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Iowa State University

Plant Sciences

1995

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Genetic Markers And Horticultural Germplasm Management, P. K. Bretting, Mark P. Widrlechner Dec 1995

Genetic Markers And Horticultural Germplasm Management, P. K. Bretting, Mark P. Widrlechner

NCRPIS Publications and Papers

This paper is adapted from the text of a seminar of the same title presented as part of the Workshop on Sustainability of Vegetable Breeders’ Genetic Resources, 26 July 1993, at the 90th Annual Meeting of the American Society for Horticultural Science. It represents the distillation of a more extensive treatment of genetic markers and germplasm management (Bretting and Widrlechner, 1995).


Production And Quality Characteristics Of Forage Soybeans For Livestock Feed, Dwayne Buxton, Kenneth Moore, Daren Redfearn, Witjaksana Darmosarkoro Nov 1995

Production And Quality Characteristics Of Forage Soybeans For Livestock Feed, Dwayne Buxton, Kenneth Moore, Daren Redfearn, Witjaksana Darmosarkoro

Proceedings of the Integrated Crop Management Conference

When first introduced into the United States, soybean was used predominately as a summer annual forage legume. Soybean is still consider a viable alternative when supply becomes limiting and additional forage is needed. During the past few years, many forage producers have experienced difficulty establishing alfalfa because of excessively wet or dry springs. Additionally, some loss of established stands has occurred through winter kill. Failure of spring seedings or loss of established stands is usually not apparent until sometime into the growing season. Because of their later planting date than alfalfa, summer annual crops fill an important role in the ...


Soybean Cyst Nematode- Biology And Management, Gregory L. Tylka Nov 1995

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

Proceedings of the Integrated Crop Management Conference

Soybean cyst nematode, Heterodera glycines, is a small, unsegmented plant-parasitic roundworm that attacks the roots of soybeans. Many plant-parasitic nematodes are believed to be endemic or native to the United States, but soybean cyst nematode is thought to have been introduced from Japan. Soybean cyst nematode was first discovered in the United States in 1954 in North Carolina (Winstead et al., 1955), and has since spread to 26 additional states in the Southeast and Midwest (Noel, 1992). It was first discovered in Iowa in Winnebago County in 1978. In 1995, soybean cyst nematode was identified for the first time in ...


Soil Testing To Guide Nitrogen Fertilization In Manured Cornfields, Alfred M. Blackmer, D. J. Hansen, Antonio P. Mallarino Nov 1995

Soil Testing To Guide Nitrogen Fertilization In Manured Cornfields, Alfred M. Blackmer, D. J. Hansen, Antonio P. Mallarino

Proceedings of the Integrated Crop Management Conference

Land application of animal manures can supply N needed for com production. The amounts of N supplied, however, vary greatly with source of manure, type of storage, method of application, time of application, rate of application, and weather after application. A major problem is that substantial losses of plant-available N by ammonia volatilization, leaching, denitrification, and/or immobilization frequently occur soon after the manure is applied. Another problem is that it is difficult to determine how rapidly N in the manure becomes available to plants. These problems make it difficult to estimate how much fertilizer N should be applied.


Major Diseases In 1995 And Management For 1996, Gary P. Munkvold Nov 1995

Major Diseases In 1995 And Management For 1996, Gary P. Munkvold

Proceedings of the Integrated Crop Management Conference

This year (1995) will be remembered as a year with less-than-ideal growing conditions which led to less-than-desirable yields in most crops. Whenever plants are under stress caused by weather conditions, there is a potential for increased disease susceptibility. In some cases, the conditions causing stress on the plants are also very favorable to the development of pathogens and diseases.


Integrated Wheat Disease Management, Patrick E. Lipps Nov 1995

Integrated Wheat Disease Management, Patrick E. Lipps

Proceedings of the Integrated Crop Management Conference

Disease is a major factor limiting yield of wheat in midwestern states. It ranks with weather, nutrition, cultivar and type of cultivation as a significant factor affecting yield potential. In the humid Midwest, losses as high as 20-40% have been reported in locations where disease control has not been practiced. Fortunately, most grain producers use sound disease control practices. The use of modem high yielding varieties, crop rotation, delayed planting date, and balanced fertility are well accepted agronomic practices that significantly limit the extent of yield losses due to disease.


