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Iowa State University

1997

Plant Sciences

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Effects Of Bt Transformation On Diseases Of Corn, Gary Munkvold, W. Mark Carlton, Richard Hellmich, Marlin Rice Nov 1997

Effects Of Bt Transformation On Diseases Of Corn, Gary Munkvold, W. Mark Carlton, Richard Hellmich, Marlin Rice

Proceedings of the Integrated Crop Management Conference

The availability of genetically engineered com hybrids that are resistant to insect pests is an exciting development for com producers and the entire com industry. These hybrids are likely to become very popular as they continue to demonstrate dependable insect protection and yield performance. But these hybrids have other advantages as well. Because of the relationship between com insects, particularly the European com borer, and certain diseases, Bt hybrids have shown reduced levels of these diseases in side-by-side comparisons.


Stress Related Soybean Diseases, X. B. Yang, Sourn Sanogo Nov 1997

Stress Related Soybean Diseases, X. B. Yang, Sourn Sanogo

Proceedings of the Integrated Crop Management Conference

Soybean plants are subject to a wide array of stresses that ultimately render the plants susceptible to pathogens. Stresses can be classified in four categories: physical, biological, chemical, and physiological. Physical stresses include extreme variation in factors such as temperature and moisture. Conditions such as cold and wet soils are unfavorable to soybean plant growth, but are conducive to many root diseases. Similarly, agricultural chemicals such as fertilizers and herbicides, when applied in excessive amounts, can lead to increase in root diseases in soybean. Infestations by other pests, such as soybean cyst nematode and insects, can stress soybean plants and ...


Reliability Of Manure Application Rates To Predict Availability Of Swine Manure-N In Cornfields, David J. Hansen, Alfred M. Blackmer Nov 1997

Reliability Of Manure Application Rates To Predict Availability Of Swine Manure-N In Cornfields, David J. Hansen, Alfred M. Blackmer

Proceedings of the Integrated Crop Management Conference

Efficient use of the nitrogen in animal manures is essential for economic and environmental reasons. It requires applying the manure appropriately and making adjustments for this N if commercial fertilizer also is applied. Estimates of the amounts of plant-available N supplied by animal manures commonly are based on amounts of manure-N applied. Adjustments are often made for expected losses of N soon after application. These estimates are made with the knowledge that there is unpredictable variability in amounts of N rendered unavailable by ammonia volatilization, surface runoff, inunobilization, leaching, or denitrification. Although it is known to be substantial, there has ...


Relative Emergence Of Weeds Of Corn And Soybean, Douglas D. Buhler, Robert G. Hartzler Nov 1997

Relative Emergence Of Weeds Of Corn And Soybean, Douglas D. Buhler, Robert G. Hartzler

Proceedings of the Integrated Crop Management Conference

The success of integrated weed management relies on matching control strategies to the specific weed problem in a field. This requires information not only on what weed species and how many of these weeds are present in a field, but also knowledge of the distribution of the weeds throughout the field and the stage of development of these weeds. Weed control recommendations typically provide information on appropriate tillage methods and herbicide selection. The information concerning weed infestations used to base these recommendations typically is not of sufficient detail to optimize the efficiency of these strategies. Information on weed populations can ...


Interseeding Crp "Options And Precautions", Michael L. White Nov 1997

Interseeding Crp "Options And Precautions", Michael L. White

Proceedings of the Integrated Crop Management Conference

During the 15th Conservation Reserve Program (CRP) sign-up period which ended in May of 1997, 415,447 acres (42.6%) of the 975,478 acres of old CRP land scheduled to expire on October 1st, 1997 were accepted back into the Iowa CRP program. Many of these re-enrollment acres are subject to legume interseeding agreements signed by the landowners. The same bodes true for those entering into the 16th CRP sign-up period which ran from October 14th through November 14th, 1997. CRP contracts are accepted based on their Environmental Benefit Index (EBI) points. The factors used to arrive at an ...


Understanding Iowa Soils For Precision Agriculture Use, T. E. Fenton Nov 1997

Understanding Iowa Soils For Precision Agriculture Use, T. E. Fenton

Proceedings of the Integrated Crop Management Conference

The objectives of this presentation are to explain soil surveys and to better understand soils, their properties, and their spatial variability so that this information can contribute to improved decision-making related to precision soil, crop, and water management.


