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Fractal Description Of Soil Fragmentation For Various Tillage Methods And Crop Sequences, Bahman Eghball, Lloyd N. Mielke, Guillermo A. Calvo, Wallace Wilhelm

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

Soil structure has been difficult to quantify and, at best, has been studied semiquantitatively. Fractal representation of soil fragmentation can provide an indication of soil structure. The purpose of our study was to use fractal analysis to quantify soil fragmentation under various tillage and crop sequence treatments at different times during the growing season. We collected soil samples from four tillage treatments (established 10 yr earlier) of chisel, disk, no-till, and moldboard plow in factorial arrangement with two crop sequences of corn (Zea mays L.)-soybean [Glycine max (L.) Merr.]-corn (C-SC), and soybean- cornaoybean, (S-C-S) on a Sharpsburg (fine, …

Nebline, October 1993

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

On-the-Grow: Horticulture News

Ag Update: Agricultural News & Events

Food, Families, and Finance

The Cloverline: 4-H News & Events

Extension Calendar

Expanded Food and Nutrition Education Program (EFNEP)

Nebraska Association for Family and Community Education News

and other extension news and events

Weed Awareness Special Edition

Effect Of Organic Matter Decomposition Level On Bacterial Species Diversity And Composition In Relationship To Pythium Damping-Off Severity, Michael J. Boehm, L.V. Mdden, H.A.J. Hoitink

Department of Plant Pathology: Faculty Publications

Rhizosphere bacteria were isolated from root tip segments of cucumber seedlings grown in a suppressive, slightly decomposed light-colored peat mix, a conducive, more decomposed dark-colored peat mix, and a suppressive dark peat mix amended with composted hardwood bark. The bacteria were identified by a gas chromatographic fatty acid methyl ester analysis. The total number of taxa recovered from a single root tip segment ranged from 9 to 18. No single taxon predominated on all root tip segments harvested from any of the mixes. The highest relative population density reached by a given taxon on any root tip segment was 45%. …

The Prairie Naturalist Volume 25, No. 3 September 1993

The Prairie Naturalist

Paul B. Kannowski, Editor

Nikki R. Seabloom, Assistant Editor

Douglas H. Johnson, Book Review Editor

CONTENTS

AVAILABILITY OF EARTHWORMS AND SCARAB BEETLES TO SANDHILL CRANES IN NATIVE GRASSLANDS ALONG THE PLATTE RIVER ▪ C. A. Davis and P. A. Vohs

BLACK TERN COLONIZATION OF A RESTORED PRAIRIE WETLAND IN NORTHWESTERN MINNESOTA ▪ D. J. Delehanty and W. D. Svedarsky

MOUNTAIN PLOVER HABITAT SELECTION IN THE POWDER RIVER BASIN, WYOMING ▪ T. L. Parrish, S. R. Anderson, and W. F. Oelklaus

POST-HATCH BROOD AMALGAMATION IN LESSER SCAUP: FEMALE BEHAVIOR AND RETURN RATES AND DUCKLING SURVIVAL ▪ A. D. Afton

STATUS AND …

Proceedings Of The Workshop On Adaptation Of Plants To Soil Stresses, J.W. Maranville, V.C. Baligar, R.R. Duncan, J. M. Yohe

INTSORMIL Impacts and Bulletins

Sustainable production of food and forage with a focus on plant adaptation to stress environments will be a continued priority for developing countries in the future. Since many areas of the world which support substantial human populations are drought prone, such as the subsaharan African zone and others, the primary focus has been on drought. However, one of the greatest restraints to sustainability of agriculture worldwide is the lack of sufficient soil nutrients for crop growth, or other soil constraints such as acidity or salinity which hinder crop production substantially.

Optimizing soil fertility or amending acid and saline soils to …

Nebline, July 1993

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

On-the-Grow: Horticulture News

Ag Update: Agricultural News & Events

Food, Families, and Finance

The Cloverline: 4-H News & Events Extension Calendar

Expanded Food and Nutrition Education Program (EFNEP)

Home Extension Club News

and other extension news and events

On The Relative Importance Of Floral Color, Shape, And Nectar Rewards In Attracting Pollinators To Mimulus, Steven D. Sutherland, Robert K. Vickery Jr.