Soil Test Interpretations For Iowa High Ph Soils, Antonio P. Mallarino, David J. Dunn Nov 1995

Soil Test Interpretations For Iowa High Ph Soils, Antonio P. Mallarino, David J. Dunn

Proceedings of the Integrated Crop Management Conference

A variety of soil tests are reliable for evaluating plant available phosphorus (P) of neutral or acid soils but there is still uncertainty about appropriate soil tests and soil-test interpretations for calcareous soils. The Bray-PI is the most widely used soil-test P method by soil testing laboratories operating in Iowa, although many also offer the Olsen method. Extensive research has shown that the Bray-PI test is reliable on neutral or acid soils but that it tends to underestimate available P on many calcareous soils. The Olsen test seems more reliable for calcareous soils. Because of this problem, many soil testing ...


Isu Revised Nutrient (Fertilizer) Recommendations, Regis D. Voss Nov 1995

Isu Revised Nutrient (Fertilizer) Recommendations, Regis D. Voss

Proceedings of the Integrated Crop Management Conference

Research results from long-term and short-term experimentation in Iowa have been consistent in the response or lack of response of Iowa field crops to applications of fertilizer phosphorus (P) and potassium (K) at various soil test levels for P and K. As a consequence of the research, recommendations for P and K based on soil test results and the interpretation of soil test values are being revised. The time frame for implementation is tentatively set to be prior to the 1996 spring planting season.


Weed Management Update, Michael D.K. Owen Nov 1995

Weed Management Update, Michael D.K. Owen

Proceedings of the Integrated Crop Management Conference

A number of significant problems related to weed management developed during 1995. The most influential factor in many of these issues was the environment. However, with proper planning, adjustments could be implemented in the system to resolve many of these problems. Also, many of these problems have been building during previous years and conditions in 1995 emphasized their impact on crop production. Pigweed control was of concern during 1995. Herbicide injury from postemergence applications was widespread, particularly in soybeans. The potential for the interaction of herbicides resulting in adverse effects to crops continued to be an issue. Grower expectations for ...


The 1995 Iowa Crop- The Issues?, Garren O. Benson Nov 1995

The 1995 Iowa Crop- The Issues?, Garren O. Benson

Proceedings of the Integrated Crop Management Conference

The November Crop Report estimated Iowa com and soybean yields at 121 and 44 bu/ac, respectively. One can expect these numbers to be adjusted somewhat by the January report. If the November yield relationship holds in later estimates the soybean crop is relatively better than the com crop. The yield relationship between com and soybean varies between regions and is a reflection of the variation in growing season in the different parts of the state. Yield estimates, as of November 1, are presented by Crop Reporting District in Table 1. Yield is the result of many factors. The major ...


Yield Monitors, Variable-Rate Applicators, And N Fertilizer Recommendations For Corn, Alfred M. Blackmer Nov 1995

Yield Monitors, Variable-Rate Applicators, And N Fertilizer Recommendations For Corn, Alfred M. Blackmer

Proceedings of the Integrated Crop Management Conference

Many corn producers are purchasing on-the-go yield monitors and global positioning systems to enable mapping of yields within their fields. The underlying assumption is that the benefits of information generated will more than offset the costs of making the maps. The benefits expected usually include increases in yields and( or) decreases in expenditures for fertilizers.


Rising Conservation Tillage Acreage: Implications For Phytophthora Root And Stem Rot Of Soybean, F. Workneh, X. B. Yang, G. L. Tylka Nov 1995

Rising Conservation Tillage Acreage: Implications For Phytophthora Root And Stem Rot Of Soybean, F. Workneh, X. B. Yang, G. L. Tylka

Proceedings of the Integrated Crop Management Conference

Cropping practices are shifting to conservation tillage to counter the growing threat of wind and water erosion due to excessive soil disturbances by conventional tillage practices. In addition, reduction in costs of production and the availability of effective herbicides and drill-planters have played a significant part in decision making. Conservation tillage is defined as any tillage systems that maintain at least 30% of the soil surface covered by residues after planting (National Resource Conservation Service). No-till, mulch-till and ridge-till tillage systems meet the residue level requirement, and their practice is currently on the rise both at the state and national ...