Soybean Cyst Nematode - Biology And Management, Gregory L. Tylka Nov 1997

Soybean Cyst Nematode - Biology And Management, Gregory L. Tylka

Proceedings of the Integrated Crop Management Conference

Soybean cyst nematode, Heterodera glycines, is a microscopic, unsegmented plant-parasitic roundworm that attacks the roots of soybeans. Many plant-parasitic nematodes are believed to be native to the United States, but soybean cyst nematode likely was introduced into the United States from Japan. Soybean cyst nematode was first discovered in the United States in 1954 in North Carolina (Winstead et al., 1955) and since has spread to 26 additional states in the Southeast and Midwest (Noel, 1992). The nematode was first discovered in Iowa in Winnebago County in 1978. Currently, soybean cyst nematode is known to exist in more than 75 ...


Accessing Soybase And Other Genome Databases Via The Internet, David Grant, Marcia Imsande, Randy Shoemaker Nov 1997

Accessing Soybase And Other Genome Databases Via The Internet, David Grant, Marcia Imsande, Randy Shoemaker

Proceedings of the Integrated Crop Management Conference

The Internet or World Wide Web is increasingly in the news. It seems to be much like Mark Twain's comment about the weather - everyone talks about the Internet but no one knows much about it. In fact the Internet is full of useful information if one only can find it. This paper (and associated computer demonstration) will first describe some of the genome databases that are accessible via the Internet and then give some strategies for searching the Internet for other types of information.


How Much Do Weeds Impact Crop Yields?, Bob Hartzler Nov 1997

How Much Do Weeds Impact Crop Yields?, Bob Hartzler

Proceedings of the Integrated Crop Management Conference

The primary purpose for controlling weeds in field crops is to prevent or reduce yield losses associated with competition between weeds and the crop. Competition occurs when plants seek the same resource (light, water, etc.) that is available in limited supplies. The interaction between crops and weeds is complicated and impacted by many factors, including characteristics of the weed species, weed populations, timing of weed emergence, characteristics of the crop variety/hybrid, crop population and row spacing, and the environment. This complexity limits our ability to predict yield losses early in the growing season, therefore hindering the development of economic ...


Establishing Alfalfa, Stephen K. Barnhart Nov 1997

Establishing Alfalfa, Stephen K. Barnhart

Proceedings of the Integrated Crop Management Conference

Alfalfa is a profitable crop when well managed. It is an economical source of home grown protein, energy, minerals, and vitamins for livestock. Iowa's state average yield estimate is about 3 1/2 ton per acre, but properly managed on suitable soils alfalfa can yield 5 to 7 ton per acre or more. Although a number of important management practices are necessary to achieve high alfalfa yields, the first and a frequently mismanaged practice is stand establishment.


Implementing Fee-Based Icm Services, Kevin Kuhn, Susan Brown, Dan Frieberg, Joel Dejong, Paul Kassel Nov 1997

Implementing Fee-Based Icm Services, Kevin Kuhn, Susan Brown, Dan Frieberg, Joel Dejong, Paul Kassel

Proceedings of the Integrated Crop Management Conference

Since 1993, a group of agrichemical dealers and public sector agencies, including Iowa State University Extension (ISUE) and the Natural Resources Conservation Service (NRCS), have been exploring the potential for fee-based crop management services in northwest Iowa. The Agribusiness Association of Iowa helped to bring the public and private sector groups together. In 1995, funding from USDA, and later also U.S. EPA through the Iowa Department of Natural Resources, established the Northwest Iowa Agribusiness ICM Project. The objective of the project is to demonstrate comprehensive, fee-based ICM services by dealers, ideally as separate profit centers. All dealers in a ...


Reducing Agriculture's Contribution To Nitrate Contamination Of Surface Waters, Dana L. Dinnes, Cynthia A. Cambardella, Thomas S. Colvin, Daniel B. Jaynes, Douglas L. Karlen Nov 1997

Reducing Agriculture's Contribution To Nitrate Contamination Of Surface Waters, Dana L. Dinnes, Cynthia A. Cambardella, Thomas S. Colvin, Daniel B. Jaynes, Douglas L. Karlen

Proceedings of the Integrated Crop Management Conference

One of the most prevalent environmental issues throughout the Midwest is nitrate (N03) contamination of surface waters. Non-point source pollution resulting from nitrogen (N) fertilizer use on artificially drained agricultural land has been identified as a major contributor to this problem. High levels of nitratenitrogen (N03-N) in water supplies pose risks to humans and livestock (Tyson et. al., 1992), and has cost some communities millions of dollars for N03 removal. The city of Des Moines, Iowa alone has spent in excess of 5.3 million dollars, not including labor costs, for nitrate treatment of its drinking waters from 1992-1996 (Graham ...


