Plant Sciences Commons^™

Annual Forage Cropping-Systems For Midwestern Ruminant Livestock Production, John Ernest Mcmillan

Open Access Dissertations

Annual forage cropping systems are a vital aspect of livestock forage production. One area where this production system can be enhanced is the integration of novel annual forages into conventional cropping systems. Two separate projects were conducted to investigate alternative forage options in annual forage production. In the first discussed research trial, two sets of crops were sown following soft red winter wheat (Triticum aestivum L.) grain harvest, at two nitrogen application rates 56 and 112 kg ha-1 . The first set of crops were C4 summer annuals seeded within two weeks of wheat grain harvest and included, brown …

Evaluation Of A Cool-Season Grass-White Clover Mixture For Low-Nitrogen Input Lawns, Gabriel Adam Macke

Open Access Theses

Turfgrass lawns require supplemental nitrogen (N) to maintain green color and seasonal shoot density. Improper lawn fertilization with excess N or phosphorus has the potential to contaminate both surface and groundwater. Thus, to reduce the reliance on supplemental N fertilization, alternative strategies or novel turf systems like grass-legume mixtures need explored. White clover ( Trifolium repens L.) is a stoloniferous legume that biologically fixes N from the atmosphere and adds N into the soil via mineralization. The objective of this field study was to evaluate the persistence and feasibility of a cool-season grass-clover lawn mixture. A lawn grass mixture with …

Residual Effects Of Nitrogen Fertilization On Soil Nitrogen Pools And Corn Growth, Meghan E. Moser

Open Access Theses

Given the dynamic nature of soil nitrogen (N), inorganic N fertilization to corn (Zea mays L.) has potential to alter N pool balance by creating an accumulation or depletion of soil N. Current corn N recommendations in the common corn-soybean rotation of Indiana strive to find the best N rate that maximizes producer profit. Increasing our understanding of soil N will inform producers if they should adjust fertilizer rates for corn to influence maintenance of organic N and Carbon. Our objective was to determine residual N effects from fertilized corn in a corn-soybean rotation by measuring (1) soil N …

Cereal Rye Cover Crop Effects On Soil Physical And Chemical Properties In Southeastern Indiana, Joseph D. Rorick

Open Access Theses

Cover crops are growing in popularity in the Midwest, although questions remain about how to include them most effectively in a corn-soybean ( Zea mays L. - Glycine max L.) rotation. This study was conducted to determine the effects of cereal rye ( Secale cereale L.) on soil bulk density and water retention, soil organic carbon, soil nitrogen, and water stable aggregate mean weight diameter after four years of cover crop growth and the effects on soil moisture over a five year period. The study was conducted at the Southeast Purdue Agricultural Center (SEPAC) on silt loam soils. A 14 …

Physiological Aspects Of Relative Changes In Nitrogen And Plant Density Stress Tolerances Over A 38-Year Period Of Us Maize Hybrid Introductions, Keru Chen

Open Access Dissertations

Incremental gains in grain yield of maize hybrids over the decades are the consequence of genotype, environment and management interactions. Historically, genetic improvements in newer hybrids have included longer active grain filling periods (achieved by advancing silking and extending functional stay green in maize leaves); stronger source and sink during grain filling; enhanced tolerance to higher density; and canopy architecture changes. Newer hybrids were known to accumulate more dry matter and nitrogen in the post-silking period, but achieving a more comprehensive knowledge of pre-silking and post-silking dynamics required further understanding of dry matter and nitrogen partitioning in individual organs, as …

The Biology And Management Of Palmer Amaranth (Amaranthus Palmeri S. Wats) In Indiana, Douglas J. Spaunhorst

Open Access Dissertations

Palmer amaranth is a pernicious summer annual weed that has evolved resistance to six herbicide sites of action in the U.S. and threatens agriculture production. In 2011, Palmer amaranth was identified in flood plains in two southern Indiana counties (Posey and Vanderburgh). Determining if Palmer amaranth can survive and reproduce in northern Indiana may provide insight if this weed will be problematic for northern row crop producers. The objectives of our research were to identify fields containing Palmer amaranth and determine the distribution of herbicide resistance traits in Indiana; determine the influence of tillage frequency and tillage intervals on Palmer …

Genetic Study Of Carotenoids In Maize Grain (Zea Mays L.), Oscar Rafael Espejel Venado

Open Access Theses

Pro-Vitamin A (proVA) carotenoids, which are converted into retinol (Vitamin A) in the human body, have been the subject of human nutrition studies and are a target for biofortification of staple crops. Historically, β-carotene has been the principal target for enhancing levels of proVA, yet there is recent interest in enhancing the proVA carotenoid β-cryptoxanthin. Studies have shown that β-cryptoxanthin has excellent bioavailability, and its use in maize may be nearly as effective as β-carotene in providing retinol. The primary aim of this study was to gain a better understanding of the genetic control of levels of β-cryptoxanthin, conversion of …

