Life Sciences Commons^™

Environmental And Climatic Constraints On Large-Scale Camelina Production In Eastern Arkansas, Benjamin Robert Tracy

Graduate Theses and Dissertations

Camelina sativa is a cold weather crop that is typically grown in semi-arid environments in the Western United States, usually as a spring crop, but sometimes during the winter. Research analyzing climate data and soil hydrology is important to better understand the environmental and terrain conditions necessary for Camelina farming wherever it is proposed for large-scale production. This study focused on various conditions and constraints pertaining to the potential for Camelina as a crop biofuel in Eastern Arkansas. Due to interest in the economic potential of crop biofuels in this area, and in particular the low input costs for Camelina, …

Value Of Cover Crops In Suppressing Weeds And Protecting Cotton Yields And Likelihood Of Residual Herbicide Carryover To Cover Crops, Matheus Gabriel Palhano

Graduate Theses and Dissertations

Weed-resistance management has become a topic of concern for modern agriculture. Cost related to herbicide usage has increased greatly due to evolution and proliferation of resistant weeds. Therefore, experiments were conducted to investigate the potential for using cover crops to suppress problematic weeds in cotton as well as chemical options for cover crop dessication, and sensitivity of cover crops to residual herbicides were evaluated. No differences were observed for cereal rye biomass production and consequently weed suppression between broadcast and drilled planting methods. Total amount of cover crop biomass was vital to effectively suppress weeds. Hence, of the cover crops …

Effects Of Cover Crop Treatments On Apple Trees, Jennifer Billig

Graduate Theses and Dissertations

Ground cover management systems affect soil quality and health and thereby orchard growth and productivity. There have been few studies in the southern US on the effects of managed drive-rows using cover crops as part of a sustainable apple orchard management system. A field study used treatments of 1) seasonal legumes (cowpea [Vigna unguiculata] and crimson clover [Trifolium incarnatum]), 2) seasonal grasses (millet [Setaria italic] and annual rye [Lolium multiflorum]), or 3) unmanaged natural vegetation drive row plantings, with mowed vegetation blown into the tree row as mulch (mow/blow) nested variable. The legume crop cycles produced more than twice as …

The Role Of African Leafy Vegetables In Food Security, Marcia M. Croft

Open Access Dissertations

African leafy vegetables (ALVs) are a diverse set of crops grown across sub-Saharan Africa. They have been a staple of traditional diets and contain many critical micronutrients but their importance has been largely ignored by researchers and policymakers at the expense of imported crops. Availability, accessibility, and utilization of ALVs are limited by factors across the supply chain. This research investigated seed systems, drought tolerance, hydroponic production, market barriers, consumer preference, and the impact of gender as related to ALVs. We found that ALVs play an important role in food security and that critical differences exist between formal and informal …

Managing Bacterial Wilt, Caused By Erwinia Tracheiphila, On Muskmelon With Early Control Of Striped Cucumber Beetle ( Acalymma Vittatum (F)), And Through Varietal Selection, Ahmad Shah Mohammadi

Open Access Dissertations

Muskmelon (Cucumis melo L), is an important vegetable crop in the United States. It is grown throughout the US, and Indiana ranked 4th in production after California, Arizona and Georgia with 12.4 thousand metric tons and market value of $7.6 million in 2015. Bacterial wilt of cucurbits, which is caused by Erwinia tracheiphila (E. F. Smith), and vectored by striped cucumber beetle (Acalymma vittatum (F)), is one of the most serious diseases of muskmelon that influences muskmelon quality and yield. Many cultivars of muskmelon are grown around the United States, especially in the Midwest. Muskmelon cultivars differ in …

Forest Industry Byproducts Improve Soil Quality And Increase Pepper Growth In Three Soils Infested With Phythophthora Blight, Xiaojun Zhao

Open Access Theses

Phytophthora blight is a serious threat to the Midwest vegetable industry, because the oomycete pathogen responsible for this disease, Phytophthora capsici, has a wide host range, can spread quickly in fields, and produces resilient oospores that can survive in soil for years. Phytophthora capsici has become resistant to commonly used fungicides and resistant crop varieties are rare. Amending soil with complex organic substrates has potential to improve soil quality and suppress soil-borne pathogens including P. capsici. Indiana has a significant forest industry with many residual products that could be used as locally available amendments to meet this goal. …

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 …

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 …

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 …

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 …

Mapping And Analyzing Energy Use And Efficiency In A Modified Hydroponic Shipping Container, Rachel E. Sparks

