Physical Sciences and Mathematics Commons^™

Legacy Effects Of Intercropping And Nitrogen Fertilization On Soil N Cycling, Nitrous Oxide Emissions, And The Soil Microbial Community In Tropical Maize Production, Lucas P. Canisares, Hanna J. Poffenbarger, Eoin L. Brodie, Patrick O. Sorensen, Ulas Karaoz, Daniel M. Villegas, Jacobo Arango, Letusa Momesso, Carlos Alexandre Costa Crusciol, Heitor Cantarella

Plant and Soil Sciences Faculty Publications

Maize-forage grasses intercropping systems have been increasingly adopted by farmers because of their capacity to recycle nutrients, provide mulch, and add C to soil. However, grasses have been shown to increase nitrous oxide (N₂O) emissions. Some tropical grasses cause biological nitrification inhibition (BNI) which could mitigate N₂O emissions in the maize cycle but the reactions of the N cycle and the microbial changes that explain the N₂O emissions are little known in such intercropping systems. With this in mind, we explored intercropping of forage grasses (Brachiaria brizantha and Brachiaria humidicola) with distinct …

Impacts Of 1.5 °C And 2 °C Global Warming On Net Primary Productivity And Carbon Balance In China’S Terrestrial Ecosystems, Li Yu, Fengxue Gu, Mei Huang, Bo Tao, Man Hao, Zhaosheng Wang

Plant and Soil Sciences Faculty Publications

Assessing potential impacts of 1.5 °C and 2 °C global warming and identifying the risks of further 0.5 °C warming are crucial for climate adaptation and disaster risk management. Four earth system models in the Coupled Model Intercomparison Project Phase 5 (CMIP5) and a process-based ecosystem model are used in this study to assess the impacts and potential risks of the two warming targets on the carbon cycle of China’s terrestrial ecosystems. Results show that warming generally stimulates the increase of net primary productivity (NPP) and net ecosystem productivity (NEP) under both representative concentration pathway (RCP) 4.5 and RCP8.5 scenarios. …

Determination Of Tobacco Alkaloid Enantiomers Using Reversed Phase Uplc/Ms/Ms, Huihua Ji, Ying Wu, Franklin Fannin, Lowell P. Bush

Kentucky Tobacco Research and Development Center Faculty Publications

Nʹ-Nitrosonornicotine (NNN), a carcinogenic tobacco-specific Nʹ-nitrosamine (TSNA), is on the FDA list of harmful and potentially harmful constituents (HPHCs). Nornicotine, a product of the demethylation of nicotine, is the immediate alkaloid precursor for NNN formation. Nicotine, nornicotine and NNN are optically active. The accumulation of the isomers of nicotine, nornicotine, and NNN impacts their biological activity. In this paper, we report the determination of tobacco alkaloid enantiomers (including nicotine, nornicotine, anabasine, and anatabine) in samples of different tobacco lines using a reversed phase ultra-performance liquid chromatography-tandem mass spectrometer (UPLC/MS/MS) method. Current method demonstates excellent detection capability for all alkaloid enantiomers, …

Nitrogen Fertilizer Suppresses Mineralization Of Soil Organic Matter In Maize Agroecosystems, Navreet K. Mahal, William R. Osterholz, Fernando E. Miguez, Hanna J. Poffenbarger, John E. Sawyer, Daniel C. Olk, Sotirios V. Archontoulis, Michael J. Castellano

Plant and Soil Sciences Faculty Publications

The possibility that N fertilizer increases soil organic matter (SOM) mineralization and, as a result, reduces SOM stocks has led to a great debate about the long-term sustainability of maize-based agroecosystems as well as the best method to estimate fertilizer N use efficiency (FNUE). Much of this debate is because synthetic N fertilizer can positively or negatively affect SOM mineralization via several direct and indirect pathways. Here, we test a series of hypotheses to determine the direction, magnitude, and mechanism of N fertilizer effect on SOM mineralization and discuss the implications for methods to estimate FNUE. We measured the effect …

