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Switchgrass For Biomass Feedstock In The Usa, Matt Sanderson, Paul Adler, Akwasi Boateng, Michael Casler, Gautam Sarath

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

Switchgrass has received much study for biomass feedstock production and conversion through research funded by the US-DOE and USDA during the past two decades. We have an improved understanding of the adaptation of existing cultivars and new cultivars with yield and adaptation improvements are now appearing. We also have a good understanding of the agronomics of switchgrass production, mainly from its use as a forage crop. There remain several constraints to switchgrass use in bioenergy cropping systems, including reliable establishment methods to obtain productive stands in the first year, targeted fertilization and nutrient management techniques to efficiently use nitrogen fertilizer, …

Bovine Immune Response To Shiga-Toxigenic Escherichia Coli O157:H7, Mark A. Hoffman, Christian Menge, Thomas A. Casey, William Laegreid, Brad T. Bosworth, Evelyn A. Dean-Nystrom

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

Although cattle develop humoral immune responses to Shiga-toxigenic (Stx⁺) Escherichia coli O157:H7, infections often result in long-term shedding of these human pathogenic bacteria. The objective of this study was to compare humoral and cellular immune responses to Stx⁺ and Stx^- E. coli O157:H7. Three groups of calves were inoculated intrarumenally, twice in a 3-week interval, with different strains of E. coli: a Stx2- producing E. coli O157:H7 strain (Stx2⁺O157), a Shiga toxin-negative E. coli O157:H7 strain (Stx^-O157), or a nonpathogenic E. coli strain (control). Fecal shedding of Stx2⁺O157 was …

Agronomic And Quality Effects In Winter Wheat Of A Gene Conditioning Resistance To Wheat Streak Mosaic Virus, L. A. Divis, R. A. Graybosch, C. J. Peterson, P. Stephen Baenziger, G. L. Hein, B. B. Beecher, T. J. Martin

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

Wheat streak mosaic virus (WSMV) is one of the most important diseases limiting winter wheat (Triticum aestivum L.) production in the western Great Plains of North America. There is no known effective WSMV resistance within the primary gene pool of wheat. However, a resistance gene (Wsm1) has been transferred to wheat from a perennial relative, intermediate wheat-grass [Thinopyrum intermedium (Host) Barkworth & DR Dewey]. Nebraska-adapted winter wheat lines carrying Wsm1 were used to characterize the effects of this alien introgression on agronomic and quality traits. Sister-lines from six breeding populations were evaluated under virus-free conditions, …

The Circuitous Path To The Comparison Of Simulated Values From Crop Models With Field Observations, Albert Weiss, Wally Wilhelm

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

The Journal of Agricultural Science, Cambridge has been a fixture in dissemination of crop simulation models and the concepts and data upon which they are built since the inception of computers and computer modeling in the mid-20th century. To quantify the performance of a crop simulation model, model outputs are compared with observed values using statistical measures of bias, i.e. the difference between simulated and observed values. While applying these statistical measures is unambiguous for the experienced user, the same cannot always be said of determining the observed or simulated values. For example, differences in accessing crop development can be …

Grazing Management Effects On Sediment And Phosphorus In Surface Runoff, Matthew M. Haan, James R. Russell, Wendy J. Powers, John L. Kovar, Jamie L. Benning

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

Sediment and phosphorus (P) in runoff from pastures are potential non–point-source pollutants in surface waters that may be influenced by surface cover, sward height, treading damage, surface slope, soil moisture, and soil P. The objectives of the current study were to quantify sediment and total P loads in runoff produced during simulated rainfall from pastures and to evaluate their relationships with the physical and chemical characteristics of the soil and sward. Five forage management treatments— ungrazed (U), hay harvest/fall stockpile grazing (HS), continuous stocking to a sward height of 5 cm (5C), and rotational stocking to sward heights of 5 …

Convergence Of Agriculture And Energy: Implications For Research And Policy, Kenneth Cassman, Vernon Eidman, Eugene Simpson, Larry Berger, Robert Loomis, Marie Walsh, Todd A. Peterson, Edward Runge

