Soil Science Commons^™

Toward Optimizing Fruit Production In Utah Soils: Apple Salt Tolerance Screening And Tart Cherry Fertility Management, Kaitlin Dabbs

All Graduate Theses and Dissertations, Fall 2023 to Present

Fruit production in Utah can be challenging due to local climate and soil conditions. Tart cherries and apples are major fruit crops in Utah, and improvements to these cropping systems would be beneficial for farmers and local consumers. Two experiments were conducted to evaluate desired improvements for these crops. The first study looked for salt tolerance in ten new apple rootstocks. Salty soils can be found throughout the state limiting the land suitable for apple production. When grown in salty soils apple trees often have reduced growth and production potential. A specialized drip irrigation system was constructed in a greenhouse …

How Quickly Do Eastern Floodplains Store Carbon? Quantifying Reference Carbon Flux On The Dead Diamond River, Jacob Schnell

Earth Sciences Undergraduate Senior Theses

Terrestrial Earth systems sequester an estimated 30% of annual anthropogenic CO2 emissions. The largest share is stored in global soils which collectively store more than 3 times the amount of carbon as the atmosphere. Floodplains and river systems, while covering only 5–8% of land area, store 20–30% of the global soil organic carbon (SOC), yet, the rate at which floodplains sequester carbon remains highly uncertain. Here I constrain floodplain carbon sequestration rates for a model northeastern river that has not been impacted by development or significant human activity. I calculate carbon stock using total organic carbon and derive carbon flux …

Evaluating Soil Health And Crop Yield In Louisiana Agricultural Systems: Impacts Of Best Management Practices And Prediction Models, Hector J. Mendoza Lagos

LSU Doctoral Dissertations

The adoption of conservation management practices is critical for improving soil health, enhancing nutrient use efficiency, and sustaining crop productivity in row crop systems in Louisiana. This study evaluated the role of conservation agronomic practices, soil biochemical indicators, and machine learning predictive models to improve soil nutrient dynamics, soil health indicators, microbial communities (MC), and crop productivity on a corn (Zea mays L.) research plot scale and in a commercial forty-hectare cotton (Gassypium hirsutum L.)-corn-soybean (Glycine max L.) rotation system in northeast Louisiana. The objectives of the study were to evaluate soil nutrient dynamics and MCs under …

Decomposition In Urban Forest Patches Across A New York-New Jersey Urbanization Gradient, Cailee Sprouse

Theses, Dissertations and Culminating Projects

"Urbanization causes habitat fragmentation, pollution, homogenization of soil profiles, and replacement of native flora and fauna, which can alter vital ecological processes like decomposition. It is essential to investigate the impacts urbanization may have on ecosystem functioning to better inform urban land management. Studies have shown conflicting results on the impacts of urbanization on soil decomposition rates, with some showing higher, lower, or similar decomposition rates in urban soils compared to rural soils. This study aims to investigate the effects of urbanization and soil characteristics on decomposition rates in three urban forest patches in New Jersey and New York using …

Soil Moisture Regime Effects On Near-Surface Soil Chemical Properties In Alfisols Under Native Tallgrass Prairie In Arkansas, Sydney M. Talley

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Tallgrass prairie ecosystems provide many crucial ecosystem services, including nutrient cycling and storage, organism habitat, and soil and water conservation. However, tallgrass prairies are considered an endangered ecosystem, particularly in the Ozark Highlands and Grand Prairie regions of Arkansas, where less than 0.05% of Arkansas’ original prairie land area remains. Understanding soil nutrient supplies over time in native tallgrass prairie ecosystems is critical for quantifying the success of restoration and rehabilitation activities. The objective of this study was to evaluate the effects of soil moisture regime (SMR) (i.e., aquic and udic), region (i.e., Ozark Highlands and Grand Prairie), and their …

Grazed Pasture Effects On Greenhouse Gas Emissions In The Ozark Highlands, Tyler Buchanan

Graduate Theses and Dissertations

In the United States (US), grazinglands serve as the main foundation for the livestock industry, and, in Arkansas specifically, pastures are essential for rotational grazing and dairy operations. Climate change is increasingly becoming a concern in the agriculture industry, largely caused by anthropogenic activities increasing greenhouse gas (GHG) concentrations in the atmosphere, at least partly due to the nutrient recycling that occurs from animal manure additions in grazinglands. Therefore, quantifying GHG emissions from pastures is essential to better understanding the impacts of grazing on the environment. The objective of this study was to quantify and evaluate the potential effects of …