Switchgrass Extractives Have Potential As A Value-Added Antimicrobial Against Plant Pathogens And Foodborne Pathogens, Alexander Ian Bruce

Masters Theses

Panicum virgatum (switchgrass), a perennial grass native to North America, is a leading biomass feedstock candidate for the manufacture of cellulosic ethanol. Switchgrass is considered a viable option for biofuel production due to its cheap production cost and ability to grow on marginal land. Biofuel derived from switchgrass has been shown to be very energy efficient, producing 540% more renewable energy versus nonrenewable energy expended. Switchgrass-derived biofuel is also estimated to have greenhouse gas emissions that are 94% lower than emissions from gasoline (Schmer et al 2008). Biofuels are created through biochemical processes that utilize various enzymes and microorganisms for …

Quantitative Trait Loci (Qtl) For Salt Tolerance In Soybean And Physiological Response To Salt Stress During Early Growth Stage, Cindy Massiel Lopez Ramirez

Graduate Theses and Dissertations

Soybean is a major cash crop used as a source of high–quality protein and oil. Salt stress is one of the main abiotic stresses causing significant yield losses in soybean, which is considered a moderately salt–sensitive crop. Breeding selection is a promising strategy to improve salt tolerance as soybean germplasm display wide variation in response to salinity stress. However, the physiological and genetic mechanisms for salt tolerance are not quite clear. The discovery of novel QTL/genes associated with salt tolerance facilitates the development of tolerant cultivars through marker-assisted selection (MAS). The objectives of this study were: 1) identify/confirm QTL associated …

Quantitative Trait Loci Mapping, Genome-Wide Association Analysis, And Gene Expression Of Salt Tolerance In Soybean, Ailan Zeng

Graduate Theses and Dissertations

Salt stress is a common abiotic stress causing yield reduction in soybean. There are differential responses, namely tolerance (excluder) and intolerance (includer), among soybean germplasm. However, the genetic and physiological mechanism for salt tolerance is not clear. Identification of novel QTL for salt tolerance and genes that are differentially expressed under salt stress would help elucidate the salt tolerance mechanism and facilitate the development of salt tolerant cultivars through marker assisted selection (MAS). The objectives of this study were to identify new QTL or genes responsible for salt tolerance using three approaches: QTL mapping, association analysis, and RNA sequencing (RNA-seq). …

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 …

Dissecting Salt Tolerance In Soybean By Profiling Differential Physiological Responses Under Salt Stress, Jade Amber Newsome

Graduate Theses and Dissertations

Saline soils are common worldwide and limit the yield potential of many crops. Plants respond in a variety of ways to the stress imposed by saline soils. Plants under salt stress must first sense their surroundings and transmit a signal alerting the rest of the plant to the saline conditions. Salt tolerance in soybeans is typically defined by exclusion of chloride ions from foliar tissues. Though differences in ion uptake among soybean genotypes is well documented, the key mechanisms employed by tolerant cultivars to cope with salt stress on the whole-plant level are still largely unknown. Objectives of the current …

A Study Of Short-Season Winter Cover Crops For Organic High Tunnel Production Systems, Luke Riley Freeman

Graduate Theses and Dissertations

This two-year study investigated short-season winter cover crops to improve soil quality and growth of subsequent vegetable crops in an organic high tunnel production system. Five winter cover crop treatments including a nontreated control, Austrian winter peas (Pisum arvense), bell beans (Vicia faba), mustard (Brassica juncea cv. Kodiak), and Daikon radish (Raphanus sativus var. longipinnatus) were grown in a high tunnel in a randomized complete block design from mid-November to mid-March, mowed and incorporated into the soil, and followed by a succession of vegetable crops including tomato (Lycopersicon lycopersicum, cv. ‘Plum Dandy’) and broccoli (Brassica oleracea var. italica, cv. ‘Bay …

Effects Of Harvest Conditions And Thickness Fractionation On Physicochemical Properties, Cooking And Sensory Characteristics Of Long Grain Rice, Sara Esther Jarma Arroyo

Graduate Theses and Dissertations

Previous research has demonstrated the extensive impacts of various environmental and processing conditions on rice milling and processing characteristics. Nevertheless, little is known about the influences of these conditions on cooking and sensory qualities of rice. The present study aimed to determine the impact of cultivating location, harvest moisture content (HMC), and thickness fractionation on the physicochemical properties, and cooking and sensory characteristics of long-grain rice. Four long-grain rice cultivars (purelines: Cheniere and V3501, and hybrids: XP760 and XL753) were cultivated at Harrisburg, AR and Alvin, TX, and harvested at three HMC. Rough rice lots were conditioned and a portion …