Growth, Yield Performance And Quality Parameters Of Three Early Flowering Chia (Salvia Hispanica L.) Genotypes Cultivated In Southwestern Germany, Samantha J. Grimes, Timothy D. Phillips, Volker Hahn, Filippo Capezzone, Simone Graeff-Hönninger

Plant and Soil Sciences Faculty Publications

The combination of consumer’s ongoing demand for chia (Salvia hispanica L.) alongside the increased demand for regionally produced food products provided the impetus for this study. Its aim was to test if a regional cultivation of new chia genotypes, which were adapted to day lengths greater than 12 h, is feasible under Central European conditions. Therefore, three early flowering chia genotypes (Sahi Alba 914, W13.1, G8) were cultivated in a randomized block design at two experimental stations in Southwestern Germany (Ihinger Hof, Eckartsweier) over the course of two years (2015, 2016). Mean yields ranged from 100 to 1290 kg …

New Market Opportunities And Consumer Heterogeneity In The U.S. Organic Food Market, Gwanseon Kim, Jun Ho Seok, Tyler B. Mark

Agricultural Economics Faculty Publications

This paper investigates what factors and characteristics of organic consumers affect annual organic food expenditure by using Nielsen’s consumer panel dataset from 2010 to 2014. To be specific, this paper explores new marketing opportunities by investigating organic consumer heterogeneity in different household income levels by utilizing the multilevel model. Findings in this study will contribute to the previous and existing literature in three-folds. First, we find that the organic consumers are more heterogeneous in the high-level of income groups (approximately above $60,000), as well as the low-income households between $35,000 and $45,000. This finding demonstrates that the income levels above …

Point-Of-Sale Specific Willingness To Pay For Quality-Differentiated Beef, Kar Ho Lim, Michael Vassalos, Michael R. Reed

Agricultural Economics Faculty Publications

Despite the growing interest of producers and consumers toward grass-fed, local, and organic beef, the supply chain for these products to reach consumers is not always clear-cut. Among the available options are direct-to-consumers and the conventional food supply chain. Although consumers may pay a premium for beef differentiated by quality attributes, the willingness to pay (WTP) difference across point-of-sales is unclear. In this study, we contrast the WTPs for conventional, grass-fed, local, and organic beef by brick-and-mortar supermarkets (B&Ms), farmers’ markets, and via online stores. We conduct a choice experiment with a nationwide online sample of American consumers. The findings …

Is Aging The Important Factor For Sustainable Agricultural Development In Korea? Evidence From The Relationship Between Aging And Farm Technical Efficiency, Jun Ho Seok, Hanpil Moon, Gwanseon Kim, Michael R. Reed

Agricultural Economics Faculty Publications

This paper examines the effects of aging and income subsidies on farm efficiency in Korea by utilizing the Korean Farm Household Economic Survey from 2008 to 2015. A stochastic frontier model with a non-monotonic assumption on the effect of efficiency factors is implemented to reflect a super aging and less developed production structure in Korean agriculture. This study finds continuously decreasing farm efficiency with age, which contradicts the commonly assumed inverted-U relationship between age and productivity. Especially, we find that labor is the most important factor to explain recent farm efficiency losses in Korea. Furthermore, this paper finds that the …

Cover Crops And Fertilization Alter Nitrogen Loss In Organic And Conventional Conservation Agriculture Systems, Rebecca E. Shelton, Krista L. Jacobsen, Rebecca L. Mcculley

Horticulture Faculty Publications

Agroecosystem nitrogen (N) loss produces greenhouse gases, induces eutrophication, and is costly for farmers; therefore, conservation agricultural management practices aimed at reducing N loss are increasingly adopted. However, the ecosystem consequences of these practices have not been well-studied. We quantified N loss via leaching, NH₃ volatilization, N₂O emissions, and N retention in plant and soil pools of corn conservation agroecosystems in Kentucky, USA. Three systems were evaluated: (1) an unfertilized, organic system with cover crops hairy vetch (Vicia villosa), winter wheat (Triticum aestivum), or a mix of the two (bi-culture); (2) an organic …

Assessing Intra-Event Phosphorus Dynamics In Drainage Water Using Phosphate Stable Oxygen Isotopes, William Ford Iii, Mark R. Williams, Megan B. Young, Kevin W. King, Eric Fischer

