Life Sciences Commons^™

Nitrogen Source And Application Method: Does It Matter?, Gilbert D. Miller, Jay C. Andersen

Archived Natural Resources Publications

Irrigation management has a greater effect on the amount of nitrate that is leached out of the root one than does the type of nitrogen applied.

Simulating Winter Wheat Shoot Apex Phenology , G. S. Mcmaster, Wallace Wilhelm, J. A. Morgan

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

Simulation models are heuristic tools for integrating diverse processes and help to increase our understanding of complex processes and systems. Models that predict crop development can serve as decision-support tools in crop management. This paper describes a phenology simulation model for the winter wheat shoot apex and reports validation and sensitivity analysis results.

The complete developmental sequence of the winter wheat shoot apex is quantitatively outlined and correlated with commonly recognized phenological growth stages. The phyllochron is used to measure the thermal time between most phenological growth stages, thereby increasing the flexibility over the growing degree-day (GDD) and photothermal approaches. …

Low Pressure Center Pivot And Soil Management Effects On Runoff, L. N. Mielke, J. R. Gilley, Wallace Wilhelm

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

The objective of this research was to determine the influence center-pivot sprinkler irrigation methods in combination with tillage practices for corn (Zea mays L.) have on surface runoff of irrigation and rainfall. A center pivot irrigation machine was redesigned to apply water by high-pressure-impact (HPI), low-pressure-impact (LPI), and low-pressure-spray (LPS) nozzles. The center-pivot was a standard 10-tower machine, 395 meters in length and 38.4 meters tower spacing. Three tillage systems were used -- till-plant (T), disk (D), and subtill (S) which was till-plant with subsoiling between rows with straight single shanks, 360 mm deep, after last cultivation. The soil …

Simulating Winter Wheat Spike Development And Growth, Gregory S. Mcmaster, Jack A. Morgan, Wallace Wilhelm

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

Mechanistic crop simulation models can aid in integrating and directing research, and in improving farm management strategies. Information derived from recent research on spike development and growth of winter wheat (Triticum aestivum L.) was incorporated into a submodel, SPIKEGRO, and added to an existing model called SHOOTGRO. This manuscript discusses the SPIKEGRO submodel.

SPIKEGRO emphasizes the reproductive functioning of the shoot apex. The complete developmental sequence of the shoot apex is outlined and quantified. All developmental events and growth stages are predicted, most using the phyllochron approach. Spikelet and floret primordium initiation, growth, and abortion; ovule fertilization and growth; …

Visions For Agriculture, Department Of Agriculture, Western Australia

Agriculture reports

This workshop grew out of a conversation between Maurice Barnes, a Trayning farmer and member of the Research Advisory Committee of the Dryland Research Institute, and Steve Porritt, the officer in charge of the Dryland Research Institute at Merredin. Maurice was interested in the idea of posing the question 'What would agriculture be like if we had known as much about this landscape in 1829 as we know now?', to a group of farmers and others interested in the central wheatbelt and its future. Maurice saw this question as a first step toward achieving some shared vision for the future …

Proceedings Of The Workshop Social Science Research And The Crsps, C. Milton Coughenour, John M. Yohe, Anne E. Ferguson, Jere L. Gilles, Jo Purcell

INTSORMIL Impacts and Bulletins

Contents

Executive Summary: A New Agenda for CRSP Social Science Research - C. Milton Coughenour . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Session 1

Developing a Strategic Research Agenda David G. Cummins, Chair

Framing a Strategic Research Agenda.-John Yohe ................ 3

Social Sciences and Collaborative Research: Toward an Agenda for the Social Sciences in Agriculture -Jere Lee Gilles ............... 7

Session 2

Technology Development and Sustaining Household Food Security Kathleen DeWalt, Chair

Technology Development and Household Food Security - …

Arkansas Rice Research Studies 1991, 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 1991, Arkansas Agricultural Experiment Station Research Series 421. 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.

