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Microbial Biomass And Nitrogen Availability Under The Invasive Plant Species Lonicera Japonica And Native Grasses In Wetland Soil, Kimberly R. Payne, Mary C. Savin, Peter J. Tomlinson

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Invasive plants decrease aboveground biodiversity and suitable wildlife habitat. Wetlands are especially valuable ecosystems because they provide habitat, floodwater control, and function as filters for urban runoff. Wetland soils also act as sinks for nutrients. This characteristic reduces levels of excess nutrients often found in adjacent aquatic systems. The importance of soil functions in wetlands necessitates further investigation of the effects of invasive species on belowground nutrient pools. Approximately 75% of a small neighborhood wetland located in Fayetteville, Ark., has been invaded by Lonicera japonica. The effects of L. japonica and its replacement with native grasses on soil microbial biomass …

Fifteen Years Of Plant Community Dynamics During A Northwest Ohio Oak Savanna Restoration, Scott R. Abella, John F. Jaeger, Lawrence G. Brewer

Public Policy and Leadership Faculty Research

Midwest oak savanna communities are noted for their unusual plant assemblages, but these communities have been reduced by more than 98% because of changing land uses and conversion to closed-canopy forests. We initiated an ongoing 15-year experiment in 1988 to restore a 40-ha black oak (Quercus velutina) savanna by applying burn treatments that historically maintained this vegetation type. Groundlayer composition changed significantly for both the burn treatment and the control, with the burn treatment exhibiting slight increases in herbs such as wild lupine (Lupinus perennis) and hairy puccoon (Lithospermum caroliniense), both of which are species requiring greater insolation. Burn treatments …

Relationships Between Needle Nitrogen Concentration And Photosynthetic Responses Of Douglas-Fir Seedlings To Elevated Co2 And Temperature, James D. Lewis, Melissa S. Lucash, David M. Olszyk, David T. Tingey

Environmental Science and Management Faculty Publications and Presentations

• Here we examined correlations between needle nitrogen concentration ([N]) and photosynthetic responses of Douglas-fir (Pseudotsuga menziesii) seedlings to growth in elevated temperatures and atmospheric carbon dioxide concentrations ([CO₂]).
• Seedlings were grown in sunlit, climate-controlled chambers at ambient or ambient+3.5^° C and ambient or ambient +180 μmol mol^-1 CO₂ in a full factorial design. Photosynthetic parameters and needle [N] were measured six times over a 21-month period.
• Needle [N] varied seasonally, and accounted for 30–50% of the variation in photosynthetic parameters. Across measurement periods, elevated temperature increased needle [N] by 26% and light-saturated …

Instructions For Authors, Discovery Editors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

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Effects Of Vegetation Removal On Native Soil Quality In Eastern Arkansas, Lorena Moreno, Kristofor R. Brye

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Aboveground vegetation removal practices, such as cutting and baling and burning, can both positively and negatively affect a prairie ecosystem. Burning can stimulate growth and species diversity, but removing vegetation and the nutrients it contains without equal replenishment of those nutrients could cause a steady decline in available soil nutrients. The objective of this study was to evaluate the effects of vegetation removal techniques in a native tallgrass prairie in east-central Arkansas. Soil samples were collected from the top 10 cm in each soil mapping unit that existed in each of three prairie areas that differed by the amount of …

Aerobic Stability Of Heat And Orchardgrass Round-Bale Silage, Robert T. Rhein, Wayne K. Coblentz, Charles F. Rosenkrans Jr., D. Wayne Kellog

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

In Arkansas, silage is typically stored as balage in long rows of round bales wrapped in plastic film. It is important to evaluate the aerobic stability of this fermented forage when it is exposed to air, especially during the winter months when most of it is fed to livestock or sold as a cash crop. Two types of forage, orchardgrass (Dactylis glomerata) and wheat (Triticum aestivum), were harvested in May 2002 and stored as balage. Twenty-one bales of each balage type were unwrapped and exposed to air on 10 Dec. 2002 for 0, 2, 4, 8, 16, 24, or 32 …

Identification Of Bacterial Pathogens Causing Panicle Blight Of Rice In Louisiana, Xianglong Yuan

