s field, and its spatial variability was investigated by using geostatistical techniques. Since direct measurement of hydraulic conductivity is time-consuming and arduous, pedo-transfer functions …
Can Increasing Grass-Fungal Endophyte Symbiotic Diversity Enhance Grassland Ecosystem Functioning?, Mahtaab Bagherzadeh
Can Increasing Grass-Fungal Endophyte Symbiotic Diversity Enhance Grassland Ecosystem Functioning?, Mahtaab Bagherzadeh
Theses and Dissertations--Plant and Soil Sciences
The relationship between biodiversity and ecosystem functioning is important in maintaining agroecosystem sustainability. Plant-microbe symbioses, such as exists between the grass tall fescue (Schedonorus arundinaceum) and the asexual fungal endophyte Epichloë coenophiala, can be utilized to enhance agroecosystem functions, such as herbivore resistance. “Novel” E. coenophiala strains that vary in the production of mammal- and insect-toxic compounds have been identified, inserted into tall fescue cultivars, and are planted in pastures globally. Novel fungal endophyte-tall fescue associations may have divergent ecosystem function effects. This study assessed effects of different fescue-endophyte symbiotic combinations on pasture ecosystem function, including aboveground …
Exploring Spatial And Temporal Variability Of Soil And Crop Processes For Irrigation Management, Javier Reyes
Exploring Spatial And Temporal Variability Of Soil And Crop Processes For Irrigation Management, Javier Reyes
Theses and Dissertations--Plant and Soil Sciences
Irrigation needs to be applied to soils in relatively humid regions such as western Kentucky to supply water for crop uptake to optimize and stabilize yields. Characterization of soil and crop variability at the field scale is needed to apply site specific management and to optimize water application. The objective of this work is to propose a characterization and modeling of soil and crop processes to improve irrigation management. Through an analysis of spatial and temporal behavior of soil and crop variables the variability in the field was identified. Integrative analysis of soil, crop, proximal and remote sensing data was …
Soil Hydraulic Property Estimation Under Major Land-Uses In The Shawnee Hills, Trinity Joseph Baker
Soil Hydraulic Property Estimation Under Major Land-Uses In The Shawnee Hills, Trinity Joseph Baker
Theses and Dissertations--Plant and Soil Sciences
The ability to map soil moisture is becoming more important with changing climates and modeling these effects depends on reliable estimations of hydrologic soil properties under different land managements. This study: 1) tests the application of existing soil hydraulic property estimation methods against in-situ values of six catenas under two covers (forest and grass); 2) validate Random Forest Algorithm (RF) estimates informed from the six catenas on two separate catenas; 3) identify Rapid Carbon Assessment (RaCA) sites within the Shawnee Hills Region that represent different land-uses (Crop, Conservation Reserve Program (CRP), Forest, and Pasture); 4) apply RF learning tree informed …
Evaluating Soil Physical And Chemical Properties Following Addition Of Non-Composted Spent Coffee And Tea For Athletic Fields, Shuang Zhou
Theses and Dissertations--Plant and Soil Sciences
Physical and chemical properties of non-composted spent coffee (CF) and tea (T) suggest they may have applications as soil amendments for improving poor soils. Studies were conducted to determine 1) the effect of amendments on grass growth and soil properties, 2) the effect of incorporation versus surface application of amendments on soil properties, and 3) the effect of amendment application frequency on grass growth and soil properties. In the first study, amendments were mixed with sand and planted to bermudagrass. Treatments included CF, T, and peat moss (PM) mixed with sand, and 100% sand as a control. In the second …
Effects Of Epichloë Coenophiala−Tall Fescue Symbiosis On Plant-Microbe-Soil Interactions In A Temperate Pasture, Lindsey C. Slaughter
Effects Of Epichloë Coenophiala−Tall Fescue Symbiosis On Plant-Microbe-Soil Interactions In A Temperate Pasture, Lindsey C. Slaughter
Theses and Dissertations--Plant and Soil Sciences
Plants interact in myriad ways with microorganisms to influence ecosystem processes such as nutrient cycling, which can regulate ecosystem response to global change. One important plant-microbe symbiosis occurs between cool-season grasses and asexual fungal Epichloë endophytes, such as tall fescue (Schedonorus arundinaceus) and Epichloë coenophiala. Because the common toxic strain of the endophyte (CTE) harms grazing livestock, non-livestock toxic endophyte (NTE) strains have been developed and are increasingly deployed in pastures. Little is known about how these symbioses impact other plant-microbe interactions and microbe-mediated soil processes in grassland ecosystems. I conducted three studies to determine how E. …
Soil Management And Nitrogen Dynamics In Burley Tobacco Rotations, Congming Zou
Soil Management And Nitrogen Dynamics In Burley Tobacco Rotations, Congming Zou