Response Of Central Plains Taligrass Prairies To Fire, Fertilizer, And Atrazine, Robert A. Masters, Kenneth P. Vogel, Robert B. Mitchell

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

Tallgrass prairies are an important forage resource in the eastern Central Great Plains. The effect of spring burning, fertilization, and atrazine [6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine- 2,4-diamine] on standing crop of selected herbaceous species and categories of vegetation was determined in 6 tallgrass prairie environments located near Lincoln and Virginia, Neb., from 1987 through 1989 and 1 site near Bloomfield, Neb., in 1987. The grasslands were in good to excellent condition at the time these studies were conducted. Portions of each site were burned in mid-to late spring, atrazine was applied at a rate of 2.2 kg a.i. ha^-1 in late April to …

Arkansas Soil Fertility Studies 1991, Wayne E. Sabbe

Arkansas Agricultural Experiment Station Research Series

Contained within this publication are progress reports on the specific aspects of the soil fertility program at the University of Arkansas in 1991. In most instances, the reports are not final reports, but they may contain data from several years. Further details on each report can be obtained from the respective project leaders.

Simulating Winter Wheat Production In Three Tillage Systems Using The Nitrogen Tillage Residue Management Model, B. Davidoff, Wallace Wilhelm, Joseph M. Skopp

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

Crop production system analysis is necessary to identify tillage and residue management practices that affect crop production. The objective of this study was to evaluate the potential of using the Nitrogen Tillage Residue Management (NTRM) model to evaluate the influence of tillage practices on winter wheat (Triticum aestivum L.) yield. Modifications of the NTRM model were required to simulate winter wheat production. The model was calibrated using site-specific information obtained from a tillage-nitrogen rate experiment conducted at the High Plains Agricultural Laboratory near Sidney, NE, on an Alliance silt loam (fine silty, mixed, mesic Aridic Argiustoll). Model output was …

Herbicide Trials On Field Crops 1991, Robert Frans, Marilyn Mcclelland, David Jordan

Arkansas Agricultural Experiment Station Research Series

Herbicidal weed control is economically important for production of field crops. Field experiments are conducted annually in Arkansas to evaluate the activity of developmental ancommercial herbicides for selective control of weeds in several important crops. These experiments serve both industry and Arkansas agriculture by providing information on the selectivity of herbicides still in the developmental stage and by comparing the activity of these new herbicides with that of recommended herbicides.

Arkansas Cotton Variety And Strain Tests 1991, F. M. Bourland, J. S. Dacus

Arkansas Agricultural Experiment Station Research Series

Varieties and advanced strains of cotton were evaluated in 1991 by the Arkansas Agricultural Experiment Station. Varieties and some advanced breeding lines were evaluated in the 1991 Arkansas Cotton Variety Test. Entries in the 1991 Commercial Cotton Strain Test included both released varieties that have not been evaluated in Arkansas and advanced breeding lines that may soon be available to producers.

Proceedings Of The 19th Annual Meeting, Southern Soybean Disease Workers (February 19-20, 1992, St. Louis, Missouri), J. Allen Wrather, Patrick D. Colyer, Glenn R. Bowers Jr., Brian M. Anderson, Glenn G. Hammes

Southern Soybean Disease Workers: Conference Proceedings

Contents

Southern Soybean Disease Workers 1991-1992 officers

1991-1992 Program Committee

Graduate student competition

Interactions of Macrophomina phaseolina with two soybean cultivars under four irrigation regimes. SR Kendig and JC Rupe

Influence of soybean planting dates on the incidence and severity of Sudden Death Syndrome. SS Alghamdi, PT Gibson, and MA Shenaut

The interrelationship of Heterodera glycines and Fusarium solani in sudden death syndrome of soybean. KS McLean and GW Lawrence

Frogeye leaf spot of soybean: evaluation of cultivars and isolates. PF Pace, DB Weaver, and LD Ploper

Soybean cyst nematode race symposium

SCN race scheme: a historical perspective. JA Fox …

Determination Of Root Biomasses Of Three Species Grown In A Mixture Using Stable Isotopes Of Carbon And Nitrogen, H. Wayne Polley, Hyrum B. Johnson, Herman S. Mayeux

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

A method is evaluated that employs variation in stable C and N isotopes from fractionations in C and N acquisition and growth to predict root biomasses of three plant species in mixtures. Celtis laevigata Willd. (C₃), Prosopis glandulosa Torr. (C₃, legume) and Schizachyrium scoparium (Michx.) Nash (C₄), or Gossypium hirsutum L. (C₃), Glycine max (L.) Merr. (C₃ legume), and Sorghum bicolor (L.) Moench (C₄) were grown together in separate, three-species combinations.