Casual Agents And Management Of Soybean Seedling Diseases, X. B. Yang, Peter Lundeen, S. S. A. Rizvi, B. Q. Zhang Nov 1995

Casual Agents And Management Of Soybean Seedling Diseases, X. B. Yang, Peter Lundeen, S. S. A. Rizvi, B. Q. Zhang

Proceedings of the Integrated Crop Management Conference

Seedling diseases are among the most widely distributed soybean diseases (Sinclair and Backman, 1989). Under field conditions favorable for seedling disease development, yield losses can be significant. As the use of no-till farming practices increases, there are increasing number of questions about potential problems of seedling disease in early planted soybean and in no-till soybean fields. Management of seedling diseases become an interesting topic for the soybean industry. In Iowa, no comprehensive survey on the causal agents of seedling disease has been conducted. Currently, seed treatment is the major method to control soybean seedling diseases, and effectiveness of the treatment ...


Alternative Approaches To Weed Management, Douglas D. Buhler Nov 1995

Alternative Approaches To Weed Management, Douglas D. Buhler

Proceedings of the Integrated Crop Management Conference

Herbicide technology and use have been the focus of weed management research for the past several decades. Herbicides are an important component of weed management and will remain so for years to come. However, there is increasing pressure to improve the efficiency of herbicide use and develop alternative control methods. Herbicides are used on over 95% of the com and soybean in the Com Belt because of the presence of weeds and the need to minimize their adverse economic impacts. Large inputs of herbicides and tillage are needed to control weeds because of the lack of knowledge of weed biology ...


Progress In Using Biotechnology By-Products As Fertilizer, Stanley J. Henning, Russell Doorenbos Nov 1995

Progress In Using Biotechnology By-Products As Fertilizer, Stanley J. Henning, Russell Doorenbos

Proceedings of the Integrated Crop Management Conference

Byproducts from fermentation industries using modem, biotechnological fermentation processes are produced in large volumes, up to several thousand tons per year. The byproducts consist of the biomass from the microorganisms that reproduced in fermentation, the raw products contained in the fermentation solution, and both major and minor products of fermentation. In addition, the byproducts may contain chemicals added to assist in the recovery of the product especially where ion exchange resins have been used. Annual energy consumption by the microorganisms carrying out the fermentation processes in Iowa industries amounts to over five million bushels of com that has been refined ...


Weed Seeds- The Source Of All Problems, Bob Hartzler Nov 1995

Weed Seeds- The Source Of All Problems, Bob Hartzler

Proceedings of the Integrated Crop Management Conference

The primary reason for controlling weeds during crop production is to prevent crop yield losses due to competition with weeds. However, the majority of Iowa farmers strive to obtain higher levels of weed control than necessary to protect crop yields. The rationale for this contradiction is the concern about the production of seeds by weeds left in the field. Since the majority of weeds found in Iowa row crops are summer annuals, the seed bank is the source of new weed infestations each spring. The seedbank influences both the weed populations that occur in a field and the success of ...


Roundup Ready Soybeans: An Overview Of The Technology, D. R. Harper Nov 1995

Roundup Ready Soybeans: An Overview Of The Technology, D. R. Harper

Proceedings of the Integrated Crop Management Conference

Roundup Ready™ Soybeans will be the first product of biotechnology that will be widely available in soybeans. These soybeans are the culmination of over 10 years of research and development by Monsanto Company and selected soybean seed company partners and will offer soybeans growers selective post emergent weed control from Roundup© the world's most widely used herbicide.


Managing Resistant And Other Difficult To Control Weeds, Loyd M. Wax Nov 1995

Managing Resistant And Other Difficult To Control Weeds, Loyd M. Wax

Proceedings of the Integrated Crop Management Conference

Currently, weed control is practiced to a very intensive level of management in the Midwest. Most all acres of com and soybean production are treated with one or more herbicides, and often with multiple applications of herbicides. And yet weed problems remain that cause concern to the grower, in some instances because of potential losses due to competition and harvest losses, and in other instances because of grower, landlord, and neighbor expectations for near perfect control of all weedy species in growing crops. Some of these greater expectations come as a result of product guarantees and respray programs, which are ...


