Soil Science Commons^™

Agronomic Management Practice Effects On Particulate Organic Matter And Infiltration In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Johan Desrochers

Graduate Theses and Dissertations

Improving the understanding of conventional and alternative management practices and their interactions on aggregate-derived particulate organic matter (POM) fractions and soil hydraulic properties, particularly infiltration, is instrumental to soil and groundwater management and long-term sustainability in the Lower Mississippi River Delta (LMRD) region of eastern Arkansas. The objective of this long-term wheat (Triticum aestivum L.)-soybean (Glycine max [L.] Merr.), double-crop (WSDC) field study in a silt-loam soil (Glossaquic Fraglossudalf) in the LMRD region of eastern Arkansas was to evaluate the effects of conventional and alternative management practices, including wheat-residue level, residue burning, tillage and irrigation, on i) POM fractions and …

The Effect Of Preflood Nitrogen And Flood Establishment Timing On Rice Development, Nitrogen Uptake And Grain Yield, Tyler Richmond

Graduate Theses and Dissertations

Urea-N fertilizer is typically applied at the 5-leaf stage to rice (Oryza sativa L.) grown in a dry-seeded, delayed-flood production system. How long the preflood-N can be delayed without adverse effects on yield potential is poorly understood. The research objective was to determine the effects of preflood-N application and flood establishment timing on aboveground-N content, 50% heading, yield components, and grain yield. Trials were established on silt loam soils at the Pine Tree Research Station (PTRS) and Rice Research and Extension Center (RREC) during 2015 and 2016. Urea-N was applied at 0, 45, 90, 135, and 180 kg N ha-1 …

Laboratory Resistivity Measurements For Soil Characterization, Behdad Mofarraj Kouchaki

Graduate Theses and Dissertations

Field based electrical resistivity measurements, such as electrical resistivity tomography (ERT) and capacitively coupled resistivity (CCR), are geophysical methods that offer a non-destructive and rapid means to collect continuous data. As such, ERT and CCR are becoming increasingly popular tools for geotechnical engineers; however, it is challenging to derive geotechnical information such as soil type, density, and water content from the data. A laboratory geophysical investigation was carried out to gain a better understanding of the parameters that affect the electrical resistivity of soils and devise a relationship between resistivity and soil type or classification. In this study, a soil …

Characterization Of The Relationships Between Soybean Yield, Trifoliolate Leaf Chloride Concentration, And Cultivar Chloride Inclusion/Exclusion Rating, Dillon Cox

Graduate Theses and Dissertations

Chloride toxicity is recognized as yield limiting problem in soybean [Glycine max (L.) Merr.] production. Limited information is available to accurately diagnose and manage Cl toxicity. The only recommendation for Cl toxicity management is to plant an excluder cultivar, however the cultivar Cl sensitivity rating system (excluder, includer, and mixed) does not appear to capture the variability in cultivar Cl tolerance. The objectives of this research were to i) develop critical tissue-Cl concentrations in which yield loss occurs for excluder and includer cultivars and ii) investigate the variability in cultivar Cl ratings. A study was conducted across five site-years using …

Development Of A Multiband Remote Sensing System For Determination Of Unsaturated Soil Properties, Cyrus D. Garner

Graduate Theses and Dissertations

A multiband system including active microwave sensing and visible-near infrared reflectance spectroscopy was developed to measure unsaturated soil properties in both field and laboratory environments. Remote measurements of soil volumetric water content (θv), soil water matric potential (ψ), and soil index properties (liquid limit [LL], plastic limit [PL], and clay fraction [CF]) were conducted. Field-based measurement of θv was conducted using a ground-based radar system and field measurements within 10 percentage points of measurements acquired with traditional sampling techniques were obtained. Laboratory-based, visible and near infrared spectroscopy was found to be capable of obtaining empirical, soil specific regression functions (partial …