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

Access to an adequate energy supply at reasonable cost is crucial for sustained economic growth. Unfortunately, oil prices and the need to import from politically unstable countries lowers the reliability of the U.S. energy supply and hinders economic development. Although biofuels have been identified as an important component of the national strategy to decrease U.S. dependence on imported oil, the ability to sustain a rapid expansion of biofuel production capacity raises new research and policy issues. This document seeks to identify the most critical of these issues to help inform the policy development process. The goal is to enhance the …

Comparison Of Heat Tolerance Of Feedlot Heifers Of Different Breeds, T. M. Brown-Brandl, J. A. Nienaber, Roger A. Eigenberg, Terry L. Mader, J. L. Morrow, J. W. Dailey

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

Heat stress in cattle causes decreases in feed intake and feed efficiency; in extreme cases, it can cause death. These losses amount to millions of dollars each year. A study was designed to determine severity of heat stress among four breeds of cattle. Throughout two summers, 256 feedlot heifers of four different breeds were observed. Respiration rates, panting scores, and surface temperatures were taken twice each day on 10 animals/breed for several weeks during the summers of 2002 and 2003. Twenty-four-hour behavior measurements were recorded for four heat-stress and four thermoneutral days. Results showed during the afternoon, Angus cattle (black) …

Heat Stress Risk Factors Of Feedlot Heifers, T. M. Brown-Brandl, Roger A. Eigenberg, J. A. Nienaber

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

Heat stress in cattle results in millions of dollars in lost revenue each year due to production losses, and in extreme cases, death. Death losses are more likely to result from animals vulnerable to heat stress. A study was conducted to determine risk factors for heat stress in feedlot heifers. Over two consecutive summers, a total of 256 feedlot heifers (32/ breed/ year) of four breeds were observed. As a measure of stress, respiration rates and panting scores were taken twice daily (morning and afternoon) on a random sample of 10 heifers/ breed. Weights, condition scores, and temperament scores were …

Heat Stress Risk Factors Of Feedlot Heifers, Tami M. Brown-Brandl, Roger A. Eigenberg, John A. Nienaber

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

Heat stress in cattle results in millions of dollars in lost revenue each year due to production losses, and in extreme cases, death. Death losses are more likely to result from animals vulnerable to heat stress. A study was conducted to determine risk factors for heat stress in feedlot heifers. Over two consecutive summers, a total of 256 feedlot heifers (32/ breed/ year) of four breeds were observed. As a measure of stress, respiration rates and panting scores were taken twice daily (morning and afternoon) on a random sample of 10 heifers/ breed. Weights, condition scores, and temperament scores were …

Isolation Of An Active Lv1 Gene From Cattle Indicates That Tripartite Motif Protein-Mediated Innate Immunity To Retroviral Infection Is Widespread Among Mammals, Laura M.J. Ylinen, Zuzana Keckesova, Benjamin L.J. Webb, Robert J.M. Gifford, Timothy P.L. Smith, Greg J. Towers

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

Lv1/TRIM5α (tripartite motif 5α) has recently emerged as an important factor influencing species-specific permissivity to retroviral infection in a range of primates, including humans. Old World monkey TRIM5α blocks human immunodeficiency virus type 1 (HIV-1) infectivity, and the human and New World monkey TRIM5α proteins are inactive against HIV-1 but active against divergent murine (N-tropic murine leukemia virus [MLV-N]) and simian (simian immunodeficiency virus from rhesus macaque [SIVmac]) retroviruses, respectively. Here we demonstrate antiviral activity of the first nonprimate TRIM protein, from cattle, active against divergent retroviruses, including HIV-1. The number of closely related human TRIM sequences makes assignment of …

Estimating The Cost Of Invasive Species On U.S. Agriculture: The U.S. Soybean Market, D. J. Lee, C.S. Kim, G Schaible