Sequential Products Of Anaerobic Denitrification In Calcareous And Noncalcareous Soils By Use Of The Gas Chromatograph, Grant S. Cooper

All Graduate Theses and Dissertations, Fall 2023 to Present

The sequential products of anaerobic denitrification were determined on seven Western soils (four alkaline, two acid, and one neutral) by soil and gas analysis. The soils with 1% alfalfa and added KNO3 were incubated at moistures slightly greater than field capacity and with an atmosphere of He. The soils and gases were periodically analyzed and balance sheets prepared. The sequence of NO3-->NO2-->N2O-->N2 operated in all soils. The rates of nitrogen interchanges and maximal amounts of nitrate, N2O2 and N2 were determined. From this data it was postulated that the rate-limiting process for denitrification in acid soils is …

Real-Wastewater-Derived-Struvite Effects On Micronutrients In Runoff Water, Lauren E. Pruitt

Crop, Soil and Environmental Sciences Undergraduate Honors Theses

Phosphorus (P) is an essential nutrient needed in agriculture for proper plant growth and development and is often introduced into agricultural systems in the form of synthetic P fertilizers. Mined rock phosphate is the primary P source for the production of synthetic P fertilizers and is a finite resource. Struvite (MgNH₄PO₄·6H₂O) is a compound that can be precipitated from municipal wastewater, recovering P, and is currently being evaluated for its potential use as an alternative fertilizer-P source. The objective of this study was to evaluate the effects of fertilizer-P source [i.e., synthetic electrochemically precipitated …

Impacts Of Climate-Smart Agriculture On Greenhouse Gas Emissions In Southeast Arkansas Cotton, Cassandra Seuferling

Graduate Theses and Dissertations

Increasing concerns of climate change have led to the evaluation of greenhouse gas (GHG) emissions [i.e., carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)] from agroecosystems, particularly cotton (Gossypium hirsutum) production. Technology improvement and conservation agriculture methods [i.e., reduced-tillage (RT) instead of conventional tillage (CT) and the use of cover crops (CC)] require further evaluation regarding GHG emissions from Arkansas cotton production. The first objective of the study was to evaluate four gas-flux-determination methods [i.e., linear or exponential regression models, with negative fluxes (WNF) included in the dataset or replacing negative fluxes (RNF)] on CO2, CH4, and N2O fluxes …

Recent Wetland Elevation Dynamics In Coastal Louisiana, Usa, Elizabeth Harris

LSU Master's Theses

Coastal marshes globally are increasingly vulnerable to accelerating relative sea-level rise (RSLR), which threatens their capacity to maintain elevation through feedbacks among sediment supply, vegetation productivity, hydrology, and soil processes. Although many marshes can persist under moderate rates of sea-level rise through vertical accretion and belowground biomass production, this resilience is strongly constrained by sediment availability and subsurface processes such as autocompaction and organic matter decomposition. High accretion is often assumed to confer marsh resilience; however, subsurface processes, particularly autocompaction driven by surface loading, can substantially offset elevation gains. Coastal Louisiana experiences among the highest rates of RSLR worldwide due …

Biogeochemical Controls On Phosphorus Transport And Legacy Storage Across A Coastal Watershed, Lee Potter

LSU Doctoral Dissertations

Excess phosphorus (P) loading is a key driver of eutrophication and harmful algal blooms (HABs) in aquatic systems worldwide. This relationship is of increasing concern in coastal Louisiana, where climate variability, altered hydrology, and land-use change converge, resulting in increased hydrologic and nutrient loading into coastal systems. This dissertation examines controls on P cycling in the Lake Pontchartrain Basin through a multi-scale framework linking estuarine processes, watershed loading, climate and weather patterns, and sediment dynamics. The dissertation begins with an overview of the study region, P dynamics, and changes in hydrology and nutrient loading patterns. Chapter 2 presents a spatial …

Environmental Impact Of Preventative Fire-Retardant Applications On Soil Water Chemistry, Patrick C. Michelsen