Possible Influence Of Global Warming On Climate Variability In The Central United States, S. Elwynn Taylo Nov 1995

Possible Influence Of Global Warming On Climate Variability In The Central United States, S. Elwynn Taylo

Proceedings of the Integrated Crop Management Conference

The primary manifestation of climate change may be variability, or the effects of variability, as opposed to climatic shift. During the 1960s, there was a good deal of concern within the academic community and, to some extent, expressed by the public regarding the global cooling trend that had become apparent in several parts of the world. From about 1910 to 1940, the earth experienced a warming trend, followed by an abrupt decrease in global temperature that continued until about 1972. Observations of glacial activity in the Austrian Alps and on Mount McKinley in Alaska revealed a marked glacial retreat up ...


Pigweeds Of The Midwest- Distribution, Importance And Management, Loyd M. Wax Nov 1995

Pigweeds Of The Midwest- Distribution, Importance And Management, Loyd M. Wax

Proceedings of the Integrated Crop Management Conference

A number of pigweed species can be found throughout the Midwest, but we are most concerned about those species that are commonly found in cropping situations. The most common weedy pigweeds can be separated into three distinct groups according to their taxonomic characteristics and overall appearance. The first group includes some of the most common pigweeds in the Midwest: redroot pigweed (Amaranthus retroflexus), smooth pigweed (Amaranthus hybridus) and Powell amaranth (Amaranthus powellii).


Preparing For The Cca Exam And Other Adventures, Anne R. Warshaw, Wendy K. Wintersteen, Jill C. King Nov 1995

Preparing For The Cca Exam And Other Adventures, Anne R. Warshaw, Wendy K. Wintersteen, Jill C. King

Proceedings of the Integrated Crop Management Conference

The need for certification of crop advisors, agronomists, and others in agriculture has not been clearly established. However, in other industries, such as accounting (Certified Public Accountant), and medicine (AMA-certified), certification has become a consumer expectation. Given the complexities of the crop advising profession, it is logical that standards for practice be established by a certification program. In response to this need, the industry has developed certification programs aimed at reassuring the public that individuals involved in agriculture are technically competent, experienced, and committed to ethical production and business practices (Demaray 1994; Hall1995; Peterson 1995).


Gray Leaf Spot Of Corn, Patrick E. Lipps Nov 1995

Gray Leaf Spot Of Corn, Patrick E. Lipps

Proceedings of the Integrated Crop Management Conference

Gray leaf spot (GLS) is a foliar disease of com caused by the residue-borne fungus, Cercospora zeae-maydis. This disease has become a widespread problem affecting com production in the United States over the past two decades (Latterell and Rossi, 1983). The increase in disease prevalence has accompanied an increase in the practice of using conservation tillage for com production, especially in areas that grow continuous com (Latterell and Rossi, 1983; Payne, Duncan and Adkins, 1987). Farm legislation has required participating growers to maintain a certain number of acres of com in production each year as a basis on which the ...


Fungicidal Control Of Leaf Diseases In Corn, Charlie A. Martinson, Gary P. Munkvold Nov 1995

Fungicidal Control Of Leaf Diseases In Corn, Charlie A. Martinson, Gary P. Munkvold

Proceedings of the Integrated Crop Management Conference

For the first time in 14 years of testing fungicides for efficacy on com, we examined the potential for control of naturally occurring leaf diseases in commercial com fields. In 1994 gray leaf spot had developed extensively over Iowa and there was a high potential for inoculum of the fungus for 1995. The pathogen overwinters on com residue and the disease potential was especially high where com was planted into com stubble.


Scab Of Wheat And Barley, Gregory Shaner Nov 1995

Scab Of Wheat And Barley, Gregory Shaner

Proceedings of the Integrated Crop Management Conference

During the past 15 years, scab has severely damaged soft red winter wheat crops in several Corn Belt states, hard red spring wheat and spring barley in the Red River Valley of the northern plains, and soft white wheats in Michigan, New York, and Ontario. In Indiana, scab was a major problem in 4 of the past 10 years: 1986, 1990, 1991, and 1995. Scab is not a new disease. J. C. Arthur, the first plant pathologist at Purdue, described the disease in 1891. He said the disease was new to science but was familiar to farmers as "scab." Until ...


The Iowa State Corn Yield Test, Kenneth E. Ziegler Nov 1995

The Iowa State Corn Yield Test, Kenneth E. Ziegler

Proceedings of the Integrated Crop Management Conference

The seventy-fifth year for the test was completed in 1994. For each of those 75 years Iowa State University has provided Iowa com growers with performance evaluation data on varieties and hybrids of com available for them to grow. Over the course of the past 75 years, the program has changed a lot. For a description of the early history of the Com Yield Test see Chapter 8 in the book "The Iowa Crop Improvement Association" by Joe L. Robinson and Oliver A. Knott, Iowa Crop Improvement Association, Ames, IA 50011, 1963. Mention of other early historical events of the ...