Scs Water Surface Profile Model - Wsp2, William H. Merkel, Donald E. Woodward

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

The Soil Conservation Service (SCS) has revised its mainframe water surface profile model WSP2 and is distributing it as a microcomputer program. WSP2 is used by SCS and others in flood plain management studies and project planning. The model uses the standard step method for computing one-dimensional steady flow profiles for channel and flood plain cross sections and computes backwater at bridges and culverts.

Unique features of WSP2 are described with respect to input data, calculation procedures, user manual, error checking, and output. The use of WSP2 with other SCS hydrologic software is described.

New Diets For Production Of House Flies And Stable Flies (Diptera: Muscidae) In The Laboratory, Jerome Hogsette

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

A diet for rearing the house fly, Musca domestica (L.), was developed from feed constituents available on a year-round basis in Gainesville, FL. The diet, called the Gainesville House Fly Diet, performed as well or better than the Chemical Specialties Manufacturers' Association fly larval medium (CSMA) and can be mixed, bagged, and delivered by a local feed mill within 3 d. By adding pelleted peanut hulls 1:1 by volume, the house fly diet becomes suitable for rearing the stable fly, Stomoxys calcitrans (L.). Use of these diets and the economics involved are discussed further.

Comparative Toxicity Of Aqueous Solutions Of Boric Acid And Polybor 3 To House Flies (Diptera: Muscidae), Jerome Hogsette, Philip Koehler

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

LC₅₀s and LT₅₀s of boric acid and polybor formulated in water and 10% sucrose were determined for 3- to 5-d-old adult house flies, Musca domestica (L.), of mixed sex. Differences between boric acid and polybor toxicities were significant in 10% sucrose, but not in water. However, borates formulated in water had significantly lower LC₅₀S than those formulated in 10% sucrose. Rate of kill for formulations in water was fairly uniform over time, whereas mortality from sucrose formulations was not observed until 17 h after treatment. Reasons for differences in the manifestation of mortality and …

Spontaneous Tetraploid Melons, Perry E. Nugent, Dennis T. Ray

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

Since 1968, three spontaneous 4x melons (Cucumis melo L.) plants were discovered in our field or greenhouse plantings. Two were found in the cultivar Planters Jumbo and one in the virescent marker C879-52. Each of these 4x plants had rounded cotyledons, shorter internodes, thicker stems and leaves, more hairs, and smaller fruits, with larger stem and blossom scars, than their 2x counterparts. Also, their flowers, pollen grains, stomates, and seeds were larger. The discovery of a 4x virescent plant in 1987 allows easier germplasm transfer between ploidy levels. Morphological characteristics of 2x and 4x melons will allow identification without …

Comparison Of Restriction Fragment Length Polymorphisms In Chloroplast Dna Of Five Leafy Spurge (Euphorbia Spp.) Accessions, Scott Nissen, Robert A. Masters, Donald Lee, Martha Rowe

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

Chloroplast DNA (cpDNA) restriction fragment length polymorphisms (RFLPs) were analyzed to assess genetic variation and relatedness among selections of North American and Eurasian leafy spurge. Leafy spurge accessions from Nebraska, Montana, Russia, Italy, and Austria were evaluated. Total DNA was extracted from young leaves and digested with the restriction endonuclease, EcoRI. CpDNA fragment patterns were determined by Southern blot analysis using mung bean cpDNA probes. Colinearity between the mung bean and leafy spurge chloroplast genomes was indicated by the observation that common fragments were hybridized by adjacent probes. Minimum estimates of chloroplast genome size for the five leafy spurge …

Loop Rating Curves From Goodwin Creek, Roger A. Kuhnle, Andrew J. Bowie

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

Two types of hysteresis loops have been observed on Goodwin Creek: those with a greater flow depth for a given discharge on the falling limb of the hydrograph (type 1) and those with a greater flow depth for a given discharge on the rising limb of the hydrograph (type 2). Causes of these 2 loop types are investigated in this paper.