Master's Theses

Between 1992 and 2012, 84% of all documented wildfires were started by humans. These fires often start around high-risk locations such as power lines and roadsides where fuel loads are near these potential human-caused ignition sources. Point source ignition sites that are surrounded by shrubs or grasslands are especially important because fires that occur within these biomes are responsible for far more destruction of property than forest fires. One strategy that is effective at mitigating the spread of fires from ignition sites that are within grassland or shrub biomes are preventative fire-retardant products (PFRPs). These PFRPs differ from traditional fire-retardant …

Depth And Soil Physical Context Govern Soil Organic Carbon, While Woody Cover Moderates Native Vegetation Relationships In California Rangelands, Dabid Zuniga Garcia

Cal Poly Humboldt theses and projects

Soil organic carbon (SOC) is central to soil function and an important component of climate mitigation in rangeland ecosystems, but the controls on SOC across California’s working rangelands remain understudied. Using data from Point Blue Conservation Science’s Rangeland Monitoring Network, this study evaluated how soil properties, vegetation structure, and recent climate relate to SOC concentration at depths of 0–10 cm and 10–40 cm across 145 ranches spanning four California regions. Linear mixed-effects models showed that SOC was consistently higher in topsoil than subsoil and highest in coastal sites relative to interior valleys. Bulk density was the strongest negative predictor of …

Below The Rows, Beyond The Roots: An Art Exhibition Depicting Agriculture Across The Globe, Maggie Enoch

Honors Theses and Capstones

In Below the Rows, Beyond the Roots, artist Maggie Enoch creates multimedia works inspired by her exposure to diverse agricultural systems and perspectives while studying geography and sustainable agriculture/food systems around the world. By integrating complex histories with the contemporary realities of farming, Maggie paints vivid pictures of the power of food in this five-piece exhibition.

Soil Organic Carbon And Soil Health Property Responses To Land Management Across Topographic Positions, Mia D. Makovsky

All Graduate Theses, Dissertations, and Other Capstone Projects

uring the last ice age, ice sheets advanced and retreated across the upper Midwest, leaving behind a landscape characterized by poorly drained hummocky topography. Well-aerated soils have formed on uplands and lowlands are dominated by hydric soils. These wetlands and hydric soils have potential to store large quantities of carbon, particularly compared to the well-aerated uplands, but many have been drained and cultivated for decades. Conservation agriculture methods have emerged to protect and conserve soil health from negative effects due to cultivation.The purpose of this study is to determine how agricultural management practices and landscape properties (e.g, topographic position) affect …

Impacts Of Burn Severity On The Hydro-Physical, Chemical And Thermal Properties Of Sub-Arctic Peat, Joshua B. Meyer Mr

Theses and Dissertations (Comprehensive)

Under current climate change, summer season in the boreal regions of Canada is becoming increasingly warmer and drier. This shift is driving increases in the frequency and intensity of naturally occurring wildfires and allowing access to areas not normally susceptible to fire such as wetlands. In peatland areas, these increasingly large fires can create complex burn scars, which contain a wide variety of different burn severities across different landcover types. This variety calls for a greater understanding of how varying fire intensity affects the hydro physical, chemical, and thermal characteristics of boreal peat. This study aims to deepen that understanding …

Impacts Of Management Practices And Soil Properties On Free-Living Nitrogen Fixation In Eastern South Dakota, Laura Galvan Nuevo

Electronic Theses and Dissertations

Free-living nitrogen (N) fixation (FLNF) may represent a sustainable pathway to supplement crop N demand in agroecosystems, yet edaphic and management factors regulating this process under field conditions remain poorly understood in the Northern Great Plains. Using 15N2 direct method to quantify potential FLNF (pFLNF) and baseline FLNF (bFLNF), this thesis investigates how crop rotations (2-, 3-, and 4-year systems), tillage management (conventional vs. no-till), cover cropping, and soil properties affect the potential of free-living diazotrophs to supply N via FLNF in a long-term no-till corn-based system in Southeastern South Dakota. A two-year field study evaluated pFLNF across four growing …

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. …

Remediation Impacts Metal Concentrations And Metal Tolerant Bacteria In Soils Of The Missouri Tri-State Mining District, Ophelia R. Pettington

