CFAES Annual Research Conference

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    Fungal pretreatment of miscanthus for fermentable sugar production: experimental and techno-economic evaluation
    (2018-04-27) Vasco-Correa, Juliana; Capouya, Rachel; Mitchell, Thomas; Li, Yebo; Shah, Ajay
    Lignocellulosic biomass is an abundant, renewable feedstock for biorefineries, but pretreatment is usually required to overcome its high recalcitrance to biodegradation. Fungal pretreatment, an alternative process to traditional pretreatments, can enhance the enzymatic digestibility of the lignocellulosic biomass. Fungal pretreatment can be performed at low temperature, without added chemicals, and no wastewater generation. However, in comparison with traditional pretreatments, longer residence times, lower yields, and feedstock sterilization requirements make it challenging to implement. This work investigated the fungal pretreatment of the dedicated energy crop Miscanthus × giganteus with the white rot fungus Ceriporiopsis subvermispora. Fungal pretreatment of non-sterile miscanthus was performed in batch using miscanthus previously colonized with the fungus as inoculum. The process enhanced the enzymatic digestibility of miscanthus by 2-fold over that of untreated miscanthus, and was comparable to the pretreatment of sterilized miscanthus inoculated with a pure culture of the white rot fungus. The finished material from the unsterilized pretreatment was used as inoculum for two more generations in a sequential fungal pretreatment process, where no increase in enzymatic digestibility was observed. A propagation of indigenous fungi that out-colonized C. subvermispora was observed through the generations, showing that sterilization is a required step for the stability and reproducibility of fungal pretreatment. A techno-economic analysis of the production of fermentable sugars from miscanthus using fungal pretreatment showed that the process was not feasible at full biorefinery scale due to the high capital cost caused by long residence time, low feedstock bulk density, and low sugar yields.
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    Soilborne Diseases in Tomato High Tunnels: An Emerging Threat
    (2018-04-27) Testen, Anna L.; Miller, Sally A.
    Ohio vegetable producers are increasingly using high tunnels to produce high-value tomatoes as these structures allow for season extension and protection from adverse environmental conditions. The protected environment and lack of crop rotation inside these tunnels leads to the build-up of soilborne pathogens. A yield-limiting soilborne disease complex is present in Ohio high tunnels and includes corky root rot (Pyrenochaeta lycopersici), black dot root rot (Colletotrichum coccodes), Verticillium wilt (Verticillium dahliae), and root knot nematodes (Meloidogyne spp.). Soilborne diseases are often ignored until they preclude profitable tomato production as they are difficult for farmers to observe and researchers to diagnose. A survey of Ohio high tunnel soils was conducted in 2017-2018 to identify the incidence of these diseases across the state, proactively providing researchers with a better understanding of disease distribution and farmers with improved knowledge of the diseases present on their farms. Soils were collected from 68 tunnels from 34 farms in 17 Ohio counties. Pathogens were detected in soils using PCR-based assays and greenhouse bioassays. The most commonly detected pathogen was C. coccodes, present in 90% of high tunnels and 97% of farms. The next most commonly detected pathogens were P. lycopersici present in 47% of high tunnels and 50% of farms and V. dahliae, present in 46% of high tunnels and 74% of farms. Root knot nematodes were detected in 38% of high tunnels and 50% of farms. This information will aid in prioritizing disease management research and providing farmers with targeted soilborne disease management recommendations.
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    Improving Sustainability and Rubber Security with New Eggshell/Silica Filled Guayule Natural Rubber Composites
    (2018-04-27) Ren, Xianjie; Geng, Yang; Soboyejo, Alfred B. O.; Cornish, Katrina
    Natural rubber (NR) is irreplaceable in current human society. Currently, all U.S. NR is produced from tropical rubber trees and imported. Guayule natural rubber (GNR) is under development as a domestic NR source and is allergy-free. GNR can supplement and eventually even replace tropical NR and some synthetic rubber. Most rubber products are reinforced with fillers, such as precipitated silica (PS), which is neither renewable nor environmental-friendly. Eggshell (ES) derived filler is produced from a food industry waste, which is mostly landfilled. In the present study, micro-sized ES filler and PS were used to reinforce GNR composites. Various filler loadings and different ES/PS fractions were compounded with GNR and cured before characterization. Lower energy was consumed during compounding with higher ES fraction and with decreasing filler loading. Tensile strength and elongation at break increased with increasing ES fraction due to strong ES-GNR interaction and more uniform filler dispersion, which was evinced by scanning electron micrographs and increased gel content. Although modulus and hardness reduced as ES fraction increased, original values could still be achieved at higher filler loadings. The tan delta of ES-filled GNR determined by dynamic mechanical analysis was high at very low temperatures but low at high temperatures, which indicated higher rubber chain motion at low temperature and less energy loss at high temperature. ES-filled GNR composites may open new markets for high performance, low cost, sustainable rubber products, and encourage the development of guayule farming and processing.