Biosystems and Agricultural Engineering Faculty Publications

Quantifying fluxes and pathways of dissolved reactive phosphorus (DRP) in tile-drained landscapes has been hampered by a lack of measurements that are sensitive to P fate and transport processes. One potential tool to help understand these dynamics is the oxygen isotope signature of phosphate (δ¹⁸O_PO4); however, its potential benefits and limitations are not well understood for intra-event dynamics at the field scale. The objectives of this study were to quantify intra-event variability of δ¹⁸O_PO4 signatures in tile drainage water and assess the efficacy of δ¹⁸O_PO4 to elucidate mechanisms and flow …

Asymmetric Price Volatility Transmission Between U.S. Biofuel, Corn, And Oil Markets, Sayed Saghaian, Mehdi Nemati, Cory Walters, Bo Chen

Agricultural Economics Faculty Publications

Linkages between agricultural commodity and energy prices have become more complex with increased ethanol production. The concern is whether the new corn–ethanol links lead to volatility-spillover transmission between food and energy prices. We investigate asymmetric volatility spillovers between oil, corn, and ethanol prices using a BEKK-multivariate-GARCH approach. Additionally, we use daily, weekly, and monthly futures prices to examine whether the use of different-frequency data leads to inconsistent results. The results support the existence of asymmetric volatility transmission between corn and ethanol prices. Furthermore, the volatility-spillover effects are different for the different-frequency prices, and positive and negative price changes generate inconsistent …

Organic Solvent Exposure And Depressive Symptoms Among Licensed Pesticide Applicators In The Agricultural Health Study, Miriam Siegel, Sarah E. Starks, Wayne T. Sanderson, Freya Kamel, Jane A. Hoppin, Fred Gerr

Epidemiology and Environmental Health Faculty Publications

Purpose

Although organic solvents are often used in agricultural operations, neurotoxic effects of solvent exposure have not been extensively studied among farmers. The current analysis examined associations between questionnaire-based metrics of organic solvent exposure and depressive symptoms among farmers.

Methods

Results from 692 male Agricultural Health Study participants were analyzed. Solvent type and exposure duration were assessed by questionnaire. An “ever-use” variable and years of use categories were constructed for exposure to gasoline, paint/lacquer thinner, petroleum distillates, and any solvent. Depressive symptoms were ascertained with the Center for Epidemiologic Studies Depression Scale (CES-D); scores were analyzed separately as continuous (0–60) …

Managing Nitrous Oxide Emissions In Agricultural Fields, Mark S. Coyne, Wei Ren

Plant and Soil Sciences Research Report

Agriculture is a major contributor to atmospheric nitrous oxide (N₂O) (Smith et al., 2014; Tian et al., 2015). Unfortunately, nitrous oxide destroys stratospheric ozone (O₃) which protects us from ultraviolet radiation (Cicerone, 1989) and it increases ground level O_3, whichis an air pollutant threatening human health and food production. Nitrous oxide is also 298 times more potent than an equivalent amount of carbon dioxide (CO₂) in terms of trapping and absorbing reflected solar radiation (Forster et al., 2007). Basic chemistry and physics assure us that increased levels of N₂O in the …

Impacts Of A Community Supported Agriculture (Csa) Voucher Program On Food Lifestyle Behaviors: Evidence From An Employer-Sponsored Pilot Program, Jairus J. Rossi, Timothy A. Woods, James E. Allen Iv

Agricultural Economics Faculty Publications

Community supported agriculture (CSA) programs have recently received attention for their potential to influence food lifestyle behaviors and health outcomes. We build on and expand inquiries into the relationship between CSA participation and behavior change by presenting the results from a controlled pilot study of first-time CSA shareholders. We offered 95 first-time shareholders a $200 voucher to participate in a CSA. Prior to and immediately following CSA participation, these shareholders completed a survey on food lifestyle behaviors. Using econometric analyses, we measured shareholder behavior changes against an 82 person control group. All participants were drawn from a pool of individuals …