Great Basin Naturalist

Pollinator preferences were observed for the six species of section Erythranthe of the genus Mimulus using greenhouse-grown plants placed in a meadow in the Red Butte Canyon Natural Area, Salt Lake County, Utah. The principal pollinators were hummingbirds and bumble bees. Hummingbirds preferred the species with the most reflexed tubular flowers regardless of color, whereas bumblebees preferred pink. lavender, or yellow flowers to red flowers regardless of shape. Results for the six species were confirmed by observations of F₂ hybrid recombinant plants selected such that flower color could be held constant and flower shape varied and vice versa.

The Prairie Naturalist Volume 25. No. 2. June 1993

The Prairie Naturalist

Paul B. Kannowski, Editor

Nikki R. Seabloom, Assistant Editor

Douglas H. Johnson, Book Review Editor

CONTENTS

RAPID GROWTH OF CHANNEL CATFISH IN FLAMING GORGE RESERVOIR, WYOMING ▪ C. B. Alexander and W. A. Hubert

MANAGEMENT EVALUATION OF BODY CONDITION AND POPULATION SIZE STRUCTURE FOR PADDLEFISH: A UNIQUE CASE ▪ M L. Brown and B. R. Murphy

DISTRIBUTION OF THE RIBBON LEECH IN NORTH DAKOTA ▪ C. M. Pennuto and M. G. Butler

SELENIUM IN EARED GREBE EMBRYOS FROM STEWART LAKE NATIONAL WILDLIFE REFUGE, NORTH DAKOTA ▪ M. M. Olson and D. Welsh

USING GEOGRAPHIC VARIATION TO PREDICT BREEDING LOCALES OF …

Nebline, June 1993

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

On-the-Grow: Horticulture News

Ag Update: Agricultural News & Events

Food, Families, and Finance

The Cloverline: 4-H News & Events

Extension Calendar

Expanded Food and Nutrition Education Program (EFNEP)

Home Extension Club News

and other extension news and events

The Polymerase Chain Reaction And Plant Disease Diagnosis, Joan M. Henson, Roy C. French

Department of Plant Pathology: Faculty Publications

The polymerase chain reaction (PCR) provides a simple, ingenious method to exponentially amplify specific DNA sequences by in vitro DNA synthesis. Three essential steps to PCR (Figure 1) include (a) melting of the target (b) annealing of two oligonucleotide primers to the denatured DNA strands, and (c) primer extension by a thermostable DNA polymerase (123). Newly synthesized DNA strands serve as targets for subsequent DNA synthesis as the three steps are repeated up to 50 times. The specificity of the method derives from the synthetic oligonucleotide primers, which base-pair to and define each end of the target sequence to be …

Arkansas Rice Research Studies 1992, B. R. Wells

Arkansas Agricultural Experiment Station Research Series

The research reports in this publication represent one year of results; therefore, these results should not be used as a basis for longterm recommendations. Several research reports in this publication dealing with soil fertility also appear in Arkansas Soil Fertility Studies 1992, Arkansas Agricultural Experiment Station Research Series 425. This duplication is the result of the overlap in research coverage between the two series and our effort to inform Arkansas rice producers of all the research being conducted with funds from the rice check-off.

Leptospira Genomes Are Modified At 5'-Gtac, David Ralph, Quideng Que, James L. Van Etten, Michael Mcclelland

Department of Plant Pathology: Faculty Publications

Genomic DNAs of 14 strains from seven species of the spirochete Leptospira were resistant to cleavage by the restriction endonuclease RsaI 1 (5'-GTAC). A modified base comigrating with m⁴C was detected by chromatography. Genomic DNAs from other spirochetes, Borrelia group VS461, and Serpulina strains were not resistant to h a 1 digestion. Modification at 5'-GTAm⁴C may occur in most or all strains of all species of Leptospira but not in all genera of spirochetes. Genus-wide DNA modification has rarely been observed in bacteria.

Dna Strand-Transfer Activity In Pea (Pisum Sativum L.) Chloroplasts, Heriberto D. Cerutti, A. T. Jagendorf

Center for Plant Science Innovation: Faculty Publications

The occurrence of DNA recombination in plastids of higher plants is well documented. However, little is known at the enzymic level. To begin dissecting the biochemical mechanism(s) involved we focused on a key step: strand transfer between homologous parental DNAs. We detected a RecA-like strand transfer activity in stromal extracts from pea (Pisum sativum L.) chloroplasts. Formation of joint molecules requires Mg2+, ATP, and homologous substrates. This activity is inhibited by excess single-stranded DNA (ssDNA), suggesting a necessary stoichiometric relation between enzyme and ssDNA. In a novel assay with Triton X-100-permeabilized chloroplasts, we also detected strand invasion of the …