Diagnosis And Management Of Nematodes In Corn, Timothy C. Todd Nov 1997

Diagnosis And Management Of Nematodes In Corn, Timothy C. Todd

Proceedings of the Integrated Crop Management Conference

Nematodes, also known as roundworms, are a phylum of nonsegmented invertebrates that are the most numerous multicellular animals present in soils and plant tissues. Although their numbers can easily exceed 10 billion per acre of soil, the importance of nematodes is often overlooked due to their small size (most are less than 1/25 inch in length). Many species are beneficial, either because they feed on fungi and bacteria, accounting for a significant amount of nitrogen mineralization in the soil, or as parasites of insect pests. Other species, however, are parasites of plant roots and, in some cases, can severely ...


Soybean Cyst Nematode - Identification And Extraction Techniques, Gregory L. Tylka Nov 1997

Soybean Cyst Nematode - Identification And Extraction Techniques, Gregory L. Tylka

Proceedings of the Integrated Crop Management Conference

A major factor limiting soybean production in Iowa is the soybean cyst nematode, Heterodera glycines. Soybean cyst nematode is now known to be present in more than 75 Iowa counties. It is very likely that the nematode is present in many other counties as well, but the nonspecific nature of the above-ground symptoms of soybean cyst nematode damage makes early identification or diagnosis of infestations difficult. Results of recent random surveys indicate that the nematode likely exists in nearly 70% of Iowa fields.


Breeding For Quantitative Resistance To Leaf Blights Of Corn: A Continuing Success Story, Martin L. Carson Nov 1997

Breeding For Quantitative Resistance To Leaf Blights Of Corn: A Continuing Success Story, Martin L. Carson

Proceedings of the Integrated Crop Management Conference

The development of high yielding, disease resistant hybrids is the goal of most public and private corn breeding programs. These programs have largely been successful in reducing the incidence and severity of foliar diseases of corn in the U.S. Significant, damaging levels of leaf diseases are considered the exception throughout most of the corn belt, and a healthy corn crop the norm. This highly desirable situation did not arise by chance or good fortune, but rather is the result of dedicated efforts of corn breeders and pathologists over the decades. Unlike most other crops, corn breeders have been able ...


Weather And Yield Variation In The Midwest: So, Sunspots, Or What?, Richard E. Carlson Nov 1997

Weather And Yield Variation In The Midwest: So, Sunspots, Or What?, Richard E. Carlson

Proceedings of the Integrated Crop Management Conference

Corn production throughout the Midwest has been variable during the last 3 decades after a fairly stable time which extended from the late 1950's through 1973. The stable period was described by Carlson (1990) and Baker et al. (1993), and others. Historically, corn production also varied before that time, but with yield levels at a lower potential. Some of this year-to-year yield variation has been apparently caused by the Southern Oscillation (SO) (Carlson et al. 1996) or sea surface temperature variation (Handler, 1984 and Thompson, 1990). The SO is closely related to El Nino and La Nina conditions (anomolusly ...


Use Of Dgps, Yield Monitors, Soil Testing, And Variable Rate Technology To Improve Phosphorus And Potassium Management, Antonio Mallarino, David Wittry Nov 1997

Use Of Dgps, Yield Monitors, Soil Testing, And Variable Rate Technology To Improve Phosphorus And Potassium Management, Antonio Mallarino, David Wittry

Proceedings of the Integrated Crop Management Conference

New technologies such as differential global positioning systems (DGPS), yield monitors and other sensors, variable rate technology, and associated practices (such as grid soil sampling) have potential to improve soil fertility management. Soil sampling in the field is one of the most important sources of error in soil testing. A very small amount of soil needs to appropriately represent thousands of tons of soil and usually there is significant spatial variability of nutrient levels. The expectation of many producers and agronomists is that grid sampling will adequately describe field nutrient availability and that variable rate fertilization will result in better ...


The Iowa Crop Management Database: An Agronomic And Economic Information Recording Tool, Craig K. Tordsen, Susan S. Brown, Gerald A. Miller Nov 1997

The Iowa Crop Management Database: An Agronomic And Economic Information Recording Tool, Craig K. Tordsen, Susan S. Brown, Gerald A. Miller

Proceedings of the Integrated Crop Management Conference

The Iowa Crop Management Database (CMD) is designed to record field-by-field agronomic and economic information for crop production in Iowa. Iowa State University Extension is promoting use of such comprehensive records by producers and crop consultants to improve management decisions and farm profitability. Extension staff can use this information and summaries of these records in educational programs, and to document pollution prevention through refined crop management practices. The CMD program is a relational database designed on a model first developed by Pennsylvania State University. The Iowa version was expanded and developed to include a wider range of information resources needed ...