Examining Denitrification In Agricultural Ditch Sediments Vegetated With Rice Cutgrass (Leersia Oryzoides): Modeling Seasonal Variation Across Increasing Levels Of Nitrate Loading And Model Application To Pre-Existing Datasets, Shannon Lee Speir

Graduate Theses and Dissertations

Nitrogen (N) derived from fertilizer application in agricultural systems may contribute to significant environmental impacts, including eutrophication of fresh and coastal waters. Rice cutgrass (Leersia oryzoides) can significantly enhance denitrification potential in agricultural ditch sediments, but relationships with known drivers are not well understood. To address this, I examined effects of nitrate (NO3-) availability on dinitrogen gas (N2) and NO3- fluxes seasonally in Chapter 2. Denitrification rates were measured as N2 flux from intact vegetated sediment cores using Membrane Inlet Mass Spectrometry (MIMS). Michaelis-Menten models were developed from observations to mathematically describe N2 fluxes across the spring, summer, and fall …

Soil And Plant Property Differences Among High-Yield Soybean Areas In Arkansas, Taylor Cass Adams

Graduate Theses and Dissertations

Continued achievement of soybean [Glycine max (L.) Merr.] yields greater than 6719 kg ha-1 (100 bu ac-1) will depend on decreasing the yield gap, which is contingent on gathering more information regarding the soil physical, chemical, and microbiological environment and the main plant factors contributing to high-yield soybean. Therefore, understanding the main factor differences between high- and average-yield areas may provide insight for making management decisions to increase yields. The objectives of this study were i) to evaluate the effects of region and soil depth on soil property differences between high- and average-soybean-yielding areas, ii) to determine which soil properties …

Liming Characteristics Of A High-Calcium, Dry Flue Gas Desulfurization By-Product And Its Effects On Runoff Water Quality, Jason Richard Burgess-Conforti

Graduate Theses and Dissertations

In 2013, only 37% of the 32 million Mg of flue gas desulfurization (FGD) by-products generated in the United States were reused beneficially. If FGD by-products could be used as a beneficial soil amendment, millions of megagrams may be diverted away from surface impoundments and landfills. The purpose of this research was to identify the liming characteristics of a high-Ca dry FGD (DFGD) by-product in comparison to a Class-C fly ash (FA) and reagent-grade CaCO3, and to evaluate the effects of land application to a managed grassland on runoff, plant, and soil quality. Liming characteristics were determined by measuring the …

Cover Crop Establishment And Potential Benefits To Arkansas Farmers, Ashley Elizabeth Humphreys

Graduate Theses and Dissertations

Soybean farmers in Arkansas need best management practices (BMPs) that maximize the benefits of using cover crops including planting date and fertilization recommendations. An evaluation of cover crop species, planting dates, seeding rates, fertilizer rates, and N accumulation aids in providing these BMPs. The first objective of this research is to assess the effect of planting date on biomass production, as well as looking at the interaction of seeding rate or fertilizer rate for legumes or non-legumes, respectively, using Austrian winter pea (Pisum sativum), cereal rye (Secale cereale), black oats (Avena strigosa), wheat (Triticum aestivum), and tillage radish (Raphanus sativus). …

Validation Of N-Star Nitrogen Rate Recommendations And Evaluation Of N-Star Soil Sampling Procedures For Clay Soils In Arkansas, Jarom Thane Davidson

Graduate Theses and Dissertations

The two methods for determining N-fertilizer recommendations for rice (Oryza sativa L.) in Arkansas are the standard N recommendation (SR) based on soil texture, previous crop, and rice cultivar, and the Nitrogen-Soil Test for Rice (N-STaR) which quantifies the potentially mineralizable-N of the soil and provides a site-specific N recommendation. The N-STaR program has recently been developed, and the validation of N-STaR for clay soils is an important step in ensuring that N-STaR predicts correct N-fertilizer rates for rice under a delayed-flood production system. Small-plot trials located across Arkansas compared the N-STaR 95 and 100% relative grain yield (RGY) N …