Open Access Theses

In urban centers today, vertical farming is becoming a popular alternative to conventional agriculture in an effort to increase local food production and improve urban food security by growing crops using hydroponic methods in controlled environment spaces. More specifically, one vertical method involves growing crops inside refurbished shipping containers, or a “farm-in-a-box” concept, which offers a flexible, mobile, and scalable means of year-round food production in a variety of climates. Despite benefits of producing food locally, some of the concerns associated with these vertical farming systems include high energy consumption from climate control and electric lighting systems as well as …

Manipulating Air And Root-Zone Temperature For Energy-Efficient Floriculture Crop Production, Madeline W. Olberg

Open Access Theses

Given the high energy costs for greenhouse floriculture production, growers are constantly searching for more energy-efficient methods of production. For example, some growers will lower greenhouse air temperature set points or grow crops in unheated high tunnels (HTs) or outdoors in order to minimize or eliminate heating costs. Unfortunately, development can be delayed and morphology can be altered if the mean daily air temperature (MDT) is reduced. We proposed that reducing MDT in combination with root-zone heating (RZH) could be an energy-efficient method for producing high-quality floriculture crops without significant delays. Unheated HT and unprotected outdoor production are very low-cost …

Defining Management Strategies To Maximize Net Soil Carbon And Nitrogen Retention In Turfgrass Systems, Quincy D. Law

Open Access Theses

Soil carbon (C) sequestration has been proposed as a method to reduce atmospheric carbon dioxide (CO2 ). Managed turf areas are both a source and a sink for greenhouse gases (GHGs) including CO 2 , methane (CH4 ), and nitrous oxide (N2 O), among others. Management practices, including turfgrass selection and mowing, influence the amount of C and N stored in the soil, as well as the direct and indirect GHG emissions. Thus, the objective of this research was to determine how turfgrass selection (both species and cultivar) and mowing practices (such as frequency and grass clipping management) influence the …

Using Energy-Efficient Technologies To Produce Bedding Plants And Microgreens In Protected And Controlled Environments, Joshua R. Gerovac

Open Access Theses

Gerovac, Joshua R. M.S., Purdue University, December 2014. Using Energy-Efficient Technologies to Produce Bedding Plants and Microgreens in Protected and Controlled Environments. Major Professor: Roberto G. Lopez. Production of bedding plants in commercial greenhouses (GHs) located in northern latitudes begins in late winter and continues through late spring when low outdoor temperatures generally necessitate active heating to maintain temperatures suitable for growth and development. Meanwhile, year-round production of microgreens using multi-layer systems requires sole-source (SS) photosynthetic lighting for production. Energy used to provide active heating in commercial GHs or SS lighting in multi-layer systems is second only to labor as …

Biochar And Vermicompost Amendments In Vegetable Cropping Systems: Impacts On Soil Quality, Soil-Borne Pathogens And Crop Productivity, Nathan Lee Shoaf

Open Access Theses

Amending soils with biochar and vermicompost has the potential to provide multiple benefits for specialty crops including pathogen suppression and increased crop productivity. Oomycete pathogens such as Phytophthora capsici can devastate crop fields and they are difficult to control presenting significant management challenges for Midwestern growers. Soils amended with a microbially-inoculated softwood biochar increased carrot root growth relative to the control and corn stover biochar in 2011, while the corn stover biochar also increased carrot root growth relative to the control, but only in two varieties. Neither biochar treatment influenced carrot growth in 2012. In greenhouse trials, vermicompost amendments provided …

Spatial Distributions Of Rhizoctonia Species In Soybean Fields Undergoing Annual Rotations With Rice, Terry Neil Spurlock

Graduate Theses and Dissertations

Aerial blight is caused by Rhizoctonia solani AG1-IA. This pathogen also causes sheath blight of rice. In Arkansas, many soybean and rice fields undergo an annual rotation of these two crops which facilitates a continuous source of inoculum from one year to the next. Aerial blight is a two stage disease in that R. solani AG1-IA colonizes the plant during the early vegetative growth stages and then aerial blight develops after the soybean canopy closes in the later reproductive stages of development. As a result of the upper portion of the canopy often being asymptomatic, significant yield loss can occur …

Groundcover Management System And Nutrient Source Impact Physical Soil Quality Indicators In An Organically Managed Apple Orchard, Neal Mays

Graduate Theses and Dissertations

In March 2006, four groundcover management systems (GMS) and two nutrient sources (NS) were implemented for their ability to alter the soil physical condition of a newly established, organically managed apple (Malus x domestica Borkh.) orchard. Annual applications of municipal green compost (GC), shredded office paper (SP), wood chips (WC), and mow-blow (MB) grass mulch were utilized as GMS, and NS supplied to trees were from composted poultry litter (PL), a commercial organic fertilizer (CF), or an untreated control (NF) in a 4x3 factorial study. An established, conventionally-managed orchard was located adjacent to the organic research orchard on the same …