Treatment Of Pea (Pisum Sativum L.) Protoplasts With Dna-Damaging Agents Induces A 39-Kilodalton Chloroplast Protein Immunologically Related To Escherichia Coli Reca, Heriberto D. Cerutti, H. Z. Ibrahim, A. T. Jagendorf

Center for Plant Science Innovation: Faculty Publications

Organisms must have efficient mechanisms of DNA repair and recombination to prevent alterations in their genetic information due to DNA damage. There is evidence for DNA repair and recombination in plastids of higher plants, although very little is known at the biochemical level. Many chloroplast proteins are of eubacterial ancestry, suggesting that the same could be true for the components of a DNA repair and recombination system. A 39-kD protein, immunologically related to Escherichia coli RecA, is present in chloroplasts of pea (Pisum sativum L.). Bandshift gel assays suggest that it binds single-stranded DNA. Its steady-state level is increased …

Molecular Basis Of The Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Activase Mutation In Arabidopsis Thaliana Is A Guanine-To-Adenine Transition At The 5'-Splice Junction Of Intron 3, Beverly M. Orozco, C Robertson Mcclung, Jeffrey M. Werneke, William L. Ogren

Dartmouth Scholarship

Analysis of the ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase gene and gene products from Arabidopsis thaliana wild-type plants and the Rubisco activase-deficient mutant strain showed that the rca mutation caused GT to be changed to AT at the 5[prime]-splice junction of intron 3 in the six-intron pre-mRNA. Northern blot analysis, genomic and cDNA sequencing, and primer extension analysis indicated that the mutation causes inefficient and incomplete splicing of the pre-mRNA, resulting in the accumulation of three aberrant mRNAs. One mutant mRNA was identical with wild-type mRNA except that it included intron 3, a second mRNA comprised intron 3 and exons 4 through …

Nebline, May 1993

NEBLINE Newsletter Archive from Nebraska Extension in Lancaster County

On-the-Grow: Horticulture News

Ag Update: Agricultural News & Events

Food, Families, and Finance

The Cloverline: 4-H News & Events

Extension Calendar

Expanded Food and Nutrition Education Program (EFNEP)

Home Extension Club News

and other extension news and events

Evidence For Virus-Encoded Glycosylation Specificity, Ing-Nang Wang, Yu Li, Quideng Que, Meenakshi Bhattacharya, Leslie C. Lane, William G. Chaney, James L. Van Etten

Department of Plant Pathology: Faculty Publications

Four spontaneously derived serologically distinct classes of mutants of the Paramecium bursaria chlorella virus (PBCV-1) were isolated using polydonal antiserum prepared against either intact PBCV-1 or PBCV-1-derived serotypes. The oligosaccharide(s) of the viral major capsid protein and two minor glycoproteins determined virus serological specificity. Normally, viral glycoproteins arise from host-specific glycosylation of viral proteins; the glycan portion can be altered only by growing the virus on another host or by mutations in glycosylation sites of the viral protein. Neither mechanism explains the changes in the glycan(s) of the PBCV-1 major capsid protein because all of the viruses were grown in …

Influence Of Microphytic Crusts On Selected Soil Physical And Hydrologic Properties In The Hartnet Draw, Capitol Reef National Park, Utah., John Dana Williams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Microphytic crust influences on selected physical and hydrologic soil properties were examined at one location in Capitol Reef National Park, Utah. Designed experiments were conducted in a sandy loam soil where microphytic crusts were present without the concomitant development of confounding physical or chemical soil conditions. Three treatments were used for all experiments: control, chemically killed (microphytes killed but left in place), and scalped (microphytic crusts mechanically removed).

A portable wind tunnel was used to deter-nine if microphytic crusts contribute to soil stability and reduce the erosive effect of wind. Significantly lower threshold friction velocity and greater wind-entrained material were …

Competitive Interaction Between Crested Wheatgrasses And Cheatgrass, Mark G. Francis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Current revegetation practices in the lntermountain West include the use of Nordan (Agropyron desertorum) and Hycrest (A. cristatum x desertorum) crested wheatgrass on rangeland susceptible to cheatgrass (Bromus tectorum) invasion, although little quantitative data exists that compares their competitive abilities. We evaluated both the competitive ability of Hycrest and Nordan in two-species mixtures with cheatgrass, and evaluated seedling establishment characteristics for all three species in a greenhouse study. Linear and nonlinear models were developed for a range of densities for each species to predict median above-ground biomass and tiller numbers. In both experiments, increasing …

