Agricultural Science Commons^™

Spatial Pattern Of Gas Exchange For Montane Moist Meadow Species, Tony Svejcar, Gregg M. Riegel

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

Montane moist meadows of western North America are relatively unique in that they are characterized by annual cycles of spring inundation followed by summer drought. Thus, plants adapted to these ecosystems must cope with a wide range of environmental conditions. We compared gas exchange and water relations of upper canopy leaves and leaf area index (LAI) of three dominant montane meadow graminoids growing at both streamside and mid-meadow locations (2.5 and 20.0 m, respectively from the stream edge). The two locations were environmentally very different in spite of their close proximity. The water table at the streamside location was ca. …

Yield And Stability Factors Associated With Hybrid Wheat, R. Bruns, C. J. Peterson

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

For hybrid wheat to be accepted in the Great Plains of the USA, hybrids must exhibit enhanced yield performance, yield responsiveness, and reasonable yield stability across a wide array of production environments. Agripro has been researching hybrid wheat since 1981 and has an established pureline release history since 1978. Yield data from 1991 to 1995 were examined to compare the trend performance and selection gains of purelines and hybrids in a large scale parallel development effort. This data set (13,739 points) reveals an average 0.454 t ha^–1 or 10.8% hybrid yield advantage over purelines in preliminary regional testing. Entries …

Physiology And Reproduction: Gross Appearance Of The Turkey Blastoderm At Oviposition, M. R. Bakst, S. K. Gupta, W. Potts, V. Akuffo

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

The blastoderm (fertilized ovum) and unfertilized germinal disc (UGD) of fresh laid eggs and eggs stored prior to incubation exhibit subtle but definable morphological variations. Such variations may lead to difficulty when attempting to determine true flock fertility based on the appearance of the blastoderm/UGD. The objectives of this study were to define and categorize such morphological variations and to determine whether sperm influence the frequency distribution of the different categories. Eleven categories of blastoderms were defined based on the relative density and appearance of the area alba, area pellucida, area opaca, and the periblast. The majority of the blastoderms …

Structure Of The Avian Oviduct With Emphasis On Sperm Storage In Poultry, Murray R. Bakst

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

The macroanatomy, histology, and fine structure of the avian oviduct is reviewed and related to its role in fertile egg production. The avian oviduct functions as a biological assembly line, beginning sequentially with the deposition of the albumen around the fertilized or unfertilized ovum, then the shell membrane, and lastly, the shell, all within 25 hr of ovulation. While in transit through the oviduct, the fertilized ovum progresses to the pre-gastrulation stage of development.

Comparative Gene Mapping: Cytogenetic Localization Of Proc, En1, Alpi, Tnp1, And Il1b In Cattle And Sheep Reveals A Conserved Rearrangement Relative To The Human Genome, N. L. Lòpez-Corrales, T. S. Sonstegard, T. P. L. Smith

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

The cytogenetic locations of the genes for protein C (PROC), transition protein 1 (TNP1), intestinal alkaline phosphatase (ALPI), engrailed (EN1), and human protointerleukin ß (IL1B) have been compared between cattle (Bos taurus, BTA) and sheep (Ovis aries, OAR). Bovine YAC and cosmid clones were used as FISH probes to determine the order (centromere to telomere) of four of these genes on OAR 2q, as well as the location of IL1B on OAR 3p. In cattle, IL1B and EN1 were assigned to BTA 11 and BTA 2, respectively. Alignment of the ovine, bovine, and human physical maps …

Biological Control: An Important Component In Integrated Management Of Musca Domestica (Diptera: Muscidae) In Caged-Layer Poultry Houses In Buenos Aires, Argentina, Diana C. Crespo, Roberto E. Lecuona, Jerome A. Hogsette

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

An Integrated Management program to control Musca domestica L. was developed by evaluating cultural + chemical control, cultural + biological control + granular bait (IMP 1), and cultural + chemical + biological control + granular bait (IMP 2) in poultry houses in Argentina. Adult fly density was estimated by a modified Scudder-grid method. Percentage of house fly parasitism was estimated by direct and indirect methods. Spalangia endius Walker and Muscidifurax raptor Girault & Sanders were released at a rate of 10 parasitoids/hen/week. Complete absence of control practices allowed a sustained growth of the fly population. When larvicides and adulticides were …