Graduate Theses/Dissertations

After over 100 years of Zn and Pb mining in the Tri-State mining district (TSMD), former mines continue to be sources of metals. Metal contaminated soils can be remediated using plant-microbe interactions. Plants manipulate their microbiome and recruit microbes to increase metal tolerance. Remediating bacteria are site-specific and identifying native microbes can accelerate remediation efforts. Studies relating microbes and metal concentrations in remediated areas in the TSMD are scarce. I collected root and bulk zone soils associated with Andropogon virginicus from remediated and non-remediated sites in Webb City, MO. I used 16S rRNA gene amplicon sequencing to evaluate the bacterial …

Preliminary Analysis Of Soil Volatile Organic Compounds As Soil Health Indicators, Thorne Taul

Graduate Theses, Dissertations, and Problem Reports (ETD)

Over the past decade, soil health (SH) has gained popularity due to the novelty of sustainable soil use related to human wellbeing. Soil health describes the overall quality of soil and its capacity to function over time. As interest in SH grows, researchers continue to explore new soil health indicators that can improve knowledge on how soil health is assessed and managed. Some indicators directly reflect soil health status, and some indirectly relate to processes and functions occurring within the soil. Volatile organic compounds (VOCs) are naturally occurring compounds that play a role in multiple soil processes. They are associated …

High-Resolution Mapping Of Soil Moisture Variation Using Uas Thermal And Multispectral Imagery, Jackline Amma Timah

Theses and Dissertations

In agricultural landscapes, soil moisture regulates hydrologic partitioning, nutrient transport and water quality, land-atmosphere energy exchange that shapes local climate, and ecosystem resilience. However, traditional monitoring approaches, such as in-situ sensors and satellite imagery, often lack the spatial resolution required to capture fine-scale soil moisture variability. This study evaluated whether unmanned aerial system (UAS)-derived thermal, multispectral, and terrain variables can capture fine-scale spatial variability in volumetric water content (VWC) within an SRB in central Illinois.

High-resolution imagery was collected and paired with 50 field-measured VWC observations. Land surface temperature (LST), vegetation indices (NDVI and NDRE), spectral bands, and slope were …

Essays On The Economics Of Farmland Valuation And Investment In U.S. Agriculture, Colson Tester

Graduate Theses and Dissertations

This dissertation presents three empirical essays that collectively advance the understanding of farmland valuation in key U.S. agricultural regions, emphasizing the critical advantages of comprehensive, transaction-based data over traditional survey methods. Farmland represents a significant portion of agricultural wealth, and its accurate valuation is crucial for farmers, investors, and policymakers, influencing everything from credit access to investment strategies. Historically, research has often relied on subjective survey data, which can suffer from biases, inaccuracies, and insufficient granularity. This dissertation addresses these limitations by leveraging extensive datasets of arm’s-length farmland transactions, offering a more precise and market-driven perspective on land values. The …

Increasing Soil Health In Zero-Grade, Flood-Irrigated Rice In Eastern Arkansas, Hannah Elizabeth Vickmark

Graduate Theses and Dissertations

In an effort to build and maintain soil health and sequester soil C, many producers and researchers are turning towards regenerative management practices in agricultural systems, such as reduced tillage or no-tillage (NT), the implementation of winter cover crops (CC), and the use of organic or green manures, such as biochar. However, little research is being conducted on the long-term soil health and agronomic benefits of these practices in a flood-irrigated rice (Oryza sativa L.) production system. Three replications of seven treatment combinations were applied to 6.1 x 30.5 m rice plots. Baseline soil health properties were quantified at six …

What Limits Dryland Ecosystems? Patterns Of Soil Fertility And Resource Limitation In The Chihuahuan Desert, Dylan Stover

Open Access Theses & Dissertations

Human activities are substantially altering global resource cycles with widespread implications for biogeochemistry and ecosystem functioning globally. Drylands, regions where precipitation is outweighed by water losses, are especially sensitive to these large shifts in resource cycles due to their inherently low and variable resource availability. In these regions, resource availability and biological activity are often concentrated around plants – or fertile islands – and predominantly driven by pulses of water. However, our knowledge of the processes influencing biological productivity in drylands – patterns of soil fertility and resource limitation – remains lacking, and their unique biogeochemical and biological processes create …

Agricultural Practices’ Impact On Soil Health Indicators In Mid-South U.S. Crop Production Systems, Katherine Suzanne French