LSU Master's Theses

Four hundred and two bacterial isolates isolated on the semi-specific S-PG medium from diseased rice tissues showing symptoms of panicle blighting. These isolates were purified using serial dilution in sterile water and replating on S-PG medium. A total of 420 single isolates were obtained. These isolates were subjected to pathogenicity tests on rice (Oryza sative L. cv. Cypress). Based on these tests, 339 isolates were used in BiologTM tests and identified to the species level. Bacterial strains from 39 species in 16 genera were identified, including 52 isolates representing15 Pseudomonas species and 261 isolates representing six Burkholderia species. The remaining …

Using Multi-Spectral Imagery To Evaluate Corn Grown Under Nitrogen And Drought Stressed Conditions, Shannon L. Osborne, James S. Schepers, Mike R. Schlemmer

Department of Agronomy and Horticulture: Faculty Publications

The in-season estimation of crop stresses which have the potential of adversely affecting crop yield and/or quality could allow producers to make in-season management decisions to correct for the particular stress. A field study was conducted to evaluate the use of multispectral imagery for estimating corn (Zea mays L.) grain yield, in-season biomass and nitrogen (N) concentration under varying N and drought stresses. The experiment was a split-plot design with three replications using a factorial arrangement of treatments. Three irrigation (whole-plot) treatments included dry land, irrigation based on 0.5, and full evapotranspiration (ET). Sub-plot treatments included five N …

Expression Of A Putative Flavonoid 3'-Hydroxylase In Sorghum Mesocotyls Synthesizing 3-Deoxyanthocyanidin Phytoalexins, Jayanand Boddu, Catherine Svabek, Rajandeep Sekhon, Amanda Gevens, Ralph L. Nicholson, A. Daniel Jones, Jeffrey F. Pedersen, David L. Gustine, Surinder Chopra

Department of Agronomy and Horticulture: Faculty Publications

In sorghum, ingress of Cochliobolus heterostrophus stimulates the synthesis of 3-deoxyanthocyanidins that act as phytoalexins. Apigeninidin and luteolinidin are two major phytoalexins induced in the first 24 h after infection. In an attempt to understand genetic regulation of the biosynthesis of sorghum phytoalexins, we isolated a differentially expressed partial cDNA. Characterization and comparison showed that this cDNA sequence corresponds to a putative flavonoid 3’-hydroxylase. Full length sequence characterization allowed us to establish that the sorghum putative f3’h cDNA encodes a peptide of 517 amino acids that has domains conserved among cytochrome P450 proteins functioning in …

The Use Of Proline To Determine Salt Tolerance In Eucalyptus Species And Clones, Andrew J. Woodward

Theses: Doctorates and Masters

There have been a number of studies that have examined the Eucalyptus spp. for their salt and waterlogging tolerance: but they have done so using conventional methods. A wide range of plants are known to produce greater amounts of proline when stressed, be it salt, temperature, 'drought or several other types of stress. This study looked at production of proline in salt stressed eucalypts to determine whether it can be used to differentiate between individuals andspecies. A range of Eucalyptus species and salt tolerant clones of E. camaldulensis were grown to investigate their proline response to salt stress.

The Effectiveness Of Post-Fire Weed Management And The Germination Ecology Of Selected Invasive Weed Species Of Bold Park, Brett Neasham

Theses : Honours

Bold Park is a 437 hectare A class reserve with high conservation value. Bold park is located on the Swan Coastal Plain, approximately 11 km west of the Perth CBD. Bold park is one of the few remaining coastal bushland reserves on the Swan Coastal Plain. High levels of floristic and faunal diversity contribute to Bold Park's conservation value. Weed invasion in Bold Park is reducing floristic diversity and is modifying ecosystem processes. Principle in the modified ecosystem processes is fire. While fire is a natural disturbance event in the bushland of the south-west of Western Australia, altered fire regimes …

Effects Of Temporary Par Reduction On The Seagrass Amphibolis Griffithii (Black) Den Hartog, Paul R. Mackey

Theses : Honours

Declines in seagrass health and distribution are commonly caused through human induced reductions in the availability of photosynthetically active radiation (PAR). These reductions can result from a variety of human-induced perturbations, including channel dredging. The impetus for the research was driven by the broad-scale degradation of the ecologically important southern-Australian endemic seagrass Amphibolis griffithii (Black) den Hartog in Champion Bay, Geraldton, Western Australia. The study investigated the affects of reduced PAR on A. griffithii and identified responses that may be useful in developing management triggers to minimise the impact of PAR limitation events. The study was carried out during late …

Levels And Changes Of Soil Phosphorus In Subtropical Beef Cattle Pastures, Gilbert C. Sigua, Mary J. Williams, Samuel W. Coleman