Purification And Characterization Of Intrauterine Folate-Binding Proteins From Swine, J.L. Vallet, R.K. Christenson, H.G. Klemcke

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

Folate-binding proteins (FBP) from Day 60 pseudopregnant uterine flushings and Day 60 allantoic fluid were purified by affinity chromatography on folate-Sepharose followed by G–100 Sephadex chromatography. FBP from uterine flushings had a molecular weight of 20 000; the N-terminal sequence was FNWDHXGKMEPAXKRHFXXXTXLYX, which is 72% identical to bovine milk FBP beginning at amino acid 64. Allantoic fluid FBP had a molecular weight of 30 000; and the N-terminal sequence ARAKTDMLNVXMDAKHHKPKPSXED, which is 68% identical to bovine milk FBP starting at amino acid 4. Scatchard analysis of purified allantoic fluid FBP using [³H]folic acid as ligand indicated a dissociation …

Plant Hemoglobins, Raul Arrendondo-Peter, Mark S. Hargrove, Jose F. Moran, Gautam Sarath, Robert V. Klucas

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

Hbs are ubiquitous proteins in most organisms, including bacteria, protozoans, fungi, plants, and animals (Vinogradov et al., 1993; Bolognesi et al., 1997). The known and predicted roles of Hbs in each organism encompass functions that include the reversible binding of gaseous ligands and the ability to bind other cellular molecules.

Selective And Organotypic Culture Of Intrahepatic Bile Duct Cells From Adult Pig Liver, Neil C. Talbot, Thomas J. Caperna

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

Secondary culture of nontransformed bile duct epithelium has been difficult to achieve. STO feeder cell-dependent secondary cultures of adult pig bile duct cells were established from primary cultures of adult pig liver cells. Adult pig hepatocytes exhibited limited or no replication and were lost from the secondary culture at Passage 3 or 4. In contrast, adult pig bile duct cells replicated and were carried for 4-8 passages in secondary culture. A simple method to produce nearly pure pig intrahepatic bile duct cultures was first to freeze a relatively crude liver cell preparation. Upon subsequent thawing, all hepatocytes and most macrophages …

Growth Traits Among Sorghum Genotypes In Response To Aluminum, J. H. Bernal, R. B. Clark

Department of Agronomy and Horticulture: Faculty Publications

Aluminum (Al) has many detrimental effects on plant growth, and shoots and roots are normally affected differently. A study was conducted to determine differences among sorghum [Sorghum bicolor (L.) Moench] genotypes with broad genetic backgrounds for growth traits of plants grown at 0,200,400,600, and 800 uM Al in nutrient solutions (pH 4.0). Genotypes were categorized into "Al-sensitive", "intermediate Al-tolerant", "Al-tolerant", and SC 283 (an Al-tolerant standard). As Al increased, shoot and root dry matter (DM), net main axis root length (NMARL), and total root length (TRL) became lower than controls (0 Al). Aluminum toxicity and/or nutrient deficiency symptoms become …

Atrazine, Deethylatrazine, And Deisopropylatrazine Persistence Measured In Groundwater In Situ Under Low-Oxygen Conditions, Sharon Papiernik, Roy Spalding

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

The degradation of atrazine [2-chloro-4-(ethylamino)-6-isopropylamino-1,3,5-triazine], deethylatrazine [DEA; 2-amino-4-chloro-6-(isopropylamino)-1,3,5-triazine], and deisopropylatrazine [DIA; 2-amino-4-chloro-6-(ethylamino)-1,3,5-triazine] was assessed under limited oxygen conditions using in situ microcosms. Denitrification was induced in a shallow sand and gravel aquifer to measure the potential for degradation of atrazine, DEA, and DIA under low-O2 conditions. The dissolved oxygen content decreased from 7-8 mg/L to ≤1 mg/L within 4 days and remained ≤ mg/L for the remainder of the 45-day experiment. Atrazine, DEA, and DIA concentrations (normalized to the bromide concentration at each sampling time to account for dilution) did not show a significant decrease with time, indicating that these …

Silvopasture: An Agroforestry Practice, Ned B. Klopfenstein, W. J. Rietveld, Richard C. Carman, Terry R. Clason, Steven H. Sharrow, Gene Garrett, Bruce Anderson

Agroforestry Notes (USDA-NAC)

Although some form of silvopasture management has been practiced for centuries, silvopasture as an agroforestry practice is specifically designed and managed for the production of trees, tree products, forage, and livestock. Silvopasture results when forage crops are deliberately introduced or enhanced in a timber production system, or timber crops are deliberately introduced or enhanced in a forage production system. As a silvopasture, timber and pasture are managed as a single integrated system.