Effect Of Salinity (Nacl) On Germination, Growth, Ion Accumulation, And Protein Synthesis In Alfalfa (Medicago Sativa L.), Thamir S. Al-Niemi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

To study the effect of NaCl stress on gene expression in alfalfa (Medicago sativa L.), greenhouse and laboratory experiments were conducted with 22 cultivars during germination and post-germination growth. The ability of alfalfa cultivars to germinate at the different NaCl concentrations was not related to their postgermination performance (salt tolerance) under those conditions.

Genetic effects were evident for Na and Cl ion uptake and accumulation in alfalfa shoots and roots. The strategies of alfalfa cultivars to cope with NaCl stress includes exclusion of Na from shoots and Cl from roots or from the whole plant depending on cultivar and …

The Role Of The Seed Coat In The After-Ripening Process Of American Pokeweed (Phytolacca Americana L.), Jason E. Cox

Honors Theses

As plants evolve into new forms and shapes, the reproductive structures are often the last to change because of the importance of successful reproductive organs to the survival of the plant's hereditary information. Because of this particular feature, one very common method of determining how advanced a species is evolutionarily is the study of its reproductive cycle (Gifford and Foster, 1989). A few advanced classes, most notably the general class groupings of the Gymnosperms and Angiosperms, have developed seeds as a part of their reproductive cycle. Normally, there are several stages through which the seed must go in order for …

Population Dynamics In Response To Fire In Quercus Laevis - Pinus Palustris Barrens And Related Communities In Southeast Virginia, Allen E. Plocher

Biological Sciences Theses & Dissertations

Permanent plots in the Zuni Pine Barrens (Isle of Wight Co., Virginia) were sampled in order to: quantify plant population dynamics in response to fire, compare these dynamics among different moisture regimes, compare the effect of mechanical understory removal to that of fire on tree seedling and herbaceous dynamics, and determine the effect of dense lichen (Cladonia spp.) coverage on pine seedling establishment and survival. Fire resulted in 40% aboveground mortality in the overstory, 80% in the sapling/large shrub layer, and nearly 100% in the understory, followed by a 3.3 to 10.6 fold increase in understory density. Regeneration …

Porphyrin Accumulation And Export By Isolated Barley (Hordeum Vulgare) Plastids (Effect Of Diphenyl Ether Herbicides), Judith M. Jacobs, Nicholas J. Jacobs

Dartmouth Scholarship

We have investigated the formation of porphyrin intermediates by isolated barley (Hordeum vulgare) plastids incubated for 40 min with the porphyrin precursor 5-aminolevulinate and in the presence and absence of a diphenylether herbicide that blocks protoporphyrinogen oxidase, the enzyme in chlorophyll and heme synthesis that oxidizes protoporphyrinogen IX to protoporphyrin IX. In the absence of herbicide, about 50% of the protoporphyrin IX formed was found in the extraplastidic medium, which was separated from intact plastids by centrifugation at the end of the incubation period. In contrast, uroporphyrinogen, an earlier intermediate, and magnesium protoporphyrin IX, a later intermediate, were located mainly …

The Vascular Flora Of Spangler Farm, Julie A. Vannerson

Honors Theses

During a ten-month period in 1992, vascular plants were collected at Spangler far, in the city of Chattanooga,TN. The specimens were colelcted from various habitats ranging from ponds bed to dry, rocky areas. Of the 379 specimens collected, 70 families, 182 genera, and 267 species were identified. Several range extensions and non-native species occur. Observations were made from information collected concerning the distribution and origin of introduced species occuring on the farm. Spangler Farm is the property of the city of Chattanooga. As a city park, the area is preserved for the enjoyment and use of the community. The purpose …

Proceedings Of The 20th Annual Meeting, Southern Soybean Disease Workers (March 28-30, 1993, Fort Walton Beach, Florida), Patrick D. Colyer, Glenn R. Bowers Jr., John C. Rupe, Brian M. Anderson, Glenn G. Hammes

Southern Soybean Disease Workers: Conference Proceedings

Contents

Sustainable agriculture symposium

Sustainable Agriculture and the Soybean Industry: Building a Winning Strategy. D Hubbard and MS Fitzner