Determination Of Optimum Fall And Spring Nitrogen Fertilizer Rate For Maximizing Grain Yield Of Soft Red Winter Wheat Sown At Variable Planting Dates, Lucas Vasconcelos Vieira

Graduate Theses and Dissertations

An optimum planting date is important for winter wheat nitrogen (N) management as it dramatically changes the growing environment including temperature and moisture, ultimately affecting fertilizer efficiency and grain yield (GY). In Arkansas, high precipitation in the fall often forces farmers to delay planting and current Arkansas recommendations include the application of fall N when soft red winter wheat (SRWW) is sown later than optimum, despite the lack of data supporting this practice. This study evaluated the effect of rate and timing of N application on GY of SRWW sown at variable planting dates in Arkansas. Granular urea was split …

Evaluation Of Rusle 2 To Estimate Soil Loss From Pastures, Stasha Katrina Balkissoon

Graduate Theses and Dissertations

The accurate estimation of soil erosion by the Revised Universal Soil Loss Equation version 2 (RUSLE2) is critical for several conservation assessments, least of which is its use in the Phosphorus Index (PI) to identify and rank the vulnerability of agricultural fields to phosphorus (P) runoff. Earlier versions of RUSLE reported a soil loss overestimation, which were revised to give RUSLE2, where biomass production in different climatic regions was more accurately represented. RUSLE version 2.0, which contains the new vegetative biomass production routine, was evaluated using two performance indices, the Nash Sutcliffe Efficiency Index (NSE) and Index of Agreement (D) …

Validation Of Soil-Test-Based Phosphorus And Potassium Fertilizer Recommendations For Rice And Soybean, Matthew Scott Fryer

Graduate Theses and Dissertations

The science of soil-testing for nutrient management and fertilizer recommendations is widely accepted among scientists and agronomists. Although this science is unsurpassed in predicting soil nutrient availability, soil-test interpretations are seldom validated. Major research objectives for irrigated soybean [Glycine max (L.) Merr.] and direct-seeded, delayed-flood rice (Oryza sativa L.) were to: i) validate the accuracy of Mehlich-3 soil-test P (STP) and K (STK) interpretations and ii) published critical tissue-P and -K interpretations in predicting the yield response to fertilizer at different significance levels (p≤0.05 to 0.25), iii) examine how seed nutrient concentrations are influenced by fertilization and crop response to …

Available Nitrogen And Denitrification In Soil Altered By Ground Cover And Nutrient Source In An Organic Apple Orchard, Jade Nicole Ford

Graduate Theses and Dissertations

A shift in public demand towards more organic and locally produced fruit and vegetables has been occurring across the United States in recent years. A common practice in organic fruit production is the application of organic ground covers to supply nutrients while enhancing other soil properties. A need for research exists in the southern region of the U.S. examining the effects of regionally applicable ground cover and nutrient management on nitrogen availability and the microbial community to provide information to organic farmers in the region. Two studies were conducted to determine how 12 treatment combinations of four ground covers (compost, …

Defining The Potassium Nutritional Requirements And Distribution Among Plant Parts Of Representative Soybean Cultivars From Different Maturity Groups, Md. Rasel Parvej

Graduate Theses and Dissertations

The potassium (K) requirement of soybean [Glycine max (L.) Merr.] was investigated to determine whether cultivar sensitivity to K deficiency was affected by growth habit (determinate or indeterminate) and how cultivars from each growth habit accumulate and distribute K among plant structures. We also diagnosed K deficiency across reproductive growth stages (R2-6) using trifoliolate leaf- and petiole-K concentrations and at harvest (R8) using seed-K concentration. Soybean responded similarly to K deficiency in terms of yield, selected yield components, and seed-K concentration, regardless of growth habit. The yield loss from K deficiency was greatest on the middle to upper nodes of …