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    Augmentative biological control of twospotted spider mite on hops in the Midwest
    (2018-04-27) Ndiaye, Susan; Welty, Celeste
    The twospotted spider mite, Tetranychus urticae is a key pest on hops, affecting the quality and quantity of yield. Hop production is a new industry in the midwestern USA, and little is known about mite management in this region. During 2016, a trial was conducted to determine the efficacy of augmentative biological control. Treatments of high and low rates of both Neoseiulus fallacis and Galendromus occidentalis were compared. T. urticae populations were monitored weekly at four Ohio hop yards. When populations reached a threshold of one T. urticae per ten leaves, predatory mites were purchased from a commercial insectary and released. Hop yields did not differ significantly among treatments. During 2017, a similar trial was conducted using more intense sampling, to ensure early detection of spider mites in a system where mite density varies widely within plants and between adjacent plants. Treatments compared N. fallacis released at both a high and low rate. The yield showed no significant treatment effect. Although yields in the field release trial did not show treatment differences, concurrent enclosure studies showed that N. fallacis does provide adequate control of spider mites when released at a rate of two predators per ten spider mites. Enclosure studies showed that the naturally occurring predator complex, which includes N. fallacis, provides substantial control of T. urticae. Future studies might concentrate on identifying tactics for conservation biological control where growers would enhance the activities of natural enemies already present in the system, rather than releasing purchased predators.
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    Upgrading effluent from anaerobic digestion of dairy manure through hydrothermal carbonization
    (2018-04-27) Cui, Zhifang; Shah, Ajay
    The coupling of hydrothermal carbonization (HTC) and anaerobic digestion (AD) is investigated in this paper. Effluent from AD of dairy manure was collected as feedstock for the HTC process. Three parameters, temperature, reaction time and pH, were investigated. Central composite design (CCD) and response surface methodology (RSM) were applied for the optimization of hydrochar production. Mass balance was performed for the HTC process. The results showed that temperature was the most significant parameter for hydrochar production. With the increase of temperature and time, the energy and mass yields of hydrochar decreased, while the high heating value (HHV) increased. Optimization models set up for hydrochar production showed that 260oC, 70 min with AD effluent of pH 6 was the best option. Hydrochar with HHV of about 20.18 MJ/kg could be achieved with mass and energy yields of 49.09% and 62.99%, respectively. Chemical oxygen demand (COD) of resulting HTC process water was analyzed. More than 30% COD remained in the liquid, which showed that HTC processed water could have a potential to be recirculated back to the AD system. HTC of the AD effluent could greatly reduce odor issues caused by AD processes, and the hydrochar had good dewatering and drying properties. Consequently, integrating HTC after AD promises to be a way to deal with various wastes in an environmental friendly way.
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    Obtaining Uniform Distribution of Granular Fertilizers with a Spinner Disc Spreader in Variable Rate Scenarios
    (2018-04-27) Colley, Richard, III; Fulton, John; Virk, Simerjeet; Hawkins, Elizabeth
    Broadcast fertilizer distribution through spinner-disc spreaders is a widely accepted practice throughout the agricultural industry due to ease of use and low economic impact on producers. Typically, operators can apply pre-mixed granular fertilizer blends of nitrogen, phosphorus and/or potash. The ability to independently-meter multiple fertilizer products at variable application rates allow for site-specific management of in-field fertility. Fertilizer granules of various sources and densities possess different physical and aerodynamic properties when being spread. The purpose of this study was to evaluate the effect of fertilizer composition on distribution uniformity between independently metered and blended fertilizer sources, and determine the effect of metering type on spread of multiple products. A spreader with a dual bin, and the ability to independently meter two products onto spinner-discs was used for this study. Prior to spreading fertilizer, particle analysis determined that the bulk density of diammonium phosphate (DAP), muriate of potash (KCl), and a blended fertilizer (10-26-26) were 1009, 1105, 1025 kg/m3, respectively. All three fertilizer sources were broadcast and nutrient distributions determined. Specifically, the DAP components of the patterns were analyzed for any changes across all three fertilizer sources. DAP only spread patterns differed from that of the independently metered and the blended mixture, while the independently metered and blended fertilizer patterns were almost identical. Pan collection test results showed independently metered DAP and potash spread patterns were not significantly different than the blended mixture. These results indicate that there is a need for in-field spreader adjustments during a variable rate scenario.
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    World Species of the Genus Chromoteleia Ashmead (Hymenoptera, Platygastridae, Scelioninae)
    (2018-04-27) Chen, Huayan; Talamas, Elijah J.; Valerio, Alejandro A.; Masner, Lubomír; Johnson, Norman F.