Impact of Pest Interactions on Management Programs. J Funderburke

Introducing Procedures of Sustainable Agriculture, a Team Approach. J Bradley

Sustainable Agriculture Practices and Their Impact on Plant Diseases. C Rothrock

Graduate student competition

Effect of Increasing Initial Inoculum Levels of Rotylenchus reiformis on Soybean. JJ Cornelius and GW Lawrence

Effect of Frogeye Leaf Spot on Yield of Soybean Lines Near-Isogeneic for Resistance. PF Pace, DB Weaver, LD Flopper, and PA Backman

Heritability and Genotype X Environment Interaction of Partial Resistance to …

Comparison Of The Phosphate Requirements Of Burr Medic And Yellow Serradella With That Of Wheat In The Low Rainfall Wheatbelt Of Western Australia, Blakely Paynter, Mike D. Bolland

Grain and Other Field Crops Research Articles

The responses of burr medic (Medicago polymorpha) and yellow serradella (Ornithopus compressus) to topdressed phosphate were compared with the response of wheat (Triticum aestivum) to drilled phosphate on a range of soils in the low rainfall wheatbelt of Western Australia. Species were compared firstly on the amount of applied phosphorus (P) required for 90% maximum yield at 3 harvests, and secondly on the ratio of their curvature coefficients from the Mitscherlich relationship between absolute yield and P applied. On 7 marginally acidic, medium-textured soils, the comparative requirements of burr medic (cvv. Serena or Santiago) and wheat (cv. Gutha) for applied …

The Prairie Naturalist Volume 25. No. 1. March 1993

The Prairie Naturalist

Paul B. Kannowski, Editor

Nikki R. Seabloom, Assistant Editor

Douglas H. Johnson, Book Review Editor

CONTENTS

FACTORS AFFECTING BIRD COLONIZATION OF RESTORED WETLANDS ▪ L. M. Hemesath and J. J. Dinsmore

RESPONSE OF DABBLING DUCKS TO EARLY-SPRING PARTIAL DRAWDOWN ON LAKE ERIE MARSHES ▪ T. Z. Riley and T. A. Bookhout

OVER-WATER NESTING BY DUCKS IN NORTHEASTERN SOUTH DAKOTA ▪ . K. L. Solberg and K. F. Higgins

ADDITIONAL MOUNTAIN PLOVER SIGHTINGS IN MONTANA ▪ D. M. Prellwitz

SMALL MAMMALS OF WOODED HABITATS OF THE KONZA PRAIRIE RESEARCH NATURAL AREA, KANSAS ▪ D. W. Kaufman, G. A. Kaufman, and E. …

Life History And Description Of Immature Stages Of Procecidochares Stonei Blanc & Foote On Viguiera Spp. In Southern California (Diptera: Tephritidae), John F. Green, David H. Headrick, Richard D. Goeden

Horticulture and Crop Science

Procecidochares stonei Blanc & Foote is a facultatively multivoltine, stenophagous, gall-forming fruit fly on Viguiera laciniata Gray and V. deltoidea Gray var. parishii (Greene) Vasey and Rose (Asteraceae) in southern California. The latter host record is new; other published host records are questioned. Eggs, first through third instar larvae, and puparia are described for the first time. Galls formed on both host plants are described. The severe drought in southern California during the last 5 years has reduced the densities of P. stonei on V. d. var. parishii. Fly reproduction was restricted to one generation per year on the few …

Barley Yellow Dwarf Virus In Cereals, Simon Mckirdy, Roger Jones

Journal of the Department of Agriculture, Western Australia, Series 4

Worldwide, barley yellow dwarf virus (BYDV) is the most widespread and damaging virus disease of cereals. It infects wheat, barley, oats and grasses and is transmitted by several aphid species. The virus is not seed-borne and to persist from one growing season to the next it must survive in over-summering grasses.

Barley yellow dwarf virus decreases grain yield and also causes shrivelled grain. Yield loss is greatest from infection early in the growing season.

Establishment Of Lupin Seedlings, Miles Dracup

Journal of the Department of Agriculture, Western Australia, Series 4

Good seedbed conditions lead to high and rapid seedling emergence and vigorous seedlings best equipped to avoid disease, weed competition and sand-blasting. Good establishment is needed for a high yielding crop.

In Western Australia, seedbed moisture and temperature are most likely to limit successful emergence of lupins, especially with the trend toward early sowing.

Research by the Department of Agriculture is helping to define seedbed temperature and moisture requirements for successful lupin establishment that will help future research for improving seedbed conditions.