Physiological Effects Of Low Mowing Heights, Rolling, And Foot Traffic On Creeping Bentgrass Putting Greens, Joseph Ronald Young

Graduate Theses and Dissertations

Golf course superintendents are managing creeping bentgrass (Agrostis stolonifera L.) putting greens throughout the transition zone where temperatures can exceed optimum levels for consecutive days in the summer. The stress of creeping bentgrass associated with these supraoptimal temperatures has been well documented, but the management practices implemented on putting greens to increase green speeds may exacerbate these environmental stresses. To date, the physiological effects of these management practices in combination have not been evaluated for putting green turf. The objective of this dissertation project was to determine the effect of mowing heights, light-weight rolling, and foot traffic on performance and …

Taxonomy And Dna Barcoding In The Genus Manfreda (Salisb.) Asparagaceae, William David Ritchie

Graduate Theses and Dissertations

The genus Manfreda Salisb. of Asparagaceae is a genus of potential horticultural interest and is currently subject to breeding efforts at the University of Arkansas. A lack of taxonomic clarity however undermines the classification of potential inter - and intrageneric hybrids. The study aims to assess existing species delimitation within the genus Manfreda employing morphology while investigating the potential utility of Consortium for the Barcode of Life Plant (CBOL) DNA Barcodes for identification of specific taxa and an External Transcribed Spacer (ETS) - Internal Transcribed Spacer (ITS) DNA barcode for developed hybridized taxa.

Observation of 855 herbarium specimens facilitated phylogenetic …

Evaluation Of Isothiocyanates And Herbicide Programs As Methyl Bromide Alternatives For Weed Control In Polyethylene-Mulched Tomato And Bell Pepper, Pratap Devkota

Graduate Theses and Dissertations

Methyl bromide (MeBr), a Class I ozone –depleting substance, has been banned for ordinary agricultural uses. In the absence of an effective MeBr alternative, weed control is a major challenge for commercial tomato and bell pepper production. Field trials were conducted at Fayetteville, AR, to compare allyl isothiocyanate (ITC), metam sodium, and herbicide programs with the standard MeBr application (mixture of MeBr plus chloropicrin at 67% plus 33%, respectively, hereafter referred to as MeBr) for crop injury, weed control, viable yellow nutsedge tubers, and marketable yield in low–density polyethylene (LDPE) mulched tomato and bell pepper production. In addition, herbicide programs …

Establishment Method And Cultural Practice Effects On Sports Turf, Josh Anderson

Graduate Theses and Dissertations

The use of soil-based sod on sand-based rootzones for the establishment of sports fields and golf courses is a common occurrence. Furthermore, the use of soil-based sod on sand-based rootzones can lead to potential problems associated with decreased water infiltration, gas exchange, rooting, and turfgrass quality caused by soil layering. Core-aerification and sand topdressing may help alleviate the problems associated with soil layering from the use of soil-based sod on sand-based rootzones. Therefore, the objectives of this research were to evaluate the effects of sod establishment methods and post- establishment cultural practices on the infiltration rate, moisture content, divot resistance, …

Foliar Symptoms Of Acute Ozone Injury And Exposure Response Characteristics Of Select Native Perennials, Susan Denise Frey

Graduate Theses and Dissertations

Twenty seven perennial species native to the Eastern Temperate Forests Level I Ecoregion were exposed to an acute ozone (O3) treatment consisting of a target peak O3 concentration of 2.0 ppm for 30 minutes in a closed chamber environment, during the summer of 2010. Plants were evaluated for visible foliar injury symptoms and symptoms were described and photographically documented. Ten of the 27 species developed visible foliar injury in which interspecific and intraspecific response to O3 was observed. A severity index was used to compare response to acute ozone exposure for the ten species displaying visible foliar injury. Species showing …

Characterization And Molecular Analysis Of University Of Arkansas Peach, Prunus Persica (L.) Batsch, Flesh Types And Development Of A Post-Harvest Evaluation Protocol For Arkansas Peach And Nectarine Genotypes, Paul James Sandefur

Graduate Theses and Dissertations

This study determined the effect of pre-cold storage treatment on P. persica genotypes, developed a protocol for the evaluation of breeding selection and cultivar storage performance, and provided information on post-harvest performance of these individuals. Additionally, characterization of the peach and nectarine flesh types, validation of endopolygalacturonase (endoPG) DNA markers, and investigation of endoPG marker allele combinations associated with the slow-melting-flesh (SMF) trait were done.

Fruit from 30 individuals were harvested at minimum- and well-mature states. After conditioning for 24 h at 20 ◦C, all 2010 fruit were exposed to 2 min of 1 ◦C 100 ppm chlorinated hydro-cooling, a …