Reducing Equifinality Using Isotopes In A Process-Based Stream Nitrogen Model Highlights The Flux Of Algal Nitrogen From Agricultural Streams, William I. Ford, James F. Fox, Erik Pollock

Biosystems and Agricultural Engineering Faculty Publications

The fate of bioavailable nitrogen species transported through agricultural landscapes remains highly uncertain given complexities of measuring fluxes impacting the fluvial N cycle. We present and test a new numerical model named Technology for Removable Annual Nitrogen in Streams For Ecosystem Restoration (TRANSFER), which aims to reduce model uncertainty due to erroneous parameterization, i.e., equifinality, in stream nitrogen cycle assessment and quantify the significance of transient and permanent removal pathways. TRANSFER couples nitrogen elemental and stable isotope mass‐balance equations with existing hydrologic, hydraulic, sediment transport, algal biomass, and sediment organic …

Selection Of Breeding Stock By U.S. Meat Goat Producers, Narayan Nyaupane, Jeffrey Gillespie, Kenneth Mcmillin, Robert Harrison, Isaac Stienei

Community & Leadership Development Faculty Publications

Using nationwide survey data, we investigate U.S. meat goat producer preferences and willingness to pay for meat goat breeding stock attributes. Discrete choice experiments were employed, and mixed logit and latent class models were used for analysis. Results showed that producers preferred animals that were highly masculine/feminine, had good structure and soundness, and were of the Boer breed, whereas they preferred fewer animals that were older, of Kiko and Spanish breeds, and priced higher. Significant preference heterogeneity was found among the respondents. Larger-scale producers had greater preference for high masculinity/femininity, good structure and soundness, and Boer bucks.

Using The Vehicle Routing Problem To Reduce Field Completion Times With Multiple Machines, Hasan Seyyedhasani, Joseph S. Dvorak

Biosystems and Agricultural Engineering Faculty Publications

The Vehicle Routing Problem (VRP) is a powerful tool used to express many logistics problems, yet unlike other vehicle routing challenges, agricultural field work consists of machine paths that completely cover a field. In this work, the allocation and ordering of field paths among a number of available machines has been transformed into a VRP that enables optimization of completion time for the entire field. A basic heuristic algorithm (a modified form of the common Clarke-Wright algorithm) and a meta-heuristic algorithm, Tabu Search, were employed for optimization. Both techniques were evaluated through computer simulations in two fields: a hypothetical basic …

Organelle_Pba, A Pipeline For Assembling Chloroplast And Mitochondrial Genomes From Pacbio Dna Sequencing Data, Aboozar Soorni, David Haak, David Zaitlin, Aureliano Bombarely

Kentucky Tobacco Research and Development Center Faculty Publications

Background: The development of long-read sequencing technologies, such as single-molecule real-time (SMRT) sequencing by PacBio, has produced a revolution in the sequencing of small genomes. Sequencing organelle genomes using PacBio long-read data is a cost effective, straightforward approach. Nevertheless, the availability of simple-to-use software to perform the assembly from raw reads is limited at present.

Results: We present Organelle-PBA, a Perl program designed specifically for the assembly of chloroplast and mitochondrial genomes. For chloroplast genomes, the program selects the chloroplast reads from a whole genome sequencing pool, maps the reads to a reference sequence from a closely related species, and …

Fourth-Generation Fan Assessment Numeration System (Fans) Design And Performance Specifications, Michael P. Sama, George B. Day, Laura M. Pepple, Richard S. Gates

Biosystems and Agricultural Engineering Faculty Publications

The Fan Assessment Numeration System (FANS) is a measurement device for generating ventilation fan performance curves. Three different-sized FANS currently exist for assessing ventilation fans commonly used in poultry and livestock housing systems. All FANS consist of an array of anemometers inside an aluminum shroud that traverse the inlet or outlet of a ventilation fan. The FANS design has been updated several times since its inception and is currently in its fourth-generation (G4). The current design iteration (FANS-G4) is reported in this article with an emphasis on the hardware and software control, data acquisition systems, and operational reliability. Six FANS-G4 …

Effects Of Biochar Treatment Of Municipal Biosolids And Horse Manure On Quality Of Runoff From Fescue Plots, Rachel Williams, Dwayne R. Edwards