Soybean Cyst Nematode- Identification And Extraction Techniques, Gregory L. Tylka Nov 1995

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 parasitism by the soybean cyst nematode, Heterodera glycines. Soybean cyst nematode was identified in Clinton and Scott Counties for the first time in 1995 and is now known to be present in 69 Iowa counties. It is very likely that the nematode is present in many other counties as well, but the nonspecific nature of the aboveground symptoms of soybean cyst nematode damage makes early identification or diagnosis of infestations difficult.


Using Farm Moisture Testers, Charles R. Hurburgh Jr. Oct 1995

Using Farm Moisture Testers, Charles R. Hurburgh Jr.

Agriculture and Environment Extension Publications

Accurate moisture tests are important in managing and marketing grain.


Fatty Acid Composition Of Oil From Adapted Elite Corn Breeding Materials, Francie G. Dunlap, Pamela J. White, Linda M. Pollak, Thomas J. Brumm Sep 1995

Fatty Acid Composition Of Oil From Adapted Elite Corn Breeding Materials, Francie G. Dunlap, Pamela J. White, Linda M. Pollak, Thomas J. Brumm

Food Science and Human Nutrition Publications

The fatty acid composition of corn oil can be altered to meet consumer demands for “healthful” fats (i.e., lower saturates and higher monounsaturates). To this end, a survey of 418 corn hybrids and 98 corn inbreds grown in Iowa was done to determine the fatty acid composition of readily-available, adapted, elite corn breeding materials. These materials are those used in commercial hybrid production. Eighty-seven hybrids grown in France (18 of which also were grown in lowa) were analyzed to determine environmental influence on fatty acid content. The parents of the hybrids and the inbreds were classified in one of ...


Evaluation Of A Liquid Chromatographic Method For The Determination Of Fumonisins In Corn, Poultry Feed, And Fusarium Culture Material., Larry G. Rice, P. Frank Ross, Jan Dejong, Ronald D. Plattner, Joel R. Coats Jul 1995

Evaluation Of A Liquid Chromatographic Method For The Determination Of Fumonisins In Corn, Poultry Feed, And Fusarium Culture Material., Larry G. Rice, P. Frank Ross, Jan Dejong, Ronald D. Plattner, Joel R. Coats

Entomology Publications

The performance of a liquid chromatographic method for determining fumonisins in corn, animal feeds, and culture material was evaluated. Efficiencies of extractions with the following solvent systems were determined: acetonitrile-water (50 + 50, v/v), methanol-water (75 + 25, v/v), and 100% water. The acetonitrile solvent gave both higher extraction efficiencies and faster extraction times than the other 2 solvents. Extraction was followed by C18 solid-phase extraction column cleanup. Fumonisin B1 (FB1), fumonisin B2 (FB2), and fumonisin B3 (FB3) were measured by precolumn derivatization with o-phthalaldehyde followed by isocratic separation on a C18 reversed-phase column with a mobile phase of 50 ...


Effects Of Zinc Fertilization Of Corn On Hatching Of Heterodera Glycines In Soil, J. E. Behm, G. L. Tylka, T. L. Niblack, W. J. Wiebold, P. A. Donald Jun 1995

Effects Of Zinc Fertilization Of Corn On Hatching Of Heterodera Glycines In Soil, J. E. Behm, G. L. Tylka, T. L. Niblack, W. J. Wiebold, P. A. Donald

Plant Pathology and Microbiology Publications

Experiments were conducted to determine the effects of zinc fertilizers on hatching and soil population densities of Heterodera glycines. In vitro egg hatching in solutions of reagent-grade zinc sulfate and zinc chloride and fertilizer-grade zinc sulfate was significantly greater than hatching in deionized water, whereas zinc chelate fertilizer significantly inhibited egg hatching relative to deionized water. In greenhouse experiments, no differences in cumulative percentage egg hatch were detected in soil naturally infested with H. glycines amended with fertilizer-grade zinc sulfate and zinc chelate at rates equivalent to 0, 1.12, 11.2, and 112 kg Zn/ha and subsequently planted ...