Online Master of Agricultural and Life Sciences
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The Online Master of Agricultural and Life Sciences (OMALS), http://www.cals.vt.edu/online/, is uniquely positioned to meet the evolving and dynamic needs of today’s agricultural professionals. The program offers concentrations in the areas of agribusiness, applied animal behavior and welfare, applied nutrition and physical activity, education, environmental science, food safety and biosecurity, and leadership studies, as well as plant science and pest management. In addition to engaging classes, students benefit from the opportunity to work on-on-one with well-respected faculty in Virginia Tech's College of Agriculture and Life Sciences to complete a rigorous final project, using what they've learned and developing real-world research and communication skills. This collection showcases final projects completed by current and former OMALS students.
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Browsing Online Master of Agricultural and Life Sciences by Department "Hampton Roads AREC"
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- Evaluation of commercial floating treatment wetland technologies for nutrient remediation of stormwaterLynch, Jeanette; Fox, Laurie J.; Owen, James S. Jr.; Sample, David J. (Elsevier, 2013-12)Floating treatment wetlands (FTWs) are a relatively new water treatment practice that consists of emergent wetland plants planted on floating mats constructed of buoyant material. This study utilized batch-fed mesocosms, with a seven-day retention time, to investigate the total nitrogen (TN) and phosphorus (TP) remediation capability of two commercially available FTW technologies using runoff from a combined irrigation holding and stormwater retention pond. Nutrients in the pond water are attributed to runoff from nearby fertilized research plots upgradient. The FTW technologies included Beemats (Beemats LLC, New Smyrna Beach, FL, USA) and BioHaven® floating islands (Floating Island International, Inc. Shepard, MT, USA) planted with Juncus effusus (soft rush). Due to an increase in TN and TP in the initial phase of the experiment during the plant establishment phase (weeks 1–8), BioHaven®nutrient removal was lower over the entire experimental period than the Beemat treatment. Differences between the two treatments, such as mat material or substrate materials and/or additives may account for this difference. The BioHaven® FTW removed 25% and 4%, while the Beemat removed 40% and 48% of the TN and TP, respectively expressed in terms of net removal over the entire study. During the plant growth season (weeks 9–18 of the study), the two technologies showed similar nutrient removal rates: for TN:0.026 ± 0.0032 and 0.025 ± 0.0018, and for TP:0.0074 ± 0.00049 and 0.0076 ± 0.00065 g/m2/day for Beemat and Biohaven®, respectively. A control treatment, meant to reflect nutrient removal within the pond without the presence of plants, yielded 28% and 31% removal of TN and TP, respectively. Thus, the Beemat mat yielded a significant positive net removal of TN and TP. The BioHaven® biomass was significantly greater than the Beemat treatment. Both treatments showed greater biomass accumulation in shoots rather than in roots. Plant nutrient content was similar between the two treatments.
- Evaluation of Seashore Paspalum in Southeastern VirginiaCrawford, Claudia (Virginia Tech, 2014-07-23)Seashore paspalum (Paspalum vaginatum Sw.) has been successfully grown in warm, humid environments in both the United States and southeastern Asia. In the U.S., seashore paspalum has been planted in parts of North Carolina south to Florida, Texas, California and Hawaii. Very tolerant of low mowing heights, this species has been used primarily for golf courses, but also has applicability as a turf for lawns. High salt tolerance makes it a promising turf for areas near the Chesapeake Bay and the Atlantic Ocean. Research and testing of seashore paspalum in the U.S. has been conducted primarily in Georgia and Florida. Virginia Tech has not conducted any research on this potential new turf species for Virginia. For this project, I have evaluated the adaptability of nine vegetative and three seeded cultivars of seashore paspalum in southeastern Virginia in comparison to Bermuda grass (Cynodon dactylon L.) as an industry standard for comparison. Evaluations of turf cover were made weekly during establishment and at time of spring green-up. Weed competition significantly reduced establishment, with only the vegetative cultivars ‘Sea Star’ and ‘Sea Isle Supreme’ seashore paspalum achieving greater than 65% cover during the first growing season. No cultivar planted by seed successfully established due to weed competition. All seashore paspalum cultivars planted vegetatively survived the winter; however, only Sea Isle Supreme and Sea Star had exceeded 75% turf cover by June 19, 2014, approximately 75 days after breaking dormancy. ‘Yukon’ Bermuda grass achieved an 85% turf cover in the same time frame.