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). …

Selection Of Drought-Tolerant Soybean Lines Using A Field Screening Method And Identification Of Qtls For Slow Wilting And Nitrogen Fixation Associated With Drought-Tolerance, Mirta Beatriz Dalzotto

Graduate Theses and Dissertations

Drought causes significant yield reductions in soybean. The development of drought-tolerant cultivars is an effective alternative to overcome this abiotic stress. Slow wilting, prolonged nitrogen fixation, and minimal yield reduction under water stress play an important role in evaluating breeding materials. Despite advances in knowledge about plant responses to drought conditions, there is little information on effective methodologies for phenotype screening in the field, and some QTLs have been identified for drought tolerance. Field screenings under drought and irrigated conditions are necessary to detect drought tolerant lines. In addition, QTLs and molecular makers associated with drought tolerance traits will greatly …

The Biology And Management Of Waterhemp In Indiana, Joseph M. Heneghan

Open Access Theses

Waterhemp is a dioecious weed species indigenous to the Midwestern United states yet it has only recently become problematic in agronomic crop production in Indiana. Waterhemp is a small-seeded broadleaf which has increased in prevalence in conjunction with an increase in conservation tillage practices. Waterhemp germinates and emerges from the top 3 cm of soil and is known to exhibit extended periods of continual emergence, longer than most other summer annual weed species that are typically present in agronomic production settings. As a C4 species, waterhemp then grows rapidly and is capable of producing thousands of seeds, while effectively competing …

Influence Of Application Technology On Foliar Fungicide Efficacy On Cercospora Sojina Infected Soybean, Shawn Alan Butler

Masters Theses

Due to the constant concern with off-target contamination and application technology requirements associated with future herbicide-tolerant crops, the use of drift-reduction nozzle technology (DRT) may increase. The primary objective of this research was to evaluate the effects of coarse droplets generated by drift-reduction nozzles on foliar fungicide efficacy and residual in soybean infected by frogeye leaf spot caused by Cercospora sojina. No differences in disease control, soybean yield, spray retention, and residual when applying Quadris Top SB, a premix of azoxystrobin and difenoconazole, using nozzles that produce either a medium or ultra coarse droplet spectrum were determined.

Due to …

High Throughput Phenotypic Evaluation Of Drought-Related Traits In Soybean, Hua Bai

Graduate Theses and Dissertations

Drought limits crop growth and yield in soybean. Rapid and effective methods of screening large numbers of soybean lines for drought tolerance are urgently needed. Two experiments were conducted to evaluate the effects of drought in soybean during reproductive stages. In the first experiment five genotypes from maturity groups 2 through 5 were tested under well-irrigated and drought conditions. Beginning at R5, leaf samples were taken for nitrogen concentration analysis. Pictures were taken across the top of each plot to determine the intensity of greenness using the Dark Green Color Index (DGCI). Aerial photographs were also taken to determine aerial …

Agro-Climatic Change, Crop Production And Mitigation Strategies-Case Studies In Arkansas, Usa And Kenya, John Westley Magugu

Graduate Theses and Dissertations

Although climate change impacts vary geographically and temporally, studies at local levels are not readily available for stakeholders to better understand how their local communities would be affected and what remedial measures could be more effective in their local contexts. This dissertation has examined climate change and its impacts in two different local contexts: eastern Arkansas in the USA and Nyando in Kenya. The first part of this dissertation develops agro-meteorological indicators and examines the relationship between agro-meteorological indicators and crop yields in eastern Arkansas between 1960 and 2014. Results reveal that temperature based indicators were more strongly correlated to …

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 …

Phenotypic And Gene Expression Analysis Of Diverse Rice Genotypes In Response To Drought, Miranti Rahmaningsih

Graduate Theses and Dissertations

Drought is one of the most limiting factors for rice (Oryza sativa L.) growth and development with vegetative and reproductive stages the most sensitive and distinct phases. During the vegetative stage, drought can cause reduction in growth and biomass accumulation. Moreover, water stress at reproductive stage can reduce yield significantly. Plants are protected against drought by three different mechanisms: drought avoidance, drought tolerance, and drought escape. An integrated approach combining physiology, breeding, and genomics could be an effective way to characterize and mitigate this problem. The objectives of this research were to (1) screen a diverse set of rice genotypes …