Long-Term Effects Of Alternative Residue Management Practices On Near-Surface Soil Properties And Soybean Production In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Christopher Ryan Norman

Graduate Theses and Dissertations

Adoption of management practices that maintain or increase soil organic matter (SOM), which contains 58% carbon (C) on average, may help to mitigate climate change by sequestering atmospheric C. Therefore, the main objective of this study was to determine the long-term trends in SOM, soil C and nitrogen (N), bulk density, various soil chemical properties (i.e., pH, electrical conductivity [EC], and Mehlich-3-extractable nutrients) in the top 10 cm, and soybean yield as affected by residue burning (burning and non-burning), tillage (conventional and no-tillage), irrigation (irrigated and non-irrigated), and N-fertilization/residue level (high and low) in a wheat (Triticum aestivum L.)-soybean [Glycine …

The Functional And Distributional Ecology Of Mycetozoans Under Changing Edaphic And Climatic Dynamics, Geoffrey Lloyd Zahn

Graduate Theses and Dissertations

Investigations into the distribution and ecosystem functions of fruiting amoebae revealed that local-scale environmental conditions can largely explain broad biogeographical patterns in species assemblage, the way in which amoeboid predators shape bacterial communities and how this top-down influence may affect global biogeochemical processes in a changing climate. The distribution and assemblage of protosteloid amoebae on the islands of New Zealand and Hawaii did not yield any expected patterns of island biogeography, and conformed to other global regions studied. The strongest predictor of species richness in a given region was sampling effort and these species do not appear to have any …

Rice Grain Yield And Nitrogen Uptake And Ammonia Volatilization From Urea As Affected By Urea Amendment And Simulated Rainfall, Randy Dempsey

Graduate Theses and Dissertations

The effect of rainfall between urea application and flood establishment on N loss and grain yield of rice (Oryza sativa L.) has not been studied. The first research objective was to compare the effects of simulated rainfall amounts and N-(n-butyl) thiophosphoric triamide (NBPT) urease inhibitor rate on NH3 volatilization and rice growth. Three field experiments were conducted and NH3 volatilization was measured in two experiments for 11 days after urea application (DAU) in semi-open chambers. Urea or NBPT-treated urea (NBPT-Urea) was subjected to six simulated rainfall amounts (0-25 mm) applied 5 to 15 h after urea application and flooded 7 …

Methane Emissions From Direct-Seeded, Delayed-Flood Rice Grown On A Clay Soil, Alden Daniel Smartt

Graduate Theses and Dissertations

Due to the production of methane (CH4) under flooded-soil conditions, rice (Oryza sativa L.) cultivation is a major contributor to agricultural CH4 emissions. Studies examining CH4 emissions from rice have only recently been initiated in Arkansas and no data have been collected from rice produced on clay soils in Arkansas. Therefore, research was conducted in 2012 and 2013 at the Northeast Research and Extension Center in Keiser, Arkansas to examine the factors affecting CH4 emissions from rice produced on a Sharkey clay (very-fine, smectitic, thermic Chromic Epiaquerts). The objectives of this study were to determine: 1) the effect of vegetation …

Structure, Aboveground Biomass, And Soil Characterization Of Avicennia Marina In Eastern Mangrove Lagoon National Park, Abu Dhabi, Tareefa Alsumaiti

Graduate Theses and Dissertations

Mangrove forests are national treasures of the United Arab Emirates (UAE) and other arid countries with limited forested areas. Mangroves form a crucial part of the coastal ecosystem and provide numerous benefits to society, economy, and especially the environment. Mangrove trees, specifically Avicennia marina, are studied in their native habitat in order to characterize their population structure, aboveground biomass, and soil properties. This study focused on Eastern Mangrove Lagoon National Park in Abu Dhabi, which was the first mangrove protected area to be designated in UAE. In situ measurements were collected to estimate Avicennia marina status, mortality rate (%), …