Graduate Theses and Dissertations

Soil health and regenerative agriculture are concepts gaining popularity across global agriculture systems. The effect of sustainable farming practices such as nutrient management, cover crops, adoption of no-tillage, and residue retention on crop yield, as well as environmental resilience, is increasingly being studied. This research aimed to evaluate the impacts of (i) cover cropping and nutrient management, and of (ii) soil sampling depth and timing on indicators of soil health in various mid-southern irrigated row crop systems. Soil health indicators like soil organic matter (SOM), carbon dioxide respiration (CDR), beta-glucosidase enzyme activity (BG), permanganate oxidizable carbon (POXC), and the soil …

Effect Of Seasonal Variability In Methane Emissions And Iron Redox Chemistry At Terrestrial-Aquatic Interfaces, Hermes C. Ruiz

Master's Theses

Methane (CH₄) emissions at terrestrial–aquatic interfaces (TAIs) are significant contributors to the global carbon budget, yet the mechanisms driving methanogenesis remain poorly understood. Limited data exist on how seasonal variations and redox processes influence CH₄ fluxes in these dynamic ecosystems. This study addressed two questions: (1) How are CH₄ fluxes in riverine floodplains and adjacent hillslopes impacted by seasonal variations? (2) What roles do metal redox processes (e.g., iron (Fe)) play in regulating methanogenesis?

In-situ CH₄ flux and solid-phase Fe speciation were quantified in East River, CO, under flooded and drained conditions. Groundwater chemistry, gas flux, and soil physical properties …

Impacts Of 4r Nitrogen Management And Water Optimization On Soil Health, Kamaldeep Kamaldeep

All Graduate Theses and Dissertations, Fall 2023 to Present

Farmers in Utah and Idaho are facing growing challenges due to high fertilizer costs, limited irrigation water, and pressure to improve long-term soil health. To better understand current practices and grower attitudes, a survey was conducted in 2020 targeting 5,000 producers of small grains, corn, and potatoes. Although the response rate was low, 146 growers representing over 25,000 hectares of cropland participated. Survey results showed that most growers are open to improving nitrogen and irrigation practices and care about their soil health, even if not all are fully using 4R or precision agriculture methods.

This thesis includes two field studies …

Soil Carbon Storage And Its Relation To Abiotic And Biotic Factors In The Boise Foothills, Richie William Holder

Boise State University Theses and Dissertations

Terrestrial soil sequesters a significant amount of carbon (C), and changes to this pool can impact atmospheric CO2 concentrations and climate change. Thus, it is crucial to understand the drivers of the size of this pool. Changes in plant community composition in semi-arid ecosystems can impact soil C storage. However, little is known about the impact of plant functional type on the quantity and distribution of soil C on a landscape scale relevant to ecosystem management. I conducted a study in the City of Boise’s Open Space Reserves located north of Boise, Idaho to evaluate how plant functional type affects …

Cotton Yield And Tissue-Potassium Response To Potassium Fertilization, Maria Paula Ramos Do Prado

Graduate Theses and Dissertations

Potassium (K) deficiency is a common yield-limiting factor in cotton (Gossypium hirsu tum L.) production across the U.S. Cotton Belt. Adequate fertilizer-K management is paramount to ensure optimum plant growth and development, minimizing yield losses. Currently, fertilizer K recommendations for cotton in Arkansas are derived from expected yield responses of other crops, with no calibrated fertilizer-K rates or critical tissue-K concentrations defined to maxim ize crop yield. Our research objectives were i) to investigate cotton yield response and fiber qual ity to K fertilization on soils with different K availability; ii) to correlate relative yield with tis sue-K concentrations at …

Investigating The Microbial Communities In Freshwaters Of Northern Sweden, Maizy Wilcox

Undergraduate University Honors Capstones

Climate change is shifting the stability of sensitive ecosystems in the Arctic region due to global warming, with widespread impacts on permafrost regions, including the Stordalen Mire region of Sweden. Due to climate change, the Stordalen Mire is composed of thawing permafrost shifting into a wetland (V onk et al., 2015). As permafrost thaws, the landscape transforms due to changing water environmental conditions, causing lower pH changes and higher temperatures in the water, impacting the underlying soil chemistry and biology, vegetation, and microbial communities (Webb et al., 2022). The increased temperature can enhance methanogenic microbial growth by expanding the groundwater …