- Influence of Lime Type and Rate on Pine Bark Substrate pH.Jarrett, Richard L.; Owen, James S. Jr. (Virginia Tech, 2017-12-25)Pine bark substrate in the southeastern U.S. is the substrate of choice for ornamental plant producers. The low pH of the unbuffered substrate needs to be adjusted with a lime material in order to promote proper nutrient uptake and ensure general plant health to avoid abiotic disorders. The research and data collection from this study evaluated the long-term effect of four lime materials and five rates on the pH of a pine bark substrate that was planted with rooted holly cuttings over nine-months. We found that pH is raised by lime material and rate over time, with >4.5 kg•m-3 needed to maintain an optimal pH for ornamental plant growth. Our data along with past research on the subject will benefit producers in using the proper lime material and rate for optimal plant health and to prevent abiotic disorders during crop production.
- Optimizing Induced Resistance (IR)Sirois, Jacob (Virginia Tech, 2011-05)The use of induced systemic resistance and systemic acquired resistance as a strategy for pest management is becoming more common and commercial products are increasingly available to the producer. Despite tremendous advances in the body of knowledge surrounding this method of crop protection, a complete picture of plant immunity is elusive. Despite the missing edges of the map, practical lessons can be drawn from the existing body of work to create a tentative model for optimizing the performance of elicitors of Induced Resistance (IR). The goal of this work is to develop a usable framework that will help local producers and extension agents alike to use the emerging IR products with optimal results, and provide a starting point for on-farm screening. First, a map of induction logic, Figure 1, will guide the user to the likely induction pathway depending on the nature of the stressor. Then, Table 1 and Table 2 should be helpful in verifying that the induction pathway chosen can be used in the context of the specific plant-pathosystem of interest or at least with another pathogen that employs a similar strategy. Tables 1 and 2 will also be helpful in determining the appropriate dosages, active ingredients to look for, and the expected efficacy if available. Finally, the general considerations and Figure 1 should be useful in integrating IR into IPM by pointing out potential negative/positive interactions, costs, tradeoffs and contraindications. The complex nature of these processes necessitates careful research in each product-plant pathosystem system—evolutionary divergence tends to create some surprising outcomes. Also, researchers and producers should be wary of treating IR activators like conventional products. Important differences like yield costs and a lack of direct antimicrobial action creates unique challenges. Yield costs can be minimized by combining the following approaches: using agents or concentrations that prime IR rather than activate direct defenses, using IR when pest pressures are relatively high or at least forecasted to be, activating IR during high light conditions, and carefully keeping abiotic stresses to a minimum. Furthermore, variability can be reduced by using multiple strains of Plant Growth Promoting Rhizobacteria (PGPR) and Arbuscular Mycorrhizal Fungi (AMF), avoiding frequent foliar sprays without an antimicrobial agent in the mix, and tailoring the treatment prescription to the specific plant-pathosystem (i.e. evolutionary divergence).
- Post-Planting Maintenance of Early-Stage Reconstructed Prairies within Urban Parks of IllinoisWeiss, Molly N.; Derr, Jeffrey F.; Barney, Jacob N.; Fox, Laurie J. (Virginia Tech, 2022-12-13)Tallgrass prairies are diverse ecosystems spread across the Midwest. Due to human activities such as farming and urban development, these prairies are now rare in their authentic form. The focus of this study is on the tallgrass prairies of Southwest Illinois. Prairie conservation efforts have engaged in various reconstruction projects, aiming to encourage and reestablish lost tallgrass prairie ecosystems. The objective of this study was to evaluate the effect of post-planting maintenance methods on coverage and biodiversity of native and invasive species within early-stage reconstructed tallgrass prairies in urban parks of southern Illinois. Evaluated variables included: total and individual species cover, plant type category, plant classification, species diversity, and community evenness in relation to management methods of annual mowing, manual weeding, and biannual prescribed burning. Results show total percent cover by management method is nonsignificant, but cover by plant type category revealed forb and grass cover to be significant for manually weeded beds in comparison to biannually burned and annually mowed beds. Similarly, manually weeded beds promoted the highest cover by planted native species whereas cover by invasive species was highest within annually mowed treatment beds. In conclusion, results suggest future promotion of grass species across all observed prairie systems due to their lack of presence in relation to native forbs. Manual weeding was most influential on native species flourishment, and in combating invasive species in relation to other treatments. Although, manual weeding is not always efficient and successful alone as a maintenance practice, therefore the use of long-term adaptive techniques is recommended.