Theses and Dissertations--Plant and Soil Sciences
Agronomic practices, including tillage, crop rotation and N fertilization, have been developed to efficiently manage soil N dynamics and crop N nutrition. These practices can affect soil organic carbon (SOC) and soil total nitrogen (STN) sequestration, and consequently influence soil nitrogen mineralization (SNM) and crop N nutrition. However, little research has been systematically and simultaneously conducted to examine the effect of agronomic management on (1) SOC and STN stocks; (2) SNM; and (3) crop N nutrition. Burley tobacco (Nicotiana tobacum L.) is a N demanding crop and subject to inefficiency in N fertilization. Moreover, conservation tillage and rotation have been …
Boron Nutrition Of Burley And Dark Tobacco, Laura Ann Frakes Mitchell
Boron Nutrition Of Burley And Dark Tobacco, Laura Ann Frakes Mitchell
Theses and Dissertations--Plant and Soil Sciences
The incidences of suspected Boron (B) deficiency have increased recently in Kentucky tobacco fields, potentially due to recent changes in management practices. The symptoms observed in the field include; hollow stalk, stunted growth, deformed or no bud formation, small slits on the lower leaf midrib and uncontrollable breaking of the midrib approximately two inches from the stalk. B is a micronutrient tobacco needs in minute amounts, however excessive additions of B could cause toxicity. The objectives of this work were to 1) establish critical points for B sufficiency, 2) describe and define B deficiency and toxicity symptoms and 3) develop …
Field-Scale Water And Solute Transport, Yang Yang
Field-Scale Water And Solute Transport, Yang Yang
Theses and Dissertations--Plant and Soil Sciences
Spatial variability of soil properties complicates the understanding of water and solute transport at the field scale. This study evaluated the impact of land use, soil surface roughness, and rainfall characteristics on water transport and Br- leaching under field conditions by means of a new experimental design employing scale-dependent treatment distribution. On a transect with two land use systems, i.e., cropland and grassland, rainfall intensity and the time delay between Br- application and subsequent rainfall were arranged in a periodically repetitive pattern at two different scales. Both scales were distinct from the scale of surface roughness as described …
Managing Soil Microbial Communities With Organic Amendments To Promote Soil Aggregate Formation And Plant Health, Shawn T. Lucas
Managing Soil Microbial Communities With Organic Amendments To Promote Soil Aggregate Formation And Plant Health, Shawn T. Lucas
Theses and Dissertations--Plant and Soil Sciences
The effects of managing soil with organic amendments were examined with respect to soil microbial community dynamics, macroaggregate formation, and plant physio-genetic responses. The objective was to examine the possibility of managing soil microbial communities via soil management, such that the microbial community would provide agronomic benefits. In part one of this research, effects of three amendments (hairy vetch residue, manure, compost) on soil chemical and microbial properties were examined relative to formation of large macroaggregates in three different soils. Vetch and manure promoted fungal proliferation (measured via two biomarkers: fatty acid methyl ester 18:2ω6c and ergosterol) and also stimulated …
Transformations, Bioavailability And Toxicity Of Manufactured Zno Nanomaterials In Wastewter, Sewwandi Rathnayake
Transformations, Bioavailability And Toxicity Of Manufactured Zno Nanomaterials In Wastewter, Sewwandi Rathnayake
Theses and Dissertations--Plant and Soil Sciences
In order to properly evaluate the ecological and human health risks of ZnO Manufactured nanomaterials (MNMs) released to the environment, it is critical to understand the likely transformation products in the wastewater treatment process and in soils receiving biosolids. To address this critical knowledge gap, we examined the transformation reactions of 30 nm ZnO MNMs in single component and multi-component systems, with phosphate and natural organic matter (NOM). We also assessed the influence of nano ZnO transformation on the bioavailability, and toxicity of ZnO transformation products to Triticum aestivum. The data revealed that ZnO MNMs react with phosphate at …
Abiotic Nitrate And Nitrite Reactivity With Iron Oxide Minerals, Prakash Dhakal
Abiotic Nitrate And Nitrite Reactivity With Iron Oxide Minerals, Prakash Dhakal
Theses and Dissertations--Plant and Soil Sciences
Under iron (Fe3+)-reducing conditions where aqueous Fe2+ and unreduced solid Fe3+-oxides commonly coexist, soil Fe2+ oxidation has been shown to be coupled with nitrate (NO3-) reduction. One possible secondary reaction is the involvement of NO3- and nitrite (NO2-) with Fe-oxide minerals found in many natural environments. Yet, spectroscopic measurements and kinetic data on reactivity of NO3- and NO2- with Fe-containing oxide minerals such as goethite (a-FeOOH), and magnetite (Fe3O4) are not found in the literature. The reactivity of …