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Long-term pasture management is believed to change soil chemical properties, but little is known about whether pasture management, such as fertilizer application, grazing, or haying can initiate such change in sandy and well-drained subtropical beef pastures. The objective of this study was to investigate the long term effect of pasture management (grazing+haying, GZ+HY) on soil phosphorus (P) dynamics (levels and changes) in subtropical beef cattle pastures with bahiagrass (BG, Paspalum notatum) and rhizoma peanut (RP, Arachis glabrata) with (WP) or without (WNP) P fertilization in Brooksville, FL from 1988 to 2000. Soil P dynamics in Subtropical Agricultural Research …

Aquaporins Are Observed In The Duct Epithelia Of The Epididymal Region Of The Large White Turkey, L. Zaniboni, V. Akuffo, M. R. Bakst

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The cellular and molecular mechanisms regulating the reuptake of the testicular fluid supporting sperm exiting the testes in the bird are not known. The presence of aquaporins, proteins involved in transmembrane water transport, was investigated. Observations were limited to the ductuli efferentes, collecting ducts, and ductus epididymis. Interestingly all of these ducts were positive for aquaporins-2, -3, and -9 but not aquaporin- 7. When positive, aquaporin was observed localized over the whole cell or the apical plasma membrane of the nonciliated cells and the apical plasma membrane and cilia of the ciliated cells. This study is the first to clearly …

Plasma Clearance And Tissue Distribution Of Radiolabeled Leptin In The Chicken, John P. Mcmurtry, Christopher M. Ashwell, Donna M. Brocht, Thomas J. Caperna

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Leptin is an adipose and liver tissue-derived secreted protein in chickens that has been implicated in the regulation of food intake and whole-body energy balance. In this study, the metabolic clearance and tissue uptake of leptin were examined in the chicken (Gallus gallus). Four-week-old broiler males were infused with ¹²⁵I-labeled mouse leptin. Chromatography of radiolabeled leptin in plasma produced two peaks, one at 16 kDa (free leptin) and a free iodine peak. No leptin binding protein in blood was detected. Leptin was cleared with a half-life estimate of 23 min. In order to investigate the tissue distribution …

Influence Of Different Cotton Fruit Sizes On Boll Weevil (Coleoptera: Curculionidae) Oviposition And Survival To Adulthoods., S. M. Greenberg, T. W. Sappington, M. Sétamou, R. J. Coleman

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Understanding the critical host plant factors that determine oviposition behavior and survival of boll weevil, Anthonomus grandis grandis Boheman, on cotton, Gossypium hirsutum L., is important for developing successful pest management strategies. However, published information is both conflicting and limited regarding how different cotton fruit sizes affect boll weevil oviposition choices and subsequent larval survival to adulthood. Consequently, we used a standard based on fruit size diameter to evaluate boll weevil feeding and oviposition punctures, and survival to adulthood on 10 different cotton fruit sizes: squares of diameter 1.5-2.0 (pinhead), 3.0-3.5 (matchhead), 5-6, 7-8, or 9-10 mm; candle; and bolls …

Tillage And Cropping Effects On Soil Quality Indicators In The Northern Great Plains, Mark A. Liebig, D. L. Tanaka, Brian J. Wienhold

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The extreme climate of the northern Great Plains of North America requires cropping systems to possess a resilient soil resource in order to be sustainable. This paper summarizes the interactive effects of tillage, crop sequence, and cropping intensity on soil quality indicators for two long-term cropping system experiments in the northern Great Plains. The experiments, located in central North Dakota, were established in 1984 and 1993 on a Wilton silt loam (FAO: Calcic Siltic Chernozem; USDA1: fine-silty, mixed, superactive frigid Pachic Haplustoll). Soil physical, chemical, and biological properties considered as indicators of soil quality were evaluated in spring 2001 in …

Geographic And Voltinism Differentiation Among North American Ostrinia Nubilalis (European Corn Borer) Mitochondrial Cytochrome C Oxidase Haplotypes, Brad S. Coates, Douglas V. Sumerford, Richard L. Hellmich

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

DNA sequence of European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), mitochondrial cytochrome c oxidase I (cox1) and II (cox2) genes were characterized and used for population genetic analysis. Twenty-six point mutations were identified from a 2,156 bp DNA sequence alignment. The frequency of polymorphic cox1 DdeI and HaeIII, and cox2 Sau3AI and MspI restriction sites were determined from 1,414 individuals by polymerase chain reaction restriction fragment length polymorphism. Ten haplotypes were observed. A single haplotype was present among 90% of individuals examined, and a HaeIII haplotype was not present in …