- Recovery and Distribution of Anthribus nebulosus, a scale predator introduced into Virginia in 1981Muhleman, Carrie E.; Schultz, Peter B. (Virginia Tech, 2016-04-28)Anthribus nebulosus Forster (Coleoptera: Anthribidae) is a scale predator native to Eurasia that was imported from Hungary in the 1970s and released in Virginia Beach, VA, in 1981 as a potential biological control against soft scale insects. First recovery of A. nebulosus in Virginia Beach occurred in 2010, 29 years after release. Subsequent surveys of soft-scale infested oaks over a 3-year period indicated that A. nebulosus had spread up to 32km from the initial site in multiple cities and directions, but further spread was limited by geographic barriers.
- Removal Efficacy of Nursery Tail-Water Nitrogen and Phosphorus using Ferric aided Zeolite Sieves with or without BioreactorsBirnbaum, Anna P. (Virginia Tech, 2018-12-03)Nitrogen (N) and Phosphorus (P) runoff from containerized nurseries contributes to eutrophication in impaired US waterways. Best management practices (BMPs) have been in development for much of the agricultural sector to help combat this problem. Unfortunately, the only approved BMP for the containerized nursery industry is >95% runoff containment of >19 mm rainfall through the use of retention ponds. This study aimed to evaluate the effectiveness of ferric aided zeolite sieves with or without bioreactors as a potential BMP for N and P removal of containerized nursery production tail-water. A continuous flow of nursery tail-water was pumped through nine treatment trains for twelve weeks along with a 4.5 mg·L-1 injection of iron using ferric sulfate. Aqueous nutrient samples were collected weekly and electrochemical properties were measured in situ. The ferric aided zeolite sieve without woodchip bioreactor achieved an average P removal efficiency of 29.8% with no effect on N removal. Woodchip bioreactors preceding zeolite had a net increase of P (-3.3%), but was effective for N removal with an average rate of 14.3%. Higher N removal was expected by the denitrification bioreactors; however, retention times, presumably >24hrs, and high sulfur concentrations led to dissimilatory nitrate reduction to ammonium (DNRA) as opposed to the desired denitrification which results in the product of innocuous dinitrogen gas. Results indicate that ferric aided zeolite+woodchip bioreactor treatment trains may be effective for N and P reduction in nursery tail-water if designed properly to avoid excessive retention times in the denitrification bioreactors.
- Seven Steps to Sustainable Landscaping Virginia TechOrr, William (Virginia Tech, 2014-12)Presentation and educational resources prepared for Virginia Cooperative Extension
- Small Scale Iris ProductionEagles, Ross B. (Virginia Tech, 2020-11-24)Many ornamental crops are produced by breeders, hobbyists, and garden enthusiasts through small scale operations. Making a thorough assessment of a site’s potential will determine if it is suitable for such production. Each operation will have unique materials and equipment requirements. The challenge is making appropriate choices which allow for profitable production and future growth of the operation. Organizing and using production space efficiently is important to maximize crop production and profits. Using raised beds and row are two ways to do this on a small scale. Supporting healthy soil or growing media is also important and should supply the necessary nutrients for sustainable plant growth. Soil or growing media should be properly irrigated to provide consistent moisture for optimum crop production (Straw 2015). In addition to this taking the time to learn about the different types of plant stock and find quality sources for them is important. While production costs will differ based on an operation’s supply sources there are many methods for arriving at a final price for a such products which involve some involve aspects of market research and psychology (Kohls and Uhl 2015, Uva 2009). Care for ornamental crops also involves integrated pest management (IPM), an assessment-based environmentally friendly cost-effective long-term way to manage pests in an operation as many pests can be managed effectively through good sanitation practices. In the end creating a good business plan will help to organize information, develop a budget, and think through what is needed to operate sustainably.