Effects Of Weaning On Concentrations Of Inhibin In Follicular Fluid And Plasma Of Sows, W. E. Trout, J. H. Killen, R. K. Christenson, B. D. Schanbacher, J. J. Ford

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

Changes in plasma and follicular fluid concentrations of inhibin were examined in sows after weaning at 28-32 days post partum. From 0 to 48 h after weaning, inhibin concentrations were 200-300times higher in follicular fluid from small ( < 4 mm) and medium-large( ≥4 mm) follicles than in ovarian venous plasma. Inhibin concentrations increased in follicular fluid from medium-large follicles at 24 and 48 h after weaning; concentrations in ovarian venous plasma were positively correlated with the number of medium-large follicles (r= 0·40)and with ovarian venous plasma concentrations of oestradiol (r= 0·61).Blood samples were collected for 30 days from sows (n=6) that exhibited oestrus within 5 days after weaning and from sows (n=5) that remained anoestrous for 11 days after weaning. Plasma inhibin concentrations rose in oestrous and anoestrous sows by 12 h and continued to rise for 60 h after weaning. Plasma inhibin concentrations rose further and were higher at 3·5-4·5days after weaning in oestrous sows than in sows that remained anoestrous. After oestrus, plasma inhibin concentrations declined. At weaning, plasma concentrations of follicle-stimulating hormone (FSH) were higher in sows that subsequently exhibited oestrus than in sows that remained anoestrous. After weaning, plasma concentrations of FSH declined in both groups, reached a nadir at 2·5days, and increased gradually in anoestrous sows; oestrous sows exhibited an FSH surge at oestrus. Plasma FSH returned to preweaning concentrations in both groups of sows at Days 7-8.The results demonstrated dynamic changes in plasma concentrations of FSH and inhibin in sows after weaning; an inverse relationship of these, with the exception during the preovulatory surge of FSH, typifies the porcine oestrous cycle.

Autoseparation Method For Harvesting House Fly (Diptera: Muscidae) Pupae Of Known Age, Jerome Hogsette

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

Postfeeding larvae of Musca domestica (L.) were allowed to crawl from the larval rearing medium into sand-filled collection containers to pupate. By separating postfeeding larvae and pupae from the sand at predetermined intervals, the approximate time of pupation and the pupal age could be determined. More postfeeding larvae were collected in fine, wet sand than in coarse, dryer sand. Whether or not the sand was tightly packed into collection containers was unimportant, and fly mortality was not increased by the sand-collection method. Uses for the system and implications of the results are discussed.

Jasmonate, Genes, And Fragrant Signals, Paul E. Staswick

Department of Agronomy and Horticulture: Faculty Publications

Although first recognized for its growth-inhibiting activity about 20 years ago, JA² and its fragrant methyl ester MeJA (referred to here collectively as jasmonate) are receiving renewed interest as potentially important signaling molecules in plants. This is because jasmonate markedly increases the expression of specific plant genes, some of which are wound responsive. Similarities with fatty acid-derived stress signaling molecules in animals (1) make jasmonate of general biological interest.

1992 Blueberry Research Progress Reports, Warren Hedstrom, Willem Brutsaert, David Brooks, Alfred A. Bushway, Rodney J. Bushway, Stephanie Baker, Therese M. Work, Linda J. Irvine, Mary Ellen Camire, Susan Ismail Flint, Eben Osgood, Frank A. Drummond, Constance Stubbs, Edward R. Huff, David H. Lambert, David E. Yarborough, Paul E. Capiello, Timothy M. Hess, Gill H. Lemieux, Rene Verrault, Roger Green, Delmont Emerson, H Y. Forsythe Jr, Judith A. Collins, Lixin Tian, John M. Smagula, Michele C. Marra, Kerry Apgar

Wild Blueberry Research Reports

The 1992 Blueberry Research Progress Reports pertain to and report on research conducted in 1991, and were prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include:

1992 CSRS Progress Reports:

1. Investigation of Groundwater Resources

2. Sprinkler Irrigation

3. Investigation of Preprocess Changes Leading to Berry Spoilage

4. Effect of Fertilization and Irrigation on Blueberry Quality

5. Effects of Calcium Salts and Citric Acid on Quality of Canned Lowbush Blueberries

6. Pollination of Lowbush Blueberry by Native Bees

7. Application …

'Living Soil' Seminar, Department Of Agriculture, Western Australia

Agriculture reports

Provides an opportunity for farmers and those involved in the agricultural service industry, to focus on what happens in the soil. Seminar reflects the interest detected amongst farmers in knowing more about the things that influence plant growth and a genuine concern about the environment.