Habitat Manipulation Of The Apple Orchard Floor To Increase Ground-Dwelling Predators And Predation Of Cydia Pomonella (L.) (Lepidoptera: Tortricidae), Clarissa R. Mathews, Dale G. Bottrell, M. W. Brown

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Augmenting generalist predator populations in new apple (Malus domestica Bork) plantings could potentially aid in the establishment of balanced orchard ecosystems that are less susceptible to pest outbreaks. Habitat can be an important factor in retaining predators in a system and can affect predator efficiency. We investigated the potential of increasing a complex of generalist ground-dwelling predators and enhancing biological control in a young 'Golden Delicious' apple orchard through ground habitat manipulation. We modified the orchard floor with four comparative habitat treatments: (1) detritus-rich compost mulch layer, (2) detritus-free synthetic mulch layer, (3) herbicide-treated vegetation thatch, and (4) bare …

Comparison Of Production, Meat Yield, And Meat Quality Traits Of Nwac103 Line Channel Catfish, Norris Line Channel Catfish, And Female Channel Catfish × Male Blue Catfish F1 Hybrids, Brian G. Bosworth, William R. Wolters, Juan L. Silva, Roberto S. Chamul, Sinyoung Park

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

NWAC103 line channel catfish Ictalurus punctatus, Norris line channel catfish, and Norris line female channel catfish × Dycus Farm line male blue catfish I. furcatus F₁ hybrids were compared for production, meat yield, and meat quality traits. Juvenile fish from each genetic group were stocked at 12,000 fish/ha into three, 0.04-ha ponds per genetic group. Fish were fed once daily to satiation from June through October, and fed on days when afternoon water temperatures were above 17 °C from November through December. Fish were harvested, weighed, and counted in January, and 150 fish per genetic group (50 fish …

The Accidental Plant Pathologist, Anne K. Vidaver

Department of Plant Pathology: Faculty Publications

This article presents the experiences of a woman in academic plant pathology from the 1950s to today. Topics include the social climate for women in science, personal and professional developments and research discoveries, public policy issues in agriculture and biotechnology affecting plant pathology, and projections for the future of plant pathology.

Biography Of James L. Van Etten, Christen Brownlee, James L. Van Etten

Department of Plant Pathology: Faculty Publications

Green algae, in surface layers of almost every lake or stream, are some of the most common aquatic creatures. However, unbeknownst to researchers until recently, viruses that infect algae are almost as widespread. Entire ecosystems of algal hosts and their corresponding viruses lay hidden until the 1980s, when James L. Van Etten, a professor of plant pathology at the University of Nebraska (Lincoln), and his colleague Russ Meints discovered and began to characterize the first member of what is now a rapidly expanding family of algal viruses. Van Etten and his colleagues have continued to study these intriguing viruses, focusing …

Crop And Soil Productivity Response To Corn Residue Removal: A Literature Review, Wallace Wilhelm, J.M.F. Johnson, J. L. Hatfield, W.B. Voorhees, D.R. Linden

Department of Agronomy and Horticulture: Faculty Publications

Society is facing three related issues: over-reliance on imported fuel, increasing levels of greenhouse gases in the atmosphere, and producing sufficient food for a growing world population. The U.S. Department of Energy and private enterprise are developing technology necessary to use high-cellulose feedstock, such as crop residues, for ethanol production. Corn (Zea mays L.) residue can provide about 1.7 times more C than barley (Hordeum vulgare L.), oat (Avena sativa L.), sorghum [Sorghum bicolor (L.) Moench], soybean [Glycine max L.) Merr.], sunflower (Helianthus annuus L.), and wheat (Triticum aestivum L.) residues based on …

Old-Field Grassland Successional Dynamics Following Cessation Of Chronic Disturbance, Susan Tunnell, David Engle, Eric Jorgensen

Department of Agronomy and Horticulture: Faculty Publications

Question: Does increasing i>Festuca canopy cover reduce plant species richness and, therefore, alter plant community composition and the relationship of litter to species richness in old-field grassland?
Location: Southeastern Oklahoma, USA.
Methods: Canopy cover by species, species richness, and litter mass were collected within an old-field grassland site on 16, 40 m x &#;40 m plots. Our study was conducted during the first three years of a long-term study that investigated the effects of low-level nitrogen enrichment and small mammal herbivory manipulations.
Results: Succession was altered by an increase in abundance of Festuca over the 3-yr study period. Species …

