Environmental Microbiology and Microbial Ecology Commons^™

Soil Organic Matter Fractions And Aggregate Distribution In Response To Tall Fescue Stands, I. P. Handayani, Mark S. Coyne, R. S. Tokosh

Plant and Soil Sciences Faculty Publications

The study was conducted to evaluate the influences of tall fescue management on soil organic matter fractions and macro- and microaggregate distribution. Soil samples were collected from four paired adjacent fields consisting of five years of tall fescue mono and poly stands in Western Kentucky. Soil samples from 0 to 15 cm and 15 to 30 cm soil depths were analyzed for soil organic C and N, particulate organic matter C (POM-C) and N (POM-N), macro- and micro aggregate distribution and C-associated with macro- and micro- aggregates. Significant effects were observed between stands for all the properties, except total C, …

Multimeric Hemicellulases Facilitate Biomass Conversion, Zhanmin Fan, Kurt Wagschal, Wei Chen, Michael D. Montross, Charles C. Lee, Ling Yuan

Plant and Soil Sciences Faculty Publications

Two highly active trifunctional hemicellulases were constructed by linking the catalytic portion of a xylanase with an arabinofuranosidase and a xylosidase, using either flexible peptide linkers or linkers containing a cellulose-binding domain. The multifunctional enzymes retain the parental enzyme properties and exhibit synergistic effects in hydrolysis of natural xylans and corn stover.

Soil Microbial Community Response To Hexavalent Chromium In Planted And Unplanted Soil, Ioannis Ipsilantis, Mark S. Coyne

Plant and Soil Sciences Faculty Publications

Theories suggest that rapid microbial growth rates lead to quicker development of metal resistance. We tested these theories by adding hexavalent chromium [Cr(VI)] to soil, sowing Indian mustard (Brassica juncea), and comparing rhizosphere and bulk soil microbial community responses. Four weeks after the initial Cr(VI) application we measured Cr concentration, microbial biomass by fumigation extraction and soil extract ATP, tolerance to Cr and growth rates with tritiated thymidine incorporation, and performed community substrate use analysis with BIOLOG GN plates. Exchangeable Cr(VI) levels were very low, and therefore we assumed the Cr(VI) impact was transient. Microbial biomass was reduced …

Effects Of Commercial Diazinon And Imidacloprid On Microbial Urease Activity In Soil And Sod, C. W. Ingram, Mark S. Coyne, David W. Williams

Plant and Soil Sciences Faculty Publications

Diazinon [O,O-diethyl O-2-isopropyl-6-methyl(pyrimidine-4-yl) phosphorothioate] and imidacloprid [1-(1-[6-chloro-3-pyridinyl]methyl)-N-nitro-2-imidazolidinimine] are applied to lawns for insect control simultaneously with nitrogenous fertilizers such as urea, but their potential effect on urease activity and nitrogen availability in turfgrass management has not been evaluated. Urease activity in enzyme assays, washed cell assays, and soil slurries was examined as a function of insecticide concentration. Intact cores from field sites were used to assess the effect of insecticide application on urease activity in creeping bentgrass (Agrostis palustris Huds.) and bluegrass (Poa pratensis L.) sod. Bacterial urease fromBacillus pasteurii and plant …

Fertilizer, Tillage, And Dairy Manure Contributions To Nitrate And Herbicide Leaching, C. S. Stoddard, John H. Grove, Mark S. Coyne, William O. Thom

Plant and Soil Sciences Faculty Publications

Few studies have examined the water quality impact of manure use in no-tillage systems. A lysimeter study in continuous corn (Zea mays L.) was performed on Maury silt loam (fine, mixed, semiactive, mesic Typic Paleudalf) to evaluate the effect(s) of tillage (no-till [NT] and chisel-disk [CD]), nitrogen fertilizer rate (0 and 168 kg N ha⁻¹), and dairy manure application timing (none, spring, fall, or fall plus spring) on NO₃–N, atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), and alachlor [2-chloro-2′-6′-diethyl-N-(methoxymethyl)acetanilide] concentrations in leachate collected at a 90-cm depth. Herbicides were highest immediately after application, declining to less …

Mortality Of Escherichia Coli O157:H7 In Two Soils With Different Physical And Chemical Properties, D. N. Mubiru, Mark S. Coyne, John H. Grove

Plant and Soil Sciences Faculty Publications

Wild and domesticated animals can harbor a pathogenic Escherichia coli strain designated as O157:H7. Potential health problems could occur if strain O157:H7 is a more robust survivor in defecated waste than commonly used indicator bacteria. A laboratory study was conducted to assess E. coli O157:H7 survival relative to a nonpathogenie E. coli strain in two soils with different physical and chemical characteristics. Bacteria in the inoculated soils were enumerated on a weekly basis for 8 wk using a most probable number (MPN) technique. First-order decay models were used to describe bacteria mortality in the soils. Decay series were described slightly …

Fecal Bacteria Survival And Infiltration Through A Shallow Agricultural Soil: Timing And Tillage Effects, C. S. Stoddard, Mark S. Coyne, John H. Grove

Plant and Soil Sciences Faculty Publications

Human and livestock exposure to fecal pathogens via contaminated surface or groundwater is an important water quality concern for soils receiving animal wastes. The effects of manure application timing (spring or fall application) and soil management (no-tillage or conservation tillage) on fecal bacteria infiltration through shallow karst soils in central Kentucky (the Bluegrass region) have not been evaluated. We performed a field experiment to measure fecal coliforms and fecal streptococci in leachate from dairy manure-amended no-tillage and conservation tillage soils. Manure significantly increased fecal bacteria in leachate compared with unmanured treatments. After manure application, the leachate that collected in zero-tension …

Fecal Coliform Transport Through Intact Soil Blocks Amended With Poultry Manure, S. W. Mcmurry, Mark S. Coyne, E. Perfect

Plant and Soil Sciences Faculty Publications

Poultry production in Kentucky increased almost 200% between 1991 and 1995. Their waste is typically land applied, and fecal pathogen runoff and infiltration may cause nonpoint source groundwater pollution. We looked at the preferential flow of fecal coliforms through undisturbed soil blocks since fecal bacteria typically infiltrate the soil profile to contaminate groundwater. Poultry manure was uniformly distributed on top of sod-covered or tilled (upper 12.5 cm) soil blocks and the blocks were irrigated. Drainage was collected in 100 uniformly spaced cells beneath each block and analyzed for fecal coliform content and drainage volume. The spatial distribution of drainage and …

Effect Of Sediment Particle Size And Temperature On Fecal Bacteria Mortality Rates And The Fecal Coliform/Fecal Streptococci Ratio, J. M. Howell, Mark S. Coyne, P. L. Cornelius

Plant and Soil Sciences Faculty Publications

Extended survival of fecal bacteria in sediment can obscure the source and extent of fecal contamination in agricultural settings. The variability in fecal coliform/fecal streptococci (FC/FS) ratios with time and discrepancies between observable fecal sources and measured FC/FS ratios in shallow surface water from agricultural watersheds may be explained by examining FC and FS mortality rates in response to ambient temperature and sediment particle size. We measured FC and FS mortality rates at three different temperatures and in three feces-amended sediments with different particle size in a laboratory study. In controlled conditions, using physiological saline to reduce cell death by …

So You Want To Be A Soil Microbiologist?, Mark S. Coyne

Plant and Soil Sciences Faculty Book Gallery

A tongue-in-cheek look at soil microbiology.

Nitrous Oxide Loss From Poultry Manure-Amended Soil After Rain, Mark S. Coyne, A. Villalba, Robert L. Blevins

Plant and Soil Sciences Faculty Publications

Land application of poultry wastes in Kentucky will increase as the broiler industry grows. If poultry manure stimulates N₂O loss from soil it will reduce the fertilizer N value of this waste. In contrast, stimulated N₂O loss in grass filter strips receiving the runoff from manured fields could help reduce contamination of surface water by NO⁻₃. Our objectives were to determine (i) if poultry manure stimulated N₂O loss in soil after rainfall and (ii) if there was an edge-of-field effect on N₂O loss in grass filters intercepting runoff from …

Fecal Bacteria In Agricultural Waters Of The Bluegrass Region Of Kentucky, J. M. Howell, Mark S. Coyne, P. L. Cornelius

Plant and Soil Sciences Faculty Publications

Agricultural runoff influenced by nonpoint pollution frequently exceeds the USEPA standards for bacterial contamination of primary contact water (200 fecal coliforms/100 mL). Few studies have evaluated the effect of cattle (Bos taurus) grazing on fecal contamination of ground water in the karst topography of central Kentucky. Our objectives were to: (i) observe the extent and pattern of fecal bacteria in agricultural waters from two central Kentucky watersheds; (ii) determine if monthly sampling accurately assessed the extent and variability of fecal contamination; and (iii) assess the fecal coliform/fecal streptococci ratio (FC/FS) as an indicator of fecal bacteria source. Springs, …

Nitrous Oxide Flux From Poultry-Manured Erosion Plots And Grass Filters After Simulated Rain, Mark S. Coyne, R. A. Gilfillen, Robert L. Blevins

Plant and Soil Sciences Faculty Publications

Adding carbon-rich materials to fields, like manure, may enhance denitrification. Grass filters, which are used to trap surface runoff from these fields, may also provide a carbon-rich environment that favors water infiltration and denitrification. Nitrous oxide (N₂O) may be evolved these settings. It is a radiatively important trace gas and intermediate in the denitrification pathway and several other microbial processes. We measured N₂O flux, after simulated rain, using a soil cover technique in poultry-manured plots and grass filters receiving their runoff. Intact soil cores were used to relate the N₂O flux to the denitrification …

Frequency Of Mug Negative Escherichia Coli In Kentucky Groundwater Samples, Mark S. Coyne, J. C. Shuler

Plant and Soil Sciences Faculty Publications

MUG negative Escherichia coli are a small fraction (2.5%) of the total E. coli in Kentucky groundwater samples. It is unlikely that they alone will cause a significant potential to underestimate fecal contamination using MUG as the primary criterion for that assessment. An unresolved question is how effectively MUG-based, defined-substrate tests address false negative water samples containing MUG positive E. coli.

Sunlight Induced Movement Of Planktonic Organisms And Their Relationships To Water Movements, John Calkins, Ed Colley, Jay Wallingford, Carol Hulsey, Kathy Lohr, Marc Bolling

KWRRI Research Reports

Previous studies have shown the planktonic organisms of various natural water bodies to be quite sensitive to the levels of solar ultraviolet radiation incident at the water surface in summer. It has been assumed that the majority of the phytoplankton are simply carried about in the mass of the water which they inhabit with little control of their position or sunlight exposure. Photosynthetic microorganisms must strike a delicate balance with regard to solar radiation; they must obtain enough visible light for adequate photosynthesis while avoiding an excessive exposure to the injurious solar UV-B radiation.

It is proposed that the circulation …