Short-Term Effects Of Poultry Litter Or Woodchip Biochar Amendment In A Temperate Zone Agronomic System, Katy Elizabeth Brantley

Graduate Theses and Dissertations

Biochar, a charcoal product produced by the anaerobic thermal decomposition of biomass, can provide agronomic benefits when soil applied. However, research is lacking in temperate region soils investigating specific biochar products and their effects on agronomically important crops. A greenhouse study utilizing poultry litter biochar and a field study utilizing pine woodchip biochar were conducted to observe the effects of biochar application to Northwest Arkansas soils on corn growth and nutrient availability. A third experiment investigated poultry litter and pine woodchip biochar influences on soil water retention. In all three experiments, biochar was applied at three rates (0, 5, and …

Alkaline Hydrolyzable-Nitrogen, Seeding Date, And Clay-Fixed Ammonium As Potential Indicators Of Rice Response To Nitrogen Fertilization In Arkansas, Anthony Michael Fulford

Graduate Theses and Dissertations

Several potential indicators of rice (Oryza sativa L.) response to nitrogen (N) fertilization include the soils alkaline hydrolyzableN (AHN) concentration, seeding date, and the soils clayfixed NH₄N content. Three studies were conducted to: (1) correlate AHN, determined using Illinois Soil Nitrogen Test (ISNT) or Nitrogen Soil Test for Rice (NSTaR), to plant parameters of interest and develop a fertilizer N rate calibration curve capable of predicting the 95% relative grain yield (RGY) fertilizer N rate for rice grown on clayey soils; (2) evaluate the influence of seeding date and N fertilization on rice plant growth and grain …

Carbon Dioxide Emissions From Switchgrass And Cottonwood Grown As Bioenergy Crops In The Lower Mississippi Alluvial Valley, Michele Lea Helton

Graduate Theses and Dissertations

Marginal land of the Lower Mississippi Alluvial Valley (LMAV) has the potential to be utilized for the production of bioenergy feedstocks. Soil respiration is the gaseous emission of carbon dioxide (CO₂) from microbes and plant roots in the soil, and these emissions play an important role in the global cycling of carbon. Soil respiration can act as a positive feedback affecting climate change, and has been shown to vary depending on soil moisture, temperature, and vegetation. The objectives of this study where to evaluate the effects of land use [switchgrass (Panicum virgatum), cottonwood (Populus deltoides …

Switchgrass Cultivar, Harvest Frequency, Fertilizer Source, And Irrigation Effects On Near-Surface Soil Properties In West-Central Arkansas, Alayna A. Jacobs

Graduate Theses and Dissertations

Switchgrass (Panicum virgatum L.) has been identified as a model bioenergy feedstock crop and is expected to become an important feedstock for future renewable fuel generation. Agronomic management combinations that maximize monoculture switchgrass yield are generally well understood; however, little is known about corresponding effects of differing switchgrass management combinations on near-surface soil properties. The objective of this research was to determine the residual near-surface soil property effects of three years (2008 to 2011) of consistent management combinations to maximize switchgrass biomass production, including cultivar (‘Alamo’ and ‘Cave-in-Rock’), harvest frequency (1-cut and 2-cut systems per year), fertilizer source (poultry …

Increased Effluent Dosage Effects On Septic System Absorption-Field Products Of Differing Architecture Types, Andrew Richard Gibbons

Graduate Theses and Dissertations

Nationwide, approximately 20% of all homes use an on-site septic system as a form of household wastewater treatment. Since karst features are prevalent throughout the Ozark Highlands region of Northwest Arkansas, surface and groundwater resources are susceptible to contamination. Therefore, the objectives of this study were to evaluate the effects of soil condition (i.e., wet and dry) and absorption-field-product architecture type [i.e., chamber, gravel-less-pipe (GLP), polystyrene-aggregate (PSA), and pipe-and-aggregate (PA)] on in-product solution storage and biomat thickness in a profile-limited soil, and to identify the long-term acceptance rate (LTAR) of each product. During Phase I of this study (i.e., March …