    The genus Chromoteleia was originally described by William H. Ashmead (1893), based on the colorful type species Chromoteleia semicyanea from the Caribbean island of Saint Vincent. Currently, six species have been recorded from the New World and a single species from Africa. One fossil species, C. theobaldi Maneval, was reported from Baltic amber (from 40~60 mya), but the status of this species is not clear. These creatures are parasites of insect eggs, but which host they attack is still unclear. Since its original description Chromoteleia has never been comprehensively reviewed. In this study, a total of 27 species are recognized worldwide, of which 21 are new to science. All species are described and illustrated. Several important morphological characters are provided for the identification of the species of Chromoteleia and the geographical distribution records of the genus are expanded to 29 countries in Central and South America, the Caribbean, and Africa. The documentation of the species diversity is crucial to the understanding of the evolution and interrelationships in this genus, as well as informing conservation policies.
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    Early Stages of Diversification of the Mellinger Farm
    (2018-04-27) Basnagala, Suranga; Barker, David; Chen, Wei; Culman, Steve; Klaiber, H. Allen; Kumarappan, Subbu; Lilburn, Michael; Mariola, Matthew; Moledina, Amyaz A.; Hoy, Casey W.
    Farms that achieve economies of scale by specializing and growing in size are common in US agriculture. Small and mid-sized farms, however, need a different kind of economy. Economies of scope rely on managing diverse enterprises, to access more profitable markets and reduced cost of off-farm inputs. Research, much of it from developing countries, has demonstrated that diversified production systems have ecological and economic benefits, but research on the process of diversification in US agriculture is needed. In the Agroecosystems Management Program (AMP), The Ohio State University, we are investigating the effects of the early stages of diversification on a model farm (Mellinger Farm) that has been producing primarily corn and soybeans for the past few decades. We are examining the costs and returns, particularly in the form of ecosystem services that accrue during the first three years of the diversification process. The diversification scenario includes a small grain, an oilseed crop, 3 years of a diverse pasture mix, with and without pastured broiler chicken during the first two years, and mixed vegetables. Improved yield and increased arthropod species diversity suggest that ecosystem services are beginning to accrue in the first year after diversification. Vegetable production was profitable in 2017 without the use of any off-farm inputs other than tillage and fencing. Increased arthropod diversity on 2nd year pasture plots demonstrates the importance of longer term pasture in a diversified rotation. We expect the impact of ecosystem services to increase over time in terms of measurable parameters such as yield, soil health, and biodiversity. As a result, we expect the reduction of off-farm inputs like fertilizer and pesticides to increase profitability over time.
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    Techno-economic analysis of levoglucosan production via fast pyrolysis of cotton straw in China
    (2018-04-27) Wang, Junqi; Shah, Ajay
    Pyrolysis of cotton straw is a promising technology because of the large variety of chemical species that can be produced. A more promising chemical-levoglucosan, is the subject of this study. The techno-economic feasibility of producing levoglucosan via fast pyrolysis and extraction was evaluated by modeling a 200,000 dry ton cotton straw/year facility. Experimental and modeling data were gathered from recent publications and used for analysis. For the modeled feedstock handling capacity, the results indicated that levoglucosan production could reach around 18,000 ton/year. The estimated levoglucosan production cost, including byproduct credits, was $3.3 per kg. Additionally, sensitivity analysis was performed to determine the effect of variability in different system parameters on the levoglucosan production cost.
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    Effects of magnesium source and monensin on mineral absorption and balance in lactating dairy cows
    (2018-04-27) Tebbe, Alexander; Weiss, William; Weiss, William
    Clinical deficiencies of magnesium (Mg), unlike other macro-minerals, are not uncommon in U.S. dairy cows. This is partly because cows have small labile pools of Mg. Absorption of Mg can also differ depending on dietary potassium concentrations, solubility of Mg source and supplementing monensin, a common feed additive. We investigated the interaction of Mg source (MgO vs MgSO4) and monensin in diets subject to antagonism from high dietary potassium. Our hypothesis was a more soluble Mg source (i.e., MgSO4) with monensin would increase Mg absorption, and the effects would be additive. Eighteen Holstein cows were used in a split-plot, Latin square design. The whole plot was monensin (0 or 14 mg/kg) and subplot was Mg source. This design minimizes carryover effects from monensin, but allows cows to receive each Mg source. Periods were 21 d in length. Absorption and balance of minerals was measured via total collection of feces and urine on d 16 to 20, and used to calculate mineral balances. Calcium intake was similar for all treatments, but absorption and balance were greater for MgSO4. Intake of Mg was also similar, however, apparent absorption had an interaction. Without monensin, MgSO4 increased apparent absorption, whereas with monensin, MgSO4 decreased absorption. Feeding MgSO4 increased sulfur intake and absorption compared to MgO diets; of which, urinary sulfur excretion accounted for about 89% of the greater absorption. These results suggest MgSO4 or SO42- may benefit calcium homeostasis, and suggest monensin should be considered when evaluating source and supplementation rate of Mg.