Silvopastoral systems are designed to produce a high-value timber component, while providing short-term cash flow from the livestock component. The interactions among timber, forage, and livestock are managed …

Forest Farming: An Agroforestry Practice, Mary Ellen Dix, Deborah B. Hill, Louise E. Buck, W. J. Rietveld

Agroforestry Notes (USDA-NAC)

Most public and private forest lands of North America have been modified to varying degrees from years of human activity. Certain high-value ‘non-timber forest products’ have been over-exploited and are difficult to find. Forest farming practices can be used by private enterprise to grow desirable non-timber forest products on private lands, to supplement family income, and to allow biodiversity to reestablish within forests.

Biología Silvopastoril, Steven H. Sharrow

Agroforestry Notes (USDA-NAC)

La producción forestal y la ganadería son dos usos de tierras comunes en muchos lugares del mundo que no tienen riego. El pastoreo forestal es una práctica tradicional en la mayor parte de América del Norte. Aproximadamente 25% del total de las tierras de los EE. UU., son pastoreadas. Los bosques jovenes y los bosques maduros con una copa o dosel poco denso, pueden proveer una cantidad considerable de forraje al ganado. Un itinerario de pastoreo hará más beneficioso el uso de la vegetación que crece bajo la copa de los árboles. De no ser así la vegetación competirá con …

The Biology Of Silvopastoralism, Steven H. Sharrow

Agroforestry Notes (USDA-NAC)

Forestry and livestock grazing are common competing uses for non-irrigated lands around the world. Forest grazing is a traditional practice in most of North America. Approximately 25 percent of all US forest land is grazed by livestock. Young forests and mature open-canopied forests can provide considerable amounts of forage for livestock. Prescription grazing makes beneficial use of ground vegetation that would otherwise compete with trees for soil moisture and nutrients, harbor gnawing rodents, and pose a fire hazard. Pasture grasses and legumes are sometimes seeded into newly harvested forest areas to reduce erosion, to provide high-quality food for deer and …

Growing Degree-Days: One Equation, Two Interpretations, Gregory S. Mcmaster, Wallace Wilhelm

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

Heat units, expressed in growing degree-days (GDD), are frequently used to describe the timing of biological processes. The basic equation used is GDD = [(T_MAX + T_MIN)/2] - T_BASE where T_MAX and T_MIN are daily maximum and minimum air temperature, respectively, and T_BASE is the base temperature. Two methods of interpreting this equation for calculating GDD are: (1) if the daily mean temperature is less than the base, it is set equal to the base temperature, or (2) if T_MAX or T_MIN < T_BASE they are reset equal to T …

Conservation Compliance Credit For Winter Wheat Fall Biomass Production And Implications For Grain Yield, Gregory S. Mcmaster, Wallace Wilhelm

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

Producers participating in federal farm and conservation programs must reduce potential erodibility below certain thresholds on lands classified as highly erodible. The Natural Resource Conservation Service (NRCS) will credit producer s in Colorado for the quantity of green winter wheat (Triticum aestivum L.) biomass at the beginning of the winter period towards compliance in reducing erosion. Unfortunately, few data exist on fall winter wheat biomass production and fall production varies widely based on many site-specific factors at planting and during the fall, and can be expensive to document. To address these problems, a crop simulation model called SHOOTGRO …

Proceedings Of The Global Conference On Ergot Of Sorghum, Carlos R. Casela, Jeffery A. Dahlberg