Topcross: A New Crop Production Team, Stuart L. Kaplan Nov 1997

Topcross: A New Crop Production Team, Stuart L. Kaplan

Proceedings of the Integrated Crop Management Conference

One of the biggest limitations in significantly altering the composition of corn grain to meet the needs of the end-user has been achieving these goals while maintaining commercially acceptable yield and agronomics in the resulting varieties. The purpose of this presentation is to describe a novel com production method developed by DuPont Quality Grains. This method ... the TopCross® Grain Production System ... has enabled the efficient production of high oil com on a large and growing commercial scale. In order to do this, it is first necessary to describe some fundamentals of com inheritance and reproduction.


An Evaluation Of Soil Survey Crop Yield Interpretations For Two Central Iowa Farms, A. L. Steinwand, D. L. Karlen, T. E. Fenton Nov 1997

An Evaluation Of Soil Survey Crop Yield Interpretations For Two Central Iowa Farms, A. L. Steinwand, D. L. Karlen, T. E. Fenton

Proceedings of the Integrated Crop Management Conference

This study was conducted on four adjacent 16-ha (40-ac) fields within the Clarion-Nicollet-Webster soil association to (1) determine if crop yield interpretations derived from 1:15840 soil survey maps could be used for developing field-scale management plans: and (2) to determine if soils in adjacent fields were derived using a computer-based Soil Information System (SIS) and compared with measured yields. Soil map units in all four fields were taxonomically variable, but this did not affect expected crop yields. Average expected and measured corn and soybean yields agreed within 9 and 12% for conentional management at the field-scale. We conclude that ...


Soybean Management For Increased Yield, Keith Whigham Nov 1997

Soybean Management For Increased Yield, Keith Whigham

Proceedings of the Integrated Crop Management Conference

Soybeans have become an extremely important feed, food and industrial crop in the world and the number two crop of importance in Iowa. World production during 1996 has the US as the largest soybean producer with 48%, followed by Brazil (20% ), China ( 10% ), Argentina ( 10% ), and Paraguay (2%). The remaining 10% come from many other countries. The Midwest dominates production within the US where seven states produced 71% of the 1996 soybean crop. Iowa was the leading US producer with 17.5% (416 million Bu.) of the total production, followed by Illinois (16.7%), Minnesota (9.4%), Indiana (8.5 ...


Contract Comparison In Specialty Beans, Roger Ginder, Amol Naik, Darren Jarboe Nov 1997

Contract Comparison In Specialty Beans, Roger Ginder, Amol Naik, Darren Jarboe

Proceedings of the Integrated Crop Management Conference

A major portion of the current U.S. soybean crop moves through the undifferentiated bulk commodity channel. Bulk commodity handling reduces the cost of assembly, storage, transportation, and distribution. The ability to commingle grain with widely varying physical and intrinsic properties allows the substitution of inventory in one location for another and permits the use of infinite variations in size of storage and transportation lots. With commingling of these grains, much of the differentiated value of the soybeans is lost. Until now customers have found the cost trade-offs between a bulk commodity approach and accepting a larger level of variation ...


Isu's New Nitrogen Fertilizer Recommendations For Corn: A Step Toward Site-Specific Management, Alfred M. Blackmer Nov 1997

Isu's New Nitrogen Fertilizer Recommendations For Corn: A Step Toward Site-Specific Management, Alfred M. Blackmer

Proceedings of the Integrated Crop Management Conference

Iowa State University released new nitrogen (N) fertilizer recommendations for com in May of 1997 (Pm. 1714). These recommendations are intended to help Iowa com producers obtain the economic and environmental advantages of moving toward site-specific management of N.


Soybean Designated Ax 4663-5-4-5, Walter R. Fehr, Earl G. Hammond Nov 1997

Soybean Designated Ax 4663-5-4-5, Walter R. Fehr, Earl G. Hammond

Iowa State University Patents

A method is described for producing soybean varieties and lines exhibiting palmitic acid contents of at least about 18.0% up to 30.0% or more. The novel soybean lines are obtained from a soybean seed designated A1937NMU-85 and its descendants, particular desirable progeny resulting from the cross of A1937NMU-85 with ElginEMS-421, and further with the cross of selected progeny with A89-259098.


Soybean Designated A1937 Nmu-85, Walter R. Fehr, Earl G. Hammond Nov 1997

Soybean Designated A1937 Nmu-85, Walter R. Fehr, Earl G. Hammond

Iowa State University Patents

A method is described for producing soybean varieties and lines exhibiting palmitic acid contents of at least about 18.0% up to 30.0% or more. The novel soybean lines are obtained from a soybean seed designated A1937NMU-85 and its descendants, particular desirable progeny resulting from the cross of A1937NMU-85 with ElginEMS-421, and further with the cross of selected progeny with A89-259098.