Fertilizer Nitrogen Uptake Efficiency In Soft Red Winter Wheat And The Ability Of N-Star To Detect Alkaline Hydrolyzable Nitrogen In Crop Residues, Lana Aubrey Clark

Graduate Theses and Dissertations

Soil testing methods such as the Illinois Soil Nitrogen Test (ISNT) and Direct Steam Distillation (DSD) have been developed which measure alkaline hydrolyzable-N (AH-N) as a means of estimating potentially mineralizable-N. Crop residues play an important role in N cycling. However, the ability of the ISNT and DSD methods to determine AH-N within crop residues is unknown. Therefore, the first objective of this study was to determine the ability of the ISNT and DSD to quantify potentially mineralizable-N within five different crop residues common to Arkansas. Corn (Zea mays L.), soybean (Glycine max, L.), wheat, rice (Oryza sativa, L.), and …

Quantitative Trait Loci Associated With Waterlogging Tolerance In A Soft Red Winter Wheat Mapping Population, Diana Carolina Ballesteros Benavides

Graduate Theses and Dissertations

Waterlogging is caused when water stays superficially in the soil for an extended period of time, creating an anaerobic environment which decreases plant growth and grain yield at maturity. Despite the impact of waterlogging on wheat production both globally and in the southeastern U.S., very little is known about the genetic control of waterlogging tolerance in wheat. The objective of this study was to determine the amount of genetic variation for vegetative stage waterlogging tolerance present within a wheat recombinant inbred line (RIL) population and to identify quantitative trait loci (QTL) associated with tolerance and productivity. Experiments were carried out …

Long-Term Residue And Water Management Effects On Soil Respiration And Soil Aggregate Stability In A Wheat-Soybean, Double-Crop System In Eastern Arkansas, Sharon Faye Smith

Graduate Theses and Dissertations

Sustainability in agriculture is paramount to assuring continued production from our most naturally fertile soils. Storing carbon (C) in soil as organic matter through sustainable agricultural management practices can both remove atmospheric C and improve soil quality. The objective of this study was to evaluate the long-term effects of water management (irrigation and dryland), residue management [burn and no-burn, conventional (CT) and no-tillage (NT)] and residue/fertility level (high and low) on soil respiration and aggregate stability in a wheat- (Triticum aestivum L.) soybean [Glycine max (L.) Merr.], double-crop system in a silt-loam soil (Aquic Fraglossudalf) in the Mississippi River Delta …

Variability In The Hydraulic Conductivity Of A Test Pad Liner System Using Different Testing Techniques, Matthew Jonathan Nanak

Graduate Theses and Dissertations

Historic methods (the time lag approach, the velocity approach, and the Z-t approach), utilized to reduce two stage borehole test data, were evaluated. Two of the historic methods provided viable results and were used for this research project. Additionally, these two methods are recommended for reducing two stage borehole test data in the future.

Flexible wall permeameter and soil index laboratory testing were conducted on the soil used to construct three environmentally controlled compacted clay liners (test pads) to develop a zone of acceptance (placement window). Using the results from the laboratory testing, two acceptance criterions were evaluated, while one …

Biodiesel Transesterification Byproducts As Soil Amendments, Solomon Parker

Graduate Theses and Dissertations

For every ten kilograms of biodiesel that is produced from the transesterification of vegetable oil, approximately 1 kg of glycerol is produced as a byproduct. Also known as glycerin, it is a chemical used in many products including cosmetics, foods, and desiccants. However, the crude glycerol created during biodiesel production is tainted with potassium hydroxide and methanol making it unsuitable for commercial use without costly refinement. With increase in production of biodiesel driven by rising fuel prices, the market has become glutted with glycerol and it is on the threshold of becoming a waste product. Common methods for disposing glycerol …