Biosystems and Agricultural Engineering Faculty Publications

Land-applied horse manure and municipal biosolids can increase nutrient and bacteria concentrations in runoff. Biochar has been demonstrated to have beneficial impacts on nutrient retention and runoff quality when used to treat other land-applied organic soil amendments (e.g., poultry manure). The objective of this study was to evaluate the effects of biochar addition to horse manure and municipal biosolids on runoff concentrations of nutrients and fecal coliforms. Biochar was added at 5% to 8% (wet basis) to horse manure and biosolids that were applied to 2.4 m x 6.1 m fescue plots followed by application of simulated rainfall (102 mm …

A Method For Reflectance Index Wavelength Selection From Moisture-Controlled Soil And Crop Residue Samples, Ali Hamidisepehr, Michael P. Sama, Aaron P. Turner, Ole O. Wendroth

Biosystems and Agricultural Engineering Faculty Publications

Reflectance indices are a method for reducing the dimensionality of spectral measurements used to quantify material properties. Choosing the optimal wavelengths for developing an index based on a given material and property of interest is made difficult by the large number of wavelengths typically available to choose from and the lack of homogeneity when remotely sensing agricultural materials. This study aimed to determine the feasibility of using a low-cost method for sensing the moisture content of background materials in traditional crop remote sensing. Moisture-controlled soil and wheat stalk residue samples were measured at varying heights using a reflectance probe connected …

Influence Of Source Credibility On Consumer Acceptance Of Genetically Modified Foods In China, Mingyang Zhang, Chao Chen, Wuyang Hu, Lijun Chen, Jintao Zhan

Agricultural Economics Faculty Publications

This paper examines the reasoning mechanism behind the consumer acceptance of genetically modified foods (GMFs) in China, and investigates influence of source credibility on consumer acceptance of GMFs. Based on the original Persuasion Model—which was developed by Carl Hovland, an American psychologist and pioneer in the study of communication and its effect on attitudes and beliefs—we conducted a survey using multistage sampling from 1167 urban residents, which were proportionally selected from six cities in three economic regions (south, central, and north) in the Jiangsu province through face to face interviews. Mixed-process regression that could correct endogeneity and ordered probit model …

Are Consumers Willing To Pay More For Sustainable Products? A Study Of Eco-Labeled Tuna Steak, Guzhen Zhou, Wuyang Hu, Wenchao Huang

Agricultural Economics Faculty Publications

A high demand for seafood leads to overfishing, harms the long-term health of seafood stocks, and threatens environmental sustainability in oceans. Sustainability certification is one of the major sustainability movements and is known as eco-labeling. For instance, in the tuna industry, leading tuna brands have committed to protecting sea turtles by allowing the tracing of the source of their tuna “from catch to can.” This paper relies on an Internet survey on consumers from Kentucky conducted in July 2010. The survey investigates household-level tuna steak (sashimi grade) consumption and examines consumer preferences for eco-labeling (“Certified Turtle Safe” (CTS) in this …

Effects Of Chemical Amendments To Swine Manure On Runoff Quality, Elizabeth L. Bullock, Dwayne R. Edwards, Phillip A. Moore Jr., Richard S. Gates

Biosystems and Agricultural Engineering Faculty Publications

Land-applied swine manure can be an environmental concern when runoff losses of manure constituents occur. The use of chemical amendments to mitigate these losses has been investigated for poultry litter, but materials such as swine manure have received less attention in this context, particularly at the plot scale or larger. The objective of this experiment was to evaluate the impacts of aluminum sulfate (alum; Al₂(SO₄)₃), aluminum chloride (AlCl₃), and ferric chloride (FeCl₃) addition on runoff of selected constituents of land-applied swine manure. Manure was collected from feeder pigs fed a …

An Optical Sprayer Nozzle Flow Rate Sensor, Joseph S. Dvorak, Luke E. Bryant

Biosystems and Agricultural Engineering Faculty Publications

Ensuring proper flow rates from each nozzle on an agricultural sprayer has become even more important as advances continue to be made in precision application technology. In this article, we describe the structure and testing of a sensor technology based on optical cross-correlation to determine the flow rate of individual sprayer nozzles. An advantage of this technology is that it does not require that impellers or other components be placed in the flow, which could cause plugging. The only moving part in the entire system is a solenoid used to inject a tracer dye. The objective of this study was …

Comparative Feedstock Analysis In Setaria Viridis L. As A Model For C4 Bioenergy Grasses And Panicoid Crop Species, Carloalberto Petti, Andrew Shearer, Mizuki Tateno, Mathew J. Ruwaya, Sue E. Nokes, Tom Brutnell, Seth Debolt

Horticulture Faculty Publications

Second generation feedstocks for bioethanol will likely include a sizable proportion of perennial C4 grasses, principally in the Panicoideae clade. The Panicoideae contain agronomically important annual grasses including Zea mays L. (maize), Sorghum bicolor (L.) Moench (sorghum), and Saccharum officinarum L. (sugar cane) as well as promising second generation perennial feedstocks including Miscanthus × giganteus and Panicum virgatum L. (switchgrass). The underlying complexity of these polyploid grass genomes is a major limitation for their direct manipulation and thus driving a need for rapidly cycling comparative model. Setaria viridis (green millet) is a rapid cycling C4 panicoid grass with a relatively …

The Buzz On Bees, Rebecca Ruiz

Lewis Honors College Capstone Collection

Apis mellifera, more commonly known as the honeybee, plays a pivotal role in the ecosystem and in the survival of the planet. Many do not understand, nor realize, that the honeybee offers a wide array of products and services besides sweet honey. Honeybees have become endangered at a time when their presence is vital and evidence indicates that they can be the means to a more sustainable future for our planet. Particularly focused on in this research are the ideas of honeybees’ essential presence in medical advances, their participation in global economics, and their involvement in the development of …

Biofilter Media Characterization Using Water Sorption Isotherms, Guilherme Del Nero Maia, George B. Day, Richard S. Gates, Joseph L. Taraba

Biosystems and Agricultural Engineering Faculty Publications

Compost material has been used extensively as a gas‐phase biofilter media for contaminant gas treatment in recent years. One of the biggest challenges in the use of this type of material is adequate control of compost moisture content and understanding its effect on the biofiltration process. The present work provides a methodology for characterization of biofilter media under low moisture conditions. Results indicated that low levels of equilibrium moisture content (EMC) were obtained for high levels of equilibrium relative humidity (ERH), i.e., 99% ERH produced EMC of approximately 20% (dry basis) at 25° C. Most bacteria struggle to survive in …

A Computational Tool For Estimating Off-Target Application Areas In Agricultural Fields, Rodrigo S. Zandonadi, Joe D. Luck, Timothy S. Stombaugh, Michael P. Sama, Scott A. Shearer

Biosystems and Agricultural Engineering Faculty Publications

A computational method for estimating off-target application areas based on the machine-controlled section width and the field shape was developed and implemented in software with a graphical user interface written in the MatLab environment. The program, which is called the Field Coverage Analysis Tool (FieldCAT), includes three modules: data import, data preparation, and coverage analysis. Nine field boundaries were evaluated to test the software using controlled section widths from 0.5 to 27 m and various swath orientations. The estimated off-target application area from the widest section width varied from 9% to 24% depending on the shape and size of the …

Economic Analysis Of Cellulase Production Methods For Bio-Ethanol, Jun Zhuang, Mary A. Marchant, Sue E. Nokes, Herbert J. Strobel

Biosystems and Agricultural Engineering Faculty Publications

The cost of cellulase enzymes has limited the feasibility of producing ethanol from fibrous biomass. Traditional submerged fermentation (SmF) was compared to an alternative method of producing cellulase, solid state cultivation (SSC). Results from an economic analysis indicated that the unit costs for cellulase enzyme production were $15.67 (The prices are all 2004 prices in this article, except otherwise stated. We deflated newer prices to 2004 prices using a deflation factor 0.9 per year and inflated older prices to 2004 prices using an inflation factor 1.1.) per kilogram ($/kg) and $40.36/kg, for the SSC and SmF methods, respectively, while the …