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2006

Agricultural Science

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Slides: The Real Biofuel Cycles And The Earth, Biofuels, And Reality, Tad W. Patzek Jun 2006

Slides: The Real Biofuel Cycles And The Earth, Biofuels, And Reality, Tad W. Patzek

Climate Change and the Future of the American West: Exploring the Legal and Policy Dimensions (Summer Conference, June 7-9)

Presenter: Tad W. Patzek, Professor of Petroleum Engineering, University of California at Berkeley, Berkeley, CA

2 pages and 29 slides.

Contains footnotes.


Agenda: Climate Change And The Future Of The American West: Exploring The Legal And Policy Dimensions, University Of Colorado Boulder. Natural Resources Law Center Jun 2006

Agenda: Climate Change And The Future Of The American West: Exploring The Legal And Policy Dimensions, University Of Colorado Boulder. Natural Resources Law Center

Climate Change and the Future of the American West: Exploring the Legal and Policy Dimensions (Summer Conference, June 7-9)

Sponsors: The William and Flora Hewlett Foundation; BP America; Holland & Hart; Patrick, Miller & Krope, P.C.; The Rocky Mountain Mineral Law Foundation, Rocky Mountain Natural Resource Center of the National Wildlife Federation, Western Water Assessment.

Exploring the legal and political dimensions that climate change will bring to the American West will be the focus of the CU-Boulder Natural Resources Law Center's 27th Annual Summer Conference.

Titled "Climate Change and the Future of the American West: Exploring the Legal and Policy Dimensions," the conference will be held June 7-9 at the Fleming Law Building on the University of Colorado at …


Slides: Climate Change & The Ecological Resources Of The West, Chris Field Jun 2006

Slides: Climate Change & The Ecological Resources Of The West, Chris Field

Climate Change and the Future of the American West: Exploring the Legal and Policy Dimensions (Summer Conference, June 7-9)

Presenter: Chris Field, Director, Department of Global Ecology, Carnegie Institution of Washington, DC.

39 slides.

Contains references.


Intsormil Marketing Strategies Increase Farm Income And Promote Technology Introduction In West Africa, Intsormil Jun 2006

Intsormil Marketing Strategies Increase Farm Income And Promote Technology Introduction In West Africa, Intsormil

INTSORMIL Impacts and Bulletins

The World Bank’s 2006 Human Development Report ranks Niger as the world’s second-poorest nation. Most of its 11 million citizens live in semi-arid grasslands and survive on subsistence cultivation of millet, sorghum, and other drought-resistant crops. Producers sell their crops in September and October, the peak months of the harvest season, when local markets can be flooded with grain and prices are low. These farmers often must then purchase additional food supplies in the “hungry months” of June and July when food grains reach much higher prices.

INTSORMIL’s West Africa Marketing-Processing Project, funded by USAID/WARP, is accelerating the adoption of …


Book Review: Agriculture As A Producer And Consumer Of Energy, Wally Wilhelm Jun 2006

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 May 2006

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 …


Intsormil Responds To Emerging Grain Markets In West Africa, Intsormil May 2006

Intsormil Responds To Emerging Grain Markets In West Africa, Intsormil

INTSORMIL Impacts and Bulletins

According to Lloyd Rooney, Distinguished Professor of Food Science at Texas A&M, “A consistent, high quality grain supply is the first prerequisite for the development of the food processing industry in West Africa.” The International Sorghum and Millet (INTSORMIL) Collaborative Research Support Program in West Africa is helping farmers produce a consistent supply of high quality sorghum and millet that meets the requirements of industry.

INTSORMIL’s Marketing-Processing Project, funded by USAID/WARP and directed by Botorou Ouendeba, Nigerien millet breeder and former Coordinator of the West and Central African Millet Research Network is responding to the emerging market demand by promoting …


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 Apr 2006

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 Apr 2006

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 Mar 2006

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 …


Proceedings Of The 33rd Annual Meeting, Southern Soybean Disease Workers (March 8-9, 2006, Jackson, Tennessee), Michael E. Schmidt, Ray Schneider, Daniel H. Poston, Jason Bond, Steve R. Koenning Mar 2006

Proceedings Of The 33rd Annual Meeting, Southern Soybean Disease Workers (March 8-9, 2006, Jackson, Tennessee), Michael E. Schmidt, Ray Schneider, Daniel H. Poston, Jason Bond, Steve R. Koenning

Southern Soybean Disease Workers: Conference Proceedings

Contents

Southern Soybean Disease Workers 2005 treasury report

Southern United States Soybean Disease Loss Estimates for 2005. Compiled by SR Koenning

Virulence in Phytopbthora sojae Isolates to Soybeans with Rps8 Resistance. DA Smith, TS Abney, and JG Shannon

New Sources of Resistance to SCN in Soybean. PR Arelli

Soybean Disease Management in Louisiana. B Padgett, MA Purvis, and BW Garber

Efficacy and Profitability of Foliar Fungicide in the Absence of Soybean Rust. M Newman and W Percell

Fungicide and Insecticide Combinations for Enhancing Soybean Health and Yield. RP Mulrooney and RW Taylor

Overview of Soybean Rust Monitoring in the US. …


Genic Microsatellite Markers Derived From Est Sequences Of Switchgrass (Panicum Virgatum L.), Christian M. Tobias, Daniel M. Hayden, Paul Twigg, Gautam Sarath Feb 2006

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 Feb 2006

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 Feb 2006

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 Feb 2006

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 Jan 2006

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 Jan 2006

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 Jan 2006

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 Jan 2006

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 Jan 2006

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 Jan 2006

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 Jan 2006

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 Jan 2006

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 Jan 2006

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 …


Increasing Co2 From Subambient To Elevated Concentrations Increases Grassland Respiration Per Unit Of Net Carbon Fixation, H. Wayne Polley, Patricia C. Meilnick, William A. Dugas, Hyrum B. Johnson, Joaquin Sanabria Jan 2006

Increasing Co2 From Subambient To Elevated Concentrations Increases Grassland Respiration Per Unit Of Net Carbon Fixation, H. Wayne Polley, Patricia C. Meilnick, William A. Dugas, Hyrum B. Johnson, Joaquin Sanabria

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

Respiration (carbon efflux) by terrestrial ecosystems is a major component of the global carbon (C) cycle, but the response of C efflux to atmospheric CO2 enrichment remains uncertain. Respiration may respond directly to an increase in the availability of C substrates at high CO2, but also may be affected indirectly by a CO2-mediated alteration in the amount by which respiration changes per unit of change in temperature or C uptake (sensitivity of respiration to temperature or C uptake).


Early-Successional Plants Regulate Grassland Productivity And Species Composition: A Removal Experiment, H. Wayne Polley, Brian J. Wilsey, Justin D. Derner, Hyrum B. Johnson, Joaquin Sanabria Jan 2006

Early-Successional Plants Regulate Grassland Productivity And Species Composition: A Removal Experiment, H. Wayne Polley, Brian J. Wilsey, Justin D. Derner, Hyrum B. Johnson, Joaquin Sanabria

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

Grime’s (1998) ‘‘mass-ratio’’ hypothesis holds that ecosystem processes depend in the short term on functional properties of dominant plants and in the longer term on how resident species influence the recruitment of dominants. The latter of these effects may be especially important among early-successional species in disturbed ecosystems, but experimental tests are few. We removed two groups of early-successional species, an annual forb Gutierrezia dracunculoides (DC.) S. F. Blake and annual species (mostly grasses) that complete growth early in the growing season [early-season (ES) species], from a heavily-grazed grassland in central Texas, USA dominated by a C4 perennial grass. …


Effect Of Foliar Applied Plant Elicitors On Microbial And Nematode Populations In The Root Zone Of Potato, H. P. Collins, D. A. Navare, E. Riga, F. J. Pierce Jan 2006

Effect Of Foliar Applied Plant Elicitors On Microbial And Nematode Populations In The Root Zone Of Potato, H. P. Collins, D. A. Navare, E. Riga, F. J. Pierce

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

Systemic acquired resistance (SAR) is a process whereby a plant that successfully
resists a pathogen becomes highly resistant to subsequent infection not only by the original pathogen but also by a wide variety of pathogens. Most SAR research has focused on resistance in leaves, so much less is known about the effectiveness of foliar applications of SAR compounds in the protection of plant roots and associated microorganisms in soil. This study was conducted to determine if foliar SAR-inducing applications (BTH or harpin) negatively impact the potato root system beneficial rhizosphere microbial populations and activity or influence pathogenic nematode populations. Foliar …


Un-Ionized Ammonia Exposure In Nile Tilapia: Toxicity, Stress Response, And Susceptibility To Streptococcus Agalactiae, Joyce J. Evans, David J. Park, Gregg C. Brill, Phillip H. Klesius Jan 2006

Un-Ionized Ammonia Exposure In Nile Tilapia: Toxicity, Stress Response, And Susceptibility To Streptococcus Agalactiae, Joyce J. Evans, David J. Park, Gregg C. Brill, Phillip H. Klesius

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

A series of experiments were conducted to determine the toxicity, behavior, blood glucose stress response, and disease susceptibility in Nile tilapia Oreochromis niloticus following un-ionized ammonia (UIA) exposure. The acute toxicity of un-ionized ammonia to Nile tilapia was measured in a 96-h static test. The median lethal concentration (LC50) was 1.46 mg/L UIA at 24 and 48 h postexposure, 1.33 mg/ L at 72 h postexposure, and 0.98 mg/L at 96 h postexposure. No mortalities were noted in unexposed (0 mg/ L) control fish or fish exposed to 0.5 mg/L UIA. However, 93–100% mortalities were observed within 24 h among …


Temperature Effects On Bradyrhizobium Spp. Growth And Symbiotic Effectiveness With Pigeonpea And Cowpea, Lurline E. Marsh, Raymond Baptiste, Dyremple B. Marsh, David Trinklein, Robert J. Kremer Jan 2006

Temperature Effects On Bradyrhizobium Spp. Growth And Symbiotic Effectiveness With Pigeonpea And Cowpea, Lurline E. Marsh, Raymond Baptiste, Dyremple B. Marsh, David Trinklein, Robert J. Kremer

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

Temperature is a limiting factor on legume-Bradyrhizobium symbiosis of subtropical plants in the temperate region. Twelve strains of Bradyrhizobium spp. that nodulate pigeonpea [Cajanus cajan (L.) Millsp], and cowpea [Vigna unguiculata (L.) Walp], were evaluated for tolerance to three temperature regimes (20 °C/10 °C, 30 °C/20 °C, and 38 °C/25 °C day/night temperature) by determining their growth following exposure to the regimes. The five most temperature-tolerant strains were further evaluated for symbiotic effectiveness with pigeonpea and cowpea under controlled temperatures. These strains were USDA 3278, USDA 3362, USDA 3364, USDA 3458, and USDA 3472. Plant heights of …


Upper Profile Changes Over Time In An Appalachian Hayfield Soil Amended With Coal Combustion By-Products, X. Zhou, K. D. Ritchey, R. B. Clark, N. Persaud, D. P. Belesky Jan 2006

Upper Profile Changes Over Time In An Appalachian Hayfield Soil Amended With Coal Combustion By-Products, X. Zhou, K. D. Ritchey, R. B. Clark, N. Persaud, D. P. Belesky

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

Large amounts of flue gas desulfurization (FGD) and fluidized bed combustion (FBC) by-products from burning coal, consisting primarily of gypsum, are available for potential use as a soil amendment. However, information is limited on longer-term changes in chemical and physical properties induced over time and over small depth increments of the upper soil profile after applying these amendments. This study examined longer-term effects in an abandoned Appalachian pasture soil amended with various liming materials and coal combustion by-products (CCBPs). Soil chemical and physical properties were investigated over time and depths. The results indicated limited dissolution and movement of the calcium …