Genesis And Morphology Of Mima Mounds And Associated Soils At Kalsow Prairie, Iowa, Deann K. Ricks, Lee Burras, M. E. Konen, A. J. Bolender Oct 1997

Genesis And Morphology Of Mima Mounds And Associated Soils At Kalsow Prairie, Iowa, Deann K. Ricks, Lee Burras, M. E. Konen, A. J. Bolender

Agronomy Publications

The objectives of this study were to identify the genesis of Kalsow Prairie Mirna mounds and to compare on-mound and off-mound soil properties. Kalsow Prairie is a 60 ha uncultivated prairie remnant in north-central Iowa. A 4 ha zone near the center of Kalsow Prairie containing 59 mounds was selected for detailed field study. Field methods included mapping the spatial distribution of mounds, measuring mound geometry, and sampling and describing soil profiles associated with both on-mound and off-mound landscape positions. The average height and diameter of the mounds was 0.23 m and 3.7 m, respectively. Twenty-nine of the ...


Soybean Designated A89-259098, Walter R. Fehr, Earl G. Hammond Sep 1997

Soybean Designated A89-259098, Walter R. Fehr, Earl G. Hammond

Iowa State University Patents

A method is described for producing soybean varieties and lines exhibiting palmitic acid contents of at least about 18.0% up to 30.0% or more. The novel soybean lines are obtained from a soybean seed designated A1937NMU-85 and its descendants, particular desirable progeny resulting from the cross of A1937NMU-85 with ElginEMS-421, and further with the cross of selected progeny with A89-259098.


Allozyme Variation In Domesticated Annual Sunflower And Its Wild Relatives, Richard Clark Cronn, M. Brothers, Kay Ellen Klier, P. K. Bretting, Jonathan F. Wendel Sep 1997

Allozyme Variation In Domesticated Annual Sunflower And Its Wild Relatives, Richard Clark Cronn, M. Brothers, Kay Ellen Klier, P. K. Bretting, Jonathan F. Wendel

Botany Publication and Papers

The annual sunflower (Helianthus annuus L.) is a morphologically and genetically variable species composed of wild, weedy, and domesticated forms that are used for ornament, oilseed, and edible seeds. In this study, we evaluated genetic variation in 146 germplasm accessions of wild and domesticated sunflowers using allozyme analysis. Results from this survey showed that wild sunflower exhibits geographically structured genetic variation, as samples from the Great Plains region of the central United States were genetically divergent from accessions from California and the southwestern United States. Sunflower populations from the Great Plains harbored greater allelic diversity than did wild sunflower from ...


Differences In Hatching Of Heterodera Glycines Egg-Mass And Encysted Eggs In Vitro, J. M. Thompson, G. L. Tylka Sep 1997

Differences In Hatching Of Heterodera Glycines Egg-Mass And Encysted Eggs In Vitro, J. M. Thompson, G. L. Tylka

Plant Pathology and Microbiology Publications

Hatching studies with Heterodera glycines typically have been conducted with a mixture of egg-mass and encysted eggs. Laboratory research was conducted to compare hatching of H. glycines eggs from external egg masses with that of eggs extracted from within females and cysts (encysted eggs). Egg-mass eggs were collected by soaking infected soybean roots in 0.5% sodium hypochlorite, and encysted eggs were collected from females and cysts dislodged from the same roots with a stream of water. Eggs were incubated at 25┬║C in deionized water, 3.0 mM ZnSO[sub4]solution, or one of three synthetic H. glycines hatch inhibitors ...


Quantitative Determination Of Calcium Oxalate And Oxalate In Developing Seeds Of Soybean (Leguminosae), H. Ilarslan, R. G. Palmer, J. Imsande, Harry T. Horner Aug 1997

Quantitative Determination Of Calcium Oxalate And Oxalate In Developing Seeds Of Soybean (Leguminosae), H. Ilarslan, R. G. Palmer, J. Imsande, Harry T. Horner

Botany Publication and Papers

Developing soybean seeds accumulate very large amounts of both soluble oxalate and insoluble crystalline calcium (Ca) oxalate. Use of two methods of detection for the determination of total, soluble, and insoluble oxalate revealed that at +16 d postfertilization, the seeds were 24% dry mass of oxalate, and three-fourths of this oxalate (18%) was bound Ca oxalate. During later seed development, the dry mass of oxalate decreased. Crystals were isolated from the seeds, and X-ray diffraction and polarizing microscopy identified them as Ca oxalate monohydrate. These crystals were a mixture of kinked and straight prismatics. Even though certain plant tissues are ...