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

Soybean production ranks among the largest agricultural cash crops in the U.S., second only to corn. U.S. soybean production topped 3 billion bushels in 2005 with sales of $17 billion. Approximately 58% of U.S. soybeans are grown in Iowa, Illinois, Minnesota, Indiana, and Nebraska. A small percentage of the U.S. soybean crop, 2%, goes to human consumption in the form of whole beans, soybean oil, and soybean meal products. A third of the crop, 1 billion bushels per year is exported annually to China, EU, Mexico, Japan, and Taiwan, and other countries. Most of the crop, 2 billion bushels, goes …

A Matter Of Balance: Conservation And Renewable Energy, Jane M.F. Johnson, Don Reicosky, Ray Allmaras, Dave Archer, Wallace Wilhelm

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

As communities and a country, we have a monumental task to solve the energy and global climate change problems, while maintaining our capacity to produce food, feed, and fiber for an ever increasing world population. The severity of these problems is exacerbated by the universal desire for an increased standard of living, which invariably translates to more energy use, greater demand for products, and higher quality diets (usually in the form of more fresh fruits and vegetables and more animal protein). Agriculture and forestry are in a unique position as we attempt solve these opposing problems in the most beneficial …

Book Review: Agriculture As A Producer And Consumer Of Energy, Wally Wilhelm

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

As the title of this book suggests, agriculture resides on both sides of the nation’s energy balance equation. Throughout history, agriculture has used and produced energy. Early agriculture relied on human and animal traction; much of the produce was consumed to power the enterprise. From the end of World War II through the present, a unique period in agricultural production has existed. Energy used on farms has come from sources beyond the farm gate—oil wells in the Middle East and Alaska’s North Slope, coal mines in Wyoming, and natural gas fields in Gulf States and the Gulf of Mexico. As …

Nitric Oxide Accelerates Seed Germination In Warm-Season Grasses, Gautam Sarath, Paul C. Bethke, Russell Jones, Lisa M. Baird, Guichuan Hou, Robert B. Mitchell

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

The nitric oxide (NO) donor sodium nitroprusside (SNP) significantly promoted germination of switchgrass (Panicum virgatum L. cv Kanlow) in the light and in the dark at 25°C, across a broad range of concentrations. SNP also promoted seed germination in two other warm-season grasses. A chemical scavenger of NO inhibited germination and blocked SNP stimulation of seed germination. The phenolic (+)-catechin acted synergistically with SNP and nitrite in promoting seed germination. Acidified nitrite, an alternate NO donor also significantly stimulated seed germination. Interestingly, sodium cyanide, potassium ferricyanide and potassium ferrocyanide at 200 lM strongly enhanced seed germination as well, whereas …

The Arabidopsis Homolog Of Trithorax, Atx1, Binds Phosphatidylinositol 5-Phosphate, And The Two Regulate A Common Set Of Target Genes, Raul Alvarez-Venegas, Monther Sadder, Andrej Hlavacka, Frantisek Baluska, Yuannan Xia, Guoqing Lu, Alexey Firsov, Gautam Sarath, Hideaki Moriyama, Joseph G. Dubrovsky, Zoya V. Avramova

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

TheArabidopsis homolog of trithorax, ATX1, regulates numerous functions inArabidopsis beyond the homeotic genes. Here, we identified genome-wide targets of ATX1 and showed that ATX1 is a receptor for a lipid messenger, phosphatidylinositol 5-phosphate, PI5P. PI5P negatively affects ATX1 activity, suggesting a regulatory pathway connecting lipid-signaling with nuclear functions. We propose a model to illustrate how plants may respond to stimuli (external or internal) that elevate cellular PI5P levels by altering expression of ATX1-controlled genes.

Includes supplemental supporting information.

Crossover Interactions For Grain Yield In Multienvironmental Trials Of Winter Wheat, R. Mishra, P. Stephen Baenziger, W. Ken Russell, Robert A. Graybosch, David D. Baltensperger, Kent M. Eskridge

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

Crossover interactions (COIs) are changes in ranks among cultivars across environments. Breeders are concerned about COIs because their frequency affects how well rankings from one environment predict rankings in another environment. This research was undertaken to determine the frequency and distribution of COIs for grain yield within years in two regional trials of winter wheat (Triticum aestivum L.). The trials were in Nebraska and in the south-central USA (SCUS). Each trial had four environments per year, and results from 1998, 1999, and 2000 were considered. Significance of COI for each pair of lines in each pair of environments within …

Lysine Residues In N-Terminal And C-Terminal Regions Of Human Histone H2a Are Targets For Biotinylation By Biotinidase, Yap Ching Chew, Gabreale Camporeale, Nagarama Kothapalli, Gautam Sarath, Janos Zempleni

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

In eukaryotic cell nuclei, DNA associates with the core histones H2A, H2B, H3 and H4 to form nucleosomal core particles. DNA binding to histones is regulated by posttranslational modifications of N-terminal tails (e.g., acetylation and methylation of histones). These modifications play important roles in the epigenetic control of chromatin structure. Recently, evidence that biotinidase and holocarboxylase synthetase (HCS) catalyze the covalent binding of biotin to histones has been provided. The primary aim of this study was to identify biotinylation sites in histone H2A and its variant H2AX. Secondary aims were to determine whether acetylation and methylation of histone H2A affect …

Genic Microsatellite Markers Derived From Est Sequences Of Switchgrass (Panicum Virgatum L.), Christian M. Tobias, Daniel M. Hayden, Paul Twigg, Gautam Sarath

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

Switchgrass is a large, North American, perennial grass that is being evaluated as a potential energy crop. There is a need to assess genetic diversity in stored accessions and in remaining native stands to assist breeding and conservation efforts. Marker development will also be necessary for genetic linkage mapping. Toward this end, 32 switchgrass genic di-, tri- and tetranucleotide repeat microsatellites were identified from expressed sequence tags (ESTs). These microsatellites were used to screen individuals from two different named cultivars. The markers displayed a high level of polymorphism consistent with the tetraploid, allogamous behaviour of the cultivars tested.

Soil Organic Carbon Changes In Diversified Rotations Of The Western Corn Belt, G. E. Varvel

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

Sequestration and storage of carbon (C) by agricultural soils has been cited as one potential part of the solution to soil degradation and global climate change. However, C sequestration in soils is a slow and dynamic process. The objective of this study was to evaluate the effects of crop rotation and N fertilizer management on soil organic C (SOC) levels at several points in time during 18 yr of a long-term study in the Western Corn Belt. Seven cropping systems (three monoculture, two 2-yr, and two 4-yr rotations) with three levels of N fertilizer were compared. Soil samples were taken …

The Established Intimin Receptor Tir And The Putative Eucaryotic Intimin Receptors Nucleolin And B1 Integrin Localize At Or Near The Site Of Enterohemorrhagic Escherichia Coli O157:H7 Adherence To Enterocytes In Vivo, James F. Sinclair, Evelyn A. Dean-Nystrom, Alison D. O’Brien

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

For enterohemorrhagic Escherichia coli (EHEC) O157:H7 to adhere tightly to the intestinal epithelium and produce attach and efface (A/E) lesions, the organism must express the adhesin intimin and insert the bacterially encoded translocated intimin receptor Tir into the plasma membrane of the host enterocyte. Additionally, some reports based on tissue culture experiments indicate that intimin has affinity for the eucaryotic proteins nucleolin and β1 integrin. To address the potential biological relevance of these eucaryotic proteins in the infection process in vivo, we sought to compare the proximity of Tir, nucleolin, and β1 integrin to regions of EHEC …

Chinch Bug (Hemiptera: Blissidae) Mouthpart Morphology, Probing Frequencies, And Locations On Resistant And Susceptible Germplasm, Wyatt G. Anderson, Tiffany Heng-Moss, Frederick P. Baxendale, Lisa M. Baird, Gautam Sarath, Leon G. Higley

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

Chinch bugs are common pests of many agronomic and horticulturally important crops and turfgrasses. Previous research has indicated that some grasses exhibit resistance to multiple chinch bug species, whereas others are resistant to only one species. The objectives of this research were to document differences in the probing frequencies and locations among Blissus species as well as differences in mouthpart morphology as a first step in understanding the differential responses of grasses to chinch bug feeding. Scanning electron microscopy detected differences in the total lengths of proboscises as well as individual mouthpart segments among the four species studied. Blissus occiduus …

Effect Of High-Pressure Hot-Water Washing Treatment On Fruit Quality, Insects, And Disease In Apples And Pears Part Iii. Use Of Silicone-Based Materials And Mechanical Methods To Eliminate Surface Pests, J. D. Hansen, M. L. Heidt, L. G. Neven, E. A. Mielke, J. Bai, P. M. Chen, R. A. Spotts

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

Surface arthropods on pome fruits can cause export problems and disrupt commercial markets. Eliminating insects and mites on the packing line would be the last opportunity to provide for pest-free produce. In this study, an experimental packing line was used to evaluate techniques using different surfactant baths, pressurized water sprays, and styles of rotating brushes to remove field-collected and laboratory-reared grape mealybug, Pseudococcus maritimus (Ehrhorn) (Homoptera: Pseudococcidae), the diapausing two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) and the woolly apple aphid, Eriosoma lanigerum (Hausman) (Homoptera: Aphididae). The organosilicone Silwet L-77 was no more effective than a silicone-based food grade …

Characterization Of A Higher Plant Herbicide-Resistant Phytoene Desaturase And Its Use As A Selectable Marker, R. S. Arias, Franck E. Dayan, Albrecht Michel, J’Lynn Howell, Brian E. Scheffler

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

Three natural somatic mutations at codon 304 of the phytoene desaturase gene (pds) of Hydrilla verticillata (L. f. Royle) have been reported to provide resistance to the herbicide fluridone. We substituted the arginine 304 present in the wild-type H. verticillata phytoene desaturase (PDS) with all 19 other natural amino acids and tested PDS against fluridone. In in vitro assays, the threonine ( Thr), cysteine (Cys), alanine (Ala) and glutamine (Gln) mutations imparted the highest resistance to fluridone. Thr, the three natural mutations [Cys, serine (Ser), histidine (His)] and the wild-type PDS protein were tested in vitro against seven …

Registration Of ‘Hallam’ Wheat, P. Stephen Baenziger, B. Beecher, Robert A. Graybosch, D. D. Baltensperger, Lenis Alton Nelson, Y. Jin, J. E. Watkins, J. H. Hatchett, Ming-Shun Chen, Guihua Bai

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

‘Hallam’ (Reg. no. CV-983, PI 638790) is a hard red winter wheat (Triticum aestivum L.) cultivar developed cooperatively by the Nebraska Agricultural Experiment Station and the USDA-ARS and released in 2005 by the developing institutions. Hallam was released primarily for its superior adaptation to rainfed wheat production systems in eastern Nebraska. The name Hallam was chosen to honor Hallam, NE, a town and its people rebuilding after a tornado.

Hallam was selected from the cross ‘Brule’ (Schmidt et al., 1983)/‘Bennett’ (Schmidt et al., 1981)//‘Niobrara’ (Baenziger et al., 1996) that was made in 1992. The F₁ generation was grown in …

Registration Of ‘Choptank’ Wheat, J.M. Costa, C.A. Griffey, H.E. Bockelman, S.E. Cambron, X. Chen, A. Cooper, C. Gaines, Robert A. Graybosch, A. Grybauskas, R.J. Kratochvil, D.L. Long, E. Shirley, L. Whitcher

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

‘Choptank’ (Reg. no. CV-976, PI 639724) is a soft red winter wheat (Triticum aestivum L.) that was jointly developed and released by the Maryland Agricultural Experiment Station, Department of Natural Resource Sciences and Landscape Architecture, and the Virginia Agricultural Experiment Station in 2004. Choptank is named after Maryland’s longest scenic river, which flows 70 miles from the western part of Delaware through Maryland and into the Chesapeake Bay, on Maryland’s Eastern Shore. Choptank has performed well in Maryland, Virginia, and Delaware and provides growers with a high-yielding cultivar with short stature, excellent powdery mildew [caused by Blumeria graminis (DC.) …

Laboratory And Field Assessment Of Some Kairomone Blends For Host-Seeking Aedes Aegypti, Craig R. Williams, Ramona Bergbauer, Martin Geier, Daniel L. Kline, Ulrich R. Bernier, Richard Russell, Scott A. Ritchie

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

Using laboratory Y-tube olfactometers, the attractiveness of lactic acid and 2 kairomone blends from the United States Department of Agriculture (USDA) and BioGents GmbH (BG) was assessed for attractiveness to Aedes aegypti. Four geographically disparate populations were assessed: North Queensland Australia (NQA), Florida USA, Minas Gerais Brazil (MGB), and Singapore. In descending order, populations were attracted to USE)A, BG blends, and lactic acid. MGB was poorly attracted to lactic acid alone. The blends were less attractive than human odor. Proprietary blends were modified, and their attractiveness was assessed to find the optimum attractive mixture for NQA. Adding acetone to …

Laboratory Evaluation Of Avian Odors For Mosquito (Diptera: Culicidae) Attraction, S. A. Allan, Ulrich R. Bernier, D. L. Kline

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

Attraction of Culex quinquefasciatus Say, Culex tarsalis Coquillett, Culex nigripalpus Theobald, and Aedes aegypti (L.) to avian and other host odors was investigated in a dual-port olfactometer. Although attraction to a human arm was high for Ae. aegypti (>80%) and low for all Culex spp. (<25%), all species responded similarly to a chicken (55.3-73.6%). Responses of Ae. aegypti, Cx. quinquefasciatus, and Cx. nigripalpus to feathers were low (<20%) but greater than to controls. There was no difference in attraction of Cx. tarsalis to feathers or controls. Responses to CO₂ (5 ml/min) were low for all species (<15%) except Cx. tarsalis, which were moderate (24.5%). When feathers were combined with CO2, the resulting attraction was additive or lower than responses …

Attraction Of Mosquitoes To Volatiles Associated With Blood, S. A. Allan, Ulrich R. Bernier, Donald Kline

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

Responses of the mosquitoes Aedes aegypti, Culex quinquefasciatus, and Culex nigripalpus to volatiles and compounds associated with bovine and avian blood that were presented in collagen membranes were evaluated in olfactometer and landing assays. The presence of attractants produced by blood was supported by more attraction of all species to blood than water controls in the olfactometer. Females of Ae. aegypti and Cx. quinquefasciatus were more attracted to bovine blood than to avian blood, but there was no difference in Cx. nigripalpus responses. In landing assays, significantly more females of all species landed on casings with blood than on water …

Viability Of Native Forb Seeds Stored Under Two Different Environments, John M. Row, Richard L. Wynia

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

The ability to maintain viability in seeds of native forbs for long periods of time is important to the seed industry and prairie restoration efforts. Seeds stored in eastern Kansas in an uncontrolled environment, subjected to wide fluctuations in ambient temperature and humidity, are known to experience reduced longevity. We examined seeds of 7 prairie forbs native to the Central Great Plains that were stored under two different storage environments in Manhattan, Kansas, to determine what effect the two storage conditions had on the longevity of seed viability. Three of the species stored in a controlled environment (low temperature, relative …

Sediment Transport Model For Seepage Erosion Of Streambank Sediment, G. A. Fox, G. V. Wilson, R. K. Periketi, R. F. Cullum

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

Erosion by lateral, subsurface flow is known to erode streambank sediment in numerous geographical locations; however, the role of seepage erosion on mass failure of streambanks is not well understood. In the absence of an established sediment transport model for seepage erosion, the objectives of this research were to investigate the mechanisms of erosion due to concentrated, lateral subsurface flow and develop an empirical sediment transport model for seepage erosion of noncohesive sediment on near-vertical streambanks. Laboratory experiments were performed using a two-dimensional soil lysimeter of a reconstructed streambank profile packed with three different soil layers to mimic seepage erosion …