INTSORMIL Impacts and Bulletins

In June 1996, several of us had the opportunity to see sorghum ergot in Brazil and the damage that the disease can do. We saw severe damage in seed production plots and witnessed the pain that seed producers had to go through to deal with this new problem. There was a wide spread scare in the sorghum community in the Americas because of the infamous reputation of the disease in causing damage in seed production fields. As a silver lining, we also observed first hand, the excellent research program that the Brazilians had in place. It became apparent that all …

Pathogenicity Of Escherichia Coli O157:H7 In The Intestines Of Neonatal Calves, Evelyn A. Dean-Nystrom, Brad T. Bosworth, William C. Cray Jr., Harley W. Moon

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

Cattle are an important reservoir of Shiga toxin-producing enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains, foodborne pathogens that cause hemorrhagic colitis and hemolytic uremic syndrome in humans. EHEC O157:H7 strains are not pathogenic in calves >3 weeks old. Our objective was to determine if EHEC O157:H7 strains are pathogenic in neonatal calves. Calves(A/E) lesions in both the large and small intestines by 18 h postinoculation. The severity of diarrhea and inflammation, and also the frequency and extent of A/E lesions, increased by 3 days postinoculation. We conclude that EHEC O157:H7 strains are pathogenic in neonatal calves. The neonatal calf model is …

Proceedings Of The 24th Annual Meeting, Southern Soybean Disease Workers (March 15-16, 1997, Fort Walton Beach, Florida), Robert P. Mulrooney, Gabe Sciumbato, Steve Koenning, John Russin, Glenn G. Hammes

Southern Soybean Disease Workers: Conference Proceedings

Contents

Business session

Soybean Disease Loss Estimate for the Southern United States during 1996. Compiled by PW Pratt

Treasurer report. GG Hammes

SSDW Committee chairmen for 1996-1997

Graduate student papers

Characterization of Races of Phytophthora sojae in Arkansas and Their Effects on Commonly Grown Cultivars. TA Jackson, TL Kirkpatrick, and JC Rupe

Induction of Defense Related Proteins During Compatible and Incompatible Soybean-Cercospora sojina Interactions. WA Baker, J Qiu, CB Lawrence, S Tuzun, and DB Weaver

Contributed papers

Performance and Cyst Nematode Resistance of Selected Soybean Cultivars in North Carolina Production Fields. SR Koenning and KR Barker

Distribution and Diversity …

Riparian Buffers For Agricultural Land, Michael Dosskey, Richard C. Schultz, Thomas M. Isenhart

Agroforestry Notes (USDA-NAC)

Purpose:

• Define what a riparian buffer is

• Describe what benefits a riparian buffer can provide in an agricultural landscape

• Identify situations where installing a riparian buffer should be considered

How To Design A Riparian Buffer For Agricultural Land, Michael Dosskey, Dick Schultz, Tom Isenhart

Agroforestry Notes (USDA-NAC)

Purpose: Identify four basic steps to follow when designing a riparian buffer.

A Riparian Buffer Design For Cropland, Michael Dosskey, Dick Schultz, Tom Isenhart

Agroforestry Notes (USDA-NAC)

Purpose:

• Present a general, multi-purpose, riparian buffer design suitable for most cropland situations

• Provide some guidelines for adjusting this general design to better fit site-specific conditions or landowner needs

Molecular And Functional Characterization Of A Novel Low-Affinity Cation Transporter (Lct1) In Higher Plants, Daniel P. Schachtman, Raman Kumar, Julian I. Schroeder, Ellen L. Marsh

Department of Agronomy and Horticulture: Faculty Publications

The transport of cations across membranes in higher plants plays an essential role in many physiological processes including mineral nutrition, cell expansion, and the transduction of environmental signals. In higher plants the coordinated expression of transport mechanisms is essential for specialized cellular processes and for adaptation to variable environmental conditions. To understand the molecular basis of cation transport in plant roots, a Triticum aestivum cDNA library was used to complement a yeast mutant deficient in potassium (K⁺) uptake. Two genes were cloned that complemented the mutant: HKT1 and a novel cDNA described in this report encoding a cation …

Comparative Development Of The Turkey And Chicken Embryo From Cleavage Through Hypoblast Formation, M. R. Bakst, S. K. Gupta, V. Akuffo