Characterization Of Echinochloa Spp. In Arkansas, Hussain Tahir

Graduate Theses and Dissertations

Echinochloa species are the most problematic grass weeds in rice and soybean production throughout the southern United States. The species under this genus has high intra- and interspecific variability, with many ecotypes, observed within a species. This study was conducted to: i) characterize the morphology and phenology of Echinochloa accessions from Arkansas in a common garden; ii) verify the species identity of these accessions based on their morphological traits, and iii) evaluate the dormancy characteristics of Echinochloa accessions. Junglerice (E. colona) was identified as the most common species, comprising about 78% of the accessions collected, with barnyardgrass (E. crus-galli) and …

Evaluación De La Inclusión De La Harina De Hoja De Yacón Smallantus Sonchifolius Sobre Los Parámetros Productivos Y Morfológicos En El Engorde De Pollos Ross 308 En Cundinamarca, Pablo Andrés Hernández Mendigaño

Zootecnia

La búsqueda de especies vegetales alternativas que ayuden a obtener productos de origen animal inocuo y que mejoren salud intestinal del ave es un reto de la producción animal. El yacòn es una planta que se le atribuye propiedades prebióticas, contiene serquiterpenos, latonas y flavonoides, que sugieren bajo nivel de inclusión en las dietas de las aves para no afectar sus parámetros zootécnicos, ya que no se conocen reportes de su utilización en pollos. Objetivo: Evaluar el efecto de la inclusión de la harina de hoja de yacon en la dieta de pollos de engorde sobre los parámetros productivos. Métodos: …

Crop Selection, Cost Analysis, And Irrigation System Design For The Replanting Of A Nut Orchard, Maximilian Bricker

BioResource and Agricultural Engineering

This report was made to help the landowner of Bricker Farms make decisions regarding the replanting of his orchard. The decisions that need to be made in this process include: which crop to plant, how to plant it, and how to improve the distribution uniformity of irrigation water on the orchard. The report does not give definitive final decisions, but presents viable options that the landowner can utilize when deciding. In addition to the options that are presented, the report offers suggestions to the landowner so that the replanting process is done properly in a timely and economically-friendly manner.

Compost Land Management And Soil Carbon Sequestration, Kylene A. Hohman

Senior Honors Projects, 2010-2019

Extensive fossil fuel burning has released carbon dioxide into the atmosphere. Under proper ecological conditions plants convert atmospheric carbon dioxide into stable soil organic matter, a natural and efficient means of mitigating climate change. In the symbiotic relationship between mycorrhizae and plants, mycorrhizae provide plants with essential nutrients in exchange for carbon sugars leaked from the plants. Mycorrhizae convert carbon sugars to an exudate called glomalin, a protein that assists in developing soil aggregates composed of sand, silt, and clay. These aggregates, called humus, store carbon for hundreds of years under healthy ecological conditions. Compost prompts soil microbes to aerobically …

Evaluation Of Fungicide Efficacy Against Cercospora Sojina And Selection For Qoi-Fungicide Resistance In Soybean, Alicia Mercedes Cochran

Masters Theses

Frogeye leaf spot (FLS) of soybean is caused by Cercospora sojina. In 2010, resistance to the quinone outside inhibitor (QoI) fungicides was reported. Since then, evaluating FLS for QoI-resistance has been of particular interest in Tennessee and other soybean-producing states. In order to determine alternative fungicide options, fungicides with solo and combination mode of action were tested in 2013-2014. The objectives were,1) to evaluate fungicide efficacy for disease control and yield protection, and 2) evaluate selection pressure for QoI-resistance. Treatments included the following fungicide groups: QoI, DMI, MBC, Chlorothalonil, QoI+DMI, SDHI+QoI, SDHI+QoI+DMI, and DMI+MBC. QoI and Chlorothalonil treatments failed …

An Evaluation Of Cover Crop Species And Mixtures For Tennessee Organic Production Systems, Bonnie J. Craighead

Chancellor’s Honors Program Projects

No abstract provided.

Impacts Of Biofumigation And Anaerobic Soil Disinfestation On Strawberry Production, Jennifer Renee’ Wheeler

Masters Theses

Due to the phase-out of methyl bromide, there is a need for alternative, nonchemical fumigation treatments in strawberry production. Anaerobic soil disinfestation and biofumigation are two non-chemical methods for controlling soilborne plant pathogens of strawberry. This study was designed to observe strawberry fruit nutrition and soil volatiles of a strawberry field being treated with biofumigation treatments, anaerobic soil disinfestation treatments, and a combination of the two alternative methods. A trial was conducted with 11 pre-plant soil-incorporated treatments arranged in a randomized complete block design with 6 rows (blocks). Biofumigation treatments consisted of deactivated mustard meal, deoiled mustard meal, mustard pellets, …