Resource Allocation In A Breeding Program For Phosphorus Concentration In Maize Grain, Brandon M. Wardyn, W. Ken Russell

Department of Agronomy and Horticulture: Faculty Publications

When beef cattle (Bos taurus) are fed grain of maize (Zea mays L.) in which the concentration of phosphorus (P) exceeds the animal’s need for this element, the excess P is excreted in the feces. Spreading this manure on cropland increases the potential for P pollution of surface waters by run-off. Experiments were undertaken to determine the relative magnitudes of genotypic and nongenotypic variances of P concentration in maize grain (P-Gr) to assess the ability to select maize genotypes in which this trait more closely matches the dietary need of beef cattle. Genetic variability was found in …

Common Lambsquarters (Chenopodium Album) Interference With Corn Across The North-Central United States, David W. Fischer, R. Gordon Harvey, Thomas T. Bauman, Sam Phillips, Stephen E. Hart, Gregg A. Johnson, James J. Kells, Philip Westra, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Variation in crop–weed interference relationships has been shown for a number of crop–weed mixtures and may have an important influence on weed management decision-making. Field experiments were conducted at seven locations over 2 yr to evaluate variation in common lambsquarters interference in field corn and whether a single set of model parameters could be used to estimate corn grain yield loss throughout the north-central United States.

Factors Affecting The Realized Niche Of Common Sunflower (Helianthus Annuus) In Ridge-Tillage Corn, Michael G. Burton, David A. Mortensen, David B. Marx, John L. Lindquist

Department of Agronomy and Horticulture: Faculty Publications

Because soil characteristics and weed densities vary within agricultural landscapes, determining which subfield areas are most favorable to weed species may aid in their management. Field and greenhouse studies were conducted to determine whether subfield environments characterized by higher soil organic carbon (SOC), or ridge vs. furrow microsites, affect common sunflower seed germination after winter burial, seedling emergence, or the control afforded by a preemergence herbicide in a ridge-tillage corn production system. Among seeds buried in situ during winter months and germinated in the laboratory, no differences in common sunflower seed germination or mortality were detected between high-SOC (1.8% mean) …

Test Of The Hybrid-Maize Model For Simulation Of Soil Moisture Dynamics And Maize Response To Water Deficit, Haishun S. Yang, Achim R. Dobermann, Kenneth G. Cassman, Kenneth G. Hubbard, Timothy J. Arkebauer, Shashi Verma, Daniel T. Walters

Department of Agronomy and Horticulture: Faculty Publications

The Hybrid-Maize model (Yang et al, 2004), which has been validated under optimal water conditions, was evaluated for its ability to simulate soil moisture dynamics in the root zone and effects of water deficits on maize development and final yields (Fig. 1). The experimental data for this evaluation were obtained from ongoing field studies of the Carbon Sequestration Program (CSP) at the University of Nebraska. The studies include three cropping systems, each located in a quarter-section field (57 ha), two of which are irrigated by central-pivots and the third is rainfed. One irrigated field is in continuous maize and the …

Molecular Mapping And Identification Of Soybean Fatty Acid Modifier Quantitative Trait Loci, D. L. Hyten Jr., Vincent R. Pantalone, Arnold M. Saxton, Michael E. Schmidt, Carl E. Sams

Department of Agronomy and Horticulture: Faculty Publications

Altering FA content in soybean [Glycine max (L.) Merr.] oil for improved functionality is a research goal of many soybean breeders. Several of the genes that alter palmitic, stearic, oleic, linoleic, and linolenic acids are modifier genes with small effects, causing these FA traits to act as quantitative traits. The objective of this study was to identify modifier FA quantitative trait loci (QTL) in soybean. A recombinant inbred line population was created from two prominent ancestors of currently avail-able U.S. cultivars (Essex and Williams) and grown in five environments. One hundred simple se-quence repeat markers spaced throughout the genome …

Implementation Of A Mitochondrial Mutator, Sally Mackenzie, Ricardo Vilela Abdelnoor

Department of Agronomy and Horticulture: Faculty Publications

Plant MSH1 polynucleotides and polypeptides are described. Also described are methods for the use and modulation of such MSH1 polynucleotides and polypeptides.