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

The development of the turkey and chicken embryo from the first cleavage division through hypoblast formation is described. The early development of the chicken embryo has been categorized into 14 stages. A similar staging sequence for the turkey was not proposed until 1993, when we described the early development of the turkey embryo, which was divided into 11 stages. Comparatively, differences in the temporal and spatial development of the turkey and chicken blastoderm were evident. Of significance is the observation that at oviposition the turkey is in Stage VII and characterized by the first signs of area pellucida formation. In …

Effects On White Leghorn Hens Of Constant Exposure To Ultraviolet Light From Insect Traps, Jerome Hogsette, Henry Wilson, Susan Semple-Rowland

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

Constant exposure of Hy-Line^® W-36 White Leghorn hens to ultraviolet light from insect traps resulted in no significant differences in egg production, fertility, hatchability of fertile eggs, or total hatchability. Also, there were no apparent effects on the eyes of the birds. Results were the same when either blacklight or blacklight blue tubes were used. The need for additional testing of light traps for nuisance fly control in commercial caged layer houses is discussed.

In Situ Infrared Speciation Of Adsorbed Carbonate On Aluminum And Iron Oxides, Chunming Su, Donald L. Suarez

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

Surface adsorption mechanisms of dissolved inorganic carbon species on soil minerals are not well understood. Traditional infrared (IR) study of adsorbed species of inorganic carbon using air-dried samples may not reveal true species in the solid/water interface in suspension. The purpose of this study was to obtain information on interracial carbonate speciation between solid and aqueous phases. The interaction of bicarbonate and carbonate ions with X-ray amorphous (am) A1 and Fe oxides, gibbsite (y-Al(OH)₃ ) and goethite ( α-FeOOH) was examined by electrophoresis and in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The presence of …

Selenium Speciation Of Soil/ Sediment Determined With Sequential Extractions And Hydride Generation Atomic Absorption Spectrophotometry, Dean A. Martens, Donald L. Suarez

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

Understanding the speciation of the multioxidation states of selenium is vital to predicting the mineralization, mobilization, and toxicity of the trace element in natural systems. Asequential extraction scheme (SES) was developed for identification of Se oxidation states that first employed 0.1 M (pH 7.0) K₂HPO₄-KH₂PO₄ (P-buffer) to release soluble selenate (Se^+VI) and selenide (Se^-II) and ligand-exchangeable selenite (Se^+IV). The second step involved oxidation of organic materials with 0.1 M K₂S₂O₈ (90 °C) to release Se^-II and Se^+IV associated or occluded …

Soil Temperature And Fumigation Effects On Plant Phosphorus Uptake And Related Microbial Properties, Dennis L. Mccallister, L. A. Jawson, M. D. Jawson

Department of Agronomy and Horticulture: Faculty Publications

Early season problems with growth of corn (Zea mays L.) under cool, wet conditions prompted a study of the effects of soil and environmental conditions on mineralization and plant uptake of phosphorus (P). Our objective was to determine the effect of soil test P, temperature, and soil fumigation on soil P availability and uptake during early corn growth. Corn was grown in growth chambers at temperatures of 14°C or 25°C. Soils were a high-P Hastings silty clay loam (fine, montmorillonitic, mesic Udic Argiustoll) and a low-P Sharpsburg clay loam (fine, montmorillonitic, mesic Typic Argiudoll). Plants grew for up to …

Notes: Forage Yield, Quality, And Fertility Of Sorghum X Sudan Grass Hybrids In A1 And A3 Cytoplasm, Jeffrey F. Pedersen, J. J. Toy

Department of Agronomy and Horticulture: Faculty Publications

Currently, no information is available comparing the agronomic performance of A1 and A3 cytoplasms in sorghum x sudangrass [Sorghumbi color (L.) Moench] hybrids. The objectives of this study were to compare the effects of A1 and A3 cytoplasm on the maturity, fertility, height, forage yield, and forage quality of sorghum × sudangrass hybrids. In 1989, pollen from a bulk of eight sudangrass populations was used to pollinate four sorghum lines that had been male-sterilized in both A1 and A3 cytoplasm. Hybrids were grown at the Univ. of Nebraska Field Laboratory Ithaca, NE, in 1